Montage type T rear suspension

[marfen]

Anyone come up with or seen a good upgrade to the Montage rear suspension for the t type with the square double A arm setup utilizing the Citation frt spindles. I'm going to be running V8, Porsche transaxle with 930 CVs and am wondering if there is a better rear upright to incorporate in there, maybe better A arms too. Any idea , recommendations appreciated.

[Blueovalz]

With such a "radical" change, you may need to fabricate what you're looking for. If you could post some photos of what the current set-up is, I'm sure some ideas could be thrown about.

[marfen]

965966967968 Sorry about the pic rotation.
With such a "radical" change, you may need to fabricate what you're looking for. If you could post some photos of what the current set-up is, I'm sure some ideas could be thrown about.

[Blueovalz]

Several comments:

I assume there is a toe link that was removed prior to the photo?

So the Citation front upright is inverted, and the shock-mount boss is bolted to the lower control arm. It appears it was heavily modified in order to get it to bolt on (shortened and welded on).

It appears the Citation has a 3-bolt bearing assembly? I wonder if just by chance this will match or can be modified so that a more common micro-stub bearing assembly (S10 for example) can be used instead that would then allow conversion to 911 CVs.

I'd need to ponder on this more, but as I see it right now, whole-sale removal and replace is needed for just about any improvement here, be it with unequal A-arm, or trailing link, or whatever. Based on the length of the lower arm, plus the inner lower bushing retainer length, and the already existing toe-link (I hope it had one), I'm not sure if you'd not be better going with a Corvette set-up. But I don't know how long the Corvette lower arms are though. Not sure if Dave Savage's rear uses them, but something like that might make sense after seeing what you've got.

Last thought (based on assumption that you've got some decent fabrication skills) is to fabricate an upright that is conventional in design of the 60's and 70's sports racer rear uprights (thus eliminating the toe-link requirement), but with a pinch-bolt assembly welded to the top of the upright to allow use of the current ball joint. This would allow you to get an aftermarket 930 CV micro-stub bearing assembly that would let everything bolt up, and I think, still use your existing arms.

If it was me though, I'd have to seriously consider gutting what I have, and starting fresh.

[marfen]

Very good advice. No toe link in the original Manta plans or instructions ...yikes. Fab skills no problem. Done a lot of chassis work on drag cars, hot rods, sand rails, etc but this will be first mid engine "handling" car so I appreciate any direction. The "stock" Manta suspension looks weak to me but the rear frame structure is beefy enough to handle anything. Haven't got the car up on the frame bench yet to check how square it was built, etc.
I've been considering corvette rear...which do you consider the best way to go...c4 c5 c6?
If I can't source the corvette susp I will have to go with fabbing stronger wishbones from DOM and making uprights with 930 microstubs, wilwoods, etc.

Thanks for the input and taking the time to look over these pics!

[marfen]

When I first looked under this car I thought the square wishbones were homebrewed until I looked around on line and saw these came with the kit.

[marfen]

Dismiss c4.

[Blueovalz]

Wow. So the entire toe alignment was handed by a ~1" wide boss on the lower control arm!

I think this could be faily straight forward. You've already go inner arm pickups. And fabricating a upright that is basically the same at the top as it is at the bottom (a tube with a long bolt that can go bushings (or Heims) is fairly easy as well. Doing that will allow all toe control to be handled by the arms without any trailing links. You can use common aftermarket hubs (microstub), and you're set.

A crude drawing, but you'll get the point. Very simple but effective. A narrow box with tubes on top and bottom for attachment to arms. I make mine 8" wide to provide more than enough leverage to maintain toe, especially with the Heim joins. With bushings, you'll obviously get some deflection, especially with sticky tires and high torque. I've seen more narrow uprights, but I'd go as wide as you could allow for clearance inside the wheel barrel, or reasonable without overdoing it and adding unnecessary weight. Doing it this was will be simpler than the trailing link for your application (I feel), but you would need to be very accurate on your arm geometry/dimensions to ensure no binding between the arms during suspension travel. Everything has to be parallel on the chassis. I neglected to but caliper mounts on the drawing, but that is determined by what kind of caliper you're using, and the rotor offset. You could get lucky on that location.

969

[marfen]

Terrific advice…many thx.
Fabbing tubular replacements is the way to go along with manufacturing my own uprights. Easier and it allows me to run 15s for that old school look.
Any recommends on size and thickness of DOM, rod end size for tubular wishbones?

969[/QUOTE]

[Blueovalz]

I have no engineering basis for recommending 5/8" rod ends, even though 1/2" have been observed on other projects similar to ours (good quality ends). I made my uprights out of .090, but they had internal reinforcing walls (which I would recommend on any sheet fabricated upright. You could also simply purchase 1.5" aluminum plate, have it machined with the two bolt holes, and bearing hole, and then make the shock mounts bolt-on. It would be solid aluminum, and probably heavier than the steel sheet, but it would be very simple.

[marfen]

thx again for your time and knowledge.

[marfen]

Wouldn't it have been nice if Manta had centered the rear wheels in the wheelhousing opening...I have 1" from the back of the 295/50/15s. You can see the same thing with the montage at the top of the forum page. And a little more room in the front wheelhouse for turning clearance...hard finding a tire size that's short enough so it doesn't rub...25" too tall...got to look at 24". I guess the room was needed when designing it.

[marfen]

Is there handling advantage to running as wide a rear suspension as possible upright to upright with serious positive offset rims vs a more narrow suspension - upright to upright with 4-6" taken out of the width. Playing with C5 rear stuff now and I can go either way.