pulley change question
 

Question 1: How much of a RWHP gain is typically seen going from the 3.8 pulley to the 3.6. I am the SLP/Maggy TVS2300 set up. I do have headers, CAI, and a custom tune. I am currently making 547 rwhp. I stayed with this setup because I wanted to be safe and felt I would be satisfied with the power levels. Well, now I want a little more power.

Question 2: Can I go to the 3.6 pulley without changing injectors, BAP, or upgrading the fuel pump?

Thanks

I gained about 35 going from the 3.8 to 3.6. However, 558 rwhp was all I made on my LS3 with CAI/Headers using the 3.6 pulley running just under 10 psi. Any other mods on your car getting you to almost that level with a 3.8? How much boost are you currently runnning? I didn't like that the car was at 10 psi with the 3.6 so I added a blower cam to get more power w/less boost (cam + 3.4 pulley now at just under 8 psi).

No other mods to get me there. I guess we have to keep in mind my tuners dyno my be reading high based on my setup or yours may be reading low. I have Kooks 1 7/8 LT's with hi flow cats, roto-fab and a custom tune. I did not car about boosting until going to the track last week and being out run by my brothers blown 3v Mustang. At the same time I want to be safe. If I have to start running new injectors, fuel pump or BAP... I am probably going to wait on it this years. Did you upgrade any of the things I mentioned when going to the 3.6 pulley?

Do you have any WOT runs through 4 gears showing what your current set up can maintain regarding fuel pressure and injector duty cycles. If you don't, you should and it would pretty much answer your question.

My tuner would have that. Good point.

Tuners have said the stock pump runs out around 550. I'd add the ZL1 pump over the BAP, for when you decide that XXX(whp) isn't enough then you can add a BAP and dig into the 700s if you wanted. The LS9 injectors supplied "should" be able to support the 3.6 per magnuson when I called. But as stated, your tuner can see that.

I added the Zl-1 pump, the ADM FPCM, and 65lb injectors at the same time as the 3.6. Whether it was necessary or or not for that power level, I don't know. The tuner I took it to (whom I no longer use) suggested I upgrade the injectors and fuel pump because the SLP kit w/ the 3.6 pulley and headers (their 650 HP package) came with a BAP. He said he did not like using a BAP and hence his advice to upgrade the fuel system. He also called Phastek for advice. So that was his rationale to me at least. I've since moved to ID-850s and a different tuner becuase the car ran poorly from the other shop.

Oh yeah, this was also part of the reason. I was told that he didn't want my IDC any higher, so if I moved to a lower pulley, I would need to address fuel supply.

1. I believe the rule of thumb is you gain 20 rwhp for every 2lbs of boost. IIRC.

2. I started with a 3.8 pulley and ended with a 3.4 pulley using the stock Maggie injectors, a BAP and stock fuel pump.