I was wondering I see a lot of evos in bsp and sm that run 18x9/10 but i don't see a lot of people running 17x9/10. Is there an advantage to a larger diameter rim? I would think weight would keep people from going up in size. Is it just mainly for the lower profile tire? For example hoosier a6 has 295/35/17 and 295/30/18. All the tire specs seem the same(i.e. weight, section width, overall height, etc). Just wondering.

 

the tire size the is the major factor. the 285/30-18 is the hotness.

 

is that on a 9.5 or 10" wide rim

 

...yes.

either size works well. the 10" or even 10.5" should theoretically be better, but most would be hard pressed to tell a difference performance wise.

 

Might as well share the experience of what will turn out to be a slightly over budget weekend.

http://blip.tv/file/789638/


ok interesting comparison between bsp and stu. If you open up Max Hayter's runs and hit play on Tom's run when max's light goes green they sync up pretty good.

 

I run the 285/30R18 on 18x10 CCWs.

Once you get into the 18x9.5, 18x10, 18x10.5 range, like Marshall said, it will be difficult to tell a performance difference. From my experience, there are three main things to consider -- weight, fitment (spacer needed? how thick?), and availability.

When I got my 18x10s, which was three years ago, availability outweighed weight and fitment, so I have relatively heavy wheels and use 13mm front spacers. However, since the CCWs are custom, I was able to get the exact backspacing that I wanted (just enough to clear the trailing arm in the rear).

I could probably do better now -- there are more wheels available with verified fitment.

 

is thereany nationally competitive evos the run 17x10s currently?

 

Hmmm. The only thing that would "bounce around in there" would be a piece of a valve, wouldn't it? And that should only happen if your timing belt breaks or slips a couple of notches, or if one of your connecting rods lets go and allows the piston to fly up and whack the valves. But the stock connecting rod bolts are supposed to be pretty safe up to about 7800 RPM, from what I've heard. Anyone heard differently? Was Tom running higher than 7800 RPM without replacing the conn-rod bolts?

Anyway, my understanding is that the biggest danger for us mildly tuned SP guys is that you get a tank of gas that doesn't have the octane you think it does, and you run too advanced or too lean and you burn your turbo and melt it. Sad, but not nearly as expensive as what seems to have happened to Tom.

Since I'm about to tune my car for 105 race gas, I'm anxious to hear more about this "incident".

Mike

 

This was the exact question I was about to ask.

What rev limit were you guys running?

d

 

Sorry to hear that you guys popped an engine at El Toro.

Maybe I should have gone to El Toro after all. I may be able to go faster than a broken EVO. But my butt is still sore from the kicking it got at San Diego. Plus, I want to preserve the new transfer case, rear end and clutch. Once a year is more than I care to replace those items.

I think that I may back my rev limiter down a bit. It is currently at 8000rpm.

Frank

 

I've seen spark plugs come apart and bounce the ground electrode around the cylinder.

Sounds like its time for a 2.3 short block and move on to SM... Sorry to hear about the motor, I hope you guys can piece it back together.

 

No, SM is too slow. Stick with BSP!

 

Rev limiter is ~7600 and the engine doesn't make any unusual mechanical sounds other then running on 3 cyldiners/obvious lack of compression. The sparkplugs were all intact (although one plug had the gap 'adjusted'). The damaged plug looked more like it had aluminum depsoits on it rather then something bouncing around aside from the closed gap. Prime suspect is bad gas with inadequate knock compensation leading to melted piston (or whatever else happens when you have insufficient octane level).

does anyone know of a place you can test gas for octane rating?

 

BTW, I like the way this guy thinks!

 

Yeah, I wonder about that source. My car was making good power that day on the same fuel, but I was tuned on 97-98 oct. on a 100 deg day.