built 7M lacking power

[Mikael_7m]

Dropped a built 7M in not long ago.
Typical build:
reconditioned head
Probe .20 over forged pistons
Eagle rods
Polished crank
Block and head machined
Cometic 1.3mm head gasket

Now the issue is it seems to lack power. It felt quite a bit quicker with the tired old motor!
It had code 51 so I recalibrated the TPS and the code went away. At the moment my car does not throw any codes. I checked timing, vacuum leaks and boost leaks and didn't find anything obvious. Maybe I need to double check for boost leaks.
It still hits the boost that I set it to (11 psi), but just feels and sounds like its working so hard and not really goin anywhere.

Any ideas or tips guys?

 

[Turbo Habanero]

Any exhaust leaks ?

Worn down or damaged/soft Couplers ? Maybe some closing on them selves or Vac lines having the same issue.

Did you try clearing the ecu of the stored codes?

 

[IndigoMKII]

when you say you checked timing, do you mean mechanical or electrical?

 

[Mikael_7m]

Any exhaust leaks ?

Worn down or damaged/soft Couplers ? Maybe some closing on them selves or Vac lines having the same issue.

Did you try clearing the ecu of the stored codes?

Cleared the ECU codes and it shows zero codes at the moment. I guess i can just replace some couplers but they where fine/pretty new before removal.
Will check for exhaust leaks.

when you say you checked timing, do you mean mechanical or electrical?

Both, I had to re-time the motor cause the shop that rebuilt the head didn't put cam seals in, and I didn't notice. So i pulled the front end off to do them and I doubled checked it upon installation. I also checked the timing with a timing light.
I do seem to be getting rather odd idling, sometimes its sits up at 1000rpm, and with a quick blip it drops back down, not sure what the hell that may be.

This is really driving me nuts, as I was expecting to have fun after so much work!

 

[7M4EVR]

Just a thought: maybe your expectations were too high. The rebuild you did wasn't going to durastically increase power by itself. What it will do is make it stronger more acceptable to power. Break that baby in and start jumping into air/fuel and turbo upgrades since you have the groundwork done!

 

[jg5899]

^ this
Or by some chance did you lower compression with pistons or head gasket?

 

[7M4EVR]

^Oh duh good call
I forgot about comprssion yeah you should probably check that. I would want to know the numbers after my rebuild anyway.

 

[T3rril79]

You can always compensate for the lack of compression with more boost. But yeah, that thicker headgasket can drop it a bit under the stock ratio.

 

[laotionracer101]

I think someone's been watching to many 2j dyno video's.. Jk joking aside, are you watching afr?

 

[3p141592654]

Might be cam timing. Did you align the sprocket to the camshaft using the middle dowel pin hole?

 

[Mikael_7m]

Compression was kept the same with the right size head gasket.
I'm not expecting it to be quicker, it's just that its noticeably slower....it actually feels like its choking.

 

[Mikael_7m]

Took her for a drive to work today, and it hit around 11psi and felt quick. Maybe I'm goin mad and or been expecting too much...
Think im gonna get her dynoed to see what she's making.

 

[lithium14]

^everything they said. A built motor doesn't give more power, it allows you to MAKE more power, but you still need the power mods themselves. Are you still on stock intake system? as in the AFM? turbo/IC details? What kind of exhaust? injector sizes? fuel pump?

 

[Mikael_7m]

^everything they said. A built motor doesn't give more power, it allows you to MAKE more power, but you still need the power mods themselves. Are you still on stock intake system? as in the AFM? turbo/IC details? What kind of exhaust? injector sizes? fuel pump?

Exhaust is full 3" turbo back, ECU is stock with the HKS PFC FCON piggybacking off it. Everything else is stock except for the intercooler pipe that runs from the fender to the throttle body, which has a HKS 3000 pipe and piping to match.

I never said I expected MORE power from a built motor, it's just that it felt like it had less power at one stage. It felt better today, but I'm still unsure, hence I want to dyno it.

 

[7M4EVR]

I'm not real good with the ECU tuning device issues I'm sure the other guys will jump back in here, but seeing that you have the FCON just makes me wonder if that doesn't have something to do with your problem. Have you tried letting the stock ECU learn the car and driving it (the thing will pretty much tune itself if you have no air/fuel mods.

If your running basically a stock set up other than exhaust I would try to revert back to leaving the ECU alone until you give the car a reason to "tune".(although I am pretty unfamiliar with the FCON).

 

[JDMMA70]

The pfc fcon is a plug n play piggy back it already comes with a tune programmed in it you just change chips for the injectors. I think you can fine tune it with a gcc though

 

[91Supra313]

I had an Fcon and there is a chip inside of it that you can adjust to raise or lower the fuel. I have a friend coming over today that is having the exact same issue you were having. He is running my old HKS turbo setup, and when he is on boost it is like there is nothing. It holds 11 psi no problem but there is no boost pushing. He said it is driving and accelerating like does with no boost when it should be full boost. The turbo is spinning like crazy, but nothing is going on. I had the same issue on my old 7M setup. For the life of me I can't remember what I did to stop it. If I figure out his problem today I will reply on here and let you know what I find.

 

[noel]

Lacking power?? Boost leak...timing could be off mines problem was an exhaust gasket between the back of the turbo to the downpipe

 

[91Supra313]

No boosts leaks on my friend's car. Timing is spot on with timing light and lining up the notches on the crank and cams. There are no vacuum leaks that we can find. His acts up only when the engine is hot. He said that when he left to come over to my place which is a 30-45 minute drive, that everything was great and he was getting loads of power to the ground without problems. Once the car warms up however, you can hear the turbo spooling up, but there is just nothing there. No good push like you normally get from a turbo. He did a boost leak test by using compressed air in IC system.

 

[3p141592654]

If coolant temp exceeds 95C, then ignition timing can be retarded up to 4 degrees. The max of 4 degrees happens when coolant temps hit 105C and beyond. That will make the engine feel weaker.