can I convert swing axle to IRS?

Converting to irs won't be as hard, since the trailing arm brackets are already there. Narrowing the trailing arms 1" per side will make fitting the tires/wheels you have possible (don't take this as gospel; without seeing what you have I'm just guessing here). Type 3 automatic axles (driver's? side are shorter than type 1- apparently you can get them new from EMPI) will work and the trans will need an irs differential, side covers and drive cups; someone who knows their way around transaxles will be needed here. It's fairly involved, but very doable; a great winter project. I believe the springplates are different too. Good luck; you'll love the improvement in ride and handling. Al

Another option is to buy custom made wheels, which would allow you to go with the needed offset to clear the fenders. 

A really slick alternative would be to get a pair of Porsche 924T trailing arms, complete with stub axles and disk brakes.  Get the mounting bolts with them, replace the pivot bushings with new ones and run Type 3 prop shafts and spring plates from A '69 VW sedan.  Everything should bolt together, provided that you sell your swing axle transmission and replace it with an IRS version.  Lots of these have been done on the Samba and Pelican web sites so the information and help is readily available there.  You'll need IRS spring plates for a '69 VW sedan - I would look for the dual plate versions.  Someone on here did this conversion last year AND managed to decrease the track width.  If you do a search you'll find it.

Now, the REAL problem.  In order to change the spring plates you have to get the torsion bar end caps off (the spring plates are welded to the end cap).  

In order to get the end caps off, you have to either remove the body enough to slip the end caps out underneath the forward part of the rear fender, OR you have to cut a hole in the body just forward of the rear fender opening (just like the cap on a 'real' 356).  

This will allow the outside end of the cap to protrude just enough for the inside end to slip off of the torsion bar and then angle down and out.  

It's easy if the hole is there (and makes your car look more like the real thing) but impossible if it's not.

Would I do it to my car if it were a swing arm and the mounts were there?

In a heartbeat.

So does Vintage put sway bars on the swing axles?

No.  Some people put camber compensators on their swing axles. 

Vintage Speedsters also don't come with a sway bar on the front beam.  Because I'm some guy on the internet, I have an opinion and it is that I would first restore the stock Type 1 sway bar on the front and see how the car handles before adding a camber compensator to the rear axle.  You can drive the car without a front sway bar but it definitely improves handling.      

These cars typically have a lot of negative camber so eliminating wheel tuck and jacking is probably not a huge concern unless you push them to or beyond their design limits, in which case I'd add a functional roll bar before I put on a camber compensator.

The camber compensator on a swing axle car is a must, and I feel like mine (a Beck) handles quite well with it, even with swing axles.

I am now in the process of collecting parts for my IRS conversion. Since I will have to change the tranny I am seeking advice for gear ratios. I am presently running a mild 1915 engine with a stock trans. I put about 2000 miles on it this summer-alot of highway driving and it ran fine. It never ran too hot  I installed a ch temp gauge on #3 and a sump oil  temp gauge to monitor. The car got 22-24.5 mpg  to Carlisle and back running about 65mph with occasional bursts higher. Of course 1st gear is too low but I am satisfied with2,3 and4. However I am open to suggestions. Any recommendations are appreciated. Thanks.

Joel

Swingaxle and rear anti-sway is a BIG NO NO!

Swingaxle needs a camber compensator or nothing. IRS and anti-sway bars are compatible.

The stock 1-4 gears are nearly the same between years, the primary difference in gear ratios is the ring and pinion used got taller as the engines got bigger. 1200cc -> 1600cc, 4.375 -> 4.125 -> 3.875. If you are happy with the gear ratios you have now, just find an IRS box with the same ring & pinion, but my guess is that you'd be fine with a late model 3.875 R/P box. Not sure your engine is quite big enough to handle an aftermarket 3.44 R/P and still be happy.

With a mild 1915 I'd recommend a 3.88 r&p with stock gears.  

I agree with Ron O's opinion.....  My Spyder used a 3.88R&P and the .82 4th....  It was a workable combo with the Spyder's  1,400 lbs....  It would have been better,(much) with the standard higher 4th ratio....  

At one time I had a 4.12 r&p/.82 fourth combo.  I didn't like it.  The difference between 3th and 4th was too great.  At 45 to 50 mph the car would be revving too high in 3rd and too low in 4th.

First, Danny - I don't understand your response.  IRS and an anti-sway bar go together like peanut butter and grape jelly.  Also, an anti-sway bar in a swing axle rear is OK if (and ONLY if) the bar is attached to the rear torsion tubes or pan and has "dog bone" links connecting it to the shock mounts to allow dual axis movement. That's the same set-up I had on a swing axle dune buggy years back and it acts about the same as a camber bar.

OK, now back to the original discussion and echoing some of what Justin said...

For gearing on a 1915 I would suggest the following (and this has all been covered on here several times in the past):

3:88 R/P ratio

3.09 1st gear

1.76 2nd gear

1.23 3rd gear

0.89 4th gear

These will give you a much smoother take off (and the VW 'stump puller' will be gone), and the gaps between 2, 3 and 4 will be more evenly spaced, rather than a big gap between 3 and 4.  

Try it.....you'll love it.

These should work well up to a 2332cc......above that you can move to a 3:44 R/P

I hope Jack Crosby lists his gearing - Jake did an interesting set of splits along with a 4:12 R/P. much more reminicent of the original Porsche gearing but chosen for the expected torque, driving expectations and weight of the car and contents.

also, Sam, at Rancho, can supply just about any gearing ratios you might wish....just ask.

For a low budget answer, an irs transaxle with stock first through 4th gears is the way to go. If you like to rip around town then the 4.125 r&p will be more fun and if highway cruising is your thing then the 3.88 would be the ticket. I like Gordon's ratios, but a custom 1st-2nd mainshaft/gear set is expensive (5 or $600) and the close 3rd gear (another 200-$300 with the hub welded on and ground) makes it a slightly pricier solution. If stop light dragging isn't your thing, that box would be fun in a Speedster, though.

Listen to Ron; the spread of a stock 3rd and .82 4th is too wide to be practical, no matter what the r&p is. And as Justin said, if you're happy with the gears in it now, why change? Al

PS- I've never used a 3.44, but I believe what Justin said, "not sure your engine is quite big enough to handle an aftermarket 3.44 R/P and still be happy." is right on the money. I can't see anything under 2100-2200 cc's being right for such long gears.

What's the 1915 got in it? What size carbs? cam? heads? exhaust?

Gordon--I told Jake that I wouldn't post my gearing on here. He asked that of me so I'll honor what I told him. He's always been straight with me.

 Every combo he puts out is different so it wouldn't be very helpful anyway. 

And it would take MassIVe Type 4 power to pull those gears at those RPMs, along with the added thermal conductivity that 26% more cooling fin area offered by the TIV over the T1 :-)

Al

Thanks for your imput. Your advice, along with the other guys, will definitely help.

You asked about my engine .It was a low mileage mexicrate 1600 cc that came with my  2006 Vintage that I bought used 2 years ago.Last winter I pulled it out and brought it to a 28 year experienced air cooled mechanic who bored it out and decked it for 94mm jugs. The engine now has  W100 cam [mild]

                       stock heads and valves-they were perfect.

                       new lifters

                       oil sump now have 4 qt capacity

                       heavy duty pressure plate

                       electronic ignition

                       dual weber  idf 40's

                       exhaust ceramic premium extractor {tuned headers] and a PHAT BOY

                       ss muffler.

I spent a lot of time installing the heat, the engine tin, and adjusting the carbs.The engine runs good 95% of the time-the other 5% it farts and backfires. It was a great learning experience as I had never built a VW engine. I enjoy working on the car and driving it.

Joel

Joel- Sounds like a lot of fun. Where does it peak with power- 4800 or 5,000rpm? A good winter project would be to have the heads ported with a 3 angle valve grind with some 1.25 rockers added to take advantage of flow capabilities of the new ports; another 500 rpm on the top end, 10? 12? hp and no power loss down low!

What's the compression ratio? Al

Gordon, I think my response is accurate and I stand by it. Re-read it, then maybe again if you're having trouble. Nobody knows of this special sway bar that attaches everywhere that you used on your swing axle Dune Buggy before I was born. So today, with what is commonly available: swingaxle=camber compensator, IRS=anti-sway bar, like I said above. Of course, front anti-sway is always good. I'd start with a factory bar if you have none, then move up if you get one for the rear, they need to complement each other.

For trans, Go with ALB's suggestion, great bang for the buck.

Dan:  Yup, I re-read it and agree.  For what is available today, right off the shelf, only camber compensators seem to be available.  The anti-sway bars that we used to use were from after-market shops for foreign cars and are no longer available, it seems.

I have a picture, somewhere, of the front anti-sway bar on a 356 - it mounts backwards from  our set-ups and seems to make a little more sense.  When I find the picture I'll post it just for the heck of it.

EDIT:  Found them.  As you can see (one car is a '55 and the other a '57) the original 356 had front sway bars very similar to "modern" ones, today:

I think this is the sway bar of which Gordon speaks, on my VS swing axle.

Combined with my front sway bar, makes a lot of difference in improved handling. If I push it too hard through a corner, the inside rear will eventually lift. I've learned where that threshhold is and don't venture past it. 

Sure would like to have Kevin's A-arm suspension! 

Gotcha, Guys. I am thinking suspension travel needs to be limited before the dreaded tuck-under happens, which is VERY dangerous.

I am thinking most people don't drive that hard very often, and the surprise factor(read that PUCKER factor) may cause brown shorts when she tucks under and you are along for the ride......

I have a compensator on my Beck and it handles really well.

Does the camber compensator aliviat any worries of tucking.

I am an argessive driver on some of our realy curvy roads wher I live

The handling feels very much like my 912 used too

How good is a  beck speedster handling wise compared to other Porshes and sports cars?

Doug, no worries, the whole point of the camber compensator is to prevent tuck-in. You're good, drive the snot out of it!

Tuck-in or under is a very real probability when using an anti-sway bar on a swing axle, without suspension travel limits, which was and is my point. I really don't want anyone hurt because they read on the internet that a swing axle and an anti-sway bar is a good thing. 

My swing axle has a camber compensator and I wish I had the nerve to "drive the snot out of it", but during the first week of exhilarating ownership the rear broke loose without a forewarning wiggle. Fortunately I had the entire width of an empty road to reign it in...came very close to needing a change of underwear, and have driven very conservatively ever since!

Carl - that's how I found my car's handling threshold! 

Still, I can push it just enough to leave a lot of cars in a sweeping curve or intersection corner! Too much fun!