Hey all...

Here's the situation. A buddy of mine has HP Tuners and is willing to tune me for a good price. I don't want to go with 60lbers and run a 2.7 or something... but I would like to run a 2.9 or 2.85 with the 42lbers.

My question is this... how much power is to be had from slapping on a slightly smaller pulley and tweaking with the stage 2 tune? Is it worth it?

Any insights would be greatly appreciated.

 

its been proven that a 2.85 and 2.9 are too much for the 42s the dutycycle is passed 90% for both, i had almost 100% duty cycle with with 2.85 and 42s, now i have a 2.7 and 60s and my IDCs are at 68

 

See part of me just dosen't believe that... GM Stage 3 runs a 2.9 pulley... and I've got two friends in town... one running a 2.8 and one running a 2.85... both with no issues what-so-ever.

Stage 2 is pig rich... we all know this... so I don't quite see how going a whole tenth of an inch smaller on the pulley can get from pig rich to super lean.

So if you are at less than 100% duty cycle with the 2.85... that should be fine. Why even have the injectors if you aren't going to run them at their capacity? 60 to 70% isn't even what these injectors can perform at.

Sure running them at over 100% is bad... but if you can get them at 100%... that just means they are working as they should.

 

im no expert but i think the injectors go static above like 85%... maybe someone that knows more can help me out, but i think that means that the injectors cant really control the fuel being pumped through at that rate, and could possibly cause the injector to get stuck open.

i also forgot to add that i do have gmpp stage 1 w/ a 2.9 pulley and no problems, but i dont run the car very hard.

 

first of all, the stage 3 pulley is 2.99inches and stage 2 runs lean. Ever since i got my stage 2, i throw the lean code about once a week...

 

have you tried unplugging your battery for a like 15 mins. to reset the computer.

 

Mac, ever think it could be the intake? Heard a lot of probs with the K&N...

Back on subject: I've talked to some guys down here in Florida and they are running 2.8s with S2 and running consistent 13.5-13.7 times and such with no problem.

 

Stage 2 runs lean? That's contrary to everything I've ever heard. If you are getting a lean code you need to get something checked. The intakes can cause problems with these cars... that's where I've seen all the people get lean codes from.

Thus why I'm running the airbox mod.... 100% problem free.

 

Tune with your smallest pulley, then you can slap on any larger pulley and be fine, as long as you're running the same size injectors.

As far as a lean code, it has nothing to do with how the car is actually running at WOT, you need a wideband UEGO gauge to determine that. It simply a code to say that 20% more air is being ingested into the engine than the MAF sensor is calibrated for. A simple MAF recalibration will fix it.

 

you should gain about 15-20 hp , ive heard of people gaining 10-15 WHEEL from just tweaking the stage 2 tune , and then add the drop of the pulley and a good tune i would say about 17WHP

 

So... no other opinions on this? Where's all our other guys who are running all kinda custom crap? Surely more than 6 people have an opinion or experience with this.

 

42 lb Injectors straight up run out of fuel even with a well tuned 3.0 pulley I bet I could get a set to read over 84%. I did a car with a 2.8 pulley and a set of 42's and it read a high of 122% and it didn't have a header. Just because they haven't had a problem doesn't mean their injectors aren't completely maxed out and loosing efficiency.

 

I have the stage 2 and my dyno show I was high end rich on fuel. I dyno'd before and after and my WHP before was 207 and after was 227 WHP. I would have to get my dyno sheets from the garage to tell you torque but I think it increased about 25 lbs. I also gained 500 more rpm and 3 psi on my supercharger which I guess is a bit more than the usual 2 lbs...

 

I had the 2.8 with GMstage2, and it ran like crap. It would seem to build power in steps when you floor it. The after you floor it and reach the rpm cut-off point, it would really feel, run & sound like crap. I took off the 2.8, went back with the stock 3.066" GM stage 2pulley and the car runs with no problem, no matter what.

So now I ordered 60lbs injectors, pacesetter header with bolt on downpipe (catless). All I need is to buy hptuners to install these bad boys!!