honda civic gearbox at 15000/ 20000 rpm

[LEE1969GB]

Thinking of using a honda civic gearbox (because that will drop stright in my buggy) in first gear to get 10/ 12 t0 1 reduction. I am going to put a 800 rotax engine in using the ski doo cvt and have the secondry clutch mounted on a shaft going im to the gearbox then run it in first gear. my worry is will the first half (second half will run at designed speeds) of the gearbox be ok with that sort of rpm?
Oh I lied when I said A, I am going to use 2 of them 800 rotax engines that is, I will mount the second secondry clutch on a shaft then link the 2 shafts with chain and sprockets (same size sprockets)but can not think how this will affect the clutches, will it make the engines scream or will it be ok, I think it will be ok but?
I was going to have one engine driving each rear wheel as I have talked about before but lots more work and I have most of the parts to do it this way.

[nutz4sand]

How are you thinking you will get anywhere near that RPM? ( i am just asking curious.)

Even if you do achieve a overdrive with the driven clutch (hard to do under a load usually) the 800 rotax will turn 10,500 at most and they usually peak out a good bit lower (where you WANT to be running them) So I am a lil wondering how you figure it will be that high of RPM's? Even if it can get high the rpms will not be there for long periods of time. Torque breaks things. HP is speed and that can make things run warm but if its locked in one gear you would have to spin the ($%!*) out of it for a long time. With good lube I think it would be fine. Its just rotating parts.

I also would think about the tranny out of a VW jetta or newer rabbit or the like. First off they already have the German CV flanges and the newer VW's use large ones. (not sure which use which but they are the bigger cvs on the fancier more powerful cars) The Honda tranny works for the bike motors as its not to hard to get a sprocket stabile with a bearing on each side. The CVT will put some real side pull to a shaft and hard to stabilize on a short one. With a VW front drive 4 banger tranny the input is on the other side and you could use the snowmobiles long shaft they mount the driven on to transfer power across and down a chain to the input of the tranny. Yah its using a chain but it could be a longer chain so no overheating.

If you do not wish to deal with that I understand that directly into the Honda tranny seems effcient but you may have to stabilize the outside of the driven clutch (like the Drakarts do) I will be interested to see how it works for you and what you need to do to make it run true. Any misalignment of the Honda (or any other) car tranny underload means the noise starts and the fun stops.

[LEE1969GB]

When the drive clutch if fully closed and the seconary is fully open it will do big revs?
The shaft from the gearbox (input) will be set in self aligning bearings then linked to the gear box input shaft (the one the clutch plate slides on to)

[Jay1823]

I'm with Bill where are you coming up with those rev #'s, Indy cars don't even rev to 20k i don't think. As for the tranny's that's a good question. There designed to operate in a max rev range of 7000-8500. I'd imagine you could go 10k without any problems. The only problems i could guess at would be the bearings but hey you never know until you try.

That and the 2 engines seems kinda pointless to me, i see nothing but issues with that setup.More power to ya though if ya get it to work.

[nutz4sand]

Unless you put a tach on the tranny input shaft you will not really know what it will turn. (might calculate tires size and figure the ratio with the speed to get it maybe.) Yah the clutchs CAN shift past 1 to 1 but in the real world under load not to much. Under that same load the motor will likely not be able to run past its torque peak to many RPMS.

Even if the motors spinning the drive CVT 10,500 rpm and it can over shift you might get 12,000 rpm but for how long? And chances are the motor will likely run closer to 8500 rpm to 10,000 and the clutches will not be shifted out all the way. Say drag racing or hill climbing. Even flat running due to the drag of four tires and extra weight its not gonna be spinning the clutchs full out much for long.

As long as the tranny is good and the alignment is true you are not gonna hurt it with RPMS. Maybe if you try t run 40 miles full out on flat ground. But realistically its nothing to worry about.

As for the self aligning bearings into the input are you talking about supporting the driven CVT on the outside too? How long is the shaft gonna be? That motor will put some pull on it and if the shafts short holding it straight is gonna be tough.

[Jay1823]

The only thing that's stock on the tranny that's measurable is the speedo cable. You could take apart a Civic instrument cluster, pop out the speedo and mount it to a plate. That way you can at least see what mph your at and possibly put some markings on it to get a round about RPM #. Actually the next time i take my car out i'll run it to 7500 rpm in all gears and jot down the MPH i'm at. At least then you have a reference point to go off of.

[LEE1969GB]

The shaft will be one from the ski doo snow mo so should not be a problem, no need to support the end. So anyone know what the working range of these clutches is? it looks like it will not be a problem for the gearbox then.

[LEE1969GB]

With one of these engines in my pilot (about half the weight) From the lay shaft (after the secondry clutch) it reduces by 8.2 to 1 and is driving tyres with a 1700mm circumfrence (thats not spelt correct but you know what I mean) and that feels ok, so with 2 engines and driving tyres with a 2200mm circumfrence I am thinking I need about 10 or 11 to 1 ratio which is about what the gearbox from input to diff output is in 1st gear.

[nutz4sand]

Originally Posted by LEE1969GB

The shaft will be one from the ski doo snow mo so should not be a problem, no need to support the end. So anyone know what the working range of these clutches is? it looks like it will not be a problem for the gearbox then.

??? I guess I would have to see a diagram or sketch of how you plan to do the clutch on the shaft. The ski doo shaft is long and goes all the way across the chassis. This gives it its stability.

I am picturing the car tranny centered and the motor right in front of it. That (to me) means the sled shaft will have to be shortend a lot. I hope not but this can lead to problems when the thing trys to torque sideways.

Your Pilot was quite succesful so I am guessing you will get it to work like you have in mind. Be interesting to see how you do it.

[LEE1969GB]

I was thinking of trying to get the 2 secondry clutches on one shaft but I do not think its possible (unless I modify the clutch) so I am of putting a second shaft parallel to the first with the other secondry clutch on it then linking the 2 with chain and sprockets