Dynoed my truck with the 6.0L and 90mm tbody earlier this week. With the same cam and bolt ons (in signature), the 5.3L made around 420rwhp. I was hoping for close to 500hp with the addition of the 6.0 and 90mm tbody. More cubes, better heads, smaller pulley on radix, and bigger throttle body yielded 448hp and 515tq. We switched back to the 3.0" pulley and it dropped about 8hp and 20lbs torque. The thing is an absolute beast and fun to drive, but I was hoping for more. Am I at the maggie's limits?

We also added a Zex 75 hp wet shot. The 75 shot upped the HP to around 463. About 15 more hp with a 75 shot. Is the charger a restriction? Or, is the stock MAF restricting the intake. I'm at a loss to figger this one out. On the drive home, I got to thinking that there has to be a restriction on the intake side. Was hoping to find a rat's nest in the Outlaw CAI. It was clean. AFR's were 11's under boost and IAT's were around 100 with nitrous and 140 without. No knock retard. There has to be something we're overlooking. As always, your thoughts appreciated.

 

I don't think the maf is restricting since Im making alittle more hp than you. You should be making much more power with the juice

 

I think so too. I'm at a loss to explain how a 75 shot only yields 15 more hp. I thought the truck should have been close to 500rwhp without nitrous. Well over that # with the gas.

 

Yeah, I would of definitely lost that bet with the juice. Certainly would of guessed more horse from a wet 75shot.

There are quiet a few guys putting more horses threw the radix.

Keep in mind the 90mm may be helpful and give you some gains over the 78mm, but the maf is still smaller than a 90mm tb (i am second guessing myself at the moment). You are "sucking" air thru it, not blowing. I hate typing that. You are pulling air thru the maf, not pushing. Different kind of workings.

How about your tune? What kind of timing are you using? 140*'s is the border line for me. Once I past 150* I need to start yanking some spark from her (heavier than I was). If you aren't breaking 140* on the pull, you may be pulling too much timing. I am sure your tuner is working on that on the dyno though.

 

I'm focusing on the MAF also. It looks to be the bottle neck to me. Smaller diameter than the 90mm tbody with a screen too. Was thinking of fabbing up a vacuum guage between the MAF and the tbody. That might tell the story.

 

Just visited the corvette forum. They're making 500+ with less bolt ons than I have. Does the LS2 have a bigger MAF?

 

.....wtf. not sure about that i have a little bigger motor with a 112 on it longtubes and a 228-232 cam and only 7psi makeing 535rwhp. it might be in the tune. im planing to add my crank pulley this week and alky control and hope i get some were close to 600rwhp. then a 100 shot

 

i made 504 rwhp on the 5.3 with 90mm TB and LPE GT2-3. Sounds to me you might want to look into the calibration.

 

Yeah I agree. I was justing poking to say the maf is a restiction, but it is minimal. (btw, you were one of the ones I was talking about "few guys pushng more HP" )I'd like to know your spark and IAT advance table.

 

I bet you would