t24todd

iTrader: (7)

so it seems like alot more people use the dual alternater pully when the airpump removed but on the other hand i heard the yoohoo belt is better...i have a dual alt pully now but engine rebuilt and not running so i cant test anything out yet..anyway the question is which seems to be better running the yoohoo belt or the dual? heard the yoohoo is a bitch to get right and the dual wears belts differently so this is my delimia..pros cons of each thanks

NZConvertible

The Yoohoo belt is a nasty hack. There's no way to adjust the tension, so the chances of it being right are slim. More likely it'll either be too loose or too tight, and since most people seem to avoid slipping it must be too tight. This puts extra stress on the water pump bearings, shortening their life.

Do it right and get a dual-belt pulley. In my experience there are no downsides.

t24todd

iTrader: (7)

like i said i heard it was a bitch...any others want to chime in feel free...i know this is a common question..

1SWEET7

iTrader: (1)

I have had my yoohoo belt for months with no problems. It is pretty tight though.

The Shaolin

iTrader: (5)

The only downside is that you MUST buy matched belts for the dual pulley. I bought two belts from Autozone and they are just different enough that one is a bit loose.


Where do you guys get matched belts from?

jon0886

iTrader: (1)

i agree with NZ, dual alt is the way to go.

when i got belts for my dual alt pulley setup, they were pretty darned close (lucky?) and after a few hundred miles, the smaller one stretched to match the larger one.

MaczPayne

iTrader: (5)

I've had a yoohoo belt on mine for a year so far. No problems so far.

The only downside is the install, you're gonna have fun with that.

leftcoastdrifter

iTrader: (17)

i've had a yoohoo belt on my motor and i've had no problems, even getting it on isn't that big of a deal. if you loosen both pulleys it's pretty easy. i on't think i even did that, i just got it half way on and then manually turned the motor over til it fit into place.

also, my buddy runs a dual set up and it works just fine too. so just pick what you think looks better, there isn't a performance gain to be had with either so really it just comes down to preferance.

jdmsuper7

iTrader: (1)

Finding matched alt belts is not as easy as it sounds, and most likely one of them is gonna slip anyway, and if the outer belt is the tight one, then it is doing nothing but increasing the axial torque to the alt instead of doing it to the WP. The yoohoo belt may not be in perfect tension either, but its not exactly common to hear of people blowing out a water pump bearing using one.

I'm almost always gonna side with NZ, he knows his ****, but the dual alt belts never made alot of sense to me*puts flame suit on and hides*

blmcquig

iTrader: (15)

ive had my yoohoo belt for 2 years almost. it can be a challenge to get on, but once it was on, it wasnt to tight or to loose. fit like a glove.
i never liked the idea of the dual alt. pulley anyways.

t24todd

iTrader: (7)

i do have the dual pully just wondering if i should use that compared to the yoohoo...so my problem is going to find matching belts...nothing is ever easy when working on our cars..so putting on the dual you just remove the normal alt pully i guess holing it with a pipe wrench or something then simply put on the other then? i just got a new alt so im not trying to mess up anything..is there a set torque specs for the pully?

NZConvertible

That's not actually possible. If the tight belt is not slipping then the loose one can't slip, because both belts are turning at the same speed. If the tight one slips then they're both going to slip, which means you haven't tensioned the belts properly or they've worn out.

Why would you be so silly as to leave the tight one on the outer sheave? If one belt is tighter that the other, put it on the inner sheave. Common sense.

It's not about "blowing" bearings, it's about accelerating wear and hence the bearings not lasting as long. You also increase the risk of the belt snapping and leaving you stranded. These are the same reasons you don't over-tension any belt.

On my car, with the air pump removed and a single belt driving the alternator, water pump and stock fan, the belt often slipped, usually after sitting stationary (causing the fan thermoclutch to engage) and then accelerating off. After fitting the double-belt pulley this never happened again. So it makes a great deal of sense to me, and many others with identical experiences. Those who've had bad experiences with dual-belt set-ups have usually done something wrong...

The whole issue of two belts not being perfectly matched is just not that big a deal. If your belts are so unevenly matched that one flaps around badly when the other's tight, then switch to a brand with better quality control. Having one belt slightly looser then the other doesn't matter; the loose belt is still contributing to the transfer of torque. So what if (say) one transmits 60% of the torque and the other 40%? It's still way better than one belt struggling with all of it.

FuStEr

any pics of the dual belt and belts to get

clokker

iTrader: (2)

Another alternative would be to relocate the alternator to the side of the engine which would give a single belt more engagement with the waterpump pulley.

Or- and I've never seen it done- you could fab a dummy pulley where the air pump used to be and just run two belts like stock.

MaczPayne

iTrader: (5)

Or if you're baller get the Gilmer pullies. There is also a serpentine conversion kit floating around these forums made by GuitarJunkie28. Many ways to skin a cat.

Gringo Grande

iTrader: (97)

If you are going dual alt, I suggest rotary innovation since higgi doesn't sell them anymore and especially if you want one pre-machined for a FD alternator. They have several options to fit your needs.

There is a $20 version and a beautiful $50 version (which I have).

http://www.rotaryinnovation.com/index.htm

GG

fastrotaries

the gilmer pullies are bad ***. noise, but I'd doubt I can hear it over my exhaust note anyway.

Aaron Cake

iTrader: (1)

The Gilmer setup is horrible. The constant whining can be easily heard over the engine and is actually very, very loud. Everyone will ask you to show them your bad-assed supercharger and then walk away disappointed when all they see are shiny pulleys.

I've seen bridgeported cars with open exhausts running the Gilmer setup and the bloody belts are louder then the engine...

Dual belts gets my vote. The dual belt pulley is cheap and the belts are easier to install. One could also argue that it could offer some redundancy should one of the belts snap.

t24todd

iTrader: (7)

http://www.rotaryinnovation.com/index.htm

thats exactly the one i bought..me being a cheap *** i got the $20...im painting it black to match all the other ones anyway... dual for me..like i asked before though do you just take off the single and put on the dual simple as that..i got a new alt and dont wanna mess it up.

Stanis

iTrader: (2)

I bought 2 new belts from advanced auto and they had same numbers and everything so they were a matching batch, but I got black belt dust all over. I went back to one belt and it quit making dust. I was using the racing beat dual pulley.

Downside is that you must get belts that match perfect. If you put the belts on and put markings side by side, start the car and watch the markings on the belt. After a bit they will be off (one traveling more than the other.

scathcart

I once installed a 220 mm belt on the water pump and eccentric shaft pullies (yoohoo belt) on a new rebuild. The engine was a mild street port with a new water pump, verified to have zero run-out with a dial indicator. A year later, the engine started leaking coolant, having snapped off the mounting ear for the water pump on the front iron. Disassembling the engine found accelerated wear on the top of the front stationary gear bearing and a water pump-pulley combo that now displayed significant run-out. This caused acute vibration ot the water pump and housing, which led to the cyclic fatigue failure of the front iron casting.

The water pump and stationary bearings were not designed for this kind of load. I strongly recommend AGAINST installing this belt.

jdmsuper7

iTrader: (1)

Yeah, but why wear out the alt instead of the WP? I only say this since the water pump had to have been designed with tougher bearings since it had 2 belts in contact with it stock (and most of that load on it came from the air pump belt). The alt wasn't, so if anything you are advancing the bearing wear on the alt by adding the extra belt that it isn't designed to handle. This is all for minimal gain in belt contact area on the WP. If you do a free body diagram of both parts, you'll see the alt ends up with twice the stock force on it (plus the larger bending moment along the shaft), where with a yoohoo belt the WP ends up with an increase over stock too, but it shouldn't be as much I don't think (assuming equal tensions, which might be a bad assumption). This is why I don't get the bearing wear argument. I know theres a few assumptions at work here,
but I think it gets the idea across.

Is there any easy was to measure tension on the belts?
I think the dual alt belt is certainly better than just 1 belt, I just don't understand the wear argument against the yoohoo belt.

I agree 100% there.

blmcquig

iTrader: (15)

i wonder if pineapple racing could chime in here to discuss their opinion, and tell us why they think that it is fine to use, and wont destroy our waterpumps, stat. gears, etc.

NZConvertible

Gilmer drives are like aftermarket BOV's. People will try to convince there are valid engineering reasons for them, but really they're just to get other people's attention...

Yep.

No they don't need to match "perfect". Read my post above.

It's a valid point, but because the contact area on the water pump is doubled, you don't need as much belt tension to prevent slipping. The force is not doubled as you think. When I had only one belt, I had it really tight and it still slipped. With a dual-belt pulley I don't tighten the belts as much and it never slips. Besides, alternator bearings are cheaper and easier to replace than the water pump.

I don't call doubling the contact area a minimal gain. And the important point is that it works, so there's obviously sufficient gain.

With a belt tension measurer. Seriously, you can buy them. Or you can follow the FSM's instructions for measuring deflection. Personally I've never measured it, I just use my judgement.

Chances are the belt will be tighter than it needs to be, so you're applying more force to the bearings than you need to be, and hence it'll wear faster. It's the same as overtightening any belt.

Bama420

iTrader: (1)

The "yoohoo" belt is the wide toothed belt correct? Forgive my noob misunderstanding of terms. If so, I will be doing a yoohoo belt conversion on my vert. Where can I buy the pulleys?