I think I'm gonna drop the LS1 from my vette in my truck.... once I get my LS3 Stroker done for the Vette...

 

he didnt say it was crap. he just said i had a restriction somewhere. i dont think its exhaust with lt headers and cutout. thats why we were thinking intake manifold? based on what everyone else says tho idk. i always heard the truck intake was good. i was 88 at idle and 85 wot. does that sound right?

 

i plan on staying na for now. maybe a small shot of spray in the future tho

 

Kpa tells story. If Kpa Is dropping then you have restrictions somewhere.

 

the higher the kpa # is towards 105, the more equal you are to atmosphere. So those #'s aren't correct for idle, by no means. Normally you might see 40-65kpa at idle, depending on the cam/induction setup, and 90-105kpa at wot depending on homw bad the intake restriction is.

For example my 416ci vette with port matched L76 intake has never been over 97kpa at wot (longtubes, 3" x-pipe, and cutouts for exhaust). But I still make well over 500rwhp and my idle is right around 55kpa at 800rpm with a fairly large duration hyd rolller cam.

 

I was working on his truck and the KPAs with the key in the run position without the truck running are at 88KPA, we are in El Paso and the DA can get into the 8000s at times. The reason I think there is a restriction is; at WOT from about 3500rpm KPA drops from 88 down to 86 then near redline (6300) its at 85. He runs a K&N CAI, I doubt that is the restriction, truck MAFs are 85mm so I doubt its there, however the TB and manifold are stock. I said I thought it was the intake, but you truck guys here are going against my logic. So maybe its the TB. I know that in my car I see a drop of about 1-2 KPA at 6500 and thats through a 85mm lid, 85mm maf, a 95mm TB, and a 92 ported FAST with the TB opening ported to 95mm. I was expecting a drop in KPA, but not that much. What do you guys think?

 

That drop in kpa is not enough to warrant manifold change.What do the iat's look like through the run? Meanig is there much of a temp change?

 

3kpa does show a restriction of some sort, however that is still low amount of kpa. whats exhaust look like

 

I was seeing as much as a 5kpa flutter at 5200rpm+ with my 6.0L, cam, 90mm intake and little 1 5/8" OBX's with the 3" catback. I haven't checked it in a few months after putting the 1 7/8" headers with true duals. The truck runs much better up top though.