Hi Guys,
Just wanting your opinions really. Went to Surreyrollingroad.co.uk for a rolling road day yesterday and I'm not sure whether to be happy or sad about my results. They aren't exactly bad, but I was hoping for at least over 300. The guy running the car also said he expected to get more than 300 but said the car was running spot on. I know all rolling roads are different etc but I thought I would get at least 300 on any rolling road. Anyhow here are the graphs, first at the flywheel, then the wheels:





Torque was 285 lb/tf.

Would I be right to say that the car might be more powerful on the road due to them not being able to recreate road conditions on the rollers?
The car was mapped by Simon Roe on the road and has the following spec.

1994 WRX, power fc, standard 380cc injectors running almost max idc, sti 5 top mount, full decat hks superdrager, hks evc boost controller set at 1.25 bar but is reaching just over 1.3, sard FPR set at 3 bar, walboro fuel pump, apexi induction kit. Think thats about it.

You'll have to ignore the slight dip apparently as something happened with the boost, however on another run I didn't have this problem.
The car drives great and is a hell of a lot quicker than before but I just can't believe after all those mods that I'm only running standard import Sti power.
So, do you think the readings are low? and is it possible that on the road its probably making more power? thats all I was wondering really.

Thanks
Steve

 

What boost did it make on the rollers?

 

Just over 1.3

 

Not sure whether the legacy engine might be causing an issue. . not sure what the cams are like in the legacy motor.. I think iirc it was still a TD05 on it though...

Simon

 

2 years ago my 96my uk turbo - with full scooby clinic decat and exhaust with turbo up pipe with remap ran 270hp on scooby clinic same RR set up.
minestarted with 209 hp at start.

could get no more out of it. i think your power is probably right.

 

Iirc the last time my car was on the rollers the guys operating it at The Clinic said if I had a TD04 then i would be looking at around 270 BHP @ Fly with simular mods to yourself and if I had the TD05 I would be looking at around 300 BHP @ Fly. HTH

It made 305 (must have been a TD05 )

MY 93

 

forgot to add mine also had a TDO5 and ran 17 .5 psi - scooby clinic said UK cars run about 270 - jap imports similar year non sti - could get up to 300 - due to the slightlier wilder cam profiles.

i'm sure it feels plenty quick with the extra 61 hp

 

Problem is you have no 'before' figure so you're not comparing like with like. You're comparing your 279.1 bhp with what you think the book figures are, which may not have been what yours was making in the first place before the mods. Plus you don't have anything like the proper intercooler scoop flow on the rollers, which will hurt power.

Put it this way, before you had this power run, did it feel like the mods had made a big difference? That's all that's important really.

 

Steve,

thinking out loud here.. when I mapped it the leaking injector Oring I resolved would have been coking up that cylinder as I tghink it had been leaking for a while.. the coke would have restricted the amount of timing I could put into it. Perhaps now it has been run for a while it will take more timing.. ie. with bore oil properly and any coke that is going to be burnt, burnt.

Also was there a boost graph taken.. wonder if the boost tailed off rather than holding.. iirc it held on the road though.

If you want me to take a look I am happy to do so..

Thanks
Simon

 

ive got a my 93 wrx & it made 306bhp with 303lb of torque at 1.1bar with the mods listed below! thought urs would have doe around about the same! full ss system,walbro pump,apex ind,horsham developments remap!

 

Shouldn't the torque and power curves crossed at 5252rpm.

Calculation for BHP = Torque lbft * rpm/5252

It looks like it's tried hence the dip in the torque curve, but the power has just droped instead of climbed higher then the torque. If this hadn't happened you would of seen the level of power you expected.

Should look something like this.....

 

Following on from the calcualtion I gave above.
If you apply it to my RR plot it works.
But if you apply it to yours it don't, above the torque dip.

Nice article here : http://www.itv-motoring.com/features/technical/636.asp

Which kinda makes it look like something went wrong with your RR run. Unless some other techie can come along and explain why it doesn't caclulate correctley.

 

****

Ignore all the info I gave above....just looked at your graph and they do indeed crosss at 5252rpm. What looked like a large dip in the torque curve is in fact the crossing point of Torque Vs BHP. I wasn't expecting to see the torque drop off that quick.

(it's been a long day getting my Boy baptised, and have the family round).....

It's probably as Simon said, and running a little too rich at the top or a little safe on the timing.
I don't suppose they gave you a AFR and boost plot aswell ????

 

will post up the boost graph in about 30 mins.

 

Here is the graph showing boost. Not sure why it dipped at one point but this only happened during the run he printed for me.



I also have previous graphs from Power Engineering and Engine advantages showing the car making 260bhp @ 1 bar on a Z4 ecu. The guy at Surrey rolling road reckons that my 280 there would easily have been over 300 at PE and engine advantages. Guess he's not too keen on their calculations?.

The car is bloody quick and I am well happy with it, but it just seems like I should have got more power.
Simon, thanks for the offer but i've promised myself I'm not spending any more money on the car. This was my last ditch attempt to break 300 before buying a flat and having no money for the rest of my life.
By the way, my friends evo made 358bhp @ the fly, 360 lb/ft. It was 280bhp at the wheels. He was losing boost at the top end. The technician recommended he upgrade the standard intercooler. Also his map is not perfect yet. 60bhp more than me at the wheels but he doesn't beat me by a huge amount.

Steve

 

I wasn't intending charging you for looking at it Steve.. just thought it would be worth checking it.

Sounds like the load was different from the road with it struggling to make the boost mimic the road.. with lots of dips etc..

Simon

 

Say no more - don't get too hung up on the RR figures, they're for pub talk.

 

I would say the power IMHO is not bad from 380cc injectors and the mods. Don't forget book figures are when the car was new. The car is now 12 years old. 300/310 bhp from what I have seen tops out 440cc injectors, so all things considered for a real BHP figure and not a pub talk figure I would be pleased with that result.

But that said if you want to run on the limit more, I am sure Simon could probably squeeze some more by running leaner at the top and less safe timing. It all depends on the driving style, and how you use the car. If you punish the car most of the time then I would say stop where you are. If you can afford the potential prospect of a new engine at some time in the future then go for it.

 

Well I'm certianly not wanting to replace the engine, so I'm happy to leave things as they are. As you say, the results are not exactly bad. As long as the car is safe then I'm happy.

Cheers for all the help guys.
Steve

 

I would say if JollieGreenMonster was willing to have a look at the settings FOC, let him, especially if he has been conservative due to a potential problem, it would make sense IMHO. give it a go what you got to loose.

 

Ok Simon, I'm tempted by your offer. If my brother decides to use you to map his skyline then maybe you can take a look at mine the same day.

Thanks
Steve

 

No problem Steve.. probably best you drop me an email to discuss when etc..

Thanks
Simon