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..
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.
Hey Austin,
What's the latest
Are you making any progress
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?
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?
Why are you not running any braces from the frame to the muffler?
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.
The muffler would have to be supported by rubber hangers much like a normal exhaust. Flex couple would not be a bad idea either.
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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