All you need is right there!

 

Don't the 285s fit under the stock front fenders? Joe of joe250.com has then with stock fenders, or is there some major modification there? I thought the rear fenders were where the clearance issues are.

 

EVO8LTW,
Not to speak for Joe, but any thing over a 265 is going to rub front and rear, in about 5 places, even with rear fender mods. It may be acceptable for 3 min of autocross, but I would think about using 255s for track or street. Joe car has altered front fenders.

 

I run against Joe250. At the moment he is using 285/30/18 on all 4 corners. He always complains about tires....

His fenders used to rub, but they lost the battle to the will of the tires. To combat the rubbing, he has raised it up to almost stock height.

I can't speak for him, but I think he is looking for something in a more popular (cheaper) tire size.

 

Some interesting info on the 18x10 size. I was strongly considering chasing a set-up with wheels like that for my track days; having them try to destroy my fenders would be a big problem.

What wheel and tire sizes are working well for someone willing to roll their fenders? I've been running RA-1s this year (stock size) and they have been good budget track R compounds.

 

Some other thoughts..

There's always lots of talk about camber and toe but..
How much caster does the Evo come with? Are there any offset bushings that provide more? Anybody considered running camber plates rotated 90 degrees for caster (can camber be obtained at the bottom of the strut on an Evo?) This has proven useful on other cars, I'm assuming its uncharted territory on an Evo.

I also just saw that Buschur has an intake manifold available, and they're claiming some fairly substantial gains. Not sure a short runner design is what we need for this application, but if the gains are any sign there's probably some torque there too. I still want to see a dyno run.

Other questions that I don't know the answer to:

Anybody started to look at the control arm geometry at all?

Are the body panels on an Evo steel, including the hood/fenders? Good bit of weight, as previously mentioned, but doing the fenders right also means there's more room for a wide wheel and tire, and a wider front track.

 

"Stock" specification for caster is 3 degrees, 55 minutes -- just a tick under 4 degrees. You could run camber plates at an angle -- wouldn't have to be 90 degrees. Neal's Scirocco in Oscoda had camber plates rotated roughly 60-70 degrees.

Camber can definitely be obtained at the bottom of the strut. That's how the stock suspension allows for selection of either "-1" or "-2" degrees camber, by flipping an eccentric bolt where the strut joins the knuckle. I say "-1" or "-2" in quotes because very few people have been able to get -2 degrees with the stock suspension. By further elongating the hole in the bottom mount of the strut, you could add more camber. You'd probably want to fabricate a spacer to fill in behind the eccentric bolt to make sure that the bolt would stay where you put it.

The body panels are steel, except for the hood and front fenders which are aluminum. The roof, doors, rear fenders, and trunk lid are steel.


Thinking about weight reduction... Would it be permissible to run a smaller fuel tank in SM? I'm thinking of the line in the rules which states: "Drivetrain and related components (induction, ignition, fuel systems, etc.) are unrestricted..."

Is the fuel tank part of the unrestricted "fuel systems" or is it considered a body/chassis component? I know that SP rules permit installation of a "full size" fuel cell, but that comes with some serious penalties, like requiring installation of a roll cage.

 

I have a question, I'm not ready to do this anytime soon (Damn tuition), but can you put a full roll cage in a street mod vehicle?

 

Yes

 

To clarify further, you can put a full roll cage in a Stock-class vehicle.

 

I think that an alternate fuel tank would be legal in SM. How much weight do you think you could save?

 

I don't know, what does the empty fuel tank weigh? I've seen some fuel tanks for other cars (Camaro/Mustang) for sale with shipping weights listed in the 30-35 pound range -- that seems like a good guess to me. I'm sure one could build a small steel fuel tank and solidly secure it in a safe location with total weight of probably 6-8 pounds. Other than the obvious weight savings in the tank itself, a small fuel tank could be designed to be essentially immune to fuel starvation due to slosh or cornering forces, so you could reasonably start an autoX run with only a half gallon of fuel or so in the car.

Personally, I likely wouldn't go that route, because a 3-4 gallon tank would basically make the car unstreetable except in dense urban/suburban areas. And from looking at the tech manual for the Evo, installing/removing the stock fuel tank looks like a fairly time consuming job -- not something that could be swapped in or out easily.

 

A better way might be to have a bevel installed in the stock gas tank that allows you to fill it with the minimum amount of fuel and still have it siphon and not slosh around. Not sure how beneficial it would be though.

 

I have talked to some different venders, Camber caster plates are on their way... I should have a set shortly. I have tried rotating the camber plates to offer more caster and found a couple of short comings.

1) Bump steer is really nasty when you have such quick steering like we do.

2) the extra caster might cause clearance issues with the inner fender wells when running a 275/40/17 or larger.

3) the extra caster creates this big "vague spot" or to be more specific, it reduces the feedback you get through the steering wheel. It would make a nicer street ride, but combined with the bump steer issue,

I am currently running just over 4' degrees caster, I am not sure we need much more than that.

 

I've wondered for awhile while Neal opted not to go the full 90 degrees, since we can get as much camber as we could possibly use down low. But since an Evo can get < 2 degrees at the bottom, a 45 or 60 degree rotated plate may be a great solution. Any idea how much more you could gain by elongating that hole?

Figures the body panels you can change in SM are already aluminum. I really like the idea of doing wider front fenders to cover a wider front track - maybe 2-4" wider than the rear.

The idea of a fuel cell is pretty interesting. At first glance, the SP allowance looks like it's focused on safety. But seeing as there are no restrictions (comparitively) in Prepared, the SP allowance looks more like a way to allow Solo 1 or GCR legal road race cars to be classed in SP. Based on this, it certainly seems like it would be legal in SM. Would be worth a letter to the SEB first though. Even if you did something as large as an 8 gallon tank, it will still be a fair bit lighter and, theoretically, will allow you to run the minimum fuel load possible without worrying about starvation.

Nobody's done any control arms yet? Wasn't that a main issue with clearancing 285s in the rear?

Also, what kind of bushings are people running?