Injector/tune question.

[XLRVIII]

They were free along with the MAF from a friends Lightning. Overkill or not the question is will they run right with a tune? FI is in my future but not before big brake upgrade, so the injectors are staying unless they cant be tuned.

Why on earth would you put a MAF and Injectors from a 330 cubic inch FORCED INDUCTION combo on a 281 cubic inch N/A combo is beyond me.

Even IF forced induction IS on your list of planned mods, putting these injectors and MAF on your car is going to gain you exactly ZERO bang for the buck.

Even considering these parts were "FREE", you still need a 300-400 tune to HOPEFULLY get them to "RUN"...
and still you are going to gain ZERO HP for your efforts.

Do yourself a favor, put the Supercharged parts on the SHELF until you get an ACTUAL supercharger ON the car.

you're just going to create a tuning nightmare, in the end..
you'll blame the tuner for "not making your car live up to YOUR expectations" and you will have wasted time, money and effort on a "meaningless modification".

IN the event you DO get TWICE too much injector to work on your car, you will be running them far below their "minimum threshold", the pulsewidth will have to be decreased SO much that you WILL run into "drivabilty issues".

OF course a tuner will tell you "they CAN" tune your car for those, but that is how they "make their money", by TUNING your car.

Will the tuner tell you that you are making a mistake?

Maybe, but that depends if they are "trying to help YOU, or trying to make money.

If you ask 10 people, you'll probably get 10 different answers, but just look in this thread, there are a few VERY knowledgeable people giving you STRAIGHT ANSWER..

yet you are ignoring them and waiting until "some one else tells you what you want to hear".

Why not ask Geno what injectors he has on his N/A mark 8?

That in itself should help you figure out that 42's on a NA motor is pointless.

 

[XLRVIII]

P.S. I dont need 42lb injectors to PEG my speedometer
nor do I need big brakes to stop the car after pegging my speedometer.

140+ MPH is 140+ MPH regardless of "how fast the car got UP to 140".

 

[unity]

P.S. I dont need 42lb injectors to PEG my speedometer
nor do I need big brakes to stop the car after pegging my speedometer.

140+ MPH is 140+ MPH regardless of "how fast the car got UP to 140".

lol, thank you

 

[XLRVIII]

lol, thank you

No problem sir!

this thread reminds me of a local kid who took his 4.6 sohc apart and installed "blower cams".. of course he doesnt have a BLOWER.

now his car is a TURD, it runs like crap, and is about 1.5 seconds slower in the 1/4 than it was before he "didn't listen and put blower cams on a NA motor".

Putting FI parts on a NA car is GAY.
Dont be GAY.

 

[vr4]

ok try this....accelerate for 700 feet and stop. measure the total distance travelled. now increase the horsepower of the car by 200 and do the same test.

i stand by my previous statement.

 

[Aquabrit]

ok try this....accelerate for 700 feet and stop. measure the total distance travelled. now increase the horsepower of the car by 200 and do the same test.

i stand by my previous statement.

I know what you are trying to say here, vr4. The car with more power will reach a higher speed in that 700 feet, therefore better braking would be an advantage. Guys have misunderstood your other post, thinking same speeds.

 

[NateRW21]

42lb injectors for N/A...

Think about it like this...

Injectors are rated by flow capacity... that is, lb/hr delivered. There is a window of time in which you have to deliver all of the fuel needed for the engine (this is the intake stroke of the 4-cycle theory). The reason you would increase injector size would be due to the engine requirements for fuel exceeding how much flow the injectors can provide in that window of time.

See, you've got to remember that the amount of power your engine puts out is not driven by how much fuel you provide it. Actually it is quite the opposite. The amount of fuel your engine requires is driven by the amount of power the engine puts out. In virtually any internal combustion engine, the key factor to making power is how much AIR is moved from the atmosphere to the cylinder on the intake stroke.

This brings us back to the injectors. Injectors are mechanical units; essentially solenoids with a needle valve. Remember how I said there is a window of time to deliver the fuel at a specified rate? I'll give you an example... although the numbers are most certainly inaccurate, the basis and theory are spot on. Lets say any given cylinder on your engine requires .2 pound of fuel for the correct air/fuel ratio. We'll also say your window of time to deliver this fuel at a redline RPM is 1 second (this is obviously WAY off). Since a 24lb injector will deliver .4lb in a second, your engine will get its supply of fuel required within that window; only taking half of the allotted time for the supply to be delivered. Lets take that same engine and increase the injector size to 42lb; which has a flow rate of .8lb/sec. Since you only require .2lb/sec, this injector will have to cycle itself in 1/4 of a second in order to provide the correct amount of fuel. So there we have the relationship between the engines needs for fuel and the injectors ability to flow.

On to more about injectors... Being they are electric solenoids, they have a certain minimum cycle speed (think milliseconds). This is part of the problem when you start talking about running injectors too large for your application. What happens is, because they flow at such a high rate, they have to cycle much quicker... as demonstrated in the previous paragraph. What you run into is, the injector is unable to open, then close fast enough to correctly provide the right amount of fuel. This will generally lead to delivery of too much fuel. There is no way to tune for this; it is a mechanical limitation.

Next on the list of issues: Atomization! What will provide the best distribution of fuel in a flow of air; a heavy, very short spray... OR... A lighter, longer spray? This is another reason that injectors must be sized correctly in accordance with fuel needs. The very best mixture happens when you stretch out the time the fuel is sprayed. Running an injector much larger than needed will also prove less likely to fully atomize the fuel into the air... resulting in pooling in your intake... and... a fuel rich condition.

Now... onto other problems involved with running injectors which are too large... It is entirely possible to run an engine rich enough that fuel will dump into your cylinders and wash away the oil. This leads to scored cylinder walls and low compression (plus, bearing wash out if you get enough fuel dumped into the oil). We're talking severe mechanical problems. Plus, if you live in a state which has emissions testing/inspections... a rich condition will damage your catalytic converters... actually clogging them.




SO, in conclusion... Listen to what people are saying here; remove the 42lb injectors and lightening MAF. Not only do you not need it, but you're asking for some expensive repairs if you continue to use it.

 

[lscmkviii]

Thanks Nate! Now I fully understand. I put the 24s back in. But I still want a tune.

 

[XLRVIII]

Thanks Nate! Now I fully understand. I put the 24s back in. But I still want a tune.

Glad to hear you are back on the right track.
I assure you, that you'll be happier going this route.

Definately get a tune, one of the easiest mods and offers a good "bang for the buck" when the right person calibrates your PCM.

 

[lscmkviii]

One more question... With the 24s back in, can I use the 90mm MAF from the lightning if I swap the sensors for the 24s? Because it is 90mm vs. 80mm and I have a cold air intake that goes down to where the air compressor was? I am thinking I might run into a lean issue???

 

[XLRVIII]

ok try this....accelerate for 700 feet and stop. measure the total distance travelled. now increase the horsepower of the car by 200 and do the same test.

i stand by my previous statement.

I understand your previous statement and also understand how numbers can be manipulated to support your statement.

But free your mind for a moment and consider this.

take a 4000lb car that runs 9.0 in the 1/8th mile (660 ft) rather than 700 ft as you mentioned.

Say this car runs 9.0 @ 80 mph, that takes 277 flywheel hp
(reasonable numbers very close to mine)

Then take the same car add 200hp and the 4000lb car now runs 7.50 @ 90 MPH making 479 flywheel hp.

your 200HP only increased the MPH by 10MPH in 660 feet.

Does that really indicate the need for "bigger brakes"?

These caculations were done using the HP caculators on www.wallaceracing.com, which aren't accurate to the bazillionth degree, but are accurate enough for "message board coversations".

Just some data from "the far side" for you to think about.

 

[XLRVIII]

One more question... With the 24s back in, can I use the 90mm MAF from the lightning if I swap the sensors for the 24s? Because it is 90mm vs. 80mm and I have a cold air intake that goes down to where the air compressor was? I am thinking I might run into a lean issue???

Not so much a lean issue, but the larger maf which offers more resolution at higher RPMs ALSO offers LOWER resolution in the lower RPM's which could affect idle control, load caculations that your PCM uses to make your car "shift right" and also will affect "timing caclulations".

Now if you have a blower and NEED the higher resolution in the upper RPMs this is a fair trade off.. you lose a little "bottom end" fuel control to keep your motor "happy and safe" in the upper RPM's.

The PCM CAN be calibrated for this MAF because it's a ford part and has a good consistant and known transfer function.. but you will still have some "street" driveabilty issues.

I had the same problem with an aftermarket MAF I had on my car.
It misreported the load caculations, which in turn skewed the timing caculations, and also affected the transmission functions in a not so desirable manner.

I have MADE this mistake, and have since put the stock meter back on my car in the stock airbox.. and as expected the car went faster and quicker than it had ever gone with the aftermarket "JUNK" on my car.

I picked up almost .2 by ditching the aftermarket meter which allowed my PCM to accurately evaluate the actual air that was entering the motor rather than "lying to the PCM" and screwing up all the caculations.

Tuning after going back to the stock meter was so easy.. even a 5th grader could do it.

ALL my driveabilty problems disappeared, and the car was faster and quicker.

I now have gone faster with a paper filter and a stock air box than I had when I had Cold Air, K&N and Aftermarket Meter.

 

[NateRW21]

Thanks Nate! Now I fully understand. I put the 24s back in. But I still want a tune.

No Problem! Certainly look into getting a tune; it is one of the easiest ways to get a little more power, and often times if you drive conservatively... a touch more in the mpg department!

When you get ready to throw that blower on... then you'll need to think about installing those injectors and MAF.

btw...I'd run your stock MAF right now... as someone above me said, the trade off on running the lightening MAF isn't worth the potential gain; which in reality is rather small. The airflow needs of your engine as is likely do not exceed the stock MAF's ability to flow (that is in addition to the resolution noted above...)