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Wed May 07, 2008 7:57 pm

I am working on a very light IRS mid engine special. It will be a scratch built frame using a standard Bug transaxle and drive shafts.

But I do not want to use the standard Bug IRS rear wheel assembly. I would rather use a modern front wheel drive wheel assembly that will mate to a standard VW Bug drive shaft or CV joint. This will allow me to make up a five link rear or a wishbone rear system.

What I need to know is which, if any, front-wheel-drive wheel assemblies will mate to the standard Bug IRS drive shaft or CV joint. It would be ideal if the assembly came from a sub compact or compact car and perfection it was a wishbone system to start with. But McPherson strut will be ok too.

Thoughts, suggestions and advice are greatfully appreciated.

Thanks

Wed May 07, 2008 10:35 pm

moniker wrote: I am working on a very light IRS mid engine special. It will be a scratch built frame using a standard Bug transaxle and drive shafts.

But I do not want to use the standard Bug IRS rear wheel assembly. I would rather use a modern front wheel drive wheel assembly that will mate to a standard VW Bug drive shaft or CV joint. This will allow me to make up a five link rear or a wishbone rear system.

What I need to know is which, if any, front-wheel-drive wheel assemblies will mate to the standard Bug IRS drive shaft or CV joint. It would be ideal if the assembly came from a sub compact or compact car and perfection it was a wishbone system to start with. But McPherson strut will be ok too.

Thoughts, suggestions and advice are greatfully appreciated.

Thanks

Your description of what you're contemplating is pretty confusing. You say you want to use "modern front wheel drive wheel assemblies", but in your first paragraph you say you plan on using a "standard bug transaxle and drive shafts". I think that means you don't want to use a fwd engine/transaxle.

When you say drive shafts, I think you mean, half axles. When you say wheel assemblies, I'm assuming you don't mean "wheels and tires", (which is what wheel assemblies are) I think you must either mean stub axles or maybe fwd spindle bearing carriers and stub axles.

I think Rabbit, Golf or Jetta half axles might bolt up to VW bug CV flanges. However, If you plan on keeping a bug transaxle, I can't see any advantage to adapting fwd spindle bearing carriers on the rear of your buggy, five links, wishbones or not. The VW IRS rear suspension works fine.

However, if you install a complete small, powerful, cheap, fwd engine/transaxle like a 16 or 20 valve Toyota 4A-GE engine and 5 speed transaxle in a mid-engine configuration in your buggy, I could see enormous advantages. I've seen packages like this installed on a VW pan, using the VW torsion bar suspension.

Thu May 08, 2008 5:21 am

Agreed - doubt you'll find a FWD hub assy that will directly "bolt right up" to old school VW CV's and axles. Could be wrong, but I haven't come across anything like this.
I'd look into platforms that already use an independent rear suspension and RWD or AWD. Maybe an older BMW? Miata? Audi? Maybe Toyota MR2.

I've seen lots of modern small SUV's that are only FWD, but have the infrastructure for 4WD and might provide donor uprights and hub assemblies?

Likely any way you go - you'll be doing lots of fabrication and adapting.
Plus, if you don't properly design the suspension and pick-up points you could end up with an evil handling (or even dangerous) car after all the work.

I lucked into a set of NOS Chassis Shop rear uprights (no longer made) designed for all T1 innards - stub axle, bearings, etc. This helped avoid adapting some stuff, but still pretty complicated to make work as I wanted!

Jeff

Thu May 08, 2008 6:47 am

Thanks for the replies,

Yes the suspension will have to be sorted out for best handling, but that is part of the fun.

Sorry for the confusion in terminology. I was using language from an old VW book. I guess it is out dated now.

The advantages of using fwd spindle bearing carriers, uprights and stub axles with the old VW IRS half axles in the rear as well as in the front include the following:

1. Minimum machining and fabrication on the uprights even if they are McPherson strut type = low cost.
2. Front and rear disks at low cost.
3. They are lighter than the VW equivalent in front and rear (especially if you include the rest of the VW suspension parts) and avoid complex and expensive cast uprights or fabricated steel uprights = low cost.
4. I already have the VW rear and engine = low cost.
5. The system will allow great flexibility in arranging and adjusting suspension parameters.
6. The system will allow the use of a longitudinal engine rather than a transverse engine. I want longitudinal.
7. They will provide the "look" that I want.

The picture below is the "look" I am after for some fun at autocross.

It sure would be a help if someone could tell me what year fwd spindle bearing carriers, uprights and stub axles mate with the old VW IRS half axles or CV flanges.

Thanks

Thu May 08, 2008 9:21 am

Don't the Chevy S-10 stub axles or the Audi stubs have the VW CV bolt pattern/ size? Thought I remember hearing that somewhere. Don't quote me on it!
JiI

Thu May 08, 2008 9:30 am

This has some information that might help.

http://www.sand-bug.com/sb1/index.html

Sat May 10, 2008 6:14 am

Here's an easy (sic) upright that can be fabricated without too much trouble and is adaptable to many different car designs. Perhaps you've watched the thread on this car.
This is an off the shelf bearing carrier from Empi. It fits stock VW beetle stub axles and parts

Here's the upright welded and with brakes bolted on.

A setup like this with lighter brakes and longer travel cv joints would be plenty strong for your project.

Sat May 10, 2008 9:27 am

Aren't Beetle axle assemblies the same as A1 Rabbit stuff?

Sat May 10, 2008 10:06 am

moniker wrote: Thanks for the replies,

Yes the suspension will have to be sorted out for best handling, but that is part of the fun.

Sorry for the confusion in terminology. I was using language from an old VW book. I guess it is out dated now.

The advantages of using fwd spindle bearing carriers, uprights and stub axles with the old VW IRS half axles in the rear as well as in the front include the following:

1. Minimum machining and fabrication on the uprights even if they are McPherson strut type = low cost.
2. Front and rear disks at low cost.
3. They are lighter than the VW equivalent in front and rear (especially if you include the rest of the VW suspension parts) and avoid complex and expensive cast uprights or fabricated steel uprights = low cost.
4. I already have the VW rear and engine = low cost.
5. The system will allow great flexibility in arranging and adjusting suspension parameters.
6. The system will allow the use of a longitudinal engine rather than a transverse engine. I want longitudinal.
7. They will provide the "look" that I want.

The picture below is the "look" I am after for some fun at autocross.

It sure would be a help if someone could tell me what year fwd spindle bearing carriers, uprights and stub axles mate with the old VW IRS half axles or CV flanges.

Thanks

Just go out and buy used Formula "Vee" and do it.... You can probably find one with a trailer and log books and only spend 3k to 4k... Much less that than a build will cost you... A formula Vee with some 13 inch formula FORD tires on it will put it right on ground and a good 2000cc motor and you got a "tiger by the tail"....And do not under estimate a swing axle car for simplicity of construction and performance driving....

We Auto-X buggies and they weigh in at about 1100 pounds.... Only a couple of hundred more that what you are attempting to build.... And with good 2000cc motor the are fast.... But yes a mid engine will provide better handling.

Out of the 6 car in picture above, 4 of them placed 8, 10, 14, 25 out of a field of 146 cars for fasted cars at event...

Do a search -GOOGLE- for "formula vee", may or may not have to use use "VW" or "volkswagen" in search sting..

Dale

Sat May 10, 2008 10:19 am

moniker wrote: Thanks for the replies,

Yes the suspension will have to be sorted out for best handling, but that is part of the fun.

Sorry for the confusion in terminology. I was using language from an old VW book. I guess it is out dated now.

The advantages of using fwd spindle bearing carriers, uprights and stub axles with the old VW IRS half axles in the rear as well as in the front include the following:

1. Minimum machining and fabrication on the uprights even if they are McPherson strut type = low cost.
2. Front and rear disks at low cost.
3. They are lighter than the VW equivalent in front and rear (especially if you include the rest of the VW suspension parts) and avoid complex and expensive cast uprights or fabricated steel uprights = low cost.
4. I already have the VW rear and engine = low cost.
5. The system will allow great flexibility in arranging and adjusting suspension parameters.
6. The system will allow the use of a longitudinal engine rather than a transverse engine. I want longitudinal.
7. They will provide the "look" that I want.

The picture below is the "look" I am after for some fun at autocross.

It sure would be a help if someone could tell me what year fwd spindle bearing carriers, uprights and stub axles mate with the old VW IRS half axles or CV flanges.

Thanks

Ummm... so why not just buy a Formula Vee or Super Vee? Or purchase a Formula Ford, or Lotus, like the one in the picture -

If you realy desire to roll your own chassis & get into tuning a suspension system, I don't believe that I'd start with a strut design... to many compromises in geometry & travel.

Here is an option I've considered for a future project - look at a Mazda Miata IRS rear suspension & cradle. It's comprised of upper & lower controls arms, disc brakes, etc., mounted to a stamped steel carrier/cradle. Imagine removing the axles & differential, and installing the cradle over the top of a VW T1 gearbox flipped to a mid-engine configuration, or possibly using a 914 trans.

Now, using the pickup points of the Miata upper & lower control arms, replace the cradle with a tubular framework, using the Miata bits & geometries. Voila! You have a tunable rear suspension that will utilize Miata aftermarket tuning potential - you'll have to fab axles, but expense is no object, right? :wink:

Similarly, you could also use the Miata front suspension bits to create an IRS, disc brake front suspension; the Miata cradle unbolts from the car. Use it to copy the front suspension pickup points. Use custom coilover front shocks for a Miata & lighter spring rates.

Points to ponder - hmmmmm...

bnc

Sat May 10, 2008 11:47 am

You also might want to read the book, "Chassis Engineering" by Herb Adams, from HP Books...

There is a lot more to setting up a chassis and IRS suspension then welding a few tubes together, you get it wrong, you have a ill handling beast you can never tame, if it ain't drivable, it ain't fun...

Dale

Sat May 10, 2008 7:57 pm

Hey guys,

Thanks for the great info.

I happen to own two Formula Vee chassis. One of them is homolgated with the SCCA. I just want something a bit more sophisticated in suspension design. Not only that, but I really don't fit the Vee chassis. That is one reason I want to go from scratch. I will have more room and be able to sit more upright. I like that.

I also have a Mazda Miata ('92) with a thrown rod. It can be used as a donor car. But I don't think its right for this project. I might be able to get suspension pick-up points from it though.

To clear up some confusion, although the Rabbit front suspension is a strut type, the strut can be removed and replaced with a fabricated upright that makes using the modified parts as an upright member in a double wishbone suspension a breeze. That is what I intend to do. I have most of the suspension figured out in my mind except for dealing with anti-squat and anti-dive. I am working on that. Any help on that is more than welcome.

As for using a VW engine, that is in the works. I am thinking of going to two liters but I do not know much about building one that big and getting some life out of the engine and still do it on a budget. I have thought that some judicious picking at the local junkyard might result in adapting FI to the beast. But I have not seen anyone do that without resorting to high buck racer parts. I am not a racer. Just looking to have a little fun.

I also have a set of front and rear Formula Ford wheels. They are for 5 bolt VW wheels. I am not sure I will use them. I may sell them off and use something else on a 4 bolt suspension. If I could do the IRS with five bolt I might keep them. Hmm.

As you can see, I have a long way to go. Any help is welcome.

Thanks

Sun Mar 25, 2012 4:15 pm

The Ford escort drive axles are the SAME for an IRS bus....so you could use that front end parts for what you want...

Don