IRS improvements for OFF ROAD

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Old-Towd
Posts: 233
Joined: Wed Apr 07, 2010 5:00 am
Location: Yorba Linda, Calif.

IRS improvements for OFF ROAD

Post by Old-Towd »

My buggy Wrecker has a 8" beam ( Laser Innovations - Anaheim,Ca.) with adjusters and the adjusters are set at lowest load with V.W. Bus shocks ( #211513031NBR ) the rear torsion bars spring plate are set unloaded to half cover the bottom left cover bolt hole.

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So far no complaints the ride is very comfortable. Did a trip to El Mirage Dry Lake with buddy Kevin and his Meyers Toad doing a little Hair & Hound of course I was the hound we came across I call " real tight motorcycle woopers " The front end was handling it but the rear would hop off the ground and at that point would hit the full extend stopper on the spring plates mounts man it was a load bang like you hit it with a sledge hammer. The white KYB's were doing nothing with that load. So heres the dilemma how far do you go to improve your suspension Question #1 how often do you push your buggy off road Question #2 how much do you want to spend Question #3 do you REALLY realize how much alteration it will take.

Wrecker's rear suspension has only failed me a couple times, so I'm thinking maybe mild improvements like heavy duty trailing ams and a set of Fox shocks with remote reservoir ( was told remote reservoir keeps the oil & gas from mixing ) New trailing arms ? we've seen some of our buggy buddies break the stock trailing arm in half, so heavy duty it is. Now what about all the talk about 3x3's 3 inches longer and 3 inches wider you can buy these in all kinds of combinations. I don't want to be wider and if you go longer remember it will change your tire placement in the wheel-well. I was told that it's better to go to light offroad IRS torsion bars ( Sway-a-way ) to achieve the ride height I want with out so much preload slowing down my topping out problem and

Fox can set up my shocks to help the problem too. I was trying to think out the wider longer trailing arm dilemma like a custom 1x1 worth the money, if you go longer it should give you a little more travel with out a lot of alterations.

I'll update this link with any new progress - feel free to add any Info.

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jsturtlebuggy
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Re: IRS improvements for OFF ROAD

Post by jsturtlebuggy »

Jay,
The rear stock shock location on a IRS suspension is not really in the right location. It to far forward in relationship to axle center line. It works fine for average use, but when pushed in higher speed and rougher conditions, its short comings appear. Yes I know that some off road class require using the stock location for shock mounting and they make them work. It just that the ride becomes more severe then most would like for a play buggy.
Using a larger diameter torsion bar and setting at less preload does help, but you still need more shock to control it.
If you have the room, mounting of the shock on top of trailing arm and close to axle center line you can use a lighter valve shock to control movement.
Going to a 1in longer trailing arm like what the 1/2 1600 and 5/1600cc classes use will give you more travel. The stock Bug CVs will limit amount of travel you can get. Switching to something like the EMPI Bus (type II) Race Prep CV joints will allow for more travel without the CVs binding. EMPI CVs have proven themselves to be decent quality with good reliability in many off road races. I am using the EMPI 930 CVs with good results.
With going to the 1in longer trailing arms and the race prep type II cv joints, larger diameter (24-25mm) 26 9/16in long torsion bar and mounting a longer travel shock on top trailing arm should allow for a softer with more travel (10-12in) and more controlled ride.
On my own buggy I am using 3x3 arms, 930EMPI Race PREP CVs, 26MM 26 9/16in long torsion bars, and a 12in travel FOX remote reservoir shock. I am getting 13in of usable travel. I could get more travel out of suspension, but are limited to clearance between tire (33in) and body clearance and making the CVs last longer by not pushing them to their limits.
I also have cut off the lower spring plate stop on the torsion housing and using limit straps to control how far wheel travels at full droop. The upper stock shock mount is cut off too, and a urethane bump stop on fabricated bracket is used to limit how far wheel travels up.
I am also using a 6.5x15in wheel with 4 1/8in back spacing to reduce wheel track back closer to stock (also to get tires under the fenders) to be able to fit on narrow trails.
Ed-Chenal
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Location: SoCal

Re: IRS improvements for OFF ROAD

Post by Ed-Chenal »

Thank you for the information Joseph. I plan to use it on the Four Seat Buggy.
Old-Towd
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Joined: Wed Apr 07, 2010 5:00 am
Location: Yorba Linda, Calif.

Re: IRS improvements for OFF ROAD

Post by Old-Towd »

Thanks Joseph for adding great Info. Ed the new four seater is for you to drive or at your stage of Buggy Career will you be sitting in the back.
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manxvair
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Location: Mohave Valley, AZ

Re: IRS improvements for OFF ROAD

Post by manxvair »

Some great information Joseph, Thanks.
Question; will a type 2 stub axle fit in a type 1 trailing arm? Lori Ann's tow'd has type 2 inner, type 1 outer CV's.
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jsturtlebuggy
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Re: IRS improvements for OFF ROAD

Post by jsturtlebuggy »

Mike, to use the Type II, IV (100mm) CV joints at the outside end you need Thing (type 181), Porsche 924, or 944 NonTurbo stub axles. I have found many sets in wrecking yards over the years. I don't have any extras at present time.

Or you can go to the person Art had the stock type 1 stub axles modified for 930 CVs(108mm) and I sure he makes them to fit the 100mm CV joint.

Since EMPI is having a problem with their 930 stub axle like Art had break on him, I would stay away from the ones they sell for the 100mm CV joint. They could start having a breakage problem too.
dcamomanx
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Joined: Tue May 18, 2010 5:00 am

Re: IRS improvements for OFF ROAD

Post by dcamomanx »

Mike,

The short answer is no. The type 2 axle is longer and thicker then the type one. Having said that it can be done. You would need to find the correct bearings and then run bus brakes and drums to fit the larger Axle and 46 mm axle nut. I don't know if you saw but at the Bay of LA there was a blue baja bug on a trailer with the divers side wheel missing. They were running this set and the bearing failed and were unable to find replacements. There plan was to take the baja to the finish line on the trailer and try and limp it across for the class win as they were the only ones in that class. I don't know if that actually worked out for them.

There is an easy way to get a type 2/4 cv joint on the out position. You can use a thing/ Porsche 924 or 944 sub axle. They have the same axle size as the type 1 but with a type 2/4 cv flange. The nice part is it slips right into the type one arms and uses the type one bearings.

The other thing you have to change is the axles. You need a slightly shorter axle with longer splines to be able to run type 2/4 cv with a bus transmission in a type one set up. Again the solution comes from the thing or Porsche 924/944. These axles are shorter then the type one axle and have the correct splines.

This is the setup I'm running in the manxter. At the time I found a 924 at the local pick your part and got the axles sub axles and cvs and cv bolts. All I did was clean them up inspect and repack the cv and bought new cv boots. They have been In The manxter for the 8 trouble free years. Each complete axle was about $40

This can also be done with aftermarket parts,but I like the idea of running German parts plus I like the "frugal" approach to things :wink:

Hope that helps
Doran
Ed-Chenal
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Location: SoCal

Re: IRS improvements for OFF ROAD

Post by Ed-Chenal »

Old Towd wrote:Thanks Joseph for adding great Info. Ed the new four seater is for you to drive or at your stage of Buggy Career will you be sitting in the back.
I'll be driving the four seat buggy for the next 31 years then, I'll move to a rear seat position where I'll sit inside an Urn.

I think the stainless steel model would be the most practical.
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manxvair
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Re: IRS improvements for OFF ROAD

Post by manxvair »

Thanks, for the info guys. i didn't mean to steal Jays thread. Just curious about all the CV, range of travel talk.
Old-Towd
Posts: 233
Joined: Wed Apr 07, 2010 5:00 am
Location: Yorba Linda, Calif.

Re: IRS improvements for OFF ROAD

Post by Old-Towd »

Manxvair, no stolen thread it generated more great Info. thanks
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