I need a 4 door for a field sales position I am taking and have liked the LS since I first saw it a few years ago. The only problem is coming from a heavily modified 2001 SS Camaro it will be hard to buy a daily driver that does not have much of an aftermarket and runs mid 15’s.

Looking around all I can find is a CIA and dress up components. Are there any real parts for the LS? I’m already planning on putting a little bottle on it if I buy one.

Here are my points of interest:

Intake (I’ll probably fab something up for a CIA)
Throttle body.. Is it portable? What size is it? What material is it made of?
Cam.. Any after market options?
What fuel injectors are used? Can SVO 30’s be used? (Probably need bigger ones if I do a cam)
What fuel pressure is being seen in the fuel rails? This will come in to play with injectors..
Headers? Anything on the market or will I be using stock manifolds?
How are the stock cats attached to the ex manifolds? Would it be easy to just get a couple flanges and make straight pipes to replace them?
Cat backs I’m not too worried about, I’ll probably do a single 3” electric cut out and use the stock cat back :) or up it to 2.5 to the cut out.


Thanks for all your input and help :)

Cam.. Any after market options?
Headers? Anything on the market or will I be using stock manifolds?
How are the stock cats attached to the ex manifolds? Would it be easy to just get a couple flanges and make straight pipes to replace them?
Cat backs I’m not too worried about, I’ll probably do a single 3” electric cut out and use the stock cat back :) or up it to 2.5 to the cut out.


I'm sure there aren't any aftermarket cams, but I'm also sure you can regrind the stockers to your liking. This is how the V6 Mustang cam "aftermarket" works. People have reground stock cams to support pretty wild setups.

As far as the exhaust setup goes, it's not like a GM setup - there are two catalytic converters - one for each side. It's a true dual exhaust all the way back (with an H-pipe behind the cats). Sure, you could remove the cats, but that would violate Federal law, regardless of local emissions requirements. If you're insistent, though, you can always hollow them out - alot easier than cutting and pasting.

There is an aftermarket cat-back system available, but I've never heard of headers. You could always have some made, though.

I need a 4 door for a field sales position I am taking and have liked the LS since I first saw it a few years ago. The only problem is coming from a heavily modified 2001 SS Camaro it will be hard to buy a daily driver that does not have much of an aftermarket and runs mid 15’s.

Looking around all I can find is a CIA and dress up components. Are there any real parts for the LS? I’m already planning on putting a little bottle on it if I buy one.

Here are my points of interest:

Intake (I’ll probably fab something up for a CIA)
Throttle body.. Is it portable? What size is it? What material is it made of?
Cam.. Any after market options?
What fuel injectors are used? Can SVO 30’s be used? (Probably need bigger ones if I do a cam)
What fuel pressure is being seen in the fuel rails? This will come in to play with injectors..
Headers? Anything on the market or will I be using stock manifolds?
How are the stock cats attached to the ex manifolds? Would it be easy to just get a couple flanges and make straight pipes to replace them?
Cat backs I’m not too worried about, I’ll probably do a single 3” electric cut out and use the stock cat back :) or up it to 2.5 to the cut out.


Thanks for all your input and help :)


The intake that LLSOC makes is pretty cheesey. Its an awesome HOT air intake. Make your own and tuck it into the front bumper, or make and airbox to draw from a fender.

The throttle body differers from the 00-02's to the 03-05's. Nothing aftermarket can be done, just some time on a CNC, and a little patience. I have pictures in my "member photo garage" of my TB I bored out.

No Cams.

There is no reason to change injectors. But if you desire to, bosch injectors (like on the svo) will not work, i believe the injectors on the older LS's are denso's.

Fuel pressure will fluxuate from 25-35psi @18 ihg (The LS uses a Returnless flex fuel system) This is totally normal. To increase pressure, the duty cycle of the fuel pump is upped according to vacuum. (the fuel pressure sender is just after the 1/2in disconnect on the inlet) @0 ihg (WOT) pressure will go as high as 45psi


00-02's use manifolds...03-up's use 4-2-1 headers

The cutout idea would mean you would have to either do seperate cutouts, or put a large balance just after the headers. Either way, your o2 sensors will notice right away and get rather pissed setting the check engine light. It is best not to touch the LS exhaust before the cats.

The intake that LLSOC makes is pretty cheesey. Its an awesome HOT air intake. Make your own and tuck it into the front bumper, or make and airbox to draw from a fender.

First of all it's not cheesy. Why? Because I'm the one that is part of making those. Also, tucking the intake into the bumper of the LS is probably one of the worse things you can do. It's really suseptible to water ingestion there. However, we are currently making a box to shield the filter. This way it will draw the air from underneath the car and keep the filter from ingesting water.

You can make your own CAI tube with some time and patience. Just be careful where you route the filter. Below is a picture of our air box design. We are experimenting with some insulation so disregard the wrap on the bottom of the tube. With the insulation inside the air box the temperature of the box never got above 110 degrees on a 95 degree day.

http://myfilelocker.comcast.net/christy817/airbox6.jpg

First of all it's not cheesy. Why? Because I'm the one that is part of making those. Also, tucking the intake into the bumper of the LS is probably one of the worse things you can do. It's really suseptible to water ingestion there. However, we are currently making a box to shield the filter. This way it will draw the air from underneath the car and keep the filter from ingesting water.

You can make your own CAI tube with some time and patience. Just be careful where you route the filter. Below is a picture of our air box design. We are experimenting with some insulation so disregard the wrap on the bottom of the tube. With the insulation inside the air box the temperature of the box never got above 110 degrees on a 95 degree day.

http://myfilelocker.comcast.net/christy817/airbox6.jpg

I was going to try and make my own...and still haven't given up...I just need to find someone that's interested in trying to do so. I failed to get a reply from one company I emailed...so...I'm going local. Plus...it can't be that cheesy because there's not another one available...believe me...I've searched...feel free to prove me wrong. Anyway...

You probably know this but...I wouldn't worry about insulating the intake tube itself. The air will be travelling at a speed great enough to not be effected by the minimal heatsoak on the intake tube. I think it would be much like the throttle body coolant bypass on the LS1. There's really no point in doing it. Because of the air speed as it enters the throttle body, even if the coolant has increased the t.b. temperature...it has nearly no impact on the actual temp of the air as it enters the engine.

We were just seeing what the effects of the insulation on the tube would have on the TB. It was basically a waste of time but we did it anyway. I was pleasantly surprised at the temperature difference in the box though. The temp read much higher on the outside of the box so it worked on insulating the inside. As cooler days lie ahead the box may not make that much of a difference. However, it's definitely recommend for the warmer days.

Anyone can make their own CAI but there would only be a handful that would. If you can make one yourself then by all means have at it. Just let us know how it goes.

The throttle body differers from the 00-02's to the 03-05's. Nothing aftermarket can be done, just some time on a CNC, and a little patience. I have pictures in my "member photo garage" of my TB I bored out.


Too bad the internal diameter is the same.

early LLSOC CAI:

http://www.llsoc.com/V2R1/registry/registry.svc.getobject.asp?id=1740

with the hood closed:
http://www.llsoc.com/V2R1/registry/registry.svc.getobject.asp?id=1342

Too bad the internal diameter is the same.


If you are refering to the TB i bored out, it is NOT the same. If you look at the ls TB it tapers to a smalled diameter from the TB to the plenum. I bored the TB out as far as i could until the walls by the throttle arm seals were getting thin. The throttle arm itself was widened, and i used a plate from an 04 F150 we had warrentied for a bad drive by wire motor and spun it down on the lathe to fit inside the new TB diameter. From what i remember i got about 7 more mm out of it. If you really need me to prove this to you, i will take a picture of the TB being measured by a digital caliper, and then you can measure a stock TB. No sense in arguing without the facts.


AS for the LLSOC intake.. if you guys put out that heatshield it will make a huge difference, then i wont think it is "cheesey" anymore. The first intake i made for my LS was done the same way, I had the IAT just after the MAF before the bank one PCV. When sitting at a red light on a fully warmed engine, on a moderate day (70ish) my IAT would readout upwards of 150F (according to my scan tool), as i would accelerate, and start to cruise, the IAT would start dropping within 20F of ambient air temp (close to 85F). I had shot it with my infrared thermometer for the hell of it, and read 206F at the TB. After doing the preheat bypass on the TB (looped it under the intake manifold) now when i shoot the TB i am usualy under 100F, its so much cooler than the rest of the engine it almost feels cold (cant say it adds any power though).

Question on your intake: I used a 1/2in to 3/8in grommet for the IAT to mount to the intake tube, did the same with the turbo setup, after a while the grommet would start to get cut up from the pipe no matter how smooth the edges. What are you using to mount the IAT, a bung of some sort? It needs to handle pressure when i get the turbo back on obviously, so i cant have any leaks. Just wondering what you guys did to get around this. if i cant figure anything out, i am going to take a meter off of a focus and put it in my housing (meter is the same, sample tubes are diff) Because the focus MAF has the IAT built in. BTW, i had no problem with water on my setup, the filter hung just below that oval cutout under where the stock airbox was. If you look under there, it is shielded very well, and would be very hard to get splashed with water. But if you were to use a shield like you are developing, you could just draw air from that hole anyways.

Thank guys for the feedback..

My thought on a CIA.. Pick up would be next to the driver fog light. It would be a sheetmetal box tapered to one side with a 2.5-3" out that comes up and goes in to another sheetmetal box that houses a 12x6 filter, much like the LS1 F-body intake does (Might even use the stocker and just cut a hole in the bottom of it). Then to the throttle body. A semi forced induction system that will give true cold air. (Fast toys ram air works kind of like this for the F-body. Picks up a solid .1 and 1-2mph in the 1/4)

I'd also be drilling a hole in it very close to the TB for the N20 nossle.

I might see if I can get a set of maniflods off a wrecked 03-05 if I end up getting an earlier one.

As far as the exhaust. Here are some pics of my old custom Y-pipe for my F-body.

http://73-ls1.com/ypipe/1.bmp
http://73-ls1.com/ypipe/2.bmp
http://73-ls1.com/ypipe/3.bmp
http://73-ls1.com/ypipe/4.bmp
http://73-ls1.com/ypipe/5.bmp


Dyno pulls to show the difference.

HP difference
http://73-ls1.com/HP_open_vrs_closed.bmp

Torque difference
http://73-ls1.com/Torque_open_vrs_closed.bmp

I don't expect the same gains do to the lack of CI's. I figured out how to by pass the O2 issues. As long as you have long enough dumps after the O2's, you don't get and cold air rushing back to tweak the O2's. I have data to prove it with the F-body.

I figure building an X-pipe right off the manifolds with no cats and putting dual electric cut outs after the X will be beast. No O2 issues and should see some real good torque with the X-pipe. Leave the stock cat back if possible.


I think that will be a good start when I buy it :)

Question on your intake: I used a 1/2in to 3/8in grommet for the IAT to mount to the intake tube, did the same with the turbo setup, after a while the grommet would start to get cut up from the pipe no matter how smooth the edges. What are you using to mount the IAT, a bung of some sort? It needs to handle pressure when i get the turbo back on obviously, so i cant have any leaks. Just wondering what you guys did to get around this. if i cant figure anything out, i am going to take a meter off of a focus and put it in my housing (meter is the same, sample tubes are diff) Because the focus MAF has the IAT built in. BTW, i had no problem with water on my setup, the filter hung just below that oval cutout under where the stock airbox was. If you look under there, it is shielded very well, and would be very hard to get splashed with water. But if you were to use a shield like you are developing, you could just draw air from that hole anyways.

We use a 3/8" rubber grommet. The IAT is a tight fit but it needs to be.

Thank guys for the feedback..
My thought on a CIA.. Pick up would be next to the driver fog light. It would be a sheetmetal box tapered to one side with a 2.5-3" out that comes up and goes in to another sheetmetal box that houses a 12x6 filter, much like the LS1 F-body intake does (Might even use the stocker and just cut a hole in the bottom of it). Then to the throttle body. A semi forced induction system that will give true cold air. (Fast toys ram air works kind of like this for the F-body. Picks up a solid .1 and 1-2mph in the 1/4)

I had a setup similar to this (before my hood scoop) where I had a ram tube coming from the lower grill into the bottom of a box that went around the filter.

I was ok - but since my car is lowered the potential for water intake was too high for me.

I had a setup similar to this (before my hood scoop) where I had a ram tube coming from the lower grill into the bottom of a box that went around the filter.

I was ok - but since my car is lowered the potential for water intake was too high for me.



I'm going to cust a piece of sheetmetal to sit in side the bottom of the air box as a block off plate when it rains :)

We use a 3/8" rubber grommet. The IAT is a tight fit but it needs to be.


Which is exactly what i did (1/2in O.D. to 3/8in I.D.)... but my problem is the boost pressure moves it in and out, and the grommet eventualy cuts around the seams. If i don't put the focus sensor in my tube, i might just make a sealed bung, possibly tread the stock IAT. The ATI Procharger kits for GM's require you to cut off the housing, leaving the thermocouple itself the only remaing part of the IAT. The connection then seals using the WeatherTight seal already on the stock plug. Anyways, i just wanted to see what you guys did, thanks for the input.

By the way, in regards to the CAI behind the frount bumper could'nt you use an air bypass valve that AEM uses on there CAI systems that exit the engine compartment.

By the way, in regards to the CAI behind the frount bumper could'nt you use an air bypass valve that AEM uses on there CAI systems that exit the engine compartment.I tried the AEM bypass valve - and even worked with their tech support - in short - the V8 pulls too hard and actually causes the valve to open under high RPMs - so it cannot be used on the LS.

here is an old pic of my engine with it on:
http://www.llsoc.com/V2R1/registry/registry.svc.getobject.asp?id=1740

http://www.coogle.com/cat4245.jpg
I couldn't resist :)

what kind of gains are you guys seeing with the cold air setups over stock and say a drop in kn?

what kind of gains are you guys seeing with the cold air setups over stock and say a drop in kn?

I didn't dyno my car before the CAI but I did do a comparison with a stock 2003 LS. With the CAI and Magnaflow exhaust system I was pulling more HP than the stock 03. So, in essence the CAI and Magnaflow yielded 30+HP.

Of course, as soon as the new supercharger is ready I'll be installing it for roughly gains around 110 HP.

I didn't dyno my car before the CAI but I did do a comparison with a stock 2003 LS. With the CAI and Magnaflow exhaust system I was pulling more HP than the stock 03. So, in essence the CAI and Magnaflow yielded 30+HP.

Of course, as soon as the new supercharger is ready I'll be installing it for roughly gains around 110 HP.


You got a supercharger for your LS? :dancefool Where do I get in line!

hmmm 10.5:1 compression and a supercharger sounds like trouble

do these little v8's have forged pistons?

hmmm 10.5:1 compression and a supercharger sounds like trouble

do these little v8's have forged pistons?

Nope they sure dont. I wish they did. Low boost (6 lb) and conservative tune will probably have to do till we can get some pistons and connecting rods offered (probably never). It looks like someone will have to bite the bullet and call up oliver, with a stock rod and piston in hand, and pay the gobs of money to have billet ones modeled after the stockers. I already got a rough price quote. It was a few months ago, but I remember the word "insane" uttered out of my mouth.

Since Dutch was the only one to touch the cam q, I'll add my 2 cents. He was right that there is no aftermarket cams and that you could probably have them reground. However, I'm sure the cams will be the last thing to ever get any sort of aftermarket on the LS. Why? It's a dual overhead cam motor. This isn't an old school pusrod motor with one cam. If you're swapping cams, you have four cams to change instead of just one; so instead of around $200 for a new cam it'll be more like $800 or more for a set. The aftermarket is going to have to come a long, long way towards the LS before we're going to need new cams anyway.

Since Dutch was the only one to touch the cam q, I'll add my 2 cents. He was right that there is no aftermarket cams and that you could probably have them reground. However, I'm sure the cams will be the last thing to ever get any sort of aftermarket on the LS. Why? It's a dual overhead cam motor. This isn't an old school pusrod motor with one cam. If you're swapping cams, you have four cams to change instead of just one; so instead of around $200 for a new cam it'll be more like $800 or more for a set. The aftermarket is going to have to come a long, long way towards the LS before we're going to need new cams anyway.


If you take a look at the average demographic that buys these vehicles new it is usually older people, because they can afford it. The average person that is buying these vehicles brand new will have modding them for more power as a last thought in their minds. That is by far and away the biggest group the aftermarket would cater to. I would have to say that the only way the LS aftermarket will pick up in any major way would be if these engines showed up in another more sporty-imaged vehicle. We know these vehicles are sporty, but alot of others dont. Unfortunately majority rules in this case. That is the only reason why we got support for our P-TEC computers and 5R55W,S,N trannies is because of the 2005 mustang sharing these same or VERY similar parts along with a few other less notable vehicles. I believe that anything doing with the engine itself or any rotating assembly parts will be a custom application and most likely remain so in the future. I hope to god that I am wrong.

First of all it's not cheesy. Why? Because I'm the one that is part of making those. Also, tucking the intake into the bumper of the LS is probably one of the worse things you can do. It's really suseptible to water ingestion there. However, we are currently making a box to shield the filter. This way it will draw the air from underneath the car and keep the filter from ingesting water.

You can make your own CAI tube with some time and patience. Just be careful where you route the filter. Below is a picture of our air box design. We are experimenting with some insulation so disregard the wrap on the bottom of the tube. With the insulation inside the air box the temperature of the box never got above 110 degrees on a 95 degree day.

http://myfilelocker.comcast.net/christy817/airbox6.jpg


*sigh*

sorry to bring back up an old post, but for heaven sake, people keep saying "oh NO!!! don't put your intake in the bumper, it'll suck up water..."

Listen, I've dealt with this issue with the honda/acura crowd for EVER. These things put the cold air intake right next to the underbody panel in front of the passenger side wheel well (like if you're sitting in the car, it's basically just to the right of the radiator). Now, these things NEVER suck up water unless you're an idiot and drive through the part of New Orleans that's 10' BELOW sea level and a hurricane just went through there (brilliant idea to build there by the way... :slam

In short, it's not going to suck up water unless you submerge the entire freaking filter in water. Yeah it'll maybe get a few drops of water every once in a while, but that isn't gonig to do crap.

And if you're REALLY worried about it, then AEM makes filter bypass kits of varous sizes. If there's too much vacuum (like the filter is submerged in a fish tank full of water, like the test they did with an NSX), the bypass will open up and air will enter there, instead of sucking water up into the engine. And yes, even on a 290 hp 3.2L NSX at 7000ish RPM.

I tried the AEM bypass valve - and even worked with their tech support - in short - the V8 pulls too hard and actually causes the valve to open under high RPMs - so it cannot be used on the LS.

here is an old pic of my engine with it on:
http://www.llsoc.com/V2R1/registry/registry.svc.getobject.asp?id=1740

I'd tend to disagree on that. Vacuum is vacuum. A Honda at 8200 RPM (or 9000 RPM in the case of the S2000) is making a LOT of vacuum in the intake. A V8 should make about the same, more or less, regardless of displacement, I doubt the V8 makes that much more vacuum.

Nope they sure dont. I wish they did. Low boost (6 lb) and conservative tune will probably have to do till we can get some pistons and connecting rods offered (probably never). It looks like someone will have to bite the bullet and call up oliver, with a stock rod and piston in hand, and pay the gobs of money to have billet ones modeled after the stockers. I already got a rough price quote. It was a few months ago, but I remember the word "insane" uttered out of my mouth.

It can be done, just requires the right tuning.

Within about 6 months of its release, Comptech came out with a supercharger kit for the Honda S2000 (11:1 compression ratio) that added 100 flywheel horsepower (took it up to 340).

I'd tend to disagree on that. Vacuum is vacuum. A Honda at 8200 RPM (or 9000 RPM in the case of the S2000) is making a LOT of vacuum in the intake. A V8 should make about the same, more or less, regardless of displacement, I doubt the V8 makes that much more vacuum.

Well - it was AEM tech support line that I worked with - confirming that the valve actually opened at WOT and they confirmed that I should remove it.

They had me perform a couple of tests, with it on, off and with plastic around it.

It can be done, just requires the right tuning.

Within about 6 months of its release, Comptech came out with a supercharger kit for the Honda S2000 (11:1 compression ratio) that added 100 flywheel horsepower (took it up to 340).


While tuning is allot when it comes to making power and doing it the right way, it is not everything. It cannot make up for purely overstressed parts that simply cannot take much more stress by the power they are making. Correct tuning can turn a nightmare project into a smooth one, but it cannot serve as a band-aid for everything. There will be a point, probably around 8-10 psi, where no matter how good the tune is things will break.

BTW that Comptech kit was probably a 6-7 psi kit from the numbers you just told me. These cars will be able to withstand 6 psi, but I wouldnt trust them for much more before I would feel like I was riding a fine line.

This car will be my daily driver so I will only be running 6 psi on my centrifugal blower until I got the money to buy billet internals for it, which will probably be never. I will be happy with the roughly 335 rwhp I should be making with that for a DD.

While tuning is allot when it comes to making power and doing it the right way, it is not everything. It cannot make up for purely overstressed parts that simply cannot take much more stress by the power they are making. Correct tuning can turn a nightmare project into a smooth one, but it cannot serve as a band-aid for everything. There will be a point, probably around 8-10 psi, where no matter how good the tune is things will break.

BTW that Comptech kit was probably a 6-7 psi kit from the numbers you just told me. These cars will be able to withstand 6 psi, but I wouldnt trust them for much more before I would feel like I was riding a fine line.

This car will be my daily driver so I will only be running 6 psi on my centrifugal blower until I got the money to buy billet internals for it, which will probably be never. I will be happy with the roughly 335 rwhp I should be making with that for a DD.

Again, I'm new to this, but I think 6 psi on a 3.9L engine should be plenty. You're not going to set the world on fire with it, but with the right intake and exhaust setup (ported heads maybe? how restrictive are the stock heads?) you should be good for at least that 335 at the rear wheels you're talking about. I mean heck, I've seen people running 18 lbs on a 1.3L rotary putting down 550 rwhp. And I've seen people running 18 lbs on the same motor but with a different turbo put down only 350 rwhp. There's plenty of factors that go into it, and I'm sure one supercharger vs another will put out different numbers at the same intake pressure (and also different stresses on the motor).

You also have to remember, depending on how the engine is designed, each piston/rod *may* hit its max stress point at top dead center or bottom dead center, in the sudden shift from going up to down in an instant. The most stressful part of the engine cycle may not even be the combustion phase. And if that's the case, then it may have a lot more room to go as far as power.

You also have to remember, depending on how the engine is designed, each piston/rod *may* hit its max stress point at top dead center or bottom dead center, in the sudden shift from going up to down in an instant. The most stressful part of the engine cycle may not even be the combustion phase. And if that's the case, then it may have a lot more room to go as far as power.



The weakest link, connecting rods and pistons, will ALWAYS be stressed the most at the time of firing which is usually a few degrees before TDC. The rest of the time that particular piston that just fired is just coasting along for the other 3 strokes of the cycle while the other pistons fire.

What happens is when timing is advanced too far, or detonation occurs (possibly from too much boost on a high comp engine), you will totally overstress the connecting rods because they will still be on their upstroke when the plugs fire or the mixture spontaneously detonates. Think of it like hitting a baseball that is coming towards you really fast compared to hitting a baseball that is already going away from you. It takes allot more to catch up to the baseball traveling away from you, hence less stress.

There is a fine line in between those two extremes, which is why we advance timing only by a few degrees and not as much as detonation would cause. This kind of gives the compression cycle a little head start so that by the time the piston actually does reach TDC it will already have built up enough compression to make good power on the full length of the combustion stroke.

A good tune can take care of this up to a certain point. After that it comes to down to the quality of gas you get on a given day, and also the bigger factor being the total stress that the connecting rods can take. With the high compression and hypereutectic pistons that these cars have, they will not last long with boost much higher than 6-7 lbs. There will be exceptions and lucky guys who decide to run 9 lbs and make it for a while, but we are mostly talking about daily drivers that we don’t want to crap out on us on the way to work.

The weakest link, connecting rods and pistons, will ALWAYS be stressed the most at the time of firing which is usually a few degrees before TDC. The rest of the time that particular piston that just fired is just coasting along for the other 3 strokes of the cycle while the other pistons fire.

What happens is when timing is advanced too far, or detonation occurs (possibly from too much boost on a high comp engine), you will totally overstress the connecting rods because they will still be on their upstroke when the plugs fire or the mixture spontaneously detonates. Think of it like hitting a baseball that is coming towards you really fast compared to hitting a baseball that is already going away from you. It takes allot more to catch up to the baseball traveling away from you, hence less stress.

There is a fine line in between those two extremes, which is why we advance timing only by a few degrees and not as much as detonation would cause. This kind of gives the compression cycle a little head start so that by the time the piston actually does reach TDC it will already have built up enough compression to make good power on the full length of the combustion stroke.

A good tune can take care of this up to a certain point. After that it comes to down to the quality of gas you get on a given day, and also the bigger factor being the total stress that the connecting rods can take. With the high compression and hypereutectic pistons that these cars have, they will not last long with boost much higher than 6-7 lbs. There will be exceptions and lucky guys who decide to run 9 lbs and make it for a while, but we are mostly talking about daily drivers that we don’t want to crap out on us on the way to work.

Regarding the first paragraph, I haven't seen the numbers on all the engines, but it is possible that at TDC and BDC the engine is actually most stressed. The engine is spinning at, say, 6000 RPM (or in the case of race motors or small 4 cylinders, 8000+ RPM, which makes the forces exponentially greater). We're talking on the scale of thousands of g's, but only for a split second, and probably much much less time than during the combustion stroke.

Regarding the first paragraph, I haven't seen the numbers on all the engines, but it is possible that at TDC and BDC the engine is actually most stressed. The engine is spinning at, say, 6000 RPM (or in the case of race motors or small 4 cylinders, 8000+ RPM, which makes the forces exponentially greater). We're talking on the scale of thousands of g's, but only for a split second, and probably much much less time than during the combustion stroke.


The pistons and connecting rods will ALWAYS be most stressed at the very start of the combustion stroke, right before the piston hits TDC. While there may be allot of stresses in the rest of the operation, that is where the most stress on the rotating assembly always will be. When the piston hits BDC it will experience some increased stress due to it rapidly changing directions, but nowhere near the stress that same piston will experience while not only rapidly changing direction, but also supporting the load of the combustion while firing. Trust me on this I know what I am talking about. I also think I know where your probably referencing your info from being that you made a rotary engine comment. That is a TOTALLY different engine design with its own set of problems. Being that the rotary engine doesnt have pistons, and also its rotors never change direction, the stress is more linear and smooth in a rotary versus a piston fired engine. The biggest problem your dealing with in a rotary engine is inherently low torque (comes with the engine design) and sealing problems with the rotor to the engine wall being that the temporary cupped combustion chamber is only formed for a little while and then rotor rotates and the new cup comes into places for another firing sequence. I could go on and on about rotary engines. The bottom line is with piston engines, the most stressed part of the whole cycle will be the start of the combustion process. Not meaning to seem like I am getting on your case, I am just aiming to clear things up.

The pistons and connecting rods will ALWAYS be most stressed at the very start of the combustion stroke, right before the piston hits TDC. While there may be allot of stresses in the rest of the operation, that is where the most stress on the rotating assembly always will be. When the piston hits BDC it will experience some increased stress due to it rapidly changing directions, but nowhere near the stress that same piston will experience while not only rapidly changing direction, but also supporting the load of the combustion while firing. Trust me on this I know what I am talking about. I also think I know where your probably referencing your info from being that you made a rotary engine comment. That is a TOTALLY different engine design with its own set of problems. Being that the rotary engine doesnt have pistons, and also its rotors never change direction, the stress is more linear and smooth in a rotary versus a piston fired engine. The biggest problem your dealing with in a rotary engine is inherently low torque (comes with the engine design) and sealing problems with the rotor to the engine wall being that the temporary cupped combustion chamber is only formed for a little while and then rotor rotates and the new cup comes into places for another firing sequence. I could go on and on about rotary engines. The bottom line is with piston engines, the most stressed part of the whole cycle will be the start of the combustion process. Not meaning to seem like I am getting on your case, I am just aiming to clear things up.

Ok, if you add the forces together, it will make more force on the piston/connecting rod. BUT does that necessarily make for more stress on it? I don't know. The sudden change of direction might make a difference and put more actual stress on it. But yes, you're right that the total combined stress of the combustion plus changing direction would cause more force.

BUT now what if the engine is made to fire at 1 or more degrees after top dead center (I imagine turbo engines do this often when they retard timing one degree per pound of boost?)

Ok, if you add the forces together, it will make more force on the piston/connecting rod. BUT does that necessarily make for more stress on it? I don't know.

I do know. It DOES add more stress. Stress is force, force is stress. It is just an amount of energy applied against something to cause it to stop moving, start moving, or otherwise change direction.


The sudden change of direction might make a difference and put more actual stress on it. But yes, you're right that the total combined stress of the combustion plus changing direction would cause more force.

BUT now what if the engine is made to fire at 1 or more degrees after top dead center (I imagine turbo engines do this often when they retard timing one degree per pound of boost?)

Very rarely, IF EVER, will you encounter an engine that will not fire before TDC. When referring to retarding timing they are retarding it against the advanced timing they were already running. So if a car in stock form starts out as having 16 degree's of total advanced timing in it then you decide to add a shot of nitrous or forced induction and retard the timing 3 degree's then the total advanced timing would be 13 degree's advance. Also, timing advance and retardation don’t directly correlate to the size of the shot of nitrous, or lbs of boost your running. Say for instance your running a 75 shot of nitrous on a stock vehicle without higher-octane gas, and then you would probably want to retard timing by 1 degree or so. If you used race gas then you probably wont drop any timing, and if the octane were high enough and you were tuned for it, you might even advance it some. Turbo's will be the same in principal. Some things designed to let you run more boost while keeping timing is an intercooler and also race gas to name a few. The cooler the air charge going into the intake the more timing advance you can keep and the more power your going to make, because A. the air is more dense, and B. the timing is advanced further than it would be if you were running a non-intercooled setup. IF a person were to go by the rule of thumb you stated of one lb boost = 1 degree of retard then that would be one underpowered setup! That is a HUGE amount of timing retardation to boost ratio! Sorry but whomever told you that figure either didnt know their stuff at all, or had a VERY VERY VERY EXTREMELY inefficient setup and then wanted to be overly cautious on top of that! There is no set rule of thumb for this amount of boost = this amount of timing retard. It all comes down to what your setup is.


While I do frequent a luxury car site from what you see, I have a MUCH bigger background in racing and building cars for power. I know what I am talking about. I wouldn’t be saying these things unless I were 110% sure that it was that way. Once you’re on here longer and if you ever see me on any other boards you will understand that better. For now just take my word for it. Not meaning to come off as cocky but I know my stuff.

While I do frequent a luxury car site from what you see, I have a MUCH bigger background in racing and building cars for power. I know what I am talking about. I wouldn’t be saying these things unless I were 110% sure that it was that way. Once you’re on here longer and if you ever see me on any other boards you will understand that better. For now just take my word for it. Not meaning to come off as cocky but I know my stuff.

Where did you get your education & auto background? You're not one to give a brief response straight to the point are you? Do you even have an LS? Please post pics of your luxury car, no not the one with the rag top and the missing hubcap with the purple window tint.

Where did you get your education & auto background? You're not one to give a brief response straight to the point are you? Do you even have an LS? Please post pics of your luxury car, no not the one with the rag top and the missing hubcap with the purple window tint.


Ok, I have dealt with you in two previous threads the last day and now I will deal with you in here. Like I said in my previous post in HERE (http://www.lincolnvscadillac.com/showthread.php?t=2915&page=5) it is a totally childish thing to follow my posts around and make it a point to criticize my previous posts. Only someone who knows they were totally owned would do such a thing. The WORST part about it was that I was still remaining civil in the exhaust thread and then you got to pull this crap by attempting to discredit me?!? Give it a rest. Not only did you come into this thread way too late, but you also didn’t get the meaning of it too. Barwick and I weren’t arguing at all! We were talking detailed tech. To my knowledge I don’t believe Barwick thought it was any sort of confrontation either. I got respect for people like Barwick that can sit here and have a good debate about tech talk and still remain reasonable. You, on the other hand, resorted to acting like a child. The worst thing was that in your attempts to discredit me and try to prove me as some sort of troublemaker, you have only proven that the troublemaker title fits you better. You my friend are a total hypocrite. Grow up.

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.
Hmm...i noticed he didnt answer your performance education/background question or if he owned an LS. I dont know if anyone has seen the video of the mustang guy blowing his intake off with nitrous, but thats what these kind of posts and people remind me of, but i'm sure he'll say he worked with Carol Shelby or Mario Andretti. Something lacking in their personal life gets made up for with idiotic posts to a public forum. I love my LS and like reading about others experiences, but all the idoit postee's have made me visit here less and less.

If anyone is curious as to what is going on, you can refer to the 149 mph thread and the LS Exhaust thread.

I know its ok for non-LS owners to visit the thread, but when being attacked b/c you want to put a custom exhaust on the LS car is a little ridiculous.


....and the Scion thread(though you didnt seem to really be pulling much sh1t there).....Gosh that sure is alloot of threads I posted in that you just miraculously showed up in; especially being that some weren't even recently posted in.....

Attacked? Thats laughable. If you call someone voicing their opinion on something and then giving a few people a hard time when they get bent out of shape about it then I suppose it was an attack. ORRRR, you could call it an adult conversation. People are always going to disagree. I disagree with you just as much as you disagree with me and that is fine. What I did find to be a bitch move on your part is when you decided to look through my previous posts and try to start more crap from there.

The comment about the non-LS owners is weak too. The reason for this is that there is no better place to get a real and unbiased opinion than from an outside source. For the next 4 weeks until I make my purchase I will be technically an outsider, but that still doesnt mean that my opinion doesn't hold as much creedence as anyone else's here. Do we got to be Pro Baseball players to make such a comment as, "You suck! Go play for the Cubs!"??? NO, we don't.


Fla02 - If I recall correctly, you were the one that got into a debate with me about making the LS fast. You also were trying to refer to your car as an, "all out drag car" and then later tried to backpedal when I called you on it? This is the same Fla02, right? Hehehehe. Man I am not trying to start crap with you again either, but didnt you get schooled enough the first time we talked? Gosh I wish our convo hadn't been deleted by that loser hacker that messed with the site. Stop trying to jump on this little bandwagon merely because I hurt your little feelings before.

are you this guy?

http://explorerforum.com/forums/member.php?u=10040

because if you are, you've got my vote. I believe you know what you are talking about.