Rolling Road

[scottish_lion 0]

Hello, should be an easy one this, and appologies if it's been covered.

 

I have a 1.9 GTi with a standard engine fitted with a K&N cone filter. It has a standard exhaust.

 

I believe as standard this should have 128bhp, which I assume is at the flywheel.

 

I'm about to put it on a rolling road - which in my limited understanding measures power at the wheels only? - and I'd like to know what to expect.

 

What would a standard new 1.9 have made at the wheels?

 

I think my engine is in good health so I'm basically looking for a figure to aim for.

 

Hope you can help

[EdCherry 34 1 Cars]

My understanding is that it measures at the wheels only, but can estimate Flywheel power.

 

With a 20 year old 205, things wear. Id aim low and be happy if you achieve more! Its not all about figures, its about how it drives.

 

Guestimation of 95.

[welshpug 1,657]

100 - 110 at the wheels would be good for a healthy one, do bear in mind that these injection/ignition systems take some time to get setup 100%

 

saying that though, I wouldn't get hung up about figures, what's more important is that its running right, a good operator will tell you what they think its doing and what needs adjusting, if anything.

 

can they check your AFR? its a very good way to keep an eye on things.

 

here's a graph from a healthy engine (admittedly running a different management system)

 

note that the rolling road used has 2 rollers per wheel, hence the rather high looking drag figures, halve this and you get a far more feasible figure

 

Edited February 11, 2009 by welshpug

[CosKev 16]

Had mine on rollers at Skip Brown last week,did 120 bhp at wheels

 

Thats a fully rebuilt fresh engine thats just done 2000 miles with K&N,Magnex manifold and system.

 

Paul at Skips said he would expect 112 bhp at wheels for a fresh engine running standard intake and manifold.

[large 33]

Have a look on the pumaracing site as Dave has a section on how to set the car up for a RR sesion.

[lemmingzappa 75 1 Cars]

Have a look on the pumaracing site as Dave has a section on how to set the car up for a RR sesion.

 

I was just reading through that site and would you agree with this statement.....if it's true then why do people bother with Magnex etc..

 

Peugeot got the exhaust system bang on - it flows well, has good tuned lengths and an excellent manifold design - whatever you do, don't waste money on an aftermarket system - you won't get more power - you'll probably get a fair bit less.

 

[DrSarty 90 1 Cars]

I really wouldn't pin too much credibility on RR results. They vary so much. Your AMAZING Skip Brown 'result' may not be repeatable anywhere else, so why would you? What if you went to Emerald and Dave Walker told you your AFR was all over the place? I know which 'result' would be more beneficial to the longevity of my engine.

 

What I agree is important is: Does it drive well? Does it behave and tick over well warm or cold? Does it eat oil and/or fuel?

 

If you can answer positively to all of the above I'd be happy. Who cares what some person's RR says?

Edited February 11, 2009 by DrSarty

[Baz 421]

Those that know, don't.

Edited February 11, 2009 by Baz

[scottish_lion 0]

Thanks for the speedy responses.

 

The car does feel very good and revs keenly and smoothly.

 

Sometimes it doesn't seem to set the right idle for itself, like will stay at 1600 revs even when warm, but it's very good on fuel so I think it must be close to how it should be.

 

I'm looking forward to getting it on just to see really, never done it before so should be fun.

 

I'll try and get a copy of the graph on here once it's been on (28th Feb)

[DrSarty 90 1 Cars]

We look fwd to seeing it.

 

Go in expecting low, then you won't be disappointed if it is.

 

Strange idle is quite common on GTIs, but it can be rectified. Plenty of threads about it on here, and loads of knowledgable people.

[nimmo 0]

had my standard 205 1.9 gti on the rr at ecosse on the 1st nov: (with no mods)

119.5 bhp @ flywheel

117 torque @ flywheel

86 bhp @ wheels

 

the guy said it had a fuelling problem apart from that it ran good.

[dcc 855]

We look fwd to seeing it.

 

 

FML SARTY

 

less text speak dont understand a word said there

[WildCards 0]

had my standard 205 1.9 gti on the rr at ecosse on the 1st nov: (with no mods)

119.5 bhp @ flywheel

117 torque @ flywheel

86 bhp @ wheels

 

the guy said it had a fuelling problem apart from that it ran good.

 

How did they calculate the flywheel figure nimmo? What was the rolling road (brand)?

[CosKev 16]

I really wouldn't pin too much credibility on RR results. They vary so much. Your AMAZING Skip Brown 'result' may not be repeatable anywhere else, so why would you? What if you went to Emerald and Dave Walker told you your AFR was all over the place? I know which 'result' would be more beneficial to the longevity of my engine.

 

What I agree is important is: Does it drive well? Does it behave and tick over well warm or cold? Does it eat oil and/or fuel?

 

If you can answer positively to all of the above I'd be happy. Who cares what some person's RR says?

 

Who said it was AMAZING????????

 

Who said anything about caring what power figure was obtained????? How else should a car be set-up/tuned in your opinion oh wise one if rolling roads are so crap??????

[large 33]

How did they calculate the flywheel figure nimmo? What was the rolling road (brand)?

They measure the actual figure at the wheels and by letting it run down calculate the mechanical drag. Then work out your bhp at the flywheel.

[WildCards 0]

They measure the actual figure at the wheels and by letting it run down calculate the mechanical drag. Then work out your bhp at the flywheel.

 

 

Cheers Large, but how do they 'work it out', what is the equation used? and what brand e.g. Dyno Dynamics, Sun etc was/is the Dyno?

 

My experience of RR's are that they're all different. Different operators will tell you different things alot of the time depending on what you want to hear, they'll adjust setting during the run to alter the outcome and some machines, even with the best, most honest operator in the world are just a whole load of inaccurate pap. That said, I do rate the Dyno Dynamics kit and have seen very accurate ATW readings from them.

Edited February 12, 2009 by WildCards

[nimmo 0]

wildcard don't know the brand i'm affraid don't really know that much about rr's to tell you the truth i just like to know my cars run good and pretty quick, i'll talk to the guy at ecosse and hopefully be a bit more wiser and explain on here what type of brand there rr is, or scottish lion can don't want to be hi jacking his thread.

[DrSarty 90 1 Cars]

Who said it was AMAZING???????

 

Who said anything about caring what power figure was obtained????? How else should a car be set-up/tuned in your opinion oh wise one if rolling roads are so crap??????

 

Scottish_Lion>

 

Sorry. I made a mistake earlier when I said 'your' Skip Brown result...that was CosKev's and not yours. I wish you a pleasant day and a good result at the RR.

 

CosKev>

 

Why have you got so narked by what I said?

 

I think many would agree, based on typical drivetrain losses, that 120BHP at the wheels for what appears to be a fairly standard, albeit healthy 8v 1.9 GTI is a fairly ambitious, nay 'amazing' figure.

 

Others have said that RR figures could be considered pap.

 

I never said RR were useless or going to them was a waste of time. Hell: where else did I get mine done? I only believe that the result can perhaps be taken with a pinch of salt on pure power (only) runs. They are OK for mapping, certainly if the engine is destined for track use. But I'm sure it's commonly accepted that the best place to map a road car is on the road.

 

Would you not agree that perhaps if you took your car to another rolling road, the 'result' good equally be 140BHP at the wheels just as it could be 86BHP, which as mentioned earlier - taking into account drivetrain losses is a far more realistic figure?

 

It's a fair question. No need to rant. We're all on the same team.

[large 33]

Cheers Large, but how do they 'work it out', what is the equation used? and what brand e.g. Dyno Dynamics, Sun etc was/is the Dyno?

 

My experience of RR's are that they're all different. Different operators will tell you different things alot of the time depending on what you want to hear, they'll adjust setting during the run to alter the outcome and some machines, even with the best, most honest operator in the world are just a whole load of inaccurate pap. That said, I do rate the Dyno Dynamics kit and have seen very accurate ATW readings from them.

 

What you say is spot on . There are so many things that the operator can adjust the flywheel reading is a bag of s*ite. Just look at the ATW reading and try and stick to the same place.

A mate of mine goes to a guy who is very good but his RR always gives a low reading. The car is always better after a sesion and that is what you should be looking for.

[CosKev 16]

Scottish_Lion>

 

Sorry. I made a mistake earlier when I said 'your' Skip Brown result...that was CosKev's and not yours. I wish you a pleasant day and a good result at the RR.

 

CosKev>

 

Why have you got so narked by what I said?

 

I think many would agree, based on typical drivetrain losses, that 120BHP at the wheels for what appears to be a fairly standard, albeit healthy 8v 1.9 GTI is a fairly ambitious, nay 'amazing' figure.

 

Others have said that RR figures could be considered pap.

 

I never said RR were useless or going to them was a waste of time. Hell: where else did I get mine done? I only believe that the result can perhaps be taken with a pinch of salt on pure power (only) runs. They are OK for mapping, certainly if the engine is destined for track use. But I'm sure it's commonly accepted that the best place to map a road car is on the road.

 

Would you not agree that perhaps if you took your car to another rolling road, the 'result' good equally be 140BHP at the wheels just as it could be 86BHP, which as mentioned earlier - taking into account drivetrain losses is a far more realistic figure?

 

It's a fair question. No need to rant. We're all on the same team.

 

On the road mapping is best,if your ECU is mappable that is,pretty sure the ancient standard pug ECU is not????

 

Those drivetrain losses mentioned above seem to high IMO,over 30bhp on a 2wd car,sounds more like the losses of a 4x4

 

As is well known all rolling roads differ,even the same make rollers all depend on the operator.

 

All I'm interested in is that my car runs spot on,fueling was good right threw the rev/load range on the rollers,and as a bonus Paul at Skips said it was 8 bhp more than he would normally see.

 

At the end of the day I took my car there cause he has over 30 years experience tuning/setting up Talbots/Pugs,all good feedback off people that go there,so I'm happy taking his AMAZING figure of 120bhp at the wheels thank you

 

I thought the car was driving well before I took it there,but can't believe how much smoother/nicer it is after the set up