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crazycanadian
crazycanadian Reader
12/13/15 10:39 a.m.

Is it a slight drift to the right or more of a noticeable pull you can feel in the steering wheel?

Uneven castor L to R on the front is used to combat drifting/slight pulling to the right due to road crown... I'd expect a proper set up race car to drift to the right unless on a perfectly flat road..

bentwrench
bentwrench HalfDork
12/13/15 3:59 p.m.
Austin296 wrote: I went back and dug up my front suspension numbers: Caster: 0 Camber: -3 Toe: 1/8in in bentwrench, My suspension came off of a circle track race car, so the geometry is a little different from side to side. I looked at bumpsteer and I am going to move the passenger steering arm mounting point up ~1in and that removed the bumpsteer that I am currently seeing. The length of my control arms is ~8inches. I completely agree that there is a lot more geometry change with shorter arms. Regarding the tire inflation, are you suggesting I run 22-25psi on the street or at SCCA type events? Also, would that be on all 4 tires or just the fronts? The tires I have on the car now are 275/40R17 BFG Sport Comp2.

If it's not too much trouble I think you will find some caster beneficial, even as much as 8° and a little less camber.

For autocross you will probably raise tire pressure, but on the street you don't want basketballs for tires.

Lonny
Lonny New Reader
2/2/16 9:48 p.m.

Hey Austin,

What's the latest

Are you making any progress

Austin296
Austin296 New Reader
2/3/16 12:30 p.m.

Lonny,

Not really. I've been pretty busy at work lately and haven't had much time for the car. I replaced all the spark plugs and did a compression check(everything was pretty good) to make sure it can eventually handle more boost.

Also, I'm going to have to get a new muffler for the car. The vibrations broke the welds on 2 of the tips so now the muffler looks a little lopsided. I'll probably go with a non-homebuilt muffler for the next one...

Also, I don't know if I mentioned it, but I took the car to Fredericksburg, Tx in early January/late December(about 450 miles) and the car ran great. Biggest problem was that it was cold! driving with no windshield at 80+mph down the freeway in 50 degree weather isn't the most fun in the world, but it wasn't too bad. Overall I think I've got 800 miles on the car.

How's the Goblin MK2?

Austin296
Austin296 New Reader
3/31/16 8:59 a.m.

Hey guys, so its been a while since I posted on here last. Everything is working pretty well (for the most part).

I figured out why the car is pulling a little... When I adjusted the Caster/Camber, I did it with the wheels off while the car was on jack stands, so the suspension was in full droop. Based on the car not being 100% symmetrical due to building errors, the passenger side front suspension has ~2 inches more travel in droop. So when I got them matching, I forgot to take that into account... I will fix it next time I have a chance to take the front end off the car(the only way I can adjust everything...).

Also, It turns out that my home made muffler didn't hold up as well as I'd hoped. I used too thin of stainless and the metal was breaking in the heat affected zones just outside the welds.

I purchased a new muffler for it, but I had a question relating to that. How much weight can you hang off the back of the stock exhaust manifold before you need to worry about it breaking? Here is a picture with the old muffler on it(note that there is a brace going back to the engine).

Here is a link to the new muffler:

http://www.summitracing.com/parts/vpe-10632/overview/

I am a little worried that a 24lb muffler is going to break something. Any thoughts?

NOHOME
NOHOME PowerDork
3/31/16 9:02 a.m.

Why are you not running any braces from the frame to the muffler?

Warren v
Warren v Dork
3/31/16 10:30 a.m.

There's no flex line between the manifold and the muffler, so it's going to move around a lot with the engine. With the way he has it set up, the only way to support the muffler is from the engine/transaxle.

NOHOME
NOHOME PowerDork
3/31/16 1:45 p.m.

The muffler would have to be supported by rubber hangers much like a normal exhaust. Flex couple would not be a bad idea either.

Austin296
Austin296 New Reader
3/31/16 3:28 p.m.

I was initially thinking about the idea of using a flex line, but I like the look of the muffler just coming straight off the back of the engine and not protruding too far back. Regarding rubber joints, even after I replaced the rear motor mount, the engine still moves a fair bit when revved up. At the muffler, it can move about 2-3 inches up, so I think that is beyond the travel of rubber hangers.

I'm not really sure what to do beyond the 1 strap I have going up(or if anything more is needed)...

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