lonely, looking for 15x10 companion
09-28-2011, 03:45 PM
#46
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Tann3r is correct. For NASA TTS for example, one just uses a different weight/power correction factor to account for wider, non-DOT tires. As long as your corrected weight/power does not exceed the limit, 8.7 for TTS, then you can use slicks. In my case I will have to reduce power slightly over being able to run full engine power with say 225/45-15 NT01s. It is all in the NASA TT classification rules.
Tires>horsepower (within reason) so I think I will come out ahead. We will see. The real question in my mind is if for me the slicks are better and/or more cost effective than an A6/R6. Either will almost certainly be a lot faster than slightly more power on NT-01s. But also more expensive.
Sorry to the OP if we have completely jacked this thread at this point.
Tires>horsepower (within reason) so I think I will come out ahead. We will see. The real question in my mind is if for me the slicks are better and/or more cost effective than an A6/R6. Either will almost certainly be a lot faster than slightly more power on NT-01s. But also more expensive.
Sorry to the OP if we have completely jacked this thread at this point.
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09-28-2011, 04:45 PM
#47
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Tires>horsepower (within reason) so I think I will come out ahead. We will see. The real question in my mind is if for me the slicks are better and/or more cost effective than an A6/R6. Either will almost certainly be a lot faster than slightly more power on NT-01s. But also more expensive.
30whp doesn't make a 2 second difference, but going from a 225 R-comp to a 245 radial slick sure will
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09-28-2011, 06:37 PM
#49
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Anyway I plan to try this very soon, and in fact will be at TWS in November for a TT event. If this tire versus power tradeoff works out well at TWS, it will work at any of the other tracks we run at. TWS is the most horsepower oriented track we have in this area, at least until COTA is finished.
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09-30-2011, 06:06 PM
#50
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WORD. Exactly what I am thinking. I have been playing what-if scenarios with the NASA TT scoring. I would go from 325WHP to "only" 290-300WHP. I doubt I would miss it that much, even at the faster tracks like TWS.
Anyway I plan to try this very soon, and in fact will be at TWS in November for a TT event. If this tire versus power tradeoff works out well at TWS, it will work at any of the other tracks we run at. TWS is the most horsepower oriented track we have in this area, at least until COTA is finished.
Anyway I plan to try this very soon, and in fact will be at TWS in November for a TT event. If this tire versus power tradeoff works out well at TWS, it will work at any of the other tracks we run at. TWS is the most horsepower oriented track we have in this area, at least until COTA is finished.
Bob
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09-30-2011, 07:00 PM
#51
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We have to go to a shop with a Dynojet Dyno, use the NASA correction factors in the rules, and do three back-to-back runs measuring WHP (not BHP). You send the plots in to the National Director, and keep a copy with you at the track.
The vehicle is also subject to dyno verification testing at the track. It has not happened to me yet but I have seen it happen. There are ways for the cheats to cheat of course but that is the system.
The vehicle is also subject to dyno verification testing at the track. It has not happened to me yet but I have seen it happen. There are ways for the cheats to cheat of course but that is the system.
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10-10-2011, 06:14 PM
#52
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So long story short I tested the Hoosier 23.0x9.5-R15 (Formula Atlantic) slicks on Sunday at Harris Hill in San Marcos. These were mounted on 15x9 6ULs. I ran Saturday afternoon and most of Sunday on NT-01s (15x8 6ULs) due to the track being wet. Sunday was the Texas Miata Challenge.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
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10-10-2011, 07:46 PM
#53
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So long story short I tested the Hoosier 23.0x9.5-R15 (Formula Atlantic) slicks on Sunday at Harris Hill in San Marcos. These were mounted on 15x9 6ULs. I ran Saturday afternoon and most of Sunday on NT-01s (15x8 6ULs) due to the track being wet. Sunday was the Texas Miata Challenge.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
I’m still sticking to my plan of building a car around 23.5X11 R16 tires in an R75 compound.
Bob
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10-10-2011, 08:25 PM
#54
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Yep. I tried these since they were available in barely used scrubs at a cheap price. Now I am thinking maybe I should try the 245/580R15 R80 next though availability other than new is TBD.
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10-10-2011, 11:34 PM
#57
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That’s a good question. It would probably require some testing. I’m thinking it would require a lot of cutting into sill area to on the aft side of the front wheel opening to fit them and be able to turn if you put them on the front. The 11's aren’t that much bigger than 275's but I think they still will need a bit some clearance by getting the pinch weld out of the way.
FWIW. V8 track miata build with 23.5x11R16
http://www.roadraceautox.com/showthr...450#post956450
I think it needs some inner fender work to get the ride height as low as I’m running now and have the suspension optimized for height and travel.
Bob
FWIW. V8 track miata build with 23.5x11R16
http://www.roadraceautox.com/showthr...450#post956450
I think it needs some inner fender work to get the ride height as low as I’m running now and have the suspension optimized for height and travel.
Bob
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10-12-2011, 05:14 AM
#58
So long story short I tested the Hoosier 23.0x9.5-R15 (Formula Atlantic) slicks on Sunday at Harris Hill in San Marcos. These were mounted on 15x9 6ULs. I ran Saturday afternoon and most of Sunday on NT-01s (15x8 6ULs) due to the track being wet. Sunday was the Texas Miata Challenge.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
On Sunday afternoon the track dried off and finally became fast again. So I switched to the Hoosiers and went out for three separate sessions about 6-9 laps each. Between sessions I was checking tread temperatures and temperature distributions, and adjusting pressures. Probe type Longacre pyrometer. I had to add pressure to get them to heat up but each time I added pressure they were faster and felt better.
In the last session I had them into the 1:28.X range which was about 3-3.5 seconds faster than the NT-01s I had just removed. But after the 3rd or 4th lap the grip started falling off. They did not feel like they were getting greasy, just a bit less grip everywhere, with about a 2 second fall off on lap times. I tired taking a lap at a 10 second slower pace but it made no difference. After that I gave up and came in.
Overall they were not any faster than the Hankook Z214 C51 (225/45-15) I had used there before. Same car, same driver, same direction. I am allowing for the different track conditions by looking at the lap times of the other TxMC competitors compared to what they and I had done before at the same track in the same direction. My unadjusted best time for the Hankooks is actually 3 seconds FASTER than the Hoosiers, but the track was probably 2-3 seconds slower that day for everyone. So roughly speaking it is a wash.
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10-12-2011, 05:24 AM
#59
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C71 Hankooks can kiss my ***. I don't understand how a tire can go from 13-seconds under SM record pace, to 7-seconds off my previous best NT-01 laptime, in one session.
My previous best at WSIR was a 1:27.0. I couldn't get under a 1:33.4 on cycled-out C71s. Switched back to a set of old NT-01s, with a single newer tire on the LR corner (important corner), and with a car that pushed slightly I was able to get straight down to a 1:27.7.
I cannot wait for 15x10s and 245/580 glory.
My previous best at WSIR was a 1:27.0. I couldn't get under a 1:33.4 on cycled-out C71s. Switched back to a set of old NT-01s, with a single newer tire on the LR corner (important corner), and with a car that pushed slightly I was able to get straight down to a 1:27.7.
I cannot wait for 15x10s and 245/580 glory.
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