Need Advice

[Zhestokus]

Hello all

i have some problems with my car (Nissan Skyline V35 300GT 2003)

i have made some tuning works

i have installed Intake Plenum Spacer, Throttle Body Spacer, changed Z-tube with K&N air filter, changed Exhaust Header Pipes, Down Pipes and installed full dual Exhaust (i mean exhaust is without Y-Pipe), removed fuel filter in Fuel Tank and installed Universal JDM Fuel filter, installed groundig KIT

i have checked my car on Dyno and output was 212WHP which is 300HP (Engine output, 300HP because owner of Dyno sad me his dyno shows 1.13% less output than others)

and Torque was more then 380NM (i don't remember exact number , my friend tested his G35 Coupe and his car has 380NM and i remember my has more )

i found formula

WHP = Crank HP * (1 - driveline loss)

Say you suppose that driveline loss is ~20%.
WHP = Crank HP * 0.85

Crank HP = WHP/0.85

so

213*1.13=240.69

240.69 / 0.85 = 300.8625

but few days ago same model (but fully stock) overtook me

i have no idea what is wrong with my car

below is images about what have i done with my engine but some photos is old, at this time there is grounding kit and around of Z-Tube is thermal isolation

Mercedes AMG exhaust fits with minimal redesign

[The Max]

You're sure the other vehicle is completely stock? If so, maybe he just has a freak motor? Not all motors are created equal off the production line. He might just have a bit more horsepower and torque than you.

[Zhestokus]

yeas i'm sure, he have Nissan Skyline V35 300GT 2002

but his car millage is 85'000 KM and my car millage is 180'000 KM

both are JDM (from Japane)

BTW i have removed EGR, i mean i to have get header (with electronic part) of EGR and connected it to jack (i know this is not good idea but i think it is better then dirty intake plenum) :D

maybe after all of above changes i need Fuel/Air Ratio Controller? will on that car fit e.g Greddy E-Manage Blue?

or maybe problem is Differential (e.g need change oil) ?

i'm planning to change Differential (because as i know sedan with AT have diffs with ratio 3.15) and install diff of Skyline 350GT Coupe AT (with 3.35 ratio)

i have no idea what should i do :D

[Zhestokus]

i hope there is no problem with car and it was my bad driver skills :D

[The Max]

I think you're making wild guesses and the more you toy with your car without actually properly diagnosing it, the less return you're going to get from it and perhaps even do more harm than good. His engine has half the wear of yours. I wouldn't be surprised if you're pushing less power than he is due to simple engine wear, lowered compression, etc.

Guesses are wasteful, if not dangerous. Get an expert to make measurements, such as compression tests and whatnot. Only by properly diagnosing the engine through measuring instruments will you have a better idea of what's going on so that you can fix the root cause of your issues. Photos of what you've done to the vehicle will not help, I'm sorry to say. This needs to wind up in the hands of a professional.

Edited May 30, 2015 by The Max

[Nightcrawler]

With all of the mods you have done, you NEED some kind of tune. Even if it is an SAFCII (or similar) to flatten out your air/fuel mixture. By changing your intake and exhaust so heavily, your ECU has to try to deal with all of the different aspects of your airflow modification. If you are running rich then you lose power (and will foul up your plugs etc), if you are running lean your ECU will be retarding the engine timing to avoid detonation, thereby robbing you of power. Have you reset your ECU to let it relearn after you put the mods on? That is the first place I would start.

[Zhestokus]

I think you're making wild guesses and the more you toy with your car without actually properly diagnosing it, the less return you're going to get from it and perhaps even do more harm than good. His engine has half the wear of yours. I wouldn't be surprised if you're pushing less power than he is due to simple engine wear, lowered compression, etc.

Guesses are wasteful, if not dangerous. Get an expert to make measurements, such as compression tests and whatnot. Only by properly diagnosing the engine through measuring instruments will you have a better idea of what's going on so that you can fix the root cause of your issues. Photos of what you've done to the vehicle will not help, I'm sorry to say. This needs to wind up in the hands of a professional.

Thanks a lot

It is really good idea

I will test/check everything you mentioned

[Zhestokus]

With all of the mods you have done, you NEED some kind of tune. Even if it is an SAFCII (or similar) to flatten out your air/fuel mixture. By changing your intake and exhaust so heavily, your ECU has to try to deal with all of the different aspects of your airflow modification. If you are running rich then you lose power (and will foul up your plugs etc), if you are running lean your ECU will be retarding the engine timing to avoid detonation, thereby robbing you of power. Have you reset your ECU to let it relearn after you put the mods on? That is the first place I would start.

Yes i had do that

i had set key on position ON when Throttle body and some other sensors was unplugged, after that i had problems with Fuel/Air ratio(poor mix)

and after all of those changes i have reseted ECU and started all learning procedures (Closed throttle position learning, Throttle position on XX learning and learning Timings)

Edited May 30, 2015 by Zhestokus