Anyone had any success with the under drive kits on a 5.0L?? Are the power gains accurate?? Will i see that sort of gain(8-10rwkw) with a fairly stock motor(ef xr8)?? Seems like decent bang for your buck

Thanks.....

Yeah you should easily see 7-10rwkw, very easy and cheap mod. I use to have a set on mine and found them very good, the only issue is you may see the battery voltage drop a bit when idling but thats really not a problem.

What if you only put a smaller pully on the crank and not larger ones on the accessorys? Would you still see a noticeable gain?

Yeah that is what they do in the basic underdrive kits, thats what I had. Generally they give around 7rwkw or so, the 3 piece kits tend to give a bit more, 10-12rwkw.

yeah ED XR8 is right, mine i found gave me more torque then power, but you can feel a change when you get it/them put on, i got just a crankshaft pulley from BPT and that is alright, for the $200 or whatever it was it is alright.
and yeah only downfall as someone said is at idle the cars lights and stuff can sometimes dim a little, and normally when i get out of the car i just give it a rev then turn it off, coz of the alarm and battery reasons, and the car sometimes sits for a while, but there is no real need to do that, but i do.
i also found with mine, fuel comsumption got better, so have it for long enough and it'll pay itself off, but wasn't amount, but my avg fuel per km did sit at 19.2 all the time, then after i got them put it it went down to 18.4 then back up to 18.6 and now i think it's going to stay there.

got one too. excellent value.

recommended.

I'm running the March polished underdrive kit. Great value. Biggest improvement I noticed was a 2-3L/100km fuel saving. Also revs out free'er. Probably bigger improvements would be noticed by those who are running the clutch fans on the earlier engines.