Different pulley sizes

jr_vw2 · Post by **jr_vw2** » Sat Dec 24, 2005 6:32 pm

Is there really any advantage to run a smaller than stock crank pulley?? I know that it will change the weight of the rotating mass and the speed of he gennerator. BUt is tere really a BIG difference. I have always ran the smaller than stock a.k.a. "power pulley" But I never really oculd tell a diference. any insight would help. thanks p.s. Is anyone running a serpentiene belt set up? thanks

5150bossman · Post by **5150bossman** » Sat Dec 24, 2005 6:41 pm

For maximum cooling in hot environments, you always want to run a stock pully. So far as the serpintine belt, there are several who run them, but I do not and can't answer that.

joemama · Post by **joemama** » Sat Dec 24, 2005 6:45 pm

I think the biggest difference is that your fan is turning slower, and therefore not cooling your engine as efficiently. Not worth the potential sacrifice for the maybe 1/2 hp gain. Just my :2cents:

Gene-C · Post by **Gene-C** » Sat Dec 24, 2005 6:49 pm

I have always thought that the serpentine system only added tension to the belt in high rev engines. Not making any difference in speed of gen or fan! Just adds stability so the belt doesnt jump so much, and the belt is wider also, no diff in performance.

Lee · Post by **Lee** » Sat Dec 24, 2005 9:17 pm

The reason for the so-called 'power pulley' is not to give the rear wheels more horsepower by turning the fan slower, but to keep the fan and the belt intact and on the car when using a high RPM, high performance engine. Spinning the engine (and thus the fan) at higher than stock RPMs often causes the belt to turn over or get thrown from the pulleys. In extreme cases, the fan can come apart and really ruin your day. The power pulley is designed to keep the belt speed and the fan speed down in order to miminize the chances of these problems from occuring. A serpentine belt system will solve these problems and allow you to run a stock sized crank pulley so you have proper cooling. Gene Berg Enterprises sells welded and balanced fans that you can safely spin a lot faster than a stock fan.

michael cook · Post by **michael cook** » Sat Dec 24, 2005 10:30 pm

I have not ran the serpitine belt setup but Iplan on it for sure mike

Complex One · Post by **Complex One** » Sat Dec 24, 2005 11:00 pm

I have personally run both the stock size and the Power Pulley on Buggies over these past many years and as Joemama says...just not worth the little extra HP that you will achieve so stay with the stock size and you will be in good shape. As for the BMD Serpine Belt System...well that's another story. I converted my Manxter #37 to the BMD system last summer and I must say that I am very impressed. It quiets everything down, seems to run a lot better, and looks sharp. The only downside is if you are running a Sidewinder exhaust you will need to make a small modification to the cap on the idler wheel for clearance. Not a BIG deal as you can see from the pics. Hope this helps.

Gene-C · Post by **Gene-C** » Sat Dec 24, 2005 11:27 pm

So basicaly the serpentine pulley system will make the engine run quieter and looks better? How much did you pay Complex? I may order a kit if I find its worth it, besides Ill me building my engine from scratch so anyways Ill have to buy either the stock system or that one.

newmanx59 · Post by **newmanx59** » Sun Dec 25, 2005 1:00 am

The Dyno Jet dyno said replacing the stock pulley for the "power pulley" was good for 4 hp @5500 rpm on my engine. I'm running a power pulley and a stock doghouse cooler and in 4000 miles of driving this past Summer the oil temp never exceeded 195 deg. and the head temp runs 350 to 400 deg. I have spent alot of time in stop and go traffic on 95+ deg days not to mention 4 hour freeway trips in 95+ temps at 75mph. Never a hint of overheating. I think the fact that the engine isn't enclosed in an engine compartment allows you to get away with a little more as far as the cooling system is concerned. My friends 2275 race motor makes 22 hp extra without the belt. absolutely worth taking it the belt off before the race.

Gene-C · Post by **Gene-C** » Sun Dec 25, 2005 3:34 am

I run a power pulley on a 1776, modified and my main travels are off highway, offroad and in four years, no heating problems, and it's still going & going & going.......... Jimbo

5150bossman · Post by **5150bossman** » Mon Dec 26, 2005 6:40 pm

But then again Jimbo, you don't have a temp guage either

....

Complex One · Post by **Complex One** » Mon Dec 26, 2005 8:37 pm

I remember paying around $150.00 but the current price of $187.00 for the BMD Serpentine Belt Kit is currently listed on the site. http://www.bmdpulleys.com/ I'm glad I spent the money though. It made things a lot better all the way around. No more worries about jumping a stock belt off of the OEM pulley's and much easier to adjust as the belt begins to stretch although I have not had to readjust mine yet as the tension is still good from where it was originally set. I guess I will not be able to use a pair of panty hose again as an emergency repair belt in a real pinch.

HAPPY HOLIDAYS....to all

Mvovr · Post by **Mvovr** » Tue Dec 27, 2005 1:29 am

Will this pully system work with a standard pully cover?

Gene-C · Post by **Gene-C** » Tue Dec 27, 2005 5:46 am

I thought I understood that "Serpentine" had to do with the serpent (snake) like path the single belt needed to travel in order to run all the accessories with one belt. The setup pictured just looks to me like a wider flatter belt taking the place of the old-style V-belt. It _is_ a good looking rig, and if the maker wants to call it "serpentine" or if they want to call it "ethylrood" I don't care! If it works, that's great! If it works better than what it replaces, EVEN BETTER! From what was written, I gather the flat belt runs quieter than the V belt, resulting in noticably quieter operation. Kewl!!!

jr_vw2 · Post by **jr_vw2** » Tue Dec 27, 2005 12:52 pm

Well in is kind of like a serpent in the fact that there is a tensioner thrown into the mix.

Manx Club

Different pulley sizes

Different pulley sizes

Serpentine???