Dern Humpus
Dedicated LVC Member
Who has them? Are they worth it? Brands? Dyno results?
underdrive pulleys
- Thread starter Dern Humpus
- Start date
02LSE96LSC91SE84TC
Dedicated LVC Member
Steeda, ASP, March, Summit to name a few. They should all produce similar results. Most are around 25% underdriven at the crank, but then the alt and water pump pulleys are designed to give some back.Dern Humpus said:
I know Geno fimly believes in just a crank pulley. I see it as probably effective by itself.
They should produce near or around 10hp to the rear tires in my opinion.
I have a 3 pc. ASP set on my 91MarkVII and they definately made power. Could feel it in the acceleration, it revved more freely, coasted better to my surprize I could feel less drag and even the tranny shifted better without the drag. Also a noticable increase in fuel economy.
I also have a March set on a older 302 of mine, I put them on and converted to an electric fan at the same time, picked up very noticable power on that one considering it was lugging a seven blade solid mounted fan before the switch.
I'm going to be putting a set on the MarkVIII pretty soon so I'm interested in the opinions of them on the MarkVIII. I'm currently leaning to just the crank pulley as I'm concidering an electric water pump down the road a little and so that would kind of defeat the purpose of the one pulley. I also have considered if just doing the electric pump intead would produce better results anyway as most of the drag is there. Both would probably be the best.
Underdrive pulleys don't work as well on the modular engines, especially the 4.6 DOHC because of the weak oil pump gear design. There have been many reports of broken oil pump gears due to underdrive pulleys on these motors. I would not risk my engine for ~10hp...
02LSE96LSC91SE84TC
Dedicated LVC Member
I do remember reading that they weren't as effective on the mod motor as 5.0s and other motors. Don't remember any problems with what you speak of.
MediumD
Dedicated LVC Member
Where is some real world dyno data? Ass-dyno results don't mean much. The only dyno results I've seen were from a 1.9 Saturn, when they ran it without the accessory belt at all they only saw about 3hp.
02LSE96LSC91SE84TC
Dedicated LVC Member
The Mustang world has dynoed them to death, they work real well on the 5.0s and Ok on 4.6s. I agree the butt dyno isn't actually accurate, but they're quite noticeable. Keep in mind on my older 302 Mustang I switched to the electric fan at the same time, that was really noticable between the two together. Heck I got rid of the power steering too and felt it.
Theres a good reason why solid mounted fans got replaced by the clutch style, and now most everything is electric. I threw a seven blade solid fan on my old 86 T-Bird in place of the clutch style to see if it would cool better, I felt such a drag I immediately took it off.
Theres a good reason why solid mounted fans got replaced by the clutch style, and now most everything is electric. I threw a seven blade solid fan on my old 86 T-Bird in place of the clutch style to see if it would cool better, I felt such a drag I immediately took it off.
Dominus
Dedicated LVC Member
Power steering pump doesn't drag barely anything unless you are turning. The alternator will take as much horsepower as it needs to run the car, unless you pulley it so low that it stops charging correctly.
The only thing an underdrive pulley will affect that will make any difference is the water pump. The speeds at which the water pump spins at higher rpms are simply unnecessary and cost a lot of horsepower (not to mention cavatation). But for all that BS, you might as well just get the e-pump, and save your alternator from being underpowered at low rpms.
Several members including myself use the Meziere pump with no drawbacks.
The only thing an underdrive pulley will affect that will make any difference is the water pump. The speeds at which the water pump spins at higher rpms are simply unnecessary and cost a lot of horsepower (not to mention cavatation). But for all that BS, you might as well just get the e-pump, and save your alternator from being underpowered at low rpms.
Several members including myself use the Meziere pump with no drawbacks.