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Supercharger question

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Posted by: BlueLS

I am new on this forum (this is my first post). I know there have been a lot of questions regarding superchargers, and i'm sure you are all tired of hearing them. Believe me, i have seen all of the threads and read through all of them. (it's a lot of reading, I have spent the better part of the last few days reading through this forum)

I have a 00 LS V8 and i am looking to increase the HP and toque quite a bit. I have the magnaflow exhaust (actually, magnaflow piping with flowmaster 40 series) and CAI with K&M filter. I am going to order the SCT Live wire soon from fast parts network and have torrie make me a few tunes.

But i want to go a little further then just the basic bolt ons. I am looking at supercharging my LS. I have read through Quicks entire thread (Great job by the way) and i like the roots style blower, but it seems like a lot of work (Custom intake manifold, repositioning oil filler & coolant hoses, etc.).

I am looking at trying to add a centrifugal style S/C. However, space is a serious issue with this setup. I have been doing some research on smaller S/C's and i came across an article that profiled and few small S/C's that come on stock vehicles. Theses S/C's seem small enough that i could fit one under the hood by removing the air box and relocating the right side windshield washer fluid filler. I'm not sure what the air flow is on the LS (CFM). So my question is, do you think that any of these would be capable of producing 5-7PSi on an LS?(specifically the AMR300 or AMR500)
Link the the article....
http://www.autospeed.com/cms/A_2147/article.html

Now, in regards to the compression ratio of our engines (I believe it is 10.5:1 on my 00). I have heard many times about people using deck plates, copper head gasket spacers, or multiple head gaskets to lower the compression ratio of there engines. Has anyone done this on an LS (specifically QuickLS). And if not (Quick), Have you considered trying it to increase the boost you are running? Would this cause the LS to through any codes?

I know that no one has really pushed the LS to it's breaking point (at least not that i could find). So no one really knows how much boost our cars can handle. But what about shoot peening the rods to make them stronger? I had this done on a D16Y8 Honda engine before when i was running my "junk yard turbo" setup and it worked great. Has anyone considered doing this with there LS? Or would it be better to just go to JE or someone else and have custom rods made?

Wow, that was a long post, I didn't plan on writing that much. Sorry if i put you to sleep.

Posted by: Garbone

There are some guys here that I would like to hear their opinions on this as well....

Posted by: Quik LS

The reasons I didn't go with a centrifugal blower are:
1) you boost the intake
2) room
3) I didn't want to move the location of the stock air filter

on point #1 - the compressed air enters your intake before the throttle body, so you are actually boosting the intake tube.

Here the issues I felt would be present with that setup:
- The V8 does not use PCV valves - so the valve covers vent directly into the intake. Since it only ever sees vacuum I don't think it would be a good idea to pressurize your valve covers.....
- The V8 uses a feed off the IAT to leak air into a air-rail the feeds the stock fuel injectors. The air is drawn in by engine vacuum and mixes with the fuel mist to create better atomization of the mixture as it enters the valves. Since this comes off the intake - I didn't want to pressurize it - feeling since it wasn't designed for boost it may cause leaks or unwanted fuel spray....
- your fuel pressure sensor, brake booster, ....etc all count on seeing and using engine vacuum to function normally. For example - use need 18-22hg of vacuum for you brake booster to work normally, you can use vacuum canistors to 'hold' vacuum but we typically only use those on cars with 'big' cams that loose their idle vacuum...

The roots setup I have still leaves all the vacuum on the intake side - boosting only at rpm, and only into the manifold, so all the stock sensors, pcv venting, ...etc are all very close to stock still.

The other thing to consider is 'Drivability'. Although centrifugal blower have come along way - the tip-in / tip-out is still very rash - with the closing of the throttle plate slamming the intake closed while it's boosted. You can add a 'blow-off' valve in front of the throttle plate to deal with the pressure spike cause in the intake when you slam the throttle plate closed.... but... moderm MAF metered cars hate it when they metered air coming in and then that air disappears (out the blow-off valve) which creates a instant flash rich situation....

As far as the room (point #2) - the intake swap roots setup fit fairly nicely inplace, not too many hassles. The big room issue was the intercooling - I used 3" piping to a front mount. THere is just no room to come down between the engine and the compartment, no room to cross over the engine, ....etc. The centrifugal blower may be easier (depending on mounting) for the intercooler - since you come off the blower into/outof the cooler then back up into the intake - you would not have to cross the engine or squeeze between the engine and bay....

Anything's possible, and as long as it creates reliable boost and doesn't hurt the car - you'll be fine. We are all going to start breaking stuff - it's just a fact of hot rodding.....

Posted by: BlueLS

Quote:

Originally Posted by Quik LS

The reasons I didn't go with a centrifugal blower are:
on point #1 - the compressed air enters your intake before the throttle body, so you are actually boosting the intake tube.

Here the issues I felt would be present with that setup:
- The V8 does not use PCV valves - so the valve covers vent directly into the intake. Since it only ever sees vacuum I don't think it would be a good idea to pressurize your valve covers.....
- The V8 uses a feed off the IAT to leak air into a air-rail the feeds the stock fuel injectors. The air is drawn in by engine vacuum and mixes with the fuel mist to create better atomization of the mixture as it enters the valves. Since this comes off the intake - I didn't want to pressurize it - feeling since it wasn't designed for boost it may cause leaks or unwanted fuel spray....
- your fuel pressure sensor, brake booster, ....etc all count on seeing and using engine vacuum to function normally. For example - use need 18-22hg of vacuum for you brake booster to work normally, you can use vacuum canistors to 'hold' vacuum but we typically only use those on cars with 'big' cams that loose their idle vacuum...

Well, I would assume that this could be resolved by relocating the IAT, valve covers vents, and other vacuum lines before the S/C. In other words, The Outlet from the S/C would be a solid pipe going to the TB with no vacuum or sensor hookups (other than a BOV for safety). All vacuum hookups and sensors would be between the filter and S/C inlet. That way everything would all see vacuum just like normal. (as it does with your roots style)

Quote:

Originally Posted by Quik LS

The other thing to consider is 'Drivability'. Although centrifugal blower have come along way - the tip-in / tip-out is still very rash - with the closing of the throttle plate slamming the intake closed while it's boosted. You can add a 'blow-off' valve in front of the throttle plate to deal with the pressure spike cause in the intake when you slam the throttle plate closed.... but... moderm MAF metered cars hate it when they metered air coming in and then that air disappears (out the blow-off valve) which creates a instant flash rich situation....

I am definitely planning on putting on a BOV “when” I do the S/C install. I am curious as to how mikepietras04 handled the MAF issue with his turbo setup (or if he had any issues with it at all)

Quote:

Originally Posted by Quik LS

As far as the room (point #2) - the intake swap roots setup fit fairly nicely inplace, not too many hassles. The big room issue was the intercooling - I used 3" piping to a front mount. THere is just no room to come down between the engine and the compartment, no room to cross over the engine, ....etc. The centrifugal blower may be easier (depending on mounting) for the intercooler - since you come off the blower into/outof the cooler then back up into the intake - you would not have to cross the engine or squeeze between the engine and bay....

That is one of the reasons I am considering the centrifugal style. It will be much easier to install (mounting wise) and much easier to connect (piping wise). The only thing I am worried about it the space limitation. I don’t want to order a S/C and then find out that it will not fit without cutting into the hood.

I have been doing a lot of research on a lot of different S/C’s, so before I settle on anything, I am going got make a bunch of cardboard replicas and see how they fit. Once I find one that can fit, I will order the S/C and start fabricating brackets and piping.

Quote:

Originally Posted by Quik LS

Anything's possible, and as long as it creates reliable boost and doesn't hurt the car - you'll be fine. We are all going to start breaking stuff - it's just a fact of hot rodding.....

I am hoping for the best, but planning for the worst. That is why I was asking about rods.

Once other thing I would like to address is the compression ratio. I would definitely like to lower it to closer to 9.5:1 for safety, reliability and increased boost capability. Do you have any thoughts on this…

Quote:

Originally Posted by BlueLS

Now, in regards to the compression ratio of our engines (I believe it is 10.5:1 on my 00). I have heard many times about people using deck plates, copper head gasket spacers, or multiple head gaskets to lower the compression ratio of there engines. Has anyone done this on an LS (specifically QuickLS). And if not (Quick), Have you considered trying it to increase the boost you are running? Would this cause the LS to through any codes?

Posted by: Quik LS

Quote:

Originally Posted by BlueLS

not all. You still have to deal with the manifold. Remember - there is an air rail coming off the IAT and feeding threw the injectors. If you pressurize the manifold as is - you actually leak boost back up the injector sleaves and up the air rail.

You likely can't just block it off without creating some leak under pressure.

Quote:

Originally Posted by BlueLS

I am definitely planning on putting on a BOV “when” I do the S/C install. I am curious as to how mikepietras04 handled the MAF issue with his turbo setup (or if he had any issues with it at all)

He hardly had it on the car for any length time - so likely never dealt with any of these smaller but important issues. He never even tuned the car with the turbo on it - so it was a long way from finished.

Quote:

Originally Posted by BlueLS

Once other thing I would like to address is the compression ratio. I would definitely like to lower it to closer to 9.5:1 for safety, reliability and increased boost capability. Do you have any thoughts on this…

RIght - that's the largest limitation. but do you really want to reduce the performance of the car just so you can boost it? will the boost make up for the lost hp from dropping the compression ratio?

IMHO - Start simple and then if you feel you want to run more PSI then you can try dropping the compression ratio and spinning up the blower...

SHould be a cool project - good luck!!! If I can help at all - just call.

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