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Tuned PCM.

G

GTP 40TH

New member
Here goes. I've read the entire mod thread and still have questions.

Here are the specifics on my car right now. 2002 GTP. All maintenance up to date. Cold air intake. U-bend delete. Resonator delete with glasspack installed. OE mufflers replaced with turbo mufflers.

My question is this. I'm considering getting a tuned pcm. As my car sits right now: What are the pros and cons to doing this? Will I get a noticeable increase in power? Any benefit in driveability? Any concerns with KR? The list goes on.

My 1st GTP. I really do like this car. It is my DD and I plan to hold on to it for the long haul.

Help me out with some sound advice.
 


I would say bolt up some headers and go for a 3.4/3.5 pulley and a PCM tune.

If you just want to upgrade the PCM you can do that. Be sure to mention your limited mods when getting the tune. You might have improved MPG and power.

Good to have a way to measure KR regardless.
 
jdmgtp said:
I agree, your mod list is pretty small. However, the CAI will more than likely throw your fueling off which can be cause for concern.
Click to expand...

but the maf will learn trims within reason...so a tune isn't extremely necessary only with a cai
 


A pulley drop and headers are not in the plans for right now. Maybe later on down the road. I would like to free up the car a much as possible right now. I'm not looking for a whole lot. My main priority is to get the full potential safely from my car the way it sits. With the mods I've posted.

Every thing I have done has made a differance. Even my in town mileage which used to be in the 18's is now in the 19's.

A tuned pcm will offer little to no improvement to my car? Very confusing. Keep the comments coming. There is a wealth of knowledge on this site.
 
You could benefit from having a street tune. MPG and trans settings can be improved from this. I never looked into a stock pulley off-the-shelf tune. Probably not common.

Also, at 5000ft ABSL you can drop pulley sizes if your using premium fuel without further mods. Most people won't tell you to do so, but you can calculate air properties and by dropping pulleys you would effectively run like a stock car at sea level. Maybe 3.5 or 3.4 inch? I dunno, I would have to calculate it when I'm less lazy. You then can't drive to sea level pressure safely with that pulley, though.

But the exhaust is a handicap. Maybe you want to upgrade that before/with the PCM.
 
Thanks for all the replies.

I will eventually go with exhaust and pulley drop. Not anytime soon.

I'm going to go ahead with the tuned pcm. I'm certain there will be a benefit from this. MECHGUY thanks for your input. Higher elevation weighs heavy on our vehicles.

JBROWNGTP I'm near Ft. Collins.
 


Purchased a ScangaugeII. Nice. Programmed on x gauge to scan for KR. Went for a road trip yesterday to visit family in northern Wyoming. Most of the time KR sits a 0. Under load going up grades I do have knock. I see references on hear to disconnect the battery ,to let the pcm relearn fuel trims. CAI.

I did get 28.7 MPG on the trip. The best I've seen since owning the car.

I have not done the pcm yet. Will this help with KR.

Also planning to get a PLOG whenever I can locate one. Everyone seems to be going with headers. Any thoughts on the PLOG.
 
The problem with most tuned PCM's is their claim to fame is high timing with a small pulley... what they don't tell you is that WOT fueling is terrible. I've had ZZP, DHP, and Intense PCM's come on the dyno and AFRs were in the high 9's and low 10's.

Your biggest benefit will be a custom tune. Find someone in the CO area with some experience, or buy a DHP Powertuner and learn it yourself.

Also being so high up, as someone else mentioned, you could most likely get away with a smaller pulley. I'd throw a 3.5 or 3.6 on it and then tune.
 


Got my PCM. Installed it. Had case relearn done. This is hands down the best thing I've done to the car. Drives totally differant. Much improved. Still have some KR. No worse than before. My downpipe is paid for and on the way. I am actively looking for a plog.
Thanks again for everyone's input.
 
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