Why do some claim a tune is needed after a CAI??

sy1172 · May 20, 2005

I just got my JLT unit for my Saleen and noticed some people are claiming to need a tune after its installation. Why?

Thanks,

Vince
04 Saleen 281SC #80

Give Me TP · May 20, 2005

sy1172 said:
I just got my JLT unit for my Saleen and noticed some people are claiming to need a tune after its installation. Why?

Thanks,

Vince
04 Saleen 281SC #80

It will lean out the A/F ratio compared to stock.

Gearbanger 101 · May 20, 2005

Needed.....no. Prefered.....usually.

jstreet0204 · May 20, 2005

If you don't change the orientation of the MAF, or use one with an elbow directly infront of the MAF, you should not need a tune.

2000BLKGT · May 20, 2005

maybe it's being mentioned because the '05 needs a re-tune after a CAI install

YardSpecial · May 20, 2005

I get a LEAN surge at cruise because of my CAI.
A tune is needed for best drivability

langod · May 20, 2005

FWIW:
I was a at a dyno day a few weeks ago. I had the opportunity to compare my results with another similar car. Mine is an 02 GT - stock, the other an 04 GT with K&N FIPK.

The HP numbers were close, but the car with the K&N was running significantly leaner -- which may explain why the K&N equipped car was making about 6 hp less.

I realize there are many other factors that could account for this, but the consensus of the guys running the dyno was that the K&N would have and should have made an increase in HP if the car had been tuned.

streetstang03 · May 20, 2005

2000BLKGT said:
maybe it's being mentioned because the '05 needs a re-tune after a CAI install

the 05 needs a tune after every mod

super302 · May 20, 2005

Gearbanger 101 said:
Needed.....no. Prefered.....usually.

.

edbo · May 20, 2005

I heard that you could reset the computer by disconnecting and reconnecting the battery so that the computer could redetermine things like this. Not saying it is true though.

jstreet0204 · May 20, 2005

langod said:
FWIW:
I was a at a dyno day a few weeks ago. I had the opportunity to compare my results with another similar car. Mine is an 02 GT - stock, the other an 04 GT with K&N FIPK.

The HP numbers were close, but the car with the K&N was running significantly leaner -- which may explain why the K&N equipped car was making about 6 hp less.

I realize there are many other factors that could account for this, but the consensus of the guys running the dyno was that the K&N would have and should have made an increase in HP if the car had been tuned.

With an FIPK, longtubes, underdrive pulleys, offroad pipe, 70mm tb, and no tune, my a/f was almost perfect at 13:1. Most people that claim you need tune after basic mods don't have a good understanding of how the MAF based fuel injection works. If a lean conditions are not usually caused by basic mods but by something else during the install or a poorly designed product like the CAI with the elbow directly infront of the MAF.

Gearbanger 101 · May 20, 2005

langod said:
The HP numbers were close, but the car with the K&N was running significantly leaner -- which may explain why the K&N equipped car was making about 6 hp less.

Actually, the lean condition should increase horsepower, if anything? Like jstreet0204 stated......just too many variables to say.

jstreet0204 · May 20, 2005

edbo said:
I heard that you could reset the computer by disconnecting and reconnecting the battery so that the computer could redetermine things like this. Not saying it is true though.

Sort of... The EEC is designed to learn conditions and add or subtract fuel to keep the a/f in the desired range. It does this by reading how far off the a/f is with the o2 sensors, then remembering how much fuel it needed to add or subract to correct it. Disconecting the battery clears this memory and start over with a clean slate.

YardSpecial · May 20, 2005

rarely is the AF ratio the same across the RPM band.

Just what I saw on the dyno, dips, spikes and so forth.

I let you all my findings in 90 days......

SilverGTV8 · May 20, 2005

I'll let you know how my 03 does with the Demolt CAI, 75mm Accufab, C&L Plenum, magnaflow catted x, magnapack, and predator.

I figure right now I have bumped timing to the max allowed on the predator and added some fuel in both bands. I imagine I will be running rich down low and should lean out near the top. Will see.

Dyno on the 18th of June.

turboscrew · May 20, 2005

If you add a cai it tends to lean the a/f ratio.

If you add an o/r midpipe the a/f ratio richens up.

So if you add both wouldn't that tend to even things out? Just a thought.

SilverGTV8 · May 20, 2005

Valid argument.

But how much does the CAI lean it out, and how much does the O/R X richen it up.

stangGT97 · May 20, 2005

um it depends on which CAI you're adding... the FIPK is a straight shot intake with no bends before the MAF, which might lean out the A/F because of the increased air flow. However, a CAI like the Mac, or BBK ones with bends before the MAF will create a rich condition because the MAF is being hit with a dense charge of air at the outer edge of the pipe, while the inside of the bend has little air flow. That's why rotating the MAF towards the fender is the band-aid fix for the rich condition...

jstreet0204 · May 20, 2005

stangGT97 said:
um it depends on which CAI you're adding... the FIPK is a straight shot intake with no bends before the MAF, which might lean out the A/F because of the increased air flow.

People tend to forget that just because you increase the air flow some that does not make it lean. The MAF is there for a reason. The increased airflow will still be measured and acounted for when creating the a/f mixture. Your point on the CAI's with the bend is a valid one.

stangGT97 · May 20, 2005

jstreet0204 said:
People tend to forget that just because you increase the air flow some that does not make it lean. The MAF is there for a reason. The increased airflow will still be measured and acounted for when creating the a/f mixture. Your point on the CAI's with the bend is a valid one.

yeah, about the FIPK, you're right.. the maf would be pointless if it didnt compensate for the extra air... plus I doubt K&N would have designed it to cause possible problems with the car

Why do some claim a tune is needed after a CAI??

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