All right, I got the 62mm throttle body from Modern Performance yesterday and I actually believe it hurt the performance of the car. Without doing track runs I can't swear to it but it just doesn't feel as kick *** as it did before. Is it possible to get too much air, to the point that it would hurt the performance ?

The list of mods so far are Stage 0 computer ( still waiting on Howell automotive for my Stage 1 ), Stage 2 wastegate, MB exhaust, Hurst STS, K&N CAI, Mopar BOV, AGP catch can, NGK iridium plugs and Magnecor 8.5mm wires.

I'm not going to stress too much about this until I get my pcm from Howell and see what it does then ( maybe I'll get it for Xmas ) lol.

I guess I'm just wondering if since I've got much better airflow in and out is it just a problem the Stage 1 will fix or should I look at injectors. RC makes injectors I believe they are 640CFM that are bigger than my stock but not as big as Stage 2. Any suggestions you all have would be great.

 

The RC injectors I mentioned are 640cc/min,,,,,,,,,,,,not 640 CFM. You can tell my age because I'm still thinking carburetors not fuel injectors,,,,,,lol,,,Any ways, any help or suggestions would be appreciated.

 

Double check your pressure pipes and make sure they are on tight. Also check the seal between the throttlebody and intake manifold. With a turbo charged car if there are any leaks at all in these areas your performance will suffer. Also you may try presurizing the system to see if there are any leaks. I just used a heavy plastic bag (like a zip-lock bag doubled over) and clamped that onto the turbo intet (took off the CAI) then pulled off one of the vacuum lines to the manifold and pressurized the system up to about 20-25psi or so. That should tell you if you have any leaks.

I ran a 60mm throttlebody on mine even before I went with a big turbo and did notice some minor gains in performance, and I had similiar mods as yours.

Also I would recommend NOT going with the larger injectors, you'll just end up dumping way too much fuel in. The car already runs really rich from the factory.

 

Mike, I took it to a Tech friend of mine and he checked for turbo leaks and couldn't find anything. It's all tight, the turbo numbers are good also, just doesn't feel as strong as before. Does the computer have to relearn the setup ? I've only driven it probably 10-12 miles.

 

Hmm. Could it be that you were expecting more of a gain, so it has the illusion of having less power? With a stock turbo, the throttlebody size isn't going to matter much, you might pick up 5hp at the most.

The computer shouldn't care about the TB, once you go WOT the computer is looking mainly at the MAP and RPM in order to calculate how much fuel and timing to give it.

Did you have it on the dyno or at the track before the TB was added?

 

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Hmmmm,you reading my mind Mike?,,,,,,,I was thinking the same thing, that since I was expecting a kick in the performance and didn't really notice it maybe it was an illusion that it was slower. I did have some vacuum line problems being misrouted yesterday, caused a CEL and some strange performance, but after I read the vacuum diagram on here I got that straightened out. I guess she's good, just not what I was expecting.

 

O.K, the 62mm throttle body has really killed the car, I can't find a single vacuum leak but if I give it any moderate throttle it sets a P2074 cel. I had a Toyota corolla pull up on me yesterday with one of those fart can exhausts. I got walked, I gave it enough gas to pull ahead, the car threw the code and shut down. The corolla went flying by with 3 kids laughing their asses off. Hopefully the Stage 1 computer will fix this when,,,,,,,,,,,,,,,,, I get it. Meanwhile I'm trying to decide whether to re-install the original throttle body or just limp around while I wait on Mopar and Howell for next few weeks/months.

 

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I can't find P2074 in the codes that I have, but this would definitely seem to be the problem. I'd install the o-ring, reset the ECU and then see if that improves things.