Rolling road - What's involved

[Dracoro]

Can someone either tell me (or direct me to a thread) what's involved when rolling road-ing your car.

I know it's a tune up to configure your fuelling + other bits I'm sure but would like to know more. i.e. what they actually do, things I'd need to know beforehand, what one should ask for (more/less/optimum bhp etc.).

My VX 2.016v on twin weber 45's is running fine and the last rolling road (prev owner) was done 2 years and 4000miles ago (163bhp at wheels so about 190bhp flywheel?) but I guess it's a healthy thing to treat your baby to once in a while?

Also, how much do they usually cost and is there anywhere near Croydon/Surrey/Sussex/Kent that will do the job?

[studbuckle]

I'll answer most of it for you.

If you dont think you've got a problem and you've not made any changes to the engine then treat the rolling road session as an indication that all is OK and make any tweaks to get the best out of it.

The whole point of tuning on a rolling road is so you can make changes and see the effect with the engine under load as opposed to static tuning or basic tuning at different revs on your drive.

First job is to ensure that the engine is running as good as it can without load. Therefore ALWAYS service your car before a RR session and make all the double checks you would normally make before a track day on fluids etc.

There's no point spending money on a RR session if you're planning on doing some engine work in the near future, even if it's changing your plug leads.

Once you're there the RR operator should then check your timing by running the engine at various revs and verifying that the ignition advance is good.

You could then just ask for a power run, where they would run the car from idle to max power on full throttle and the RR would then produce a nice graph of what your output is. They can also do a coast down test to verify the losses through the transmission and this gives a fair estimate (only an estimate though) of power at the flywheel.

If you want a proper RR session they would also run the car at various rpm and throttle openings while monitoring the lambda in the exhaust. From this the operator would be able to check if the fuelling was correct at all throttle openings.

From there you can decide if any changes would be beneficial. i.e. would advancing the static ignition timing give more power but rough idle, would a different jet on the primary or secondary choke of the carb give more power while still running efficiently. would adding a progression hole give a smoother power delivery. There are all sorts of things that can be done but from the initial run it will be fairly clear if anything could be done and normally the opnion of the RR operator counts for a lot.

When I took the V8 we discovered that the ignition timing was spot on, the primary ran at an almost perfect lambda 1.0 but the secondary was a touch lean. However in his opnion there was no gain to be made in playing with jets as it would make next to no difference to output and might increase fuel use at the same time.

HTH

somebody else will be along with an alternative view as that's mine from 2 different RR's and 2 different cars

[james grayley]

Can someone either tell me (or direct me to a thread) what's involved when rolling road-ing your car.

brown trousers if it's your first time .....

[Mark Stanton]

Expect to hear you car make noises you never envisaged                  

[Thrustyjust]

your A*** twitch when you're asked to sit on the back of the car,because of roller traction while the cars at full chat.

[perksy]

You get to Watch your Exhaust start to change colour  

I stayed with mine when it was on the Rollers, some owners prefer not to be there, but it's interesting to learn whats going on and what the Operators doing.

Use a Rolling Road recommended by Owners on here and you should be Fine  

[BassMan]

I had my CVH done in November at Sittingbourne in Kent, and it was fine, tickover is perfect now (was really lumpy before). Good chap, does a lot of Westies. Got the max power and torque up and charged me £70 + VAT. Here's the details:

BD Engineering

Newington

Sittingbourne

Kent

01795 843980

Spotted a twisted spindle on one of my Webber carbs which gave us something to chat about