Underdrive pullys, which one?
05-22-2006, 12:04 PM
#21
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I want a pulley badly but I've read all the horror stories about installing it and issues with the crank bolt getting stuck, broke, cross threaded etc. Is this an easy/safe mod to do? The 10 hp would be nice but i care more about not damaging my car.
05-22-2006, 02:07 PM
#22
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Originally Posted by Synister_Motorsports
The March is actually one of the heaviest pieces. It is manufactured from carbon steel and filled with high viscosity fluid. However the Horsepower is not achieved through the loss of reciprocting mass so it is irrelevant.
05-22-2006, 04:00 PM
#23
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Its irrelavant in this situation, becuase your not going to see any more power between the March or the ASP on a general street/strip motor. If you have a serious high reving motor you may see a bit of seperation between the 2 above 6,500 rpm, but at that point you should probobly be running an ATI. The underdrive pulley makes power not because it has less mass but becuase it alters belt speed less parastetic drag on the accessories.
You will not see any more horsepower between the MARCH or ASP. So inconclusion yes reciprocating mass will make a difference in most applications, however test the 2 against each other and you will find the same gains. I know I have, ....long story.
That is off course unless one sets off your knock sensor !
You will not see any more horsepower between the MARCH or ASP. So inconclusion yes reciprocating mass will make a difference in most applications, however test the 2 against each other and you will find the same gains. I know I have, ....long story.
That is off course unless one sets off your knock sensor !
Last edited by Synister_Motorsports; 05-22-2006 at 04:07 PM.
05-22-2006, 04:16 PM
#24
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quick question: is an underdrive pulley a direct replacement with no ther mods to do? or do you have do get other stuff? like a new pulley for the alternator, new tensioner, new belts???
05-22-2006, 04:55 PM
#26
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Originally Posted by Cumbias
quick question: is an underdrive pulley a direct replacement with no ther mods to do? or do you have do get other stuff? like a new pulley for the alternator, new tensioner, new belts???
An underdrive pulley will require to purchase 2 new belts generally the instructions will list the part numbers that you need and these can be picked up at your local parts stores. Many of the sponsors on this site offer packages with the pulley and belts.
Generally the only time you consider an overdrive alternator pulley is if you have an AUTO trans ( auto cars idle lower than manual) or a stereo system with alot of mods. However there are many members running around on this site that have auto's and no overdrive alternator pulley.
As far as anew tensioner goes many members with the MARCH or ASP have posted issues with the belt slipping or walking and have gone to an aftermarket manually adjusted Katech style tensioners which seems to have remedied thier situation.
The SLP/Power bond has higher retiaing walls claiming that this solves the issues of its competitors belt walking.
05-22-2006, 08:14 PM
#28
A tall lip on the outside of the pulley isn't going to eliminate the need for proper belt tension. It may convince a belt that wants to walk to stay in place, but if your belt wants to walk you have a problem that should be addressed directly not forced to stay at home with a tall lip. The ASPs I have didn't come with a SFI stickers on them, but I've been running mine for several years now with no problems. Since the LSx engine don't use a distributor with manually adjustable timing the timing marks on the pulley won't see much practical use. Much better to view your timing on you laptop on an engine with a PCM, ECM, TCM, BCM, etc.
05-22-2006, 09:38 PM
#29
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Whether you have an SFI or non-SFI ASP pulley you have the same quality pulley. All the SFI does is put a plate on the front of the pulley incase the molded rubber fails the pulley won't go into the engine. The pulley never would go forward with the original design if the molding rubber failed.
A tall lip is perhaps a Band-Aid fix for a belt throwing problem. The real problem is with the tensioner pulley. It has no lip at all.
A tall lip is perhaps a Band-Aid fix for a belt throwing problem. The real problem is with the tensioner pulley. It has no lip at all.
05-23-2006, 08:24 AM
#30
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I've had my ASP on since 2001 and haven't had an issue. It's a nice piece, the install was easy and made a noticible difference in how quickly the engine revved...
05-23-2006, 09:43 AM
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i just installed an underdrive crank pulley and shortly after my check engine light kicked on. Could changing the pulley have caused it or just an awkward time for something else to go out?
05-23-2006, 10:57 AM
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I've had the March pulley on the car for about 2 years now - never thrown a belt. I'm very happy with it.
I favor the March pulley because it is an actual dampener, not just a pulley. Also, the extra weight of the March unit is irrelavant, as mentioned earlier, because it is rotational mass that matters. In the case of the March, the fluid in the pulley does not necessarily turn with or at the same rate as the body of the pulley. So really, the body of the pulley is rotating, with the fluid inside almost stationary - therefore not contributing to rotational mass.
Chris
I favor the March pulley because it is an actual dampener, not just a pulley. Also, the extra weight of the March unit is irrelavant, as mentioned earlier, because it is rotational mass that matters. In the case of the March, the fluid in the pulley does not necessarily turn with or at the same rate as the body of the pulley. So really, the body of the pulley is rotating, with the fluid inside almost stationary - therefore not contributing to rotational mass.
Chris
05-24-2006, 06:17 AM
#35
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I have just got home from installing my march pulley and T/B by pass and I can really notice the extra HP and revs,I am redlining much quicker.What a great mod can't wait till tomorrow I am installing a SSRA and 160*thermostat.
then back for another Dyno.
then back for another Dyno.
Last edited by Z28XTC; 05-24-2006 at 06:29 AM.
05-24-2006, 05:58 PM
#36
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I got the SLP pulley installed last week. I chose it over the ASP because of the higher walls. Butt dyno tells me I gained a few ponies, nothing too noticeable. When you floor it revs a lot faster. I was kind of nervous at first being an A4 but even when idling at 500rpms there are no problems. Also, there has been no difference in power steering at slow speeds which I have read that it can be an issue.
05-24-2006, 06:24 PM
#37
The gains that come from an underdrive pulley are from it's size, not weight. This being the case, I think it's best to buy the strongest, best built one. This is the reason I chose the SLP/Powerbond. Steel construction, no KR, higher retention walls, etc.
05-24-2006, 06:54 PM
#38
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I really don't believe you can feel the hp gains from a pully. I'm hopping to see a few on they dyno. Adding it to the every little bit helps catagory. I just realized I have to change the front seal too. I should have done this the same time I did my cam. 
