Just got back from PE today doing from doing a dyno, and only got 283 bhp. That figure doesn't particularly bother me especially has there was a modded 22b there that was only pusing 290. The thing thats niggling me is that there was an identical P1 to mine with exactly the same mods (full exhaust and filter) that got 305. The funny thing was this one had only 3/4k on the clock and mine has 12.5k but mine seems to pick up better but drop off at the higher end, where as the other guys P1 was more progressive. Now Im all worried particularly as someone pointed out my turbo was making a funny noise. You can hear it quite loudly spinning down even from a low burst of gas. Could this be causing power to be lost? Can engines vary this much or does anyone think there could be some problems with my ecu settings, engine, turbo, boost or anything?

Cheers

Pete

[This message has been edited by Web Guru (edited 18 August 2001).]

what was his and your power@wheel figure?,the difference there may not be so large.

john

erm I dunno! Is that important? http://bbs.scoobynet.co.uk/biggrin.gif

307 BHP at 7153 and 274 lbs/ft torque. My engine is still very tight but every time I get it to the RR the figs get better. Another 5/6000 miles and it will be just right.
The 22B had lots and lots of torque. this is where the power lies.

Edited to say 3200 miles on the clock.



[This message has been edited by bob (edited 18 August 2001).]

Bob were you using any octane booster?

No, just 97 Ron Shell. I would not worry about it. These figs are for pub talk and taking the piss out of each other. http://bbs.scoobynet.co.uk/smile.gifIts how the car goes on the road that counts and yours felt fine. http://bbs.scoobynet.co.uk/cool.gif I will however take the piss next time. http://bbs.scoobynet.co.uk/wink.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

Edited to say The garage I purchased the fuel from is a large one in Bristol with 4-6 Super Pumps it may have had the new 98Ron fuel Shell are starting to use.

[This message has been edited by bob (edited 18 August 2001).]

the way I understand it,is that power@wheels is a measurement,while flywheel is a calculation from this.things such as gear ratios affect pow,but you are comparing two P1's.just wondered if there was much between the two.

john

Yeah like I sai Im not to worried about the figures! The car is still insanely rapid!!!What is more worrying is the difference between the two. Logic tells mereally mine should have performed better as it is a 'looser' engine. I'm just concerned about a problem, what about that turbo whine bob do you think that could be an indication of a problem?

Edited to say: John (T-uk) Bob was the other P1 and I think my power at the wheel was around 200 or so

Pete


[This message has been edited by Web Guru (edited 18 August 2001).]

john is right

power at the flywheel means nothing. most likely web guru's car is faster it will have to be, really logically speaking. the dyno registers the PaW and then once the clutch is dipped the RR tries to measure the transmission resistance or something. so if you have a newer car, transmission loses will be bigger and hence higher BHP at the flywheel figures. so Bob's car will probably produce less power on the rolling road unfortunately http://bbs.scoobynet.co.uk/frown.gif
on the road what you feel is the power at the wheel and not the flywheel

if your turbo is a bit noisy that could be due to the oil grade you are using.

i hope this helps.

I see thats interesting Sam so really RR's aren't any good at all then but only serve as a kind of comparison to work to when modding etc...

Erm one thing about the turbo though, which I'm still worried about I use Silkolenes finest!!?

Pete

pete
that right for the the mods. however we need to pay more attention to PaW which is the smaller figure http://bbs.scoobynet.co.uk/frown.gif

what grade is your oil.

Sam

All Oil changes have been by Subaru Dealers barring last time where Powerstation put in some silkolene stuff it was expensive an I guess Powerstation and the dealers know what they're doing, sorry don't know what grade!

Bob do you know what your power at the wheel was??

Pete

ps Whats wrong with my turbo http://bbs.scoobynet.co.uk/frown.gif

I don’t want to start on which is right PAW or PAF But the Operator of the RR (Mervyn) not long back wrote an article on why we should not go by PAW. From what he was saying is a car on the RR will give different PAW figuars every time but the PAF will be constant. Mervyn did say he believed your turbo was on its way out. Mervyn see more Scoobs than the average mechanic so I would intend to believe what he says.
I no longer take any notice of PAW sorry.

Here is his post.:

My first post and not sure if i should do this or not!
i give it ago anyway...
I've been rolling road tuning for 9 years now and tuning cars for over 11 years at Power Eng...
4WD rolling road power figures are affected by lots of different things which i will attempt to explain.
At the end of a Power Test the figure " IS WHAT IT IS " ...
Some people pull faces and can look suicidal if their car has lost 3 BHP and we haven't even seen the car for 2 years yet the graph's can be almost identical! (this sort of result im always pleased with because 3 BHP is nothing and to get two almost identical graph's after two years proves the consistency of the set-up).
I think we have at the mo over 500 Impreza Turbo files now most of which i tested myself.
this give's me a big advantage through experience on testing these cars.
This means i can generally guess what a wheel figure should/will be and roughly what a flywheel we will see.
typical figures i would expect are;
MY01 New WRX UK 135-140 at the wheels 215-220 at the flywheel 215-220 lbs/ft torque
MY99 UK STD CAR 140-145 at the wheels 225-230 at the flywheel 218-228 lbs/ft torque
STI4 TYPE-R 200 at the wheels 280 at the flywheel 250-260 lbs/ft torque
22B 200-210 at the wheels 280-290 at the flywheel 275-280 lbs/ft torque
these are typical from what i can remember but vary Winter/Summer
We have the ability for barometric pressure adjustment but this just seems to adjust/trick the real figure ON THAT DAY IN THAT SITUATION
If a car slips on the rollers we can usual tell because we get very high or low wheel figures or strange(to the trained eye) shape power curves
Transmission losses are measured on the overrun (decel) and vary depending on many variable factors,
4 wheel alignment (tyre scrub against the rollers)
Tyre pressures (increased surface area)
Rolling radius (big wheels or chunky tyres)
Wheel bearings, binding brakes, worn diffs, tight gearboxs)
and as we all know ambient temperature...
let alone if a car make's 1 psi more boost on one run i can increase power and torque!
1 psi around 7/8 BHP and 10-12 lbs/ft torque
so we try for consistency cruise the car to stablise temps and remove dirt from the tyres
carry out a couple of power runs and record the 3rd. It work very well and our system proves this.
Sti 4 280bhp ish. the engine produces this at the flywheel on a dyno.
If we start the car from overnight and warm the engine up the first power test will have a lower wheel figure but same flywheel figure.
After 10 runs the wheel figure will climb but engine power is still the same (due to thick cold transmission oils), after 30 hard runs (ie development work, testing new products) wheel figures can look abnormally high but flywheels fairly consistent.
We know if the system has a problem (though this is quite rare) because standard cars come up with silly figures.
Two other points im sure the dyno measures torque, not power, but torque and power are mathimatically related so simple calculation.
Power and torque graphs always cross at 5250rpm unless different X and Y axis are used.
The dyno is calibrated using a metre long bar with a (cant remember this bit) weight on the end which puts a "calibrated" load on the strain gauge which equates to X BHP on the display.
We did a major overhaul on the 2wd rollers last year and when checking calibration it was only 2 BHP out.. not bad after 9 years and god knows how many million miles.
I dont know everything about rolling roads, far from it but i know a fair amount and i hope this helps a few people understand a bit more
PS
LOVED READING THE NO3 BIGEND THREAD.
WISH I COULD SAY WE KNOW EXACTLY WHAT CAUSES IT BUT LIKE YOU WE JUST HAVE LOTS OF THEORIES AND DO EVERYTHING FOR ENGINE SAFETY NOW...
Mervyn (oh dear what have i done)

So has anyone else had this turbo whine and does it effect power??

Shark did you see that! My turbo is on the way out, well its making a funny noise. You know Im going to be calling you http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

Oh and I haven't forgot about them disc http://bbs.scoobynet.co.uk/biggrin.gif

Pete

surely what mervyn is correct, but what he is saying does not make sense.

i have had couple of private sessions on a rolling road and power at the wheel figures always remained very consistant while power at the fly wheel kept changing by 10bhp at the time http://bbs.scoobynet.co.uk/confused.gif

the other thing is on the road all you feel is the power at the wheel and not the flywheel. on the RR you put the car on the rollers, foot down, rollers measures power at the wheel. so if a car A has more power at the wheel but less fly wheel power than car B, car A is faster. isn't that what are we trying to measure at the end of the day.

pete
some VF turbos are noisy, mine is very noisy some times especially after oil changes http://bbs.scoobynet.co.uk/biggrin.gif. get it checked anyway though.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Web Guru:
<B>Just got back from PE today doing from doing a dyno, and only got 283 bhp. That figure doesn't particularly bother me especially has there was a modded 22b there that was only pusing 290. The thing thats niggling me is that there was an identical P1 to mine with exactly the same mods (full exhaust and filter) that got 305. The funny thing was this one had only 3/4k on the clock and mine has 12.5k but mine seems to pick up better but drop off at the higher end, where as the other guys P1 was more progressive. Now Im all worried particularly as someone pointed out my turbo was making a funny noise. You can hear it quite loudly spinning down even from a low burst of gas. Could this be causing power to be lost? Can engines vary this much or does anyone think there could be some problems with my ecu settings, engine, turbo, boost or anything?

Cheers

Pete

[This message has been edited by Web Guru (edited 18 August 2001).][/quote]

Sorry M8 I think your plate might have something to do with it....looks like your peak had CUM to early...LOL.;-)

Take care

Moe

There are so many variables, and trying to get "specific" comparisons, is very hard.

For a start, it was very warm, and humid today. Intake temps were going sky high. Bob R's hit 86 deg'c !!!! Intake temps this high would have a dramatic effect on results, and the conditions would effect everybody, less so the guys with water injection.

RR days should be used to identify problems, get some idea how your mods are going, having a giggle, but mainly, ideal for winding up your mates http://bbs.scoobynet.co.uk/biggrin.gif

Mark.

I was just wondering what was wrong with my turbo and could it effect my power http://bbs.scoobynet.co.uk/biggrin.gif

Sam/ According to most it is all down to gearing have a look at what Bob Rawle wrote about this.

[Bob Rawle Wrote]

Interesting, the thing to remember is that PAW is totally dependant on gearing. Simple math as Adam says, so a UK car will give different figures than an STi saloon 4 door which will be different to an STi Wagaon which will be different to the STi Type R and RA's or 22b's. Imagine this, same engine put in all the different cars, the PAW would be different for each due to the gearing.
So, in actual fact tha flywheel power is the constant, only real way for that is bench dyno, Scoob transmission loss is pretty variable car to car and certainly type for type, the different set up of the variable centre diff, for example, means that the transmission seems to have lower losses.
PE always use 4th and Merv has evolved the technique to provide as consistant a result as possible, the Rolling Road itsef and its software will always affect the result but the operator makes the biggest difference.
[/Bob End]

I concede that Pete and I have the same type of car and the gearing is the same but since having the PAW debate some time ago, I have never bothered with PAW as I see that different geared cars will get different readings.
Mervyn said he had a sti with the same turbo whine sometime back the whine got louder and louder untill finally the turbo stopped. Just keep driving it untill it stops or just stays as it is.


[This message has been edited by bob (edited 19 August 2001).]

So what was your PAW figure then bob just as a matter of interest as we do have the gearing!

Don't know they don't print that on the sheet.

hi bob
very interesting i never saw that thread. i have also noticed that cars with shorter gearing gave more power at the wheels on the rollers.

i think it is very difficult to get accurate figures of actual power on the rollers but it is very good to use the roller to check mods ( which what i use it for) and also it is good as part of a RR day to compare your car against others.

cheers

sam

Hi
I did not look at the PAW fig and it is not printed on the sheet. But it is held in PE computer system as they do put it on the dyno site. PE will most probely be able to get this for you or you could wait for it to come on the dyno site could be some time though.

Sam/ worth a quick read.

so if you don't know your power at the wheel do you know your transmission loses ?

At PE we just get a sheet with BHP and Torque graphs.

Mark/
It was humid my inlet temps hit 80 between runs, cools to 40 very quickly before Mervyn runs it again.
Topcat/
Magic mate I had a little giggle myself http://bbs.scoobynet.co.uk/wink.gif
WebGuru/Pete/
It is best for you to say your car gave the right figs and mine was just a P1 in a class of its own. http://bbs.scoobynet.co.uk/wink.gif

These threads always turn into a my car is better than yours, what do you say Bob http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

Mo I think that is the worst pun ever especially as I've heard so many times now! http://bbs.scoobynet.co.uk/rolleyes.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif

I was at the Banzai Scooby thrash today and only managed to get 5.1 in the 0-60 which was a bit disappointing especially as I managed a near perfect launch but this was understandable!

I have had a few experts listening to my car today, and all of them say the turbo is fOcked. The whining actually seems to be getting worse and am often blowing out bellows of smoke when starting her up. Well to cut a long story short I came back via my local dealer and he has agreed and has put in the warranty claim. See you next time Bob, with my nice new turbo and loose engine http://bbs.scoobynet.co.uk/wink.gif

hehe

Pete

ps I knew something was wrong http://bbs.scoobynet.co.uk/frown.gif

Pete,

That was the last time m8!!! promise!

Yep your Turbo is fecked up big time!!!

Rather under warranty heh so at least you know what it is, see you again m8 when you come back with a Vengence!!!

Moe

As I said If Mervyn of PE says your turbo's on its way out. I would believe him.
Good luck with the claim. I will see you next time by then I will have 4000 miles on the clock be warned. http://bbs.scoobynet.co.uk/wink.gif http://bbs.scoobynet.co.uk/biggrin.gif http://bbs.scoobynet.co.uk/biggrin.gif