the rpms are the question here. they never take these charts out far enough . i suspect the whipple can goto 18,000 rpm like the radix and kb. if so that would seem to take the hp up a ton. someone needs to try it and see.

 

11.5ish afr, 16deg timing. I too thought I should have been much higher than 416rwhp. Christ, I ran 13.06@102mph a few weeks back in a 6100lb truck. I was thinking about a 370 actually. I'm told Combination has one they are trying to get rid of. I have also heard that the stock heads are just fine.

 

i missed the stock manifolds part. is your exhaust completely stock? not sure but that could be the problem. i would still expect more hp than you showed going from 11 to 15psi. did you log the boost? did it hold steady or did you just recored a peek number?

 

stock manifolds(until next week), Dynatech cats, Flopro muffler. Stupidly, i wasn't watching the boost gauge when we dynod and the dyno doesn't/didn't record boost. I may have been slipping like hell and not even known it. I didn't have any belt dust though. I can hold 15lbs on the street/track. 2.75" blower pulley and 7.5" crank pulley on a 2 belt whipple.

I NEED more low end power. and I NEED to get to low 12's in the 1/4.

 

Cam, headers and 4L80 Parasitic drag is the difference between us. I dont think the shorty headers contribute much. The cam made a huge difference in the upper RPM's My timing is at 15 WOT and 12lbs. You should very close. The Whipple is 0.1L bigger. Also you should hear belt slip.

 

It's obvious the blower is the limiting factor of the setup.You could go 370ci and show more boost or go 408 and show less boost. Either way the 408 will destroy the 370ci. The 408 will peak HP/torque earlier in the curve giving a higher average power.

The obvious fact is that we have a 6.0 motor pushing 15lbs of boost and it only makes 400rwhp.The timing was maximized around KR,meaning there is an issue with the existing setup that needs to be addressed.I like the route of overbuilding what you need.That gives alittle satisfaction that it can be pushed harder if you need to.

 

Thanks. This is exactly what I wanted to hear. I guess I should have asked, knowing the limitations of the whipple, which motor 370 or 408 would give me the most power, peak and overall. So now the problem is, who's 408 to buy? So many choices, so many different prices. I will never make 1000rwhp, we all know this based on the fact that I'm running a whipple. So, that being said, do i NEED to get the most expensive 408 that will support the most horsepower? If yes, so be it. I'm just trying to understand everything before I spend way more money than I have, lol.

 

Its all about the dollars in my opinion, 408 or 370 isnt realy a huge difference, I may go with a 370 and go through with a solid buildup with a T trim and use the left over for a sick hidden DP setup. Hell I may even see what a stock LQ4 will stand up to . I should be able to get tuning pretty close as I have an onboard wideband wired up.

 

hmmm....

 

c'mon teddy, don't hold out on me.

and, ffhp has a smokin deal on a 408 longblock over on ls1tech. Anyone have any thoughts on it? feel free to PM me if you have negative things to say about it. Don't want anyone to get offended.