Down 50+rwhp - 04 GTO 226/234 600/600 112+4 325rwhp?
#1
Down 50+rwhp - 04 GTO 226/234 600/600 112+4 325rwhp?
Hey guys,
My friend's 2004 GTO seems to be down about 50rwhp.
-6sp
-Kook 1-7/8"
-SLP LM2 catback
-MSD Wires
-NGK TR5 plugs
-Cam: 226/234 600/600 112+4
Here is the dyno graph. The dotted black lines are a headers only GTO.
You guys have any ideas why the power is so low?
My friend's 2004 GTO seems to be down about 50rwhp.
-6sp
-Kook 1-7/8"
-SLP LM2 catback
-MSD Wires
-NGK TR5 plugs
-Cam: 226/234 600/600 112+4
Here is the dyno graph. The dotted black lines are a headers only GTO.
You guys have any ideas why the power is so low?
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#12
TECH Addict
iTrader: (2)
I am not sure whether having the cam one tooth off brings about other symptoms other than the visibile problem you have, which is missing power.
#15
The push rod length does sound short since it is stock and the cam likely has a smaller base circle which would suggest 7.425" minimum length. Having said that, measuring the preload is the only way to determine whether the push rod is too short. Secondly, a push rod that is significantly too short would cause a lot of valvetrain noise and sometimes even low oil pressure.
I am not sure whether having the cam one tooth off brings about other symptoms other than the visibile problem you have, which is missing power.
I am not sure whether having the cam one tooth off brings about other symptoms other than the visibile problem you have, which is missing power.
A local LS1Tech member who is well known for his success with the LT1 motor did the install. I've never been involved with degreeing a cam, but from what I understand to degree the cam you have to have adjustable gears and this car has fixed gears.
#16
It certainly seems like a possibility based on the dyno-graph. The installer said he saw coolant on one of the plugs last night and believes it's a headgasket issue. If that's the case my friend is just going to wait to pull the heads until he's ready to install his new heads. It's just hard to swallow considering the compression and leakdown tests came back good and the car doesn't use any coolant.
#17
TECH Addict
iTrader: (2)
As an aside, most cam installs are done dot-to-dot and without the cam being degreed in. I am not saying that is the best method, but it is the most common.
#18
The symptoms of a short push rod vary. If it is only a little short, preload is inadequate to allow quiet operation, but it will not necessarily affect cam lift or duration because the lifter will fill with oil to take up the difference. If the push rod is signicantly too short, there is no preload. With no preload cam lift and duration can be affected but there would be a lot of valve train racket and it would be very noticeable. Oil pressure can also be erractic. Beyond that (even shorter push rod) there would likely have been valvetrain damage on the dyno at high rpm.
As an aside, most cam installs are done dot-to-dot and without the cam being degreed in. I am not saying that is the best method, but it is the most common.
As an aside, most cam installs are done dot-to-dot and without the cam being degreed in. I am not saying that is the best method, but it is the most common.
This install was done dot-to-dot.