Restriction In The Exhaust

[XKLABA]

Manual or auto ?

[Ben C34]

Manual

[Manuel Kasko]

Manual

ME?

[GTSBoy]

ME?

Que?

[XKLABA]

Manual

Oh then lol

If the exhaust housing is a restriction the turning up the boost will only make the situation worse, knock it back to 18 and see what happens, at least then we can compair apple to apples

[rondofj]

Seriously? This cannot be true. Think about it.

This really baffles me as well, but that's how it is, even when I bought the car - stock turbo, 12psi etc, it would do 100km/h in 5th at 3000rpms. Only now different story. And manual yes, Manuel Kasko, no.

[XKLABA]

Ok let's see if I can explain this good enough, for the sack of this discussion we will use 4th gear cause it is 1:1 ratio and we will assume it is a 4.11:1 diff ratio

So the crank turns 4.11 times which in turn turns the gearbox input shaft 4.11 times which tunes the output shaft 4.11 times which turns the diff input shaft 4.11 time then the diff reduces it at a ratio of 4.11:1 which turns the wheel 1 time, this NEVER changes unless you change a ratio in the drive line and is the same for every gear just with different ratios inside the gearbox applied

So revs v speed in any given gear will never change no matter how much power you throw at it

[rondofj]

^{Ok let's see if I can explain this good enough, for the sack of this discussion we will use 4th gear cause it is 1:1 ratio and we will assume it is a 4.11:1 diff ratio}

So the crank turns 4.11 times which in turn turns the gearbox input shaft 4.11 times which tunes the output shaft 4.11 times which turns the diff input shaft 4.11 time then the diff reduces it at a ratio of 4.11:1 which turns the wheel 1 time, this NEVER changes unless you change a ratio in the drive line and is the same for every gear just with different ratios inside the gearbox applied

So revs v speed in any given gear will never change no matter how much power you throw at it

^{Any of you Sydney lads welcome to go for a spin in my 34 on a weekend - we will do 5th gear at 2600rpms - seeing is believing............}

[Ben C34]

I will never believe that tuning an ecu has changed how many revs per hundred your car does.

[GTSBoy]

Shenanigans.

I am back to blaming the PowerFC. The tacho is telling lies, which implies the ECU is telling lies, which implies the ECU is having an emo fit.

[zebra]

My bet is tacho output is or was wacky from the ecu.

there s no possible way that the gear ratios which are mechanical can be changed by a few figures in a computer

[rondofj]

So are you fellows saying 100km/h in 5th should be @3000rpms?

[zebra]

What is you tyre size?

[GTScotT]

Do Ron Ron, just so that I understand this properly: your car was running the stock ecu prior and doing 3000rpm @ 100km/h, then you changed to PFC and got it tuned and are now seeing 2600rpm @ 100km/h.

Is this correct?

[XKLABA]

Nistune I believe, the ONLY way the revs v speed can change is if you did the test in one gear then later did it in a different gear and some how forgot what gear you did said test in, diff won't change revs v speed nor will tyres as the speed sensor is on the output shaft of the gearbox, I also think the signal goes speed sensor - speedo - computer but could maybe incorrect on that one

[rondofj]

Tyres diff all same, stock ecu and nistune I was doing 100km/h in 5th at 3000rpms, PFC now I'm doing 2600rpms -normal motorway cruising. And no gay 22" rims, running 18" RAYs wheels

Edited May 13, 2014 by rondofj

[Ben C34]

Something is wrong.

[rondofj]

Sumting wong.

[GTScotT]

stock ecu and nistune I was doing 100km/h in 5th at 3000rpms, PFC now I'm doing 2600rpms

He's answered it already. Stock ECU said 3k, as did the Nistune (coz its the same fking ecu). Now the PFC says 2600.

The PFC is reading the sensor voltage that little bit off and sending the wrong reading to the cluster.

WOW

SUCH DIFFICULT

MANY THINK

MUCH SOLVED

[rondofj]

Maybe GTScot is right, I always have a funny feeling now that its a bit harder to reach 7000+rpms now cos the car is already going too fast etc, as compared to before. Maybe the tacho reading is off. Maybe its doing 7400rpms already and displaying as 7000 or say I have reached 7000 already when it is showing 6600.