Jump to content
SAU Community

Recommended Posts

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.

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

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............

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?

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 :)

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 by rondofj
  • Like 1

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

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • It is a kunfine Android screen . Does anyone know the wirering diagram of the fuga ??
    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
×
×
  • Create New...