Jarren_b

Alright guys,
I did a new cam install last weekend, went it for a dyno tune and im extremely disappointed

Mods are-
Trunion upgrade
7.450 pushrods at .110 preload (changing to 7.400 to give less preload)
BBK SSI intake, BBK TB, Larger airbridge and a huge K&N Filter
Borla Longtubes, xpipe, hi-flow cats, Stock mufflers with bypass mod.
New TR55IX plugs and wires
New fuel filter
Ls7 lifters
BTR .660 lift springs, steel retainers, approx 20k miles on them.
Resurfaced stock 806 heads and new MLS head gaskets
When I pulled the heads the cylinders looked perfect
That should be everything. i was expecting just south of 400whp
I can get the tune file but I know right now that my AFR is a 12.6 at WOT
and I have 27 degrees of timing

Without naming any names or companies just yet I would like to get some opinions on my custom cam specs

232/234 .626/.626 111+4

Does this cam look strange at all? I had one person say that it has too much advance. is this true?

Here is my dyno sheet. I cannot for the life of me figure out why It doesnt make more power, I know my stock heads arent helping anything but Ive seen smaller cams make 400whp with the same mods.

Darth_V8r

iTrader: (4)

I'm no guru, but I do wonder if that cam isn't poorly matched to your stock heads. especially since yours are the very early heads. I posted the same in your other thread as well.

curious - why start a new thread for the same thing?

Jarren_b

Its definitely possible but I would think a bigger cam and more mods would atleast make close to the same power.
I did a compression test just to rule out a hurt motor.
All of my cylinders were about 135 psi and none of them were more than 5 psi different
obviously the overlap of the cam will lower the compression down low so that number may look lower than stock. but my main reason for doing so was to make sure that I didnt have a hurt motor.

Darth_V8r

iTrader: (4)

for comparison, my cranking compression is 200-210 accounting for different cylinders. the drop in cranking compression might be the answer you are looking for.

Jarren_b

You also have milled heads.
My cam has 11 degrees of overlap.
yours has 2 degrees. from reading ive been doing, it seems that bigger cams have lower cranking compression

Darth_V8r

iTrader: (4)

Yes, and a lot of guys that run big cams run 11+ to 1 static compression to compensate and get dynamic compression back up into the 8's. I chose my cam and heads combination to achieve 8.1:1 DCR. Would have gone higher, but I can't get >91 gas. Your old cam was similar to my current cam, and my heads are milled.

It's like a Rubik's cube. You can't change one thing without affecting everything else. The combination is more important than any component. A good combination of heads and cam should compliment each others strengths and help compensate for eachothers weaknesses. You had already upgraded the cam once and were probably alreadyy limited by the heads.

I honestly think you will need to address your heads to get the power out of that cam. Good luck.

99Bluz28

iTrader: (35)

Have you had it on any other dyno's ? All dyno's don't show the same hp/tq numbers.
How well does it run on the street and at the track..?
Remember a Dyno is ONLY a tuning tool, your hp/tq can easily vary 20hp/tq on another dyno. Furthermore I wouldn't expect to see much more than 380 hp/tq out of it with having stock heads.
I'd also get those shorter PRs in there before getting it on the dyno again.

RabidStreetRacer

iTrader: (1)

What transmission do you have and if automatic, what stall are you running?

SoFla01SSLookinstok

Definitely a good point about compression. Do you know what your compression ratios are?

I would think, with your setup, your dyno graph should look similar to the last graph you posted. It was an A4, & this is the net, but I noticed this. The torque peak was right at 5k rpm, like yours, & then started to fall although not as drastic. The hp peak is 6300, or something, which seems about right. Lastly the difference in hp/tq. It was close to 20 as yours is only 8. I think your car should be putting down, right around, 380whp on a dyno jet.

Your hp is dropping off too early.

RabidStreetRacer

iTrader: (1)

Also did you degree the cam?

squalor

iTrader: (3)

That was sig worthy !

Jarren_b

I definitely realize its only a tuning tool but I know several people personally that have bolt on only fbodies that put down right around 350 to the tire. so does that mean I only gained 18 hp by a cam that should gain me 40+. that simply isnt correct. I ordered some new pushrods already. I wouldnt have made any gripes if it would have made 380 or so cause I would have known it was just a low dyno.

As another comparison, you can see 10 dozen Tqv2 cams which is similar to mine make 400whp with full bolt ons on stock heads. and my cam has several degrees of overlap over the torquer v2 so in theory should make more power

Jarren_b

Verified on a cam doctor

Jarren_b

My car is an M6 by the way.

Im almost positive my long pushrods are hanging the valves open. I did a compression test and all cylinders and they were within 5psi of eachother without exception. but they were only 135psi. I know my motor is healthy and my bottom is not the issue. Also When I had heads off I had them checked for leaks and had the valves checked so I know thats not the problem. This cam should be pulling past 6k rpm and its just not right now. Im also going to get the valvesprings tested when I do the pushrods just to rule that out, even though my graph doesnt seem to show any signs of valve float, atleast that I can tell. I have seen instances where there is valvefloat but it just causes the power to fall off prematurely instead of having a wavy graph

Darth_V8r

iTrader: (4)

The long pushrods is a really good thought, and for the ease of making the change, it's definitely worth throwing in a set of 7.400" rods. That would also explain the very low cranking compression. the intake valve would be closing way later than it should.

I ran your cam through a valve event calculator, and I came up with 7.7:1 DCR. at that, your cranking pressure should at least be 180. Even if the shorter rods makes a difference, I still think you'd benefit from a 0.020" to 0.030" mill.

Jarren_b

My calculation of the dynamic compression calculation was higher i think ill run through it too.
One thing to note is that im at 5200ft elevation. Being up here on mountain Olympus doesnt help compression by any means

poltergeist 02

iTrader: (65)

I mentioned pushrods in your other thread cause I have personally seen that happen before. Now the case that I saw was very extreme with pushrods that were about .100 too long. After the correct rods were thrown in the car picked up about 60hp

Jarren_b

Well perfect! so since mine are about .050 too long maybe ill pick up 30hp haha
Im just really hoping I dont have worn springs. I hate changing them.

honestly If I can just be somewhere around 390 ill be content. Im going to throw on a borla straight pipe axleback before I go dyno. Pat G was saying that my stock mufflers might be choking me out. I havent bothered changing them yet because usually mufflers do nothing for power

poltergeist 02

iTrader: (65)

I hope it fixes your issue, but I would still have those springs checked.

Jarren_b

Yeah Im honestly betting on having to replace the springs. I might just replace them and not even have them checked just so I know its done since mine already have about 25k on them..

Can someone explain the process of measuring for shims? and with my setup, is that something I should even need to worry about?