Pics Hks 2835 Install

[infected flow]

Got the car dynoed on a different dyno yesterday afternoon - no changes just a modern dyno dynamics dyno in shootout mode.

The 341.9 horsepower - in kw is 255rwkw - sounds much better than the 275 rwhp figure from the other dyno.

Interestingly the AFR's were reading differently between the units - the original tune was done with a motec and the tuner was tuning to afr's around 12.8 - 13.1 which I thought was lean - yesterday with the autronic lambda unit it was reading rich at 10.9 - 11.3 at full load.

We tried pulling a bit of fuel out but it lost power, then tried putting 1 degree of timing in - too much knock, then tried pulling out a degree of timing out and lost 20 hp.

The motec unit must read lean as at cruise with the o2 sensor switched on it was reading about 15.8, whereas the Autronic was reading 14.7 which is about right.

We didn't muck around with it - I just wanted to do a few power runs to get a dyno readout from a different dyno.

10 kw less thasn you sly 33 - I don't have a catch can though and have the stock airbox with k&n flat panel filter.

Cheers!

whats the torque figure...?

this still sounds weird...

[infected flow]

I cant believe there isnt a tuner in Queensland who cant tune your car.Give it to someone who knows what they are doing and find that lost 100hp.

GTTR34,just get a T04Z and dont stuff around,lol

who needs a to4z when u can get the same power out of a 2835pro s ......

[Cubes]

GTS25,

o2 sensors require calibration from time to time.

Its difficult to tell who requires the calibration.

[infected flow]

thats true

but afr raio's perfect for 12.5 for this turbo and the torque should be very high....

its running too rich!

[Cubes]

If its making the power its making the torque.

You can't have one without the other.

Please ignore rolling road torque figures as simple things like tyre pressure, gear ratio's, diff ratio's, tyre size/diameter and the dyno its self all make a difference.

For example....

On the dyno I run on an RB25 making 300rwkw makes around 390nm of torque, an rb30det making 300rwkw makes 540nm. Obviously the rb30 is making the power earlier in the rev range hence its higher torque, the rb30 is also running a slightly shorter diff (4.363:1 vs the rb25's 4.11:1) which again bumps torque up slightly.

But here's an interesting comparison. my rb30det when it was making 176rwkw was making the same peak torque as the rb25 makign 300rwkw, being 390nm. Obviously I made the 176rwkw rather early in the rev range in order to achieve such a torque figure.

So... essentially.. You cannot compare dyno torque figures UNLESS you have the exact same tyre size, exact same gear ratios, exact same diff ratio and both run on the exact same dyno!

The torque curve is good when tuning as you can see easily how afr's and ign. send the torque up or down at that particular rpm point.

If it makes more torque at a particular rpm running slightly rich with more ign. timing then thats obviously optimal. Leaner doesn't always mean more torque.

Looking at 254rwkw Jarrett performance dyno graph the afr's and ign. timing definitely need to be cleaned up in order to smooth out the torque curve.

Its much nicer to drive a car where the torque comes on and continues to pull rather than come on then fade off a little then rush back on.

[infected flow]

If its making the power its making the torque.

You can't have one without the other.

Please ignore rolling road torque figures as simple things like tyre pressure, gear ratio's, diff ratio's, tyre size/diameter and the dyno its self all make a difference.

For example....

On the dyno I run on an RB25 making 300rwkw makes around 390nm of torque, an rb30det making 300rwkw makes 540nm. Obviously the rb30 is making the power earlier in the rev range hence its higher torque, the rb30 is also running a slightly shorter diff (4.363:1 vs the rb25's 4.11:1) which again bumps torque up slightly.

But here's an interesting comparison. my rb30det when it was making 176rwkw was making the same peak torque as the rb25 makign 300rwkw, being 390nm. Obviously I made the 176rwkw rather early in the rev range in order to achieve such a torque figure.

So... essentially.. You cannot compare dyno torque figures UNLESS you have the exact same tyre size, exact same gear ratios, exact same diff ratio and both run on the exact same dyno!

i agree but u can help tidy up there figures for more power but torque does give u an indication of where the power is like u just pointed out with your rb25 and rb30 story....

and your right about the rb30det it comes down to the tune.. the rb30det would be great for track since it has great torque but head for head it would be shit house but it made peak power early in the rev range so there's no point reving it out... comes down to what u want it for ..

cheers

[Cubes]

The RB30's hold power to 7000rpm+ providing you run a nice exhaust manifold, cams and turbo suitable to flow the airflow required.

You do the same to the rb30 as you would to a rb25 if you wanted the 25 holding power to 8000rpm+. As you know... a larger motors flows more air at a lower rpm.

Realistically 6-6.5k is plenty, if you require more road speed per gear its best to tweak the diff ratio than simply pushing the rpm up higher.

Remember turbo's LOVE load.

[infected flow]

The RB30's hold power to 7000rpm+ providing you run a nice exhaust manifold, cams and turbo suitable to flow the airflow required.

You do the same to the rb30 as you would to a rb25 if you wanted the 25 holding power to 8000rpm+. As you know... a larger motors flows more air at a lower rpm.

Realistically 6-6.5k is plenty, if you require more road speed per gear its best to tweak the diff ratio than simply pushing the rpm up higher.

Remember turbo's LOVE load.

well if the turbo can flow yes its true it will hold in an rb30 but it has has to come to a point to make PEAK POWER......what the point of reving it to 7000rpm when peak power is made at 6500rpm thats what im saying....

[Cubes]

well if the turbo can flow yes its true it will hold in an rb30 but it has has to come to a point to make PEAK POWER......what the point of reving it to 7000rpm when peak power is made at 6500rpm thats what im saying....

When I say hold power I am talking about holding power after peak power has been made. Holding VE up at high rpm.

Stock exhaust manifold = power nosing over quickly after peak power.

A nice aftermarket manifold = power holding up for another 500-1000rpm before it begins to slowly drop off to a point where there is no point reving the motor any harder due to a lesser average power when selecting the next gear.

Its almost always beneficial to 'over rev' a motor (well the rb's anyhow) as it results in a higher average power.

Higher average power accelerates a car quicker.

Off topic from an off topic.

[gtst25]

Yes don't worry guys the car will be getting a retune from someone different probably in Brisbane. When I first installed the turbo kit before the tune it came on a LOT harder with next to no knock.

I've run it down the quarter and after four passes I got a best of 12.89 - each run we leaned it out more and more as it's running rich as. I couldn't do any more runs as it was a competition event. Lots of wheel spin in first, sec and third, crappy 1 sec reaction time and stinking hot with track temps in the high fortys. And I'm a crap driver.

Yes it certainly is a higglty pigglty dyno curve - not very smooth but by the end of it all I'd had enough of spending money on it. It's still bloody fast - you can't do much on the street as you just go too fast.

Interestingly the tuner was making the car run leaner in some parts of the rev range and richer in others - towards the top end he leaned it out - but once on the other dyno with autronic other lambda sensor it turned out it was running very rich. I think his sensor was on the way out or something as I've had two other lambda sensors on it since and they've read the same. About 14.7 on cruise.

Cheers