SCCA CAM-C Thread

[NightmareMoon]

Also are you running any power adders?

I have E85, ported TB and ported 18+ manifold, and a high flowing closed intake box. So some extra power, but no blower, and no headers (yet).

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[Aluehrs11]

I always interpreted it as 6" from the whatever is most forward point.


It is not - '15-'17 PP cars with 3.73 ratio were only making ~59mph on a stock 275/40R19 tire (that version of MT82 has a short second gear). His tire is also shorter which lowers the max speed even more.

(18-23 on the other hand have really tall 2nd gear and you kind of have to use shorter tire or install 4.09 or higher gear in the diff for this car to move at all).

Yep makes me regret the 15. I heard complaints about 18 and up struggling to find a good gear on road course. But I didn't think about it the other way with autocross. Constantly running out of gear in 2nd.

 

[Aluehrs11]

I have E85, ported TB and ported 18+ manifold, and a high flowing closed intake box. So some extra power, but no blower, and no headers (yet).

Kudos to you for keeping up/ beating higher horsepower cars

 

[kz]

Yep makes me regret the 15. I heard complaints about 18 and up struggling to find a good gear on road course. But I didn't think about it the other way with autocross. Constantly running out of gear in 2nd.

You could try putting 3.31 in but it doesn't really buy much on a faster courses. Few locals with highly modified 15-17s are running T56 Magnums in their cars but that's hell of an expense and large amount of work.

 

[WItoTX]

I always interpreted it as 6" from the whatever is most forward point.


It is not - '15-'17 PP cars with 3.73 ratio were only making ~59mph on a stock 275/40R19 tire (that version of MT82 has a short second gear). His tire is also shorter which lowers the max speed even more.

(18-23 on the other hand have really tall 2nd gear and you kind of have to use shorter tire or install 4.09 or higher gear in the diff for this car to move at all).

I didn't see a PP in his signature, and assumed non PP car. I should know better by now, that is hand typed in LOL

 

[Aluehrs11]

You could try putting 3.31 in but it doesn't really buy much on a faster courses. Few locals with highly modified 15-17s are running T56 Magnums in their cars but that's hell of an expense and large amount of work.

Yeah that sounds like a lot of money for a few mph haha. I'm just going to try a 295/35 next season. Maybe get a couple mph from it.

 

[TeeLew]

Ifnhe did

I’m not even sure I want to run a bigger splitter, as I already scrape plenty often with my current one. Probably raising it for clearance would be less net downforce than running the slightly smaller one close to the ground. Ideally you do both low and big but practically speaking I still need to drive the car off site a little.

And this is where the trade-offs start to show up. There's likely other things to do if you need front downforce. The game of loading three feet of splitter in front of the car to make it turn tends to look a little silly and induce a *bunch* of pitch sensitivity.

 

[mustanghammer]

Yeah that sounds like a lot of money for a few mph haha. I'm just going to try a 295/35 next season. Maybe get a couple mph from it.

Yep this is spendy right now. A few years ago getting a used PP rear end and changing the ring and pinion to a 3.31 was affordable. Not now.

I have run some local events where 3rd gear was needed. I found that a short shift to 3rd worked pretty good because these engines have good torque. It would be more optimum to be able to carry 2nd to 70+MPH however.

My 2017 GT has a 3.55 and I am running a 27" tall tire. So I can get about 66MPH with the stock rev limiter

 

[Aluehrs11]

Yep this is spendy right now. A few years ago getting a used PP rear end and changing the ring and pinion to a 3.31 was affordable. Not now.

I have run some local events where 3rd gear was needed. I found that a short shift to 3rd worked pretty good because these engines have good torque. It would be more optimum to be able to carry 2nd to 70+MPH however.

My 2017 GT has a 3.55 and I am running a 27" tall tire. So I can get about 66MPH with the stock rev limiter

You aren't far from me haha. Do you go to Kansas City region autocross events?

 

[mustanghammer]

You aren't far from me haha. Do you go to Kansas City region autocross events?

Yep sure do! Just dawned on me who you are!

 

[Aluehrs11]

Yep sure do! Just dawned on me who you are!

Haha small world

 

[kz]

What version of Race Louvers center vent do I want ?

 

[WItoTX]

What version of Race Louvers center vent do I want ?

I have no good answers other than have you looked at AJ's wind tunnel data on adding one?

IIRC, there is a loss of DF unless the louver is ducted. I could be wrong, definitely not the first time!

 

[mavisky]

I'd have to go back, but I am pretty sure they saw downforce increases with all of their vent options, but the ducting would certainly work the best. I honestly had to walk the line between outright performance and aesthetics with my build so went with the Trackspec units instead. I know they don't work as well, but they just look better. Need to print up some lips for them though.

 

[NightmareMoon]

I'd have to go back, but I am pretty sure they saw downforce increases with all of their vent options, but the ducting would certainly work the best. I honestly had to walk the line between outright performance and aesthetics with my build so went with the Trackspec units instead. I know they don't work as well, but they just look better. Need to print up some lips for them though.

I fabricated a wicker for my trackspecs (I copied Plimmer). I figured that was most of the advantage of the Race Louvers, but I'm also not going to have the resources to test that in a wind tunnel (although I could make my car available if someone wants to do that test).

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