Tuners/engine builders please chime in

[98turbo]

I'm having issues with my car. I'm gonna list my mods and power output, you tell me where the problem is:

MMR900s stroker
Stock heads
Steg stage 4 ported eaton
2.8 upper/4lb lower
Afco h/e
O/R xpipe with stingers
Jlt intake, 60lbers, bap
Sct xcal3
Elbow and sbtb

My compression in my motor is 155 across give or take. Car is making 465whp with 18 degrees of timing. I have 823 miles on the engine. Why is my power down?

 

[oldmodman]

Who built the engine?

Are the cams stock?

A lot of horsepower can be gained or lost in the tune. How much advance are you running? I see that you say 18 degrees. Is that the "all in timing" Is any of the timing getting pulled? Can you check to make sure that your bypass valve on the back of the blower is operating properly. If it does not close when it should all your boost is not getting down to the engine.

There are so many things to check that you should take it to a good tuner that has worked on lots of Cobras and get it examined.

 

[itSSlow98]

Could be belt slip, could be tune, could be the type of dyno, could be the lack of long tubes............................

 

[98turbo]

Who built the engine?

Are the cams stock?

A lot of horsepower can be gained or lost in the tune. How much advance are you running? I see that you say 18 degrees. Is that the "all in timing" Is any of the timing getting pulled? Can you check to make sure that your bypass valve on the back of the blower is operating properly. If it does not close when it should all your boost is not getting down to the engine.

There are so many things to check that you should take it to a good tuner that has worked on lots of Cobras and get it examined.

MMR built the motor and it has stock cams. My worry is the compression of the engine. 150psi across the board seems low as oem should be near the 170 mark. It's the 900s, so I'm not sure if it being a stroker is causing the compression loss. The tuner is suggesting shaving the heads down to increase the compression. I just don't have the heart to change it again. I just got it running again. I did check the boost bypass and it seems to be working fine.

 

[98turbo]

Belt was brand new and no slipping. Tune is seeing 11.8 afrs and timing seems to be spot on. It's on a dynojet. It made 511whp on the stock engine with the same mods. Same tuner. Same dyno.

 

[Senkak]

Make sure your IC pump is working.

 

[SVT_Troy]

if your worried about your compression numbers do a leakdown test which is more thorough

 

[SVTRAT]

So was your engine build with stock compression or different compression? If your compression are almost similar across the board, more than likely you have a less than stock compression. Hopefully its not gonna turn into one of those.....threads....

 

[98turbo]

-18cc pistons.

 

[Brutal Metal]

Tuner wants to mill the heads to bump compression? WHAT A LAME piece of Advice!

 

[SlowSVT]

Get a bore scope down into the cylinders. With those compression numbers it sounds like the rings are giving-up the ghost. Could be burnt valves but I would be looking at the rings and pistons first. Leak-down test time.

Who built that motor?

 

[98turbo]

It's a MMR motor. The entire longblock has 800 miles on it.

 

[safado]

Tuner wants to mill the heads to bump compression? WHAT A LAME piece of Advice!

lol.. thats what I thought... why is the timing so low?

 

[Real2000CobraR]

93 tune? Timing is so low.

 

[98turbo]

The more we advanced it, the graph got sloppy and no power was being made.

 

[safado]

The more we advanced it, the graph got sloppy and no power was being made.

hmm thats odd..