Rolling Road - simple question?

[uk-maxie]

Well i thought it was a simple question...

We've (brother & I) been thinking of taking our 69 Sport Satellite to a rolling road / chassis dyno just to check hp/torque, now we've ironed out a few 'teething' problems with our 493 stroker. And to see if the figure we were given from the engine dyno were as optimistic as we suspect!
So I rang a place we found on the 'net to ask whether they would have our car in to do a power run. I said I didn't expect it to need any tuning, as that has already been done.
I expect the 'garage' (it's actually a high-end, mainly Ferrari sales/service/resto company) will be more used to having manual trans cars on their rollers, so I said it was an auto, a 727 like in a Jensen Interceptor (as they were more likely to know what that is than a Plymouth Sport Satellite).

I asked what gear they use for the test, hoping he'd confirm my expectations and say 'D', but he said '2'. And then knock it into 'N' to get the estimate for the losses thru the trans etc.

I thought it needed to be done in drive for the 1:1 ratio?

I did question it but I didn't labour the point as their fee is 2 or 3 times the cost of the other places I've been considering, so we may not choose them anyway. Having said that I was hoping to use them as I was expecting them to be more knowledgeable and careful than most if the cars they test are mostly super cars and valuable classics.

Does anyone here have any first-hand experience of running an auto on a rolling road?

Thanks, Rob & Stu, UK

 

[Darter6]

Rob, Had several car done over the years and we always used 1.1 high gear.
Usually,talking automatics, at a start rpm high enough as to not kick down into 2nd on a pull to redline rpm.
Maybe they are used to using 2nd on a pull because of sportscars having less torque on the low end of the rpm scale.
Just a thought.

 

[uk-maxie]

Rob, Had several car done over the years and we always used 1.1 high gear.
Usually,talking automatics, at a start rpm high enough as to not kick down into 2nd on a pull to redline rpm.
Maybe they are used to using 2nd on a pull because of sportscars having less torque on the low end of the rpm scale.
Just a thought.

Thanks Darter,
I'm puzzled why he thought 2nd would be the right gear to use for an auto. I explained it had 1,2 and Drive, so if they need to go into neutral straight after the pull, I'd have thought it obvious that they need to use Drive.
Even with a manual trans, I'd have thought they'd know to use top gear, or whatever gear gives 1:1. However... after a quick check online to see what ratios are in my daily driver's 6 speed manual gearbox (Alfa Romeo), none of them give exactly 1:1 (4th is 1.067, 5th is 0.875), so maybe it's not even straight forward with a manual?