Type II IRS Conversion
Getting Some Speed out of Your Old Transporter
From the March, 2009 issue of VW Trends
By VWT Staff
Most people have a lot of respect for a Transporters that are still on the job after all these years. Though they can be used to haul most anything from point A to point B (including up to a half-dozen of your closest friends), one of the largest complaints from the most people is the lack of speed. Even with engine upgrades like larger displacement and intake/exhaust mods, most stock Buses lack the power to keep up with the breakneck pace of Southern California traffic. Such is the case with our project Single Cab.
This was largely due to the reduction boxes on the end of the axles. They consist of two gears encased in a metal housing that effectively reduce the gear ratios from the transmission. Volkswagen wanted the Single Cab to be able to haul heavy loads, so instead of just lowering the ring and pinion ratio, they added four extra gears and two extra bearings to the trans. This are fine if you want to haul a 3/4-ton payload or go 65mph down the freeway with the gas pedal to the floor. But, that's not fine with us.
We checked into the idea of a 3:88 ring and pinion, like we have seen on several period Type IIs, but that would still force us to the use the reduction boxes. Since we never planned to restore the Single Cab back to factory specifications, the reduction boxes didn't really need to be there. Next, we checked out the swingaxle conversion, but using that method of deleting the reduction boxes means that you have to lower the rear of the Type II by about three inches, a look (and function) we didn't care for. We wanted to keep the height stock.
Old Speed, in Paramount, Calif., has come up with a way to accomplish what we wanted: Install an independent rear suspension (IRS ) transaxle, complete with trailing arms, C.V. joints, axles and brakes, from a 1969 and later Beetle, into the Type II. This way, you can retain the stock ride height, and the transaxle's gearing is like its Sedan counterpart, On top of it all, we would be able to keep up with the flow of traffic. If you're looking to alter the ride height in the future, the beauty of an IRS conversion is that you can sit anywhere between "in the air" and "in the weeds" and not have the tires tuck in at the top like with the swingaxle conversion.
Old Speed offers this conversion either as a kit or a "drive it in, drive it out" service. With the latter, Old Speed provides all the necessary components, such as a rebuilt IRS transaxle, (whatever performance level you require), all new brake drums, wheel cylinders and brake shoes, and all the other associated hardware.
Another nice thing about the Old Speed IRS kit is that nothing is taken away from the original setup. All the brake line tabs, mounts and hardware are still there, and the only modification, if it could be even called that, is that the original brake and parking brake lines have to be bent a little to work around the trailing arm brackets.
Since the Single Cab's main function is as a parts hauler we elected to upgrade the transaxle. Enter Kevin Richards, proprietor of KCR VW Transmissions, in Riverside, Calif. Kevin is well-versed in VW transaxles, as his dad used to work for EMPI back in "the old days," and Kevin has been around VWs for as long as he can remember. His transmissions are in some of the fastest VWs in the U.S., and one of the transaxles of choice for quite a few of the Der Renn-Kafer Cup Series cars.
When speaking to your transaxle builder be honest with your intentions. They cannot help you if you buy a stock rebuild and attempt to heal-tow the clutch at 6000 rpm all the time, and bring him back a transaxle full of metallic Jello. Kevin suggested that we go with the IRS Type 1 transaxle with a Klinkenberg 4:12 ring and pinion and a 3.80 first gear, a 2.06 second, a 1.26 third and a 0.089 fouth. In addition, he recommended that we have third and fourth gears welded, steel shift forks, hardened keyways, IRS Super-Diff. and a heavy-duty aluminum side cover. Kevin calls this his "Super Street" transaxle, and it's a terrific value.
7311 Madison Street, Unit "A"
Paramount, CA, 90723
KCR VW TRANSMISSIONS
9000 Arlington Avenue, #108
Riverside, CA 92503
This is an IRS transaxle from...
This is an IRS transaxle from Kevin Richards at KCR Transmissions, in Riverside. Although Old Speed does the installation with a rebuilt stock unit, and 99 percent of the time that's fine for most applications, we wanted to make sure the Single Cab was still fully functional as a work truck to haul things and tow future project cars. This transaxle will more than fill the bill.
The first thing Old Speed...
The first thing Old Speed does is to lift the truck up on one of their lifts and remove the engine. This is necessary to expose the core work area: the transaxle. Though this is not a job for the beginning VW enthusiast, it is something that can be done with the basic of shop tools.
Remove the brake drums and...
Remove the brake drums and parking brake cables, trailing arm bolts, cradle mount bolts the nose cone mount nuts, clutch cable, starter, and drain the oil out of the center section and both reduction boxes.
The transaxle is now lifted...
The transaxle is now lifted out of the truck.
The original Type II spring...
The original Type II spring plates can now be removed. Unlike the Type I, there is virtually no pre-load on the trailing arms in the relaxed position. They are simply tapped out with a hammer and pulled off the torsion bar splines.
Now begins the task of measuring...
Now begins the task of measuring everything to make sure the trailing arms are in straight. Old Speed uses a string line to establish the absolute center of the truck, so they can measure everything before placing the brackets in their proper place for welding.
There are three washers on...
There are three washers on the trailing arm assembly shown here, but only two of them will be used when the trailing arm is actually bolted into the brackets.
It's quite an involved process...
It's quite an involved process to make sure everything is fitted correctly before the inner brackets are welded into place. If you are doing this yourself with the Old Speed kit, take your time, measure everything carefully as many times as you need to ascertain that everything is lined up and plumb. Even Old Speed, where the conversion is done on a regular basis, takes a few tries to get everything to their liking.
A little creative bending...
A little creative bending is necessary on the emergency brake cable tubes to get them to clear the pivot brackets. As well, the brake lines need a little tweeking in order to get them to clear.
Now the assembly of the trailing...
Now the assembly of the trailing arms, with new bearings, begins. Once the brackets are welded in, it's pretty much a matter of re-assembling everything. Keep in mind that if you screw up the welding of the brackets, you could end up with a Type II that handles badly and cannot be aligned, either for camber or toe-in.
Then re-pack the Type I C.V....
Then re-pack the Type I C.V. (constant velocity) joints with fresh grease and install them on the Old Speed axles, complete with new rubber boots.
The kit comes with all new...
The kit comes with all new drums, brake shoes, wheel cylinders, axle nuts and good, used, modified, spring plates. If you want to upgrade the rear brakes you can also get the kit with the Type III rear drum brakes, or if you really want to be able to stop, Old Speed can do this with a four-wheel Porsche 944 disc-brake conversion as well.
Once the trailing arms are...
Once the trailing arms are in, the transaxle can be bolted back in, complete with the Old Speed supplied mounts you see here.
Once the trailing arms are...
Once the trailing arms are welded in, Old Speed welds in new upper shock absorber mounts.
A little trick we showed you...
A little trick we showed you a while ago was Russell Ludwig safety-wiring the throwout bearing so it can't fall off. Here, he does it to the Type II's re-packed, throwout bearing.
Everything is double and triple...
Everything is double and triple checked before tightening the spring plates to the trailing arms. After that, a third hole is drilled in the trailing arm and another nut and bolt used.
Another little trick piece...
Another little trick piece from the Old Speed kit is this little adaptor that takes up the slack in the original Type II emergency brake cables, so they can still be used on the Type I brakes.
Here is the completed conversion,...
Here is the completed conversion, just waiting for the engine to be re-installed. Once the engine is back in, and the Single Cab is back on the ground, the toe-in and camber are checked. It it is just the tiniest bit off, back up in the air it goes. The string line is re-attached and the necessary adjustments are made.
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