bus trans in a bug?

[1938vw]

Is it possible?

[turboblue]

Been done many times.
Use the 10° mount to keep the shift tube in the tunnel.

Poke through the threads on the ORF and there are many detailing this conversion.

[1938vw]

Cheers! Is it a stronger box?

[Chip Birks]

You are talking about bus IRS trans right? They are much stronger, especially when built up. Are you making tons of horsepower?

[Ol'fogasaurus]

A (091) bus in a bug (er... buggy) standard adapter that puts the nose cone above the rear of the tunnel. The transaxle is centered so the drive axles are the same on both sides.



This shows the relationship of the nose cone to the tunnel. The bus transaxle sits about 3 inches higher than a stock sedan transaxle (larger ring gear). The 10 degree nose down, bus to bug adapter puts the nose cone back in the tunnel so the stock shift rod works Iif you do a search on STF, you should find a string or two on the 10 degree mount). The engine also is at an angle but it does not seem to make a difference.



I used a sand rail shifter box mounted above the hole for the shifter on a bug. The only other way to connect the shift rod to the transaxle when it is above the tunnel is with a dropped connector. The dropped connector puts a lot of "monkey motion" in the shift rod and is probably hard on the bushing that the shift rod goes through just behind the shifter. I have two of them and will not use them either.





This is more or less the finished product (so to speak); shift rod above the tunnel. There are a lot of pros and cons to this so I am showing it for what it is, a bus to bug conversion. I made my own threaded adjuster for the shift rod since this is a 14 1/2 inch shorter than stock pan.

Lee

[1938vw]

no real power its just gonna be a 1600 turbo. i have a 1200 box and 1600 n/a engine at the min and it tops out @ about 60mph @ about 3500rpm i cant drive it anywhere far like that! i would like to cruise at about 70 -75 with out it screaming.
any idea what box to get? i think i'm swing arm not irs? i did look it up before bug cant bloody remember!

[1938vw]

looks like i'm better off sticking with a good bug one and paying a bit more for it!

[Chip Birks]

The best way to put a bus box in a street bug is to purchase a custom intermediate housing, it allows you to run the bug nose cone in the bug location. Berg is where mine came from. 1600cc turbo is gonna make 150hp max. Type 1 trans will do you just fine. What size tire do you run? A taller rear tire will get you more top speed. You could also look into have a freeway flyer trans built. Most of those have a taller r&p, coupled with a mostly stock gear stack. Your car is swing axle, making the bus conversion even harder.

[1938vw]

Cool, is there not a bug gearbox I could look for?

[Chip Birks]

Type 1 is bug. 68 bug is probably the easiest direct swap for you. That will have the longest gears, and be the least trouble free to install.

[Ol'fogasaurus]

Your swing axle limits you some what, like Chip Birks said, you have to live with; you either stay with a swing axle setup or go though the conversion to IRS process. The bus boxes I think have a lower top end and an early swing bus is going to have reduction gears which I understand can be eliminated (somehow). I think it is this years, October issue of Hot VWs, has an pretty good article on adding the trailing arm pivots, converting to IRS, and it is a fair amount of work. They say that the conversion can be done without taking the body off the pan.

The custom torsion housings that I have seen still need to have the pivots and transaxle mounts installed so the call would be yours.

With the bus conversion, I am not sure about the use of all the engine tin as I think it sits higher; not sure on that one.

It is hard to tell from the picture you posted if you have the short or intermediate length torsion bar. If you have the short bar, and you did change to IRS, the spring plates you have now may need to be modified some. With the intermediate bars, you are probably OK as long as the trailing arms are designed for the single torsion are; since there are two styles of trailing arms for the IRS and matching spring plates you need to be aware of that.

Assuming that you are going to keep the car streetable, here is a partial list of what will most likely need:

Transaxle mounts may or maynot change, padded not solid.

Trailing arm pivots to weld in and the jigs to align them (the jigs run about $100 but after you are done with them, you should be able to resell them and get most if not all of your money back), pivot arm bolt and bushings if the trailing arms you get do not have them or they are worn.

Trailing arms and (possibly matching spring plates w/ mounting bolts and nuts and. Spring plate covers if you go to the longer, smoother riding torsion bars [not necessary to the swap as a rule]). The trailing arms should be loaded with bearings, seals, spacers, stub axles, bump stops (if different), and brake components. If not, you will have to obtain them. While you are doing the conversion, you should pull apart the drive components, inspect the bearings and their races, replace the seals and re-do the brake components including slave cylinders and turning the drums if necessary.

IRS transaxle (some swings can be converted as I understand it). The Super Beetle’s gearing is more suited for freeway use. You must match the clutch components (early and late t/o bearing and pressure plate) also.

Drive axles w/CVs and bolts. (inspect and re-packing the CVs and installing new boots is a good way to start a new car)

I think this covers most of it. If you went to a bus, then the mounts, and drive axles need to be changed as well as the stub axles.

I am sure I have missed a few things, but this is a quick overview of the swap.

Lee

[1938vw]

holy crap dude!
i think its best if i leave it swing

[Ol'fogasaurus]

I wasn't trying to scare you, just make sure you knew what you were getting yourself into; there are a lot of projects out there for sale; or just sitting because someone underestimated the time and/or cost a particular job. Your asking the question before you got too heavy into the conversion was a smart thing to do. I didn't list everything like I said and you could take a chance and could wait to do the maintenance until after you finished the conversion but I would suspect you might be burned out and try to push things out even more and do some damage that would or could cost. Depending on what you want to do with your bug, the conversion is a lot of work if there is no gain over what you have now. If, say you were in the off-road community, it may be well worth the time and effort spent.

A swing axle is plenty good for enjoying your VW along with conservative driving on the street. When you start making friends with the happy pedal (gas pedal), then you need to start looking into other things to protect you and your investment.

There are things you might be able to do to the transaxle also, such as having the transaxle rebuilt with different gear rations and maybe the ring and pinion change but expect you wallet to be lightened up also. There are many contributors on STF that are very savvy on what you can do to a swing, I am not one of them.

Lee

[1938vw]

your advice is spot on, i also see loads of "unfinished projecs" around, i wont be one of them, even if it takes 25 years!
thank you.

[Chip Birks]

The cheapest, easiest and fastest way to gain MPH out of your trans is installing a larger diameter tire. What size are you running now. I used to run a 195/60-15 on my 60 bug with an early swing trans, I would drive it in the 65-70mph range. Typical revs were right around 3600 rpm on the freeway. It felt high, especially with my straight piped turbo exhaust. Now I have switched to 215/65-15s(lots of tire) these are over an inch taller, and I look forward to lower RPM while cruising, and higher top MPH(Salt flats 130 club candidate hopefully). Eventually I will have a stout bug trans built, as I do have the power to turn mine into a box of chunky goo. So I need to play nice for the time being...

Swing axle will do everything that you want it to do on the street. There are thousands of high performance VWs running them, just know that they have their limitations.