It's been awhile since I've messed with it, but anyways here's the story. I have a 2002 Z/28 M6 that has an SLP lid, Stock Maf, Pacesetter LT's, ORY, March underdrive pulley, Borla Cat Back, Torquer V.2 cam 112 LSA, Comp 918 springs, Comp 7.350 pushrods, TSP ported oil pump, LS2 timing set, and pretty much stock everything else. With these mods (7.400 pushrods at the time) it put down a poor 366 whp/ and 370 something torque. This was on a dynojet and it supposedly had no more room to tune some more power out. A/F was right around 13:1 and it only received one count of knock. I've called TSP and they have no clue, I tried swapping out the pushrods which were the stock 7.400's and didn't really seem to gain much. I installed a cut-out and didn't see tons there either. It has not been re-dynoed since those two minor changes due to the fact that I'm very dissapointed. Could it have anything to do with the lifters? or the Maf? Idk what the hell to think. I'm probably going to end up taking it down to TSP next summer. Any thoughts or insight would be greatly appreciated.

 

Pushrods should be longer than stock, something like 7.425 is moe like what you want.

Sure you arent down a cylinder or something?

 

According to Dan at Dyno Sport here in Lincoln everything seemed to be running fine. The power curves and everything even followed a couple of other cars he'd dynoed with similar set-ups. The curves were lower of course, but...

 

how many miles? have you done a leakdown test?

 

M6 or A4? How does the tune look? What kind of timing at your torque and power peaks? Getting any knock retard on the dyno? What does your air/fuel ratio look like at WOT?

918s do not always give good valve control with fast ramps like the XE-R lobes in your V2 cam. 7.425" pushrods are the correct length with that cam. 7.350s are putting your pushrods at the very top of the plunger depth. If you'd post the graph, we might be able to see if you're having valve control issues. Answer the above questions and maybe we might be able to better help you.

 

I would start with a compression and leakdown test. If the heads have NOT been milled, then the 7.350" pushrods are too short. We have been running 7.400" pushrods with this cam forever and haven't had any problems with preload or valvetrain setup at all. What did the car dyno to begin with? A graph would definitely help if you can post one up.

 

The car now has 42,000 miles on it. When I dynoed it with just the lid and catback it dynoed 321rwhp/333rwtq and had right around 35,000 miles on it. The motor is healthy, I could do a leakdown test but I don't think it has to do with compression. It was running a smooth 13:1 A/F as stated at WOT. As for the timing, it only recieved one count of knock and Dan said he didn't really wanna add any more timing because he didn't think it would yield any gains. I still have the Comp 7.400's, I guess I'll have to swap those back in. I'm gonna see if I can get the dyno graph from my tuner and I'll post it up.... I didn't even want it at the time because I was sooo frustrated

 

Is the cam degreed ok?
Do you have an adjustable timing chain?
Goodluck!

 

It's not supposed to need degreeing. I just have the LS2 timing set. Thanks I'm hoping I get to the bottom of this before next summer so I can get out and play

 

I forgot one thing, it's got a Jantzer ported throttle body too, I don't know if that would effect anything but anyways...

 

Graph would show whether you have valve control issues or not.

 

^^ I'm working on it as we speak, I emailed him hopefully he emails me back by tomorrow at least

 

Sorry I meant if the valvetiming is on.

 

^^ Hmmm, I'm not to sure what you're talking about. Fill me in

 

Are you sure the cam was installed "dot to dot?" A tooth off can throw things way out of whack..

Did you do the cam nstall or did a shop do it?

We definitely need a graph to look at..

 

I put down 375/364 with the same cam through a 6spd w/ 4.10's, mac headers, hooker cb, stock 98 heads/ls1 intake, 26 degrees timing in 65 degree air. Your numbers arent too far off, but should be more than what I did with a better intake. My final a/f was 12:8:1

 

It's not a tooth off, a buddy of mine and I did the install. He had done over 20 LS series cam swaps and he had me look at it to make sure. It's dead on dot to dot. Anyways, here's the graph but I'm not sure why it doesn't have a/f and all of that good stuff, I'll see if I can get a more in depth graph.

 

Oh and one other thing, apparently for some reason my 02 has 853 head castings. WTF???

 

What!!!
YOU should have 241's!!
Did you buy it used? if so someone swapped them out.

 

my 01 put down 410hp/374tq with the mods in my sig + the Torquer 2 on 112 ...



if you've got those heads, I wonder what your intake is