The V8 Owners Forum -

I've got a 3.9L land rover with the 4sp auto ZF HP22 and I'd like to get it on the rollers. can it be locked in 3rd or would I have to do the run in 2nd as it holds that without any mod.


Ross

It can't be locked in third.

Best bet is to see what the owner of the rolling road you have in mind has to say.

Chris.

dynos will have a fixed maximum speed depending on the dyno (its about 3000rpm at the actual dyno but rolling roads are usually geared)

they will usually want to keep the max speed of the engine just below this, without going too far below - in other words they will have a prefered speed range so just as the dyno place

Hi just to put the cat right into the birds

Yes and No This is going to come down to rolling road you go to. I'm not sure what rolling road you've been on thats geared but stay away from it, it's sounds nasty... Rolling roads avoid using gears due to the losses that are created by and gears. There are two main types of rolling raods out there (ignore the water break type they are too old) Inertia Dyno's and Braked Dyno's. The inertia type use a heavy wheel (mass) and the braked as it suggests uses a brake (thou this is normaly a electro magnectic one)

Yes speed might be a problem as a lot of the older (RAM12 etc) are limited to 150mph but alot of the later ones can do 170-190mph.

It should be possible if a braked type rolling road is used to start the run high enough to get the car into 3rd. what you realy want to do is use the gear that is nearest to 1:1. The big problem is going to happen when you want the higher number at the flywheel. The auto box will also cause problems with the torque figure.

You also have to remeber that any figure you get for you engine are valid for that day only. There are so many things that have effect on bhp down to the weather fuel and on a rolling road even the weight of the guy using it.

Hope this helps.