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Chun and his RR session

  172 Cup

As the faithful server is not letting me reply on the other topic I will have to post this instead.

Just read Chuns report on his RR session today and just wondered how fair a test this was on the Viper induction kit.

Presumably when designing the Viper PiperX took into account the fact that (cold) air would be supplied from the front of the car as it was driven (relatively fast) along?!!? As a consequence is it not that suprising that Chuns figures were not as high as he hoped bearing in mind the fact that an oversized office fan will never truly replicate the ammount of air that would be inducted when driving??

Does that make sense?


As I said in the other post. After each mod the car never felt slower. If anything alwaysa little faster. I havent fully tested the superchip yet after fitting. But its seems to do what its says on the box. Smoother power delivery response is a little better , also being no rev limiter lets me take the revs to 7200 in thrid allowing me to get right back into the power band in forth


Hi Griff..

oooo.. this has been done to death with Nick Read n Me

but.. there is no way on gods green earth that forced induction occurs on a ram air scoop or principle..

on an f1 car, with slide throttles and the need for non turbulent air.. at, say... 180 mph.. then maybe.. on a clio.... ??... on a road car.. ???

Sorry, does not compute.

ram air feed does not exist at road car proportions or speed.


  Williams 2, STi N12

Come on Captain, I think you have proved your point on this one before I seem to recall.

Im sure you have better things to get on with than going over old ground.

You are correct Sir

Again, I struggle to resist commenting on these issues.

I will go n play SOF2 Multiplayer (net based) and have a beer or 3...

  BMW 320d Sport

Hehe Joe you dont compute mate...youre giving *me* a malfunction! I dont think that your argument was proven by any stretch of the imagination. Anders read the thread again.

Ram air does work and not at 180 mph but 75mph to 80mph - which I have proven to myself in road driving (I wont go over the details again).

But I do agree that a rolling road will not do a ram-scoop/airbox setup any real advantage because the air colume and speed from the fan is nowhere near whats really hitting the front of the car at motorway speeds.

Perhaps the RR was out on its readings?

Ive heard stories of this before.

My car has been on two RR with other Clios and both times the figures have been reasonable when compared with the other cars.

1st time I recorded 160 BHP @ wheels
2nd time I recorded 153 BHP @ wheels.

I have more faith in the 2nd RR result and the guestimated flywheel BHP was 175 which I feel accurately reflects the modifications done to the car.



Perhaps the RR was out on its readings?

Ive heard stories of this before.

My car has been on two RR with other Clios and both times the figures have been reasonable when compared with the other cars.

1st time I recorded 160 BHP @ wheels
2nd time I recorded 153 BHP @ wheels.

I have more faith in the 2nd RR result and the guestimated flywheel BHP was 175 which I feel accurately reflects the modifications done to the car.



Just been out for a run and there is a noticeable increase in mid range torque as well as a slighty more revvy top end. The car does feel quicker than it use to. Maybe my car was a bit underpowered before the mods. I still did pretty well against the scooby before the viper and superchip


Thought I would shed some light on my experiances, my car ran a 15.054 1/4 when standard bar a back box, after a superchip session not just a chip, and a look into different set ups, and a viper with a intake through a foglight (pic should be in gallery) I ran 14.7 at 95 ish. The car when rollered was wrong (fueling), after the remap I left with 183 bhp at flywheel (without) viper. I noticed a marked improvment. After a long journey I can pop the bonnet and the viper is ice cold along with the tube going to the inlet manifold, with the standard kit it was very hot. My car is noticebaly faster, plus it practically drives through the rev limiter in 4th. PS thats 7800 rpm ish in mine. HE HE.

So tim what do you reckon I should do?. The fueling on the car is now spot on according to the people at powerstation.

  CTR EK9 turbo

Sounds interesting. After just my group N ecu, my car revs to 7800 rpm: Tonight i went out and raced an Escort Cosworth (N-reg) and I was having to back off to stop rear ending him. He moved out of the way and i came past at !30 and he tagged in behind. Cars in front meant slowing down was important, once they moved, off we went. I gained some ground and he could not get past me, if anything i was slowly getting away from him. That is thanks to me being able to stay in 4th gear for ages now with my new ECU, screaming revs at 7800rpm! cant be good for the engine tho! oh well. Warrranty, anyone? i feel it needs to see the rollers and the car seems to be a bit gutless between 6-7000 rpm, so a freer exhaust would probly help out at those high rpms.

Hi Chun, you ma have answered your own problem here M8

if the muppet on the rollers took it to 7600, thats yer problem, the bozo should have looked at the max power figure / rpm first.

at a given point, the graph will drop.. no superchip or other conversion (Apart from cams) will move this to any degree.

he should have tested it at 6250 rpm.

tell him to do it again


Sorry Captain I dont understand If you could kindly repeat with a bit more detail hehe. Ill tell you exactly what he did. First put the car on the rollers. then runs the car in 4th gear, got one of his workers to spray soom stuff onto each tyre before making a run, stuff spelt starting with "W". Then all he did was press hard on the accelerator till 7600rpm. Isnt that the correct way to get a power run?.



On the print out isnt the torque and power curve suppose to cross over at 5250 rpms?. Cause on mine it crosss at 6100rpm.



theoretically the torque in foot pounds should = the bhp at 5250 rpm as

Horsepower = Torque (lb.-ft.) x RPM / 5250

so at 5250 horsepower=torque due to cancellation in the equation.

so, what is the torque figure and bhp figure at 5250 on yer graph. ?

what he SHOULD have done is run the load up as the rpm increased and plotted the results .. if you have a graph, where on the graph does the peak power occur (rpm) ??

the rollers measure TORQUE only.. the bhp is a calculation.


The power run was over pretty quick. He stuck it on the rollers mashed the throttle and when he got to 7600 there was the graph. Max torque was at 5680 rpm.At 5250rpm the torque figure is about 136-138 ib/ft, power at fly was 135 Bhp, power at wheels was 105 bhp. Those where rough readings from the graph.


Hi Chun, there is a problem with the calibration on the rollers if the graph is that far out .

at least your peak power was at about the right rpm, but too low.

Ignore ANY figure at the flywheel - it is meaningless.

I would suggest that you go to another rolling road, I can recommend RE at Bury (Lancs).

If your figures are so far down at RE, then you have a problem with the addons .


Just found this on the Seat Ibiza forums

"No worries Mark, Im looking forward to the shoot out.

To be fair to PS (Powerstation) you need to know VWs and their quirks to get the best out of them...

The problem they have is that they cannot control the load on their rollers, its set in the Software they cannot alter it.. This is NOT the case with the RR software we have.
I know the guys at PS and just recently I have been tuning a very powerfull 5 litre TVR Griff on their rollers on DTA Management, guess what the TVR measured a good 40 to 50BHP down on what was guesstimated with said mods..

Their power runs are just too long, the TVR did not like it at all..

Having said that all the guys at PS are very knowledgeable and very professional, they just need to ditch that sh*te RR software they have.. I like thier actual Rolling Road though, I wish ours was the same....


Gonna wait for the cliosport rolling road day to see what you guys get on the rolling road at PS before I go off I spend more money to find out why my cars under powered.


I have been on 4 different rollers with the clio in the same spec (normal airbox, 17" wheels)

At john Noble motorsport in chesterfield
The run was done in 4th gear

The figures where:

Wheel output: 121.5 bhp
max power @ 6560rpm / 108mph
Torque: 145 lb/ft
max torque @ 5390rpm / 88mph

The torque and bhp curve crossed over at 6100ish rpm but the scale of each were slightly different, the bhp axis went to 180 and the torque went to 150, so if you dropped down the bhp curve to the same points, it would probabily have crossed at 5250rpm.

At power Engineering, the run was done in 3rd gear i believe, and the figures were

Wheel output: 114 bhp
max power @ 6776rpm
Torque: 135 lb/ft

So, just goes to show how much variance you can get. I have also been to another in reading (Clifford Cox engineering in reading) and got similar figures to John Noble.

The chesterfield run was in january, very cold and crisp morning, so the air density was probabily good for engines. The PowerEngineering run was considerably warmer and the air was definitly more humid.

Just thought i would post the figures i got.


with RR and power curvs, as wallisj said, variences are high> sot eh only point to them is to compare before and after results,there is no point comparing manufacturer published figures, cause youll never reach it.

they probably did it on a freezing cold day, with 7 crazy fans, tyres @45psi, the best engine and box of the bunch etc.

the factory tell us that the cars we get are only 166bhp anyway, and thats probably higher than your UK spec cars cause we have higher octane fuel than you.....although the car does have a knock sensor so it can figure out near the best ignition timing....but hey do come with different ECU serials.