sahwan

hi

I have I don't know what to say , the car work fine put the power is very low

I have corvette c6 Z06 with 434ci high compression

LS7 434ci
13.8:1 compression
mast 305 milled to 60cc chamber with PAC racing valve springs .700 lift
fast 102
243/254 .661/.661 113+3
hydraulic roller
1.8 rockers
8.000 pushrods


use Q16 we get only 594whp 556wtq


the power drop after 6000 rpm


what is the problem ??

is this the max power ??

Tuskyz28

What kind of dyno?

What kind of lifters is you running ?

sahwan

Dynojet and ls7 lifters

Tuskyz28

The lifters can be the problem.... I've been told over and over the LS7 lifters can rob a couple horsepower in the high rpm range which sounds like is happening to you.

On another note dynos are just for tuning and at 590 plus at the tire I'll be more interested in seeing your trap speed at the track. It tells the real story. You have a respectable number at the tire there. That's roughly 700 horse at the crank!! Some larger 454 LsX motors don't even make that.

DietCoke

iTrader: (18)

Cam too small

KCS

iTrader: (20)

Post the graph. I would think it should hold out a little further than 6k RPM.

sahwan

This is the graph ,ignore the afr



ignore the afr

KCS

iTrader: (20)

You may have some valvetrain issues judging by the look of the power curve at the top end. With the 8.0" pushrods, what is your lifted preload?

BOLO

iTrader: (40)

I think so too. But those are pretty respectable rwhp.

sahwan

It's a flat tappet

The rocker arm move a little bit left and right and not moving up and down

sahwan

It's 13.8:1 with q16

We make same whp with 434ci 11.8:1 auto transmission with pump gas 93 octane

KCS

iTrader: (20)

What? It's not a flat tappet, you said in your post that it's a hydraulic roller as all LS engine are from the factory.

Being a hydraulic roller, you should have the lifters preloaded a certain amount.

John B

iTrader: (10)

What do you have for an intake manifold and throttle body?

eaglegoat

You're running a flat tappet cam with hydraulic roller lifters? I think we found the problem. Looks like valve train issues on the graph too.

sahwan

Sorry sorry it's a Roller Tappet Lifters 😅😅

sahwan

Fast 102 and 102 tb

JakeFusion

iTrader: (7)

FAST doesn't help. More cam would help.

Realistically, 630rwhp is about the max with the FAST. Maybe 650 if you're on a generous dyno.

jleews6

iTrader: (2)

Like others have said It might need more cam timing. Did you degree this cam? I would like to see what one of Toni Mamo's ported MSD intakes would do on something like this.

slogo

Is it possible he has way to much head, the 285's were recommended to me with
445 ci, similar cam, fast 102 intake and throttle body. I'm not a pro just asking.

01 blue bullitt

I think the cam is too small I have a 447 ci same compression roughly with big cathedral heads with a 102 and my cam is 263/271. Also have you looked into e85? Before I changed the cam or anything I'd run it at the track. Dyno numbers are irrelevant, my car on one dyno made 466 rwhp but it's been 9.77 breaking up