Does anyone make an aftermakret underdrive pulley for the D2 or any rover V8? Seems like it would be an easy mod.I can't find any info on the web.
Someone must make one?

Or is there some special reason why no one makes one?

 

What would be your goal in installing one?

 

I use them on my SHO. Larger pulleys use less engine power to generate the same amount of output, and theoretically increase hp (by freeing up some power) as a result. On my SHO, I dyno'ed the car both before and after unstalling UDPs, and saw about a 5 bhp increase. I had to reconfigure the ECU to make the car idle higher, b/c at idle my lights would dim and if I ran to many things off the outlets, it would drain my battery. I have no idea if it has any effects on gas mileage, but I'd love to know.

 

re: Larger pulleys use less engine power to generate the same amount of output,

At the lower speed the alternator had reduced output, hence the performance you note. You might also consider a chip from one of the firms that makes the ECU upgrade, changing to electric main fan, new cam shaft, reprogram different injectors, etc. The Brits have used the Rover V-8 for years to "hot rod" some of their cars.

Can it be done? Yes. Will it work for everyone? Well, that depends on who is servicing the vehicle. You push the design envelope in one direction, it moves something you had not planned on. You may end up with something that gives you more trouble and you could spend more time tinkering with it rather than having a good time off road. You could end up with something that you, and you alone, can work on. It is built for bouncing in Borneo, not bleach burnouts at Riverside. The stock ECU will do its best to adjust back to what the factory said would be normal (adaptation).

You'll probably like Rover V8 - The Wedge Shop and "RPi Engineering - Specialised Rover Engines"

Most guys are just happy if it does not overheat and the front propshaft can be greased.

 

"At the lower speed the alternator had reduced output, hence the performance you note. You might also consider a chip from one of the firms that makes the ECU upgrade, changing to electric main fan, new cam shaft, reprogram different injectors, etc. The Brits have used the Rover V-8 for years to "hot rod" some of their cars."

Exactly. I used a chip to override the ECU and raise the idle. The SHO engine was built by Yamaha to use in the GT40, but Ford scrapped the project and stuck the detuned motors in the Taurus. There's a lot of power to recapture in that motor. I don't know much about the Rover V8, but it looks like an old GM boat motor, and I wonder how much power could actually be realized from UDPs. If I had to wager a guess, I wouldn't think too much. It might be interesting to see the larger UDPs effect on fuel consumption though. You might get better mileage.

 

I had one on my old suzuki 1.6 16 valve engine and I remember it was an easy mod that gave me noticable torque. I was just asking. Like many people i've added 33's and i'm looking for ways to get a few HP back. I think I'll drop into some headers and new cats.

 

Its an interesting avenue to pursue. Find a sports car/truck that uses the same alternator/ps pump/water pump/etc and see if they make UDPs for them. I'd definitely be interested in getting some more torque out my engine, especially with an easy bolt on that would relieve some engine stress. What can different headers and cats do for the Rover? Are replacing them with performance parts a common thing?

 

So which items would resize you (all of them, one of them, some of them)? As a low flying parts vulture, i am always up for exploration of opportunity at the salvage yard.

And would this lower rotational speed of the belt driven devices (1) lower cooling by reducing water pump flow at idle (sitting in traffic); (2) change power steering characteristics; (3) lower AC output (summer is coming)?

And if it needs to idle up to keep up with electrical demand, doesn't seem like we would be saving any gas at idle or slow speed.

Of course, with the aerodynamics of a pallet of bricks, and well over 4000 pounds, 5 hp extra would come in handy.

Seems like I recall that guys at the track would resize their alternator pulley to reduce the rpm of it, so it would not fly apart when the "mom's taxi" design met the 7000 rpm shift point.

 

I am not sure about D2's, but D1's get their tach reading from the alternator. If you change pully size and that is the case, your tach would be reading the wrong engine rpm. Which the trans ecu uses(among other things) to control shift points. Not to mention the trans ecu is so finnicky, that so much as a weak battery will throw tranny codes.

But, if you could find one for a deal, it'd be a good experiment

 

True about the alternator, but the D1 tranny is not electronic, it is old school pressure. No tranny ECU on D1. Having a different pulley, to boost HP, but require higher idle, and maybe decrease water pump flow, pretty soon you get to the land of diminishing returns. Of course, with gas prices being what they are, I'm not operating my engine at the peak of the horse power curve anyway.