So as you know I got headers/cam installed so I brought the car up to Robert at Advanced Dyno to get the car tuned/dyno'd. (Kooks 1 3/4 LT/Catless mids/ 236/240 111 LSA cam)

Mods are in my sig and the car dyno'd at 360/360 with ported TB, K&N intake, and Stainless Works exhaust. Robert said he's expecting to see 400+ along with a lot of the members on the forum here now that headers and cam was in, I was expecting 410-420.

First pull was 375 and I thought maybe this was just an untuned base pull and Robert tells me that it should be making more than this.

He does a few more tunes and pulls and the most we got was 388hp/375ft lbs tq. Air/Fuel ratio set and everything.

The cam is dying off around 5700 and is falling off quick instead of continuing to climb. We are concerned as this is also similar characteristics to another cam that another local just had tuned the other day. We overlayed the dyno sheet to a car that has the same header-intake set up as I have just running a stock cam and we are making IDENTICAL power throughout the power band.

We contacted Ed and he was stating that it has to be the valve train, either the preload is off or the springs can't handle the cam.

I purchased Patriot Extreme .660 lift springs and the cam is a .630/.610 lift cam so I cannot see that being the problem. I put in 7.400 hardened pushrods. Double checked on lining the cam/timing up and everything.

I am going to take off the valve covers tomorrow to retorque down the rocker bolts as I heard that after heat cycling the springs, you should retorque them down. My tuner also said that my valvetrain was abnormally loud.

In all, at the numbers its producing now, the car pulls amazingly well after the tune and it drives just as stock. I really do not know why people are so worried about "big cams" and drivability? There is no change at all even when the cam was untuned I could drive it like stock.

If anyone has any suggestions I am all ears.

 

If this Cam is a Comp Cam XER design and has any advance cut into it you could have P/V clearance issue's.I do know a 236/240 on a 112 +4 only has .020 clearance on the intake side.You could have a valvetrain problem or you could have a P/V problem.

 

Here is the cam sheet

I retorqued my rocker bolts today after heat cycling the springs

 

check your lifter pre-load..and also check the installed height of your springs,to make sure you have the correct seat pressures..

 

If your dyno number and curves are identical to another car with the stock cam, I hazard a guess that you have a stock cam in your car. 2=2=2, ya know.

BTW, I don't see any mods in your sig.

 

It is definitely NOT a stock cam in the car lol

 

Did I read on LS1GTO.com that you bought the car with the cam already installed? Could it be possible that just maybe the previous owner might not have actually installed the cam?

 

The car had a stock cam in the car when I bought it

The install was done this past weekend, 3 months after buying the car.

 

I think you need to degree that cam to verify its cam timing.

 

No cam with those stats will idle like stock on a factory tune. Another thing to check would be pushrod length.

 

Yeah, that's what I'm thinking. 236/240 duration is going to be rough (on the border of dying right after start-up) and at least buck a little under 2K without a tune???? Are you sure the cam you put in was in fact the cam that you have the card to?

 

I don't know where in my thread I said that the car sounds like a stock car? I said after tuning the car drives like stock which is what you want after a tune.

The cam is the right cam there is no doubt about it, it has to be either the pushrods or not degreeing the cam that has to be causing this



That is the car untuned, as you can see it does not sound like a stock cam, so I don't know where you guys are thinking that it is a stock cam. It even stalls 3/4 into the video. I just stated after getting the tune done, the car drives basically like stock, just need to gas it a little more, and under 1200rpm there is bucking. I chose this cam because of the reason that it was easy to tune, kept a lot of low end power, and drivability was best.

 

yeah,something isn't right here..no way would that cam idle like stock with/or without a tune...

 

well in your first post you said it idled like stock or something to that affect..
if i was you,i would check the installed height of those springs..they are a good spring,but will only give you the right seat pressures if set up correctly..

 

Yea I just stated I could drive it like stock, meaning the drivability was great. Not exactly stock, but you guys get my point, sorry for the miscommunication.

 

hope you get it figured out..since the car runs good except for the low power,i would guess it's a valvetrain issue or your cam timing is off..good luck

 

Thats a pretty telling statement. That cam SHOULD NOT 'drive like stock' untuned.

 

I find it hard to believe it that cam/intake lobe/spec didn't require some additional valve relief. The intake lobe definitely has more lift than an XE-R lobe.

 

Yeah sorry, when you were saying the car drove like stock untuned I was kind of thinking that's almost impossble... I would definetly triple check the pushrod length. I may be wrong, but the cam timing would only affect what RPM the power peaks at? That's probably wrong, but it would/will be a lot of work to check so I'd go there last.

 

Thats true too. PTV clearance would be tight to say the least.