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Discussion Starter #1
I have a question for all your autocrossers.

I have a 2005 Elise that I'm now successfully competing in SS. I'm running Hoosier A6 on rota's, blackwatch bar, sport package, and harness bar. The first autocross this year I was #4 in the PAX out of 69 cars and I felt like I still have a ways to go. Right now I'm trying to break bad habits and I'm not really concentrating on PAX time or how well I do in my class. As Sam Strano told me, regional races are just practice.

Well the point of this message is that I really believe that the performance of the Lotus is directly related to the specific type of tire. It seem the rule of thumb is going from street tires to R-compound is worth 2 seconds, but it seems in the Lotus that it is much more than that.

Today we had a really wet Autocross and I kept on my street tire Goodyear F1's. Well the car was a complete handful and almost not competitive at all in the PAX. Other cars that I normally beat by far in the PAX were also running their street tires and they were able beat me. Both my Wife and I had the exact same problem...

I could say that maybe we both just suck in the rain, but before we got the Hoosier A6 tires we were running street tires (skinny non-sport Advans) and the car was not quick at all. Last year everyone else in the class was running R-compound and I just couldn't afford it until later in the season. As soon as I went to R-compound I jumped way up the PAX and the difference was way more than 2 seconds on an average length course.

Has anyone else noticed too? That the Elise is much more sensitive to the type of tire compared to other vehicles with the same tire variances?

Thanks,
Chris
 

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I can't compare with other cars, but I just changed to the same package you are running for this season and it has made a world of difference - no doubt the AD07s are not the optimal auto-X package.. I still have a long way to go from a skills standpoint, but I'm enjoying the process!!

- Allen.
 

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Discussion Starter #3 (Edited)
Tires

When I bought the car it had: 175/55/16 front tires and 225/45/17 rear Advan's and it was really bad autocrossing. Major understeer and was not competitive at all.

I am now running 205 front and 245 rear on the street and on the track. The street are Goodyear F1 GS-D3, which I know aren't very good autocross tires, but last a long time on the road. My Hoosier A6s are the same size and in dry conditions the car rocks!

My point is that I've gone from street to R-compound tires before and I've seen plenty of other people do it too. When everyone in your class is running R-compound you better be too if you want to be competitive. It just seems like the differences in time between street and r-compound is much more than what I've experienced.

It could have something to do with not having LSD and without enough traction it is hard to get on it coming out of the corners. Maybe the R-compound just makes up the difference.

Also, if you compare tire widths to the weight of the car, we have a pretty decent contact patch!

Autocross setup:

Lotus F: (1975lbs / 205mm) = 9.63
Lotus R: (1975lbs / 245mm) = 8.06
Power to weight: 10.39

Corvette Z06 F: (3132lbs / 275mm) = 11.39
Corvette Z06 R: (3132lbs / 305mm) = 10.26
Power to weight: 6.5

Porsche GT3: (3075lbs / 245mm) = 12.55
Porche GT3: (3075lbs / 305mm) = 10.08
Power to weight: 7.4

You could probably take it a step further and compare the tire durometer reading to the car weight. A sticky tire is going to make more of a difference on a car of less weight. If everyone is running Hoosier A6 tires, they will make a bigger difference on a car that is much lighter.

Thoughts?

Chris
 

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I would tend to agree, I hate driving Elises even on the A048's. The A6's totally transform the car.
 

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I'd rather run the Elise than any of the other SS cars on street tires...

And the Elise should be totally killer in really wet conditions with Goodyear GS-D3s.
 

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Agree with John. I think the Elise is very strong on either Yoko tire.
 

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OK, I've ridden with Jer. He's logged some good time on the auto-x arena and is very competitive. Given that the elise requires a bit more finesse than the "point and shoot" approach, perhaps what tires like the A6 are doing is making up for a lack of finesse and giving the impression that driving style is less of a factor?? Just a thought here, but the elise is unlike any car I've ever driven, and I know I have a very long way to go before fully tapping its potential. I'm sure that with Jer's experience, he could run circles around my A6 car in his with AD07's....(but not for too much longer, 'cause I'm a quick study.. :) )

- Allen.
 

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A6 vs R6

I am planning to do some autocross, but probably spend more time on the track. Would like to get a set of tires good for both. I am concerned that the A6's may go off too quickly at the track, but the R6's may not grip well enough for autocross. Any thoughts?
 

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I am planning to do some autocross, but probably spend more time on the track. Would like to get a set of tires good for both. I am concerned that the A6's may go off too quickly at the track, but the R6's may not grip well enough for autocross. Any thoughts?
Hey Les - Grassroots Motorsports looked at this exact question this issue. Short answer - the A6s are fine for a light car over a typical track session (20-30 minutes). They will probably wear faster than the R6s but you should be GREAT on a per-session basis for dual track/autocross use.

Obviously they are not tires I would drive to and from the track though...
 

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Rain = less grip

Less grip rewards cars that can put the power down instead of speed maintenance in the corners. Cars that do well in low grip are of course the AWD cars, so they move up in pax in the rain. But also the Corvettes because rain means a lot more "point and shoot" driving. And when you have to brake hard for a slippery corner... you are out of the power band and good luck with that sub-100 pounds of torque.

I will go against popular opinion and suggest that the grippier the surface, the better your chance of paxing relative to many other cars, but specially the AWD cars, and the cars with gobs of torque.
 

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I still think on most courses, the difference for going to Hoosiers will be about 2 seconds, maybe even less. For a specific driver, that may not be true. Hoosiers can mask some things that will be more apparent on street tires. Speaking as someone that has been there and done that, my strength is not street tire finesse. :)
 

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The advantage of light weight allowing more grip is lost in really wet conditions.
The Elise will be more prone to hydroplaning as unlike the heavier cars, there is less weight to put down on the tyres as vertical load, hence slower, more difficult driving.

If you think the Elise is bad , try a 7 with LSD.:wave:


m
 

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The R888 is a wonderful all purpose track tire. But for autoxing it won't hold a candle to a Hoosier rain tire.

Back to Chris' first post-Chris, the Yokos are not good in the rain in my experience. While I agree that the Elise is fast on street tires, it is not fast in the rain on street tires. The 48s in my experience are nasty in the rain. The 07s are a bit better, but still not good. I hate to tell you this, but if you want to be fast in the rain autoxing the Elise, get another set of rims and mount Hoosier wets. They are unbelievable, and I loved every minute of rain racing with them. I'm one of those guys doing the rain dance when everyone else is groaning about wet conditions. :)
 

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Stiffer bar in the rain will cause problems. Take a lesson from Road Racers. Disconnect the sway bars and soften the shocks when it is wet.

Peter
 

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The R888 is a wonderful all purpose track tire. But for autoxing it won't hold a candle to a Hoosier rain tire.


I'm not saying it's the best rain tire, but if you can only have one set of tires mounted that is to be used for all situations and conditions, you should pick the R888. If you have the luxury of having more sets of wheels, then that's a different story.
 

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I'm not saying it's the best rain tire, but if you can only have one set of tires mounted that is to be used for all situations and conditions, you should pick the R888. If you have the luxury of having more sets of wheels, then that's a different story.
Now that's a true statement. I have to force myself to take them off the MR2 and save them for the track. They really are an amazing tire. Bang for your buck, fantastic.
 

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Cars that do well in low grip are of course the AWD cars, so they move up in pax in the rain. But also the Corvettes because rain means a lot more "point and shoot" driving.
Perhaps the Elise is an exception due to its need to stay in the power band, but in general mid-engined cars seem to do very well in low-grip conditions. I know from direct observation that MR2 Spyders and Porsche Boxsters gain a lot on their competition when the course is wet.

I think the power band problem is more of a course dependency than something that causes variability due to grip. I have driven a course on dry concrete where the Elise was perpetually stuck in the doldrums. Yes, having even more grip would have helped, but so would a more open, higher speed course.
 
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