NASA TT - Lets talk about spending points!

[celica73]

Originally Posted by phastafrican

I don't think you'll find any other DOT R-compound in 215/17 other than R888. The approved wheel width is 7.0" - 8.0", so 17x8" should work just fine. Just keep in mind you are seriously giving up on some lateral grip by running the narrow tire. That could be a huge performance hit and corner speed disadvantage, but I'm interested in the results...

Never mind the performance he gives up by running the R888.

[phastafrican]

Originally Posted by celica73

Never mind the performance he gives up by running the R888.

There's that too. But some will argue you can win TT on street tires (i disagree). So if the rest of the competition shows up on street tires or RA-1s, then R888 is a viable option.

[THEmailman]

I meant to say higher rated R comps like the Z214....it nets you 9 or 13 points. Its an interesting thought but it sounds like the consensus is that the wider tire is better.

And after looking around there isnt anything besides the R888 in 215 so I guess 225 it'll be.

[JustDoItMikey]

Originally Posted by phastafrican

KW v3 is a double adjustable coilover: Rebound & Compression.

*** Full slicks are worth +30pts ***
I don't think you'll find any other DOT R-compound in 215/17 other than R888. The approved wheel width is 7.0" - 8.0", so 17x8" should work just fine. Just keep in mind you are seriously giving up on some lateral grip by running the narrow tire. That could be a huge performance hit and corner speed disadvantage, but I'm interested in the results...

Depressing. Every time I check this thread I find out the mods I planned cost more points. Lol.

[phastafrican]

Originally Posted by JustDoItMikey

Depressing. Every time I check this thread I find out the mods I planned cost more points. Lol.

LOL! Now you know why my car is completely stock other than tires and brakes. All my points are assigned to Weight reduction until I can really decide. I've had my OFT/OFH combo sitting for months now. I don't think it's worth the points for engine mods once I figure out E85 transport and tune to max hp.

OFF-TOPIC: After analyzing the data from top 3 cars in TTD, there only way we can beat the E36 M3s is with higher corner speeds. That means stickiest tires and mad suspension. Hal was at 195hp and 2860lbs and on new hoosier 225 A6s... still lost out by 3mph into T1, and up to 5mph into T10 with similar corner exit speeds out of T10b and T7. Granted, he lost the most time at T3 and T5, which left him a total of 3.7 seconds off the pace (1:39.8 combined sectors for Cantor). To win Nationals at VIR or RA, it has to be done on Hoosiers!!!

[ja1217]

Originally Posted by phastafrican

LOL! Now you know why my car is completely stock other than tires and brakes. All my points are assigned to Weight reduction until I can really decide. I've had my OFT/OFH combo sitting for months now. I don't think it's worth the points for engine mods once I figure out E85 transport and tune to max hp.

OFF-TOPIC: After analyzing the data from top 3 cars in TTD, there's only way we can beat the E36 M3s is with higher corner speeds. That means stickiest tires and mad suspension. Hal was at 195hp and 2860lbs and on new hoosier 225 A6s... still lost out by 3mph into T1, and up to 6mph into T10 with similar corner exit speeds out of T10b and T7. Granted, he lost the most time at T3 and T5, which left him a total of 3.7 seconds off the pace (1:39.8 combined sectors for Cantor). To win Nationals at VIR or RA, it has to be done on Hoosiers!!!

I'm going to be testing my own theory that more power (hoping for ~15whp from header/tune) and less sticky tires (225 Maxxis Rc1) may be faster than my current set up with 225 Hoosier R6's. I'm thinking that the extra power and less rolling resistance from the tires ought to let me at least match the speed of the E36's at the end of the straight. I'm hoping that I can still keep up in the corners thanks to less weight and better suspension (also probably going to throw an clutch type LSD on too). Rolling resistance does make a significant difference. My speed at the end of the straights with street tires is consistently 3-6mph faster than with the hoosiers. All I know is my current setup was 2 seconds off Marc Cantor's pace at Summit Point earlier this year, and while I had some room to improve my driving, I certainly didn't have 2 seconds left in the car.

[phastafrican]

Originally Posted by ja1217

I'm going to be testing my own theory that more power (hoping for ~15whp from header/tune) and less sticky tires (225 Maxxis Rc1) may be faster than my current set up with 225 Hoosier R6's. I'm thinking that the extra power and less rolling resistance from the tires ought to let me at least match the speed of the E36's at the end of the straight. I'm hoping that I can still keep up in the corners thanks to less weight and better suspension (also probably going to throw an clutch type LSD on too). Rolling resistance does make a significant difference. My speed at the end of the straights with street tires is consistently 3-6mph faster than with the hoosiers. All I know is my current setup was 2 seconds off Marc Cantor's pace at Summit Point earlier this year, and while I had some room to improve my driving, I certainly didn't have 2 seconds left in the car.

Sounds like you're leaving a good bit of corner speed. With the added grip, you should be able to pick up full throttle quicker than on a tread with higher UTQ, which should translate to better top end speed. I'm 1.5 seconds faster on R6 compared to RC-1 and 2 seconds over RA-1(but it was an older set).
Give it a shot and share the results from your data analysis. It'll be interesting if the ohlins are playing a role in this regard since I compared on stock suspension. Or I possibly just got faster from being comfortable with the car.

[ja1217]

Originally Posted by phastafrican

Sounds like you're leaving a good bit of corner speed. With the added grip, you should be able to pick up full throttle quicker than on a tread with higher UTQ, which should translate to better top end speed. I'm 1.5 seconds faster on R6 compared to RC-1 and 2 seconds over RA-1(but it was an older set).
Give it a shot and share the results from your data analysis. It'll be interesting if the ohlins are playing a role in this regard since I compared on stock suspension. Or I possibly just got faster from being comfortable with the car.

I'm faster overall laptime on the R6's compared to my street tires (235/40 Z2's), but have greater straight line speed on the Z2's, even though I'm getting on the throttle earlier and carrying more speed through the turns. For example:


The green line is the Z2's and the red line is the Hoosier R6. I was just over a second slower on the street tires than the hoosiers at Summit Point Main and you can see from the graph that even though I'm on the gas earlier and carrying more speed, the street tire simply out accelerates the hoosiers on any medium to long straight. I'm hoping that a tire like the RC-1 will be a good middle ground while allowing me to pick up some more horsepower.

[celica73]

It looks like you are under driving the R6 tires in the braking zones (or they don't brake as well as the streets). The graph sure makes it look like the deltaV for the streets is much greater in roughly the same distance. That means more grip from the street tires, or not enough brake application on the race tires.

Still, it's pretty cool to see the speed difference. I never would have expected that magnitude.

[ja1217]

Originally Posted by celica73

It looks like you are under driving the R6 tires in the braking zones (or they don't brake as well as the streets). The graph sure makes it look like the deltaV for the streets is much greater in roughly the same distance. That means more grip from the street tires, or not enough brake application on the race tires.

Still, it's pretty cool to see the speed difference. I never would have expected that magnitude.

To be fair, the R6's were on their 20th heat cycle which I'm sure didn't help braking distances. Rolling resistance and acceleration still applies though.

[celica73]

Originally Posted by ja1217

To be fair, the R6's were on their 20th heat cycle which I'm sure didn't help braking distances. Rolling resistance and acceleration still applies though.

I figured there was a simple answer. With that many heat cycles, I'm surprised they had that much more grip in the turns.

[celica73]

Originally Posted by phastafrican

*** Full slicks are worth +30pts ***

It's interesting to see which rules are there to keep costs in check.

[JustDoItMikey]

Originally Posted by ja1217

I'm faster overall laptime on the R6's compared to my street tires (235/40 Z2's), but have greater straight line speed on the Z2's, even though I'm getting on the throttle earlier and carrying more speed through the turns. For example:


The green line is the Z2's and the red line is the Hoosier R6. I was just over a second slower on the street tires than the hoosiers at Summit Point Main and you can see from the graph that even though I'm on the gas earlier and carrying more speed, the street tire simply out accelerates the hoosiers on any medium to long straight. I'm hoping that a tire like the RC-1 will be a good middle ground while allowing me to pick up some more horsepower.

What are you guys using to record this data? Im thinking this needs to be the first "mod" I invest in so I can track what makes a difference and what doesnt.

Also from reading all of this, and a better understanding of what points I was misapplying it looks like there is no way around just slapping mods on the car and going out there and doing well. For instance to put a well sorted RCE T2's on the car will cost 10 points, but if you spend the time thru trial and error and get a custom spring rate custom valved non adjustable coilover you can do it for 4 points. So to me it looks like trail and error will in most cases be the only way to tell what works best for the track and your driving style while costing the least points.

[celica73]

Originally Posted by JustDoItMikey

Also from reading all of this, and a better understanding of what points I was misapplying it looks like there is no way around just slapping mods on the car and going out there and doing well. For instance to put a well sorted RCE T2's on the car will cost 10 points, but if you spend the time thru trial and error and get a custom spring rate custom valved non adjustable coilover you can do it for 4 points. So to me it looks like trail and error will in most cases be the only way to tell what works best for the track and your driving style while costing the least points.

Originally Posted by The Rules

E. SUSPENSION:
1) Non-BTM shocks/struts/dampers with an external reservoir or more than two ranges of
adjustment—must still take points for springs below +8 (example: compression (bump)
and both high & low rebound adjustments).
2) Non-BTM shocks/struts/dampers with a “Piggy Back” external reservoir (fixed reservoir
without a connecting hose) OR with shaft diameter 40mm or greater—must still take
additional points for the springs below +5
3) Non-BTM or modified/re-valved shocks/struts/dampers +3 (all others)(springs not included)
4) Changing the mounting orientation/design of the BTM shock and/or spring perch in order to
invert the front shocks/struts (includes non-BTM inverted shocks/struts) +1
5) Non-BTM or modified coil springs, leaf springs/spacers/brackets, or torsion bars +2
6) Conversion of torsion bar/leaf spring suspension to coil spring and strut/shock suspension +2
7) Add, replace, remove, or modify anti-roll bars (“sway” bars—front, rear, or both) or end
links—may have spherical joints on the end links and/or relocation of the mounting points
without additional points assessment +2

I'm not seeing that for the RCE T2. They should be 5 points. They are only double adjustable with no remote reservoirs. They are not inverted, or have large shafts. That puts them in E3 and E5 for a total of 5 points. It's no different than running off the shelf Koni's and lowering springs.