Cam Guru's please look here
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Cam Guru's please look here 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.
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.
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?
curious - why start a new thread for the same thing?
Thread Starter
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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.
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.
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.
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.
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.
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.
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From: South Florida
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.
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.
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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.
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.
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
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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
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
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.
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.
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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
One thing to note is that im at 5200ft elevation. Being up here on mountain Olympus doesnt help compression by any means
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
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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
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Can someone explain the process of measuring for shims? and with my setup, is that something I should even need to worry about?