B16 POK

Got up early this morning to visit the boys at G-Force Aylesbury.

I have plans to upgrade my car to about 350 bhp so I thought I would document the changes.

I booked a rolling road test to find out an exact figure at the moment and then go on to gauge the changes after the modifications.

After 30 mins on the rolling road the average was 279 bhp and the torque was 300+.

279bhp? What’s that about, the car standard is 265bhp and £2000.00 later only an increase of 14 bhp. The Torque sounds about right.

So is there a problem or is the 300+ bhp Prodrive upgrade a myth.

Anyone else had a dyno or knows of any problems.

Simon

scoobynutta555

+32 bhp is it not, where does 14 come from? 3 bhp out from 300, seems reasonable to me, its not a precise science, and many factors can affect it at any time.

RLE

iTrader: (2)

Seems strange Simon.

At Well Lane last week I know of one STI with PPP that produced 325bhp. To see he was surprised himself is an understatement.

B16 POK

Sorry I am Still tired, 6 am start its 279 BHP Sorry guys.

will edit above.

alwong

Depending where you take it, the figures change somewhat.

scoobynutta555

davyboy

Take it some where else and get over 300, and then you will be happy!

Although it will still drive the same

STIste

From Well Lane:
MY02 STi (PPP) 325bhp 293lbsft
MY04 STi (PPP) 312bhp 285lbsft

So you're well down on BHP but well up on torque...............All a complete load of B***ocks of course unless you run the cars on the same day at the same place & if the conditions don't change.

STi PPP's made their normal figures at Well Lane 10 IIRC so make of that what you will

B16 POK

Thanks for your feedback i was a bit depressed but wisdom is always a great healer.

IanW

Simon,

I have changed the title for you.

Ian

LG John

This is why rolling roads are a waste of time IMHO. Judge it through your **** and how much you can now leave your mates car for dead

hades

Do you know it was giving 265bhp at G-force before the PPP? If not, then you don't know you've only got +14bhp!

I'm sure I have seen at least one STi PPP that gave mid-high 290s at G-force (one of which gave 10bhp less the following week at Power Engineering), but much less than that of torque. Your bhp is possible a bit below average, your torque above. Go to another roller on another day, you'll probably get a different answer. Go to somewhere like Power Station, you might find the answer more depressing as they tend to be less optimistic rollers (which is also what makes the T25 power/torque all the more impressive)

fromage

I have seen a STi PPP run 280Bhp ish and then a STi non PPP with just a Decat get 310Bhp ish both run on the same day with about 30 mins between them.

16vmarc

I wouldnt believe a rolling road personally anyway. My MY00 PPP (with green filter lol) Should be making 250bhp on 98ron, i added a bit of ob as you do! and the figure produced was 279bhp @ 6250rpm and 242lb/ft - So thats a 29bhp increase with air filter and octane booster!

I think not!

Pinch and salt i feel!!!

B16 POK

many thanks for all the feedback.


My local Subaru Dealer has offered to have a look next week. So it will be interesting if they find anything.

But by reading your comments probably not.

Back to G Force for the APS upgrades i feel.

Let you know how i get on.

Talk Soon

Simon

TonyBurns

iTrader: (3)

How many miles has the car got on it?
You will be quite amazed how much better they get with 5k plus on them

Tony

Jeff Wiltshire

What wheel HP did you get and what where the losses....?

scoobyboy

remember if the intake temp goes above 40c it knocks back the power to save the engine what were your intake temps?

Aztec Performance Ltd

iTrader: (234)

Post your printouts up and I'm sure some of the experts will be able to tell you more.

What was your highest recorded BHP (not average)?

From reading elsewhere I thought that the figure used should be the highest recorded on a Top Mount car?

Bob

Gutmann pug

How many miles has your car done??

Pavlo

"after 30 minutes"

Hmm, alarm bells. Spending half an hour on the rollers heating up nicely is not a route for power. Furthermore comparing figures with anything other than those acheived on another Dyno dynamics rolling road is pointless. Well lane not especially consistent and tends to give optimistic figures.

Paul

R1916v

I'm guessing these are atq figures, or are they compensated crank figures?

Surely if a car is described as having 265bhp standard at the wheels power, esp on a 4wd, is going to be quite a bit less?

So say crank 265 = I dunno, 220-230 ATW, and you've now got 279 atw that's not a bad increase.

Altough I could be totally wrong so please ignore

16vmarc

No, his 279bhp will be at the fly.

Jeff Wiltshire

I would presume that they are both Crank figures not wheel figures....280 wheel HP is around 370-380 BHP at the crank for a 4WD car.

B16 POK

Thanks again for the response.


Car has done 3050 miles. The PPP was fitted at 1000 miles.

The bhp was up and down on each run but 279 bhp was the highest on two occasions.



I will Scan the read out at work tomorrow and post it.

Thx Simon

Bartop

I would say at 3000 miles the engine is still very tight - should get better with a few more miles

ex-webby

Simon,

As already mentioned.....

Intake temps will play a big part to in this. Not sure what the targets are within the PPP, but after a certain temperature ignition and boost will be reduced.

To be sure, it would need adequate cooling on a single run.

Also RR's with 4WD cars must be setup (wheelbase) correctly. The speed at both rollers must read the same as this is crucial for an accurate reading.

The fact that your car is low on mileage would also be a factor.

I wont even mention about the rollers themselves, tyre pressures, wheel sizes and the issues caused by not clutching in smoothly and correctly, concerning the effects on readings.

At the end of the day RR fugures dont mean squat really. Back to back road testing (acceleration runs in all gears and speeds) is a better way of comparison (with other cars).

Regards,
Shaun.

Lagamorph

iTrader: (12)

found this simon hope it helps:

Subaru
Technical Service Bulletin

Subject: PPP Tests
Model: Sti

We are becoming increasingly aware that owners of the above vehicles and others equipped with a PPP are taking their vehicles for a rolling road test and being advised of varying results on power output.

A rolling road test is very difficult to rely on to give an absolute figure of the output an engine is producing particularly when it is only possible to measure at the road wheels instead of the flywheel. There are also too many variables in how the test is undertaken including how much air is being blown at the car, which is rarely sufficient and the temperature at the intake/intercooler.

As a precaution against engine damage, the PPP is designed to reduce boost if the intake temperature becomes too high and this occurs as soon as 40 degrees is achieved. This can occur for example whilst a vehicle is parked for no more than a few minutes, even when the ambient temperature is low. For example, in a 4 degree ambient the intake temperature can rise to 51 degrees after 11 minutes with engine merely idling. This could easily happen prior to a vehicle being rolling road tested unless it was being monitored properly to ensure everything had re-stabilised, otherwise the engine power data obtained is unrepresentative.

When our supplier undertakes tests on rollers the figures quoted for a Sti (302bhp/305ps) are consistently obtained but this is only after making absolutely certain everything is as it should be before commencing. If the intake temperature is too high, a Sti will typically provide indications of only 285bhp/290ps very easily. An owner is then of the impression that his vehicle is under performing!

If you receive a complaint of this nature, the owner should be in a position to provide a rolling road test data log. Should it be apparent that the test was carried out with intake temperatures at or above 40 degrees an owner should be advised why the test results show a lower output than anticipated.


see you at work monday

Andy

highlander68k

Out of interest, how long had the car been on the road when the figures were obtained?

Just wondering if heat soak had caused the figures to be inaccurate.

As bob says, It would be good to see the printout.

B16 POK

My son and i drove 100 miles to get to the RR. It then sat in the workshop for 20 mins before the car was re started for the test.

Cheers Andy for the information, sounds like that is my problem.

See you at work Tomorrow.

Thanks again to everyone that contributed to this thread.

I will still post the graph for anyone who interested.

Simon