Rolling Road North Lancashire?

[sparkythecat]

Crikey, I've opened a real can of worms with this thread.

I have no experience of rolling roads but my understanding was (and I'm more than willing to be corrected) that you put your car on one so that the engine performance could be dynamically tested under load using diagnostic equipment in controlled conditions.

A graph of the engines performance is then compared with performance data for an identical 'ideal' engine

Adjustments and/or modifications can then be made and any improvement accurately measured, because the same engine test procedure can be accurately repeated.
The results should be more scientific than any subjective view from comparitive road tests.

I certainly don't want someone to repeatedly rev the bollox out of my engine on the rev limiter in an attempt to count every last pony in there.

[MarkK]

I'd certainly like to see someone listening for knock using a stethoscope while burning rubber round brands hatch! Part of tuning is surely to know the tools you have available and use them to their strengths. I'd say as long as you use the same rolling round for relative comparisons (i.e. post and pre-tuning) and ensure your car is in a comparable condition each time then a rolling road is the way to go. Who cares about absolute figures - you put it on the RR, measure it's output, spend a few hours tuning it and see the gain at the end of the day. Most of the cars I've seen being tuned have had sensible inlet temps and no harm has come to any of them.

[shadowfax]

sparkythecat said:

I certainly don't want someone to repeatedly rev the bollox out of my engine on the rev limiter in an attempt to count every last pony in there.

[oe_cosgrove]

www.pistonheads.com/gassing/topic.asp?t=262036&f=69&h=0

[ringram]

I wouldnt worry about power runs so much as dialing in timing and fuel for max torque at various load points on a dyno.
If you want a power figure cool, go and do a 1/4 mile run.

[trackcar]

shadowfax said:

sparkythecat said: I certainly don't want someone to repeatedly rev the bollox out of my engine on the rev limiter in an attempt to count every last pony in there.

why not? is there something wrong with your engine? I think you need to ask how rolling roads operate .. usually you don't venture near the rev limiter unless it's set particularly close to the point max power occurs .. but also you can specify a max revs you want the operator to go to if you like.

[shadowfax]

trackcar said:

shadowfax said: sparkythecat said: I certainly don't want someone to repeatedly rev the bollox out of my engine on the rev limiter in an attempt to count every last pony in there. why not? is there something wrong with your engine? I think you need to ask how rolling roads operate .. usually you don't venture near the rev limiter unless it's set particularly close to the point max power occurs .. but also you can specify a max revs you want the operator to go to if you like.

Trackcar... it was the first time I'd been to a rolling road, so no , I never knew how RRs operated. And there was nothing wrong with my engine. I only wanted to know it's output at the figures indicated in the book ie 4000 & 5250 respectively. I chose what I thought was a reputable company, which, with Tunit being highlighted in an article last year in Sprint mag, suggested they were. I only got assertive after hearing a noise from the garage, which turned out to have been the first run, and being told they go into the red line as a standard approach. After watching the second run, I told him not to do a third after all the smoke from the rear wheel.

I've not planned to do track days. I cant afford engine rebuilds, so the first will be some time away I hope. I dont want to hasten it by ragging the arse off it unnecessarily.

[sparkythecat]

On a lot of the dyno graphs I've seen posted, bhp and torque curves rise, peak and then begin to fall.

Can't really see the need to keep increasing engine revs once the figures start to dip.

A normally aspirated engine isn't likely to get its 'second wind', is it?

>> Edited by sparkythecat on Monday 24th April 21:17

[MarkK]

sparkythecat said:

On a lot of the dyno graphs I've seen posted, bhp and torque curves rise, peak and then begin to fall. Can't really see the need to keep increasing engine revs once the figures start to dip. A normally aspirated engine isn't likely to get its 'second wind', is it? >> Edited by sparkythecat on Monday 24th April 21:17

Exactly - if you want a peak BHP measurement any decent rolling road will stop once the figures start falling.