Custom SC belt routing - Honda Prelude Forum

ZDVS1 · 12-02-2002, 04:20 PM

In my quest for a better supercharger system, I'm trying to avoid any type of "jackshaft" contraption. With all the balancing shaft discussion lately, I was looking through the Helm manual and I got the bright idea that if I disconnect the balancing shafts, I can use that belt to drive the blower, and it *should * be a straight shot. I looked in the engine bay, and it looks like a path up from that belt would clear the strut tower and thus aviod the need for any type of jackshaft assembly.

Would this be a posability? I've never taken the motor apart, so I don't know exactly how far back the belt for the balancing shafts are. Would there be any block modification necessary for belt clearance?

Would it be better to get a belt long enough to drive the sc and the balancing shafts?

I'm also guessing the toothed belt would deter blet slippage better than a ribbed belt. I'll obviously need a custom pulley anyway, since, unless I'm mistaken, the balancing shafts spin twice the speed of the motor.

Please contribute any questions/comments/opinions.

-Scott

schwett · 12-02-2002, 09:21 PM

well, you would certainly need a pretty long belt. i would personally not let a belt that was exposed to the elements run inside the timing belt cover, but that's just me. i suspect you would drastically decrease the life of that belt, and to a lesser degree, the timing belt. there is a reason honda put that cover on there with a seal all the way around it.

i will also assume that you're not going to use the jr blower and jr intake manifold adapters. with them on there, there is absolutely no way to get where you're planning on going from the blower - the new belt would run straight through the manifold. you can see that here, if you imagine a path coming toward you from the blower pulley :

it looks like it might be pretty close to making it almost to where the nose of the blower is now. might have to get a longer nose. eaton makes those, not sure if the counterrotation will be a problem. the blower for the rsx has a really long snout, for example.

also, don't underestimate the sheer quantity of crud that is under that innocent looking timing belt cover :

both spin much faster than the engine, not sure if it's 2x or not, but you can estimate from the size of that big cog in front. for whatever reason, the rear balance shaft has a reduction gear in the casing.

if i were doing this project, and not spending a ton of casht o blueprint/balance my engine to the highest possible tolerances, i would desperately try and find a way to do it without removing the balance shafts!

schwett · 12-02-2002, 09:36 PM

the more i look at some old pics, the more stuff i think is in the way..... including possibly the shock tower : (not the shock itself, but the body just to the inside of it.)

ZDVS1 · 12-03-2002, 09:04 AM

It's definitely going to be a custom manifold. I'm not even using an Eaton blower, much less the JR setup. I'm planning to use a Whipple 1600 blower (lysholm charger). There's a pretty good thread from a month or two where Artifex and I were discussing some ideas. I'm also wondering if i could retain the balancing shafts AND drive the blower at the same time. I am expecting decreased life from the belt, though it's not the timing belt itself, so I don't know what would happen if it were to break. About the strut tower, I wouldn't mind some trimming to make clearance for the belt. I'm imagining I could modify the timing belt cover to reduce the exposure to the engine bay. All of this is going to be done on a spare motor, out of the car, so shouldn't have a problem with that. Thanks for the input, the pictures really help.

Artifex · 12-03-2002, 06:42 PM

Hey Scott, still shooting for the custom SC ? Cool.

Yeah, I see that the belt routing issue is the single biggest problem on the H22. Be very nice if you could find a solution to that.

Regrettably, I am kind of with schwett on this one. I think that driving a blower off of the balancer shaft is a bad idea. Using it as a power transmission device would severely limit its lifespan I think.

I like the way you are thinking though. There has to be a way get a damn belt back to the blower. I just keep thinking that belt changes are going to be a nightmare though.

I have a radical idea: are there any hydraulic or similar power transmission devices? You could put the drive side on an accessory pulley, and the driven side powers the blower shaft. hmm.. I have seen stuff like this before, but it sounds exotic and expensive. I know that Garett announced they were working on a drive system of this type several years ago (I saw it in TOO's archives), but I don't think anything ever came of their project.

ZDVS1 · 12-04-2002, 03:19 PM

Yea, the Custom SC is still on the roadmap.

I did a lil research on the Hydrostatic transmission as a drive system, and I kinda like that idea. The site you linked to is exoctic and expensive, as it's for large tractors, HOWEVER

I found that there are many higher end lawnmowers and snowblowers that use "Hydrostatic Drive Systems." My thinking is that if these systems are strong enough to move one of those lawnmowers through tall grass as fast as I've seen them go, spinning a SC shouldn't be a problem. I'm sure mounting a small Hydrolic pump would be much easier than routing a whole belt system back there. Pricing shouldn't be too bad either as some of the whole lawnmowers were a little more than a grand. I'm pretty sure I can find a repair shop that can get me just the drive system and fab that in there. I'll look into it more, but it sounds doable. It's not like I'm looking to make a system from off the shelf parts.

Thanks for the idea,
-Scott