Cosie Convert

Mmmm Rolling roads correct the bhp for conditions but what happens to the torque figure ? Is the torque curve on the print out at the wheels or flywheel ? and is it subject to the same questionable correction factor or not ?

Richie1

Only the BHP is corrected hence the DIN70020 thingy. Torque is at the wheels AFAIK.

Cosie Convert

It's just that if one is corrected and the other is not then the curves will not cross at 5250 rpm. I think

Sam Elassar

hi
for the people who have subscribed to this thread please check this one

http://www.scoobynet.co.uk/bbs/threa...ThreadID=72818


HARVEY
i will have a look at that and get back to you. did your graph have the crossover point at 5252? check the other thread as well. i have found that the cross over point varied a lot with the load as well.


sam

teknopete

Sam,

Jus checked all my past plots & the only 1 where the Norm power & torque cross @ that point is the 1 from 12/08/01. Had a quick sift through the last batch of results and cant say i say 1 that crossed at that point Hell my last 1 didn`t cross till appro 6700rpm. If it is indeed the Norn power(cyan) u r talking about? If it`s engine power (purple) then thats closer to 5200rpm

BTW i take it u had a pretty eventfull day then?? (NOT)

L8r m8
Pete

[Edited by teknopete - 2/5/2002 1:54:46 AM]

Sam Elassar

i totally agree with you there Brian. at 1.1bar (standard) with exhaust and filter you should be running around 310-315bhp, and then add 12bhp per 0.1 bar all the way to 1.7 bar that should give you the 385bhp the turbo is rated at @1.7bar. makes sense to me.

running 1.4 bar should give me very similar results to what RC development claim 349bhp. so my car should be roughly around 340bhp maybe slightly more by a couple of BHP not nothing more.

the reason the evo are not very accurate on the rollers my be due to couple of things, bigger wider tyres, active diffs, faster acceleration, shorter gearing, all this will contribute to higher transmission loses. cams allow the car to produce max bhp really high up the rev range, and this will contribute to the high BHP figures when compared to scoobs. my power at the wheels did not drop until 6500rpm !!

the problem is these are the base figures for our cars regardless how wrong they are. so star better not change or otherwise my next mod will gain me -20bhp

sam
ps i forgot to mention that the only why i could think of to get our figures back in line with the rest of the world would be to increase the load off the rollers so it takes a little longer for the revs to climb up. i am not sure if this is done autmatically on star perfromance? i mean have you seen the transmission loses on the skyline 130bhp and above. maybe the software should be adjusted for this, isn't the roller optimised for VWs?

[Edited by Sam Elassar - 2/5/2002 1:24:16 PM]

john banks

I can't see your logic Sam that revving it higher gives you more PAW - the figure is not adjusted like the DIN power from what I observed. The rolling road was plotting the PAW graph real time - when it reached max PAW at x RPM it doesn't know you are going any higher to y RPM and the realtime PAW curve is the same as the one printed. The only reasons I wanted a flywheel power was to compare my car with the much larger available dataset from Star and also to see what power I am getting up to my change up point - it is best to change when the power at wheels in the next gear has become higher than in the current gear - with raised boost at the top end (even on a TD04) this often doesn't occur and therefore it is worth revving higher before changing up. So if you change 3rd to 4th at say 6000rpm because that is peak wheel power, you go down to 4500rpm (ish) after the change. If the power at wheels at 4500rpm is lower than it is at 6000rpm you have changed too early even if you have passed the peak wheel power point. Now to do this better you would have to plot for several gears and see where the curves cross, and then there are transmission errors again. But if you want maximum acceleration you should not change up at peak wheel power or flywheel power, but when the wheel power in the next gear is higher. Is this correct?

I hope I would get better next time by running 1-1.5PSI more at 5500-6000 RPM.

I think the load was switched on or whatever they do at completely the wrong time to simulate the road - how can a peak boost arriving 700RPM later than on the road in the same gear be accurate for a torque measurement? I expected peak torque below 3000rpm - it looks like a big turbo curve as it is and completely unrepresentative from how it drives on the road. I don't think the load is high enough to get the same boost you get on the road.

I am very sceptical about the whole process - there are far too many variables. My car feeling sluggish for several miles afterwards (as well as two points where the torque and power drop a bit high up probably due to knock and retard) suggests it isn't too good for the car either along with the Link car detting which is fine on the road.

I will go back if they sort the intercooler setup out and put the load on from say 1700rpm if that is safe to do, as that is where my turbo spools up not at 2500rpm. The amount of time to accelerate from 1700-6500rpm would also surely be more representative if the load was more road like?

Too many errors for my liking.

[Edited by john banks - 2/5/2002 1:35:46 PM]

john banks

"do you agree that the higher speed achieved will give you more power at the fly wheel?"

Entirely agree. But not about PaW. With increasing drivetrain losses as revs increase peak flywheel power will always be at higher engine speed than peak PaW.

I still want my car revved to 6500rpm as I sometimes go that high driving it for good reason - it is quicker! If you see g-force plots there is a considerable drop when changing up. Therefore whilst I get more g safely higher up I rev it higher. I say safely because if my charge temps go too high then I defeat the object, but I only run 14.5-15 PSI at 6000rpm.

I think it is a fallacy to say that there is no point revving a UK Scooby beyond peak power. The point is that you should change up if the power at the wheels becomes less by revving further than it would be from changing up - so you should go beyond the peak power point to get best performance.

[Edited by john banks - 2/5/2002 1:58:54 PM]

john banks

I expect you are right Sam, but from what you said about your VF23 it sounded a bit laggy on the road? On the track that clearly was not an issue.

The lag of the MY99/00 (and it is better than earlier cars) as standard is quite horrendous IMHO, but I only realise this now after modding. It is very rare that I am caught off boost now, and I would hate to lose that. Of course I want more top end who doesn't?

I have not driven a MY99/00 UK with a big turbo. Maybe I should But it's not like they are common enough to go and go to a dealer for a test drive like a P1 or STi-UK.

I have driven a P1 (Town and County's) and found it was good when over 4000 RPM but not barn stormingly fast like your Evo. I did not think it was quicker than a decatted PPP car OVERALL, and considerably slower if you were tootling along. It was also MORE laggy than your Evo, which to be honest did not really feel very laggy at all and a I could easily live with that - hence you have converted me!

http://dyno.scoobynet.co.uk/uk/99_ppp_vs_sti5_std.htm

This and other dyno plots helped sell me on the idea of a PPP.

I would go Link again because I am able to fiddle a bit more now. I am sure you understand the feeling

Maybe there is something about the Evo engine which makes it better off boost, but Subarus feel horrid off boost.

[Edited by john banks - 2/5/2002 5:27:30 PM]

T-uk

I agree with the cooling issues at Star,to have a top mount fan, however puny and not use it is crazy .

in fact **** it,I'll just start gauging my performance from seat of pants and K/hill,theres just too much bollox and risk in a rolling road.

[Edited by T-uk - 2/5/2002 6:44:21 PM]

Richie1

Ouch, my "poxy" chip and intercooler upgrades pales in comparison to that RS4

Sam, lemme know when your going and I'll see if I can come along a I need to get my car run at some point to see what this chip etc is giving me (I am paying for mine of course Jim ) Wanna do a 0-60 run as well





[Edited by Richie1 - 2/8/2002 12:56:02 PM]