I was wrong, I'd have two points left over, not three. Fuck.

No, no flat powerband for me unfortunately. Just a pleb making 140 at peak and 110 at 5k. This is east side regional competition, nothing too hardcore.

If it is an NA, bump steer. Might not seem important but it increase mean average grip on long bumpy turns. You have to look at A/B data to see it. or know your exit speeds everywhere.

It's an NA, and oh yes, it suffers from typical NA bump steer woes. This is for Lime Rock, track and curbing are decently smooth. If WGI was going to be open again this season, I'd address that.

I fucked up my points transferring from D to E. Same setup puts me 22 points with TTE* vs 19 for TTD*, assuming my base tire is in fact 235 for TTE* (still waiting on word from Greg).

I need to shave one point to be TTE legal. Right now the set up is:

*- 7 points
205 R7s (two heat cycles, fresh)- 3 points
4.1 Torsen (no Giken budget)- 3 points
Dampers- 3 points
Springs- 2 points
Roll bars- 2 points
949 11.75" front brakes and m-tuned 11" rear brakes- 2 points

=22 points

My springs are 12/7kg/mm, should probably be stiffer. I have a 4.3 open diff sitting in a carrier in my garage. I'm thinking of swapping that in and keeping my sway points and brake points. I know my stock brakes would be fine, but I'm short on prep time and it seems easier to swap carriers than do all that other stuff, plus sways are kind of important with my spring set up.

brakes or sway bars. I think a few/many PTE cars run stiffer springs and use the oem sway bars.

If you have points for sway bars, it makes for a car that's more versatile, easier to drive and setup. But a stock sway bar setup can be fast too. Lots of front spring (900-1100) and about the same rear. Our fastest ever PTE car (2013 rules) ran stock NB bars and 1000/400#.

^I agree with both of you, stiffer springs and stock brakes are the better option, but different springs aren't an option for next weekend. I won't have time to get them or install them.

I'm asking what will be faster on a 60 second, relatively smooth track (Lime Rock Park) using R7s:
Option #1- stock sways with current springs (670/390) plus 4.1 Torsen diff
Option #2- 1.125" Race front sway with current springs plus 4.3 open

I need to either ditch my brakes and my sway bars or just my LSD.

2

Gearing wins. Better yet, Kia Sportage 4.77 # 0K014-27-110
Don't underestimate the value of gearing, particularly if you don't have a Kansas relief map powerband.

Interesting. So assuming the engine doesn't make within 5whp of peak over 3000 rpms, you're saying:

OS Giken > 6 SPD > Torsen Correct?

Lower gearing keeps the engine closer to peak power for more of the track.

Diff is a different question. I won 2012 NASA nationals at Mid Ohio with an MSM Torsen (classed as an MSM). It sucked. In my video you can hear lots of wheel spin. Tuned OSG would have been worth probably .5s there. Some tracks it can be .7s.

Ideally you have both a tuned OSG (not default OSG tuning) and either 4.77 or 4.875. On some tracks, such a diff is worth well over 1s.

I just never considered the trade-off of open diff with 6-spd vs torsen with 5-spd... Thought that's what you were suggesting.

EDIT: assuming shortened rear end ratio in either case.

Sounds good to me. 4.3 open it is. Doubt I can get my hands on the kia gears in time.

Oh well- open diff it is.

a


Edit: Sorry, my one year old posted this.

tte/pte base is 130whp/2400lbs
Ok so no aero, bulk up, not sure what is meant by the points reclass/dyno reclass.

Finally anyone know where I can peak through the freebee points section?

Holy shit dude, have you even read the rules?

Umm... the rule book? lol

If you read it, should answer all your questions. If not, read it again.

You guys are the best, thank you so much for your assistance!!! Have a wonderful afternoon.

Seriously?

What do you want us to do, go to the rulebook for you and copy/paste the entire free points section?

It's right here:
https://nasaproracing.com/rules

Just to clarify this, Greg's typo was in allowing you to use sport brakes without taking points?

Think its the 245 base size is the typo.

What JSpeed said. Only the 245 base tire was the typo. His clarifying email still said that I can use sport brakes.

I didn't trust my spare diff when I went to swap it in last weekend. I stayed in TTD, and managed a class win both days. Free purple crack, sweet.

Sorta related. This is a customers car, recently completed by TC Design in Campbell, CA. This particular car had it's engine provided by Trackspeed Engineering. Diff, wheels, clutch and several other bits from us, including the tub. The owner has a second car with an engine, wheels, Xidas from us.

The bare tub started life here with the intent of building an T25 E3 specific car. We had the tub dipped to remove paint, sealant etc. TC Design seam welded, caged for us late 2012. My intent was to run a fuel cell in the pax floor with 2" filler on the RR fender just under the B pillar. Not having to run around the other side of the car would save about 6s per stop. The special jug would dump 5g in about 6s. All in all we would drop our usual 40s 10g stop down to about 18s stationary. Beyond the time saved, the CoG and PMI would both be improved by this change. Mounts built into the cage for the carbon skin top. The box you see in the OEM tank area was repurposed as a bin to hold other stuff, such as a battery, alternator, fire bottle, etc. I'm not sure if it got used in this customers build.

We ended up running Crusher in E1 (and won) two E3's and an E2 car. This tub "Bubbles" never got built. A customer called early this year for parts going into national level PTE car. He bought the bare tub from us, we shipped it back to TC and here is the result.

Since it is not our car, I'm not able to answer too many questions about it. From the pics you can see it has an NB1 engine, USDM intake manifold, header and sway bars, no aero so do the math on class config

PTE pron

https://cimg1.ibsrv.net/gimg/www.mia...b4f20237b.jpg?

https://cimg4.ibsrv.net/gimg/www.mia...66ec1a5a5.jpg?

https://cimg6.ibsrv.net/gimg/www.mia...1b0a8b608.jpg?

https://cimg8.ibsrv.net/gimg/www.mia...486035e5b.jpg?

https://cimg0.ibsrv.net/gimg/www.mia...ac01aa4f2.jpg?

https://cimg2.ibsrv.net/gimg/www.mia...540165842.jpg?

https://cimg4.ibsrv.net/gimg/www.mia...b30fe8f9f.jpg?

Super sexy. How do you like the MCS? Why not Xidas?

"Since it is not our car, I'm not able to answer too many questions about it. "

TC is an MCS dealer and worked with them for a long time. He has put Xidas on a few other builds there though.

Ah. Though TC was just cage stuff. Makes sense.

Trackspeed radiator in this application seems like big-time overkill and unnecessary weight in a not-so-good place. ??

Beautiful car though. I dig the metallic interpretation on 949 Orange -- the first combat scar will be painful.

I think the burnt orange is coincidence. Not our car.

TSE rad works. Yes a fair bit heavier than some other options but I'm guessing that was the option offered when the engine was being built. FWIW, our revised crossflows are on a boat, due here next month. Not availablel when this car went together.

What about going from S7 to SM7?
I am kind of in the same boat, looking at options.

The new 205/50 Rival S and RE71R are awfully fast. :party:

Faster than say... SM7s with three or four sessions on them?

Million dollar question. From the little data I've gathered, fresh RE71-R's and Rival-S are only about 1-1.5s off R7's on a 2 minute course. So about as fast as an RR. Yes, stupid fast. 1.5g on street tires w/o aero fast. That's at full tread but that condition is not persistent should you avail yourself of their grip for more than about an hour.

So pretty much as fast as SM7s.

Has Greg given them a point value yet? I'd guess he is waiting until after nationals.

Hold up! Where's the data on sm7s being that much slower than r7s? I missed it......

Per the rules, they are a 200tw DOT-legal tire, so they are +2.

Below the tire points list:

Per the rules, they are actually +30 at this point in time.

Bringing this back up, I'm extremely curious. This would directly effect my tire budgeting

I don't have real data, just putting together internet conjecture. Here is what Dragoo had to say about the SM7.

What I've read on the R7 is that it is a faster than the R6 tire once you change your setup to match it.

Direct comparisons of the SM7 and R7 are going to be difficult to find since PTE is likely the only place that is meaningful.

Ya, SM7 is just as fast as R7. just use it because its cheaper ;)

Direct personal experience in controlled A/B testing? Where did you get that info? Great news if it's verifiable.

I think the winky face was very important in that statement.

My dream of being half-way competitive with $150 SM7 take-offs has been demolished! I'll fork out the pennies for R7s and hope to win a tire or two with contingency. Thankfully the TTE field is typically 5+ ppl in the SouthEast

NASA NCM July 2015
 

So Jason, what the heck is Aaron's setup that allows a GT250? Looks like you had a few HP on him and better suspension but tires went off a bit. Car looked neutral so I'm guessing starting pressures too high? You sit too far from the wheel BTW.:)

Great racing at the Corvette Museum this past weekend. I drove down and hung out on Sunday and was pretty jealous that I wasn't racing with those guys. I think I'm ditching my turbo plans and going back to PTE. :party:

Yea, it looked like a blast with everyone down there. That track looks awesome too, 3.2 miles?!

Aaron's 2:21.8 qualifying lap:

Seems like it has a 4.3. Shifting at 6800 most of the time. Interesting that it either has no power above 7000 or the motor isn't built to be safe up there.

Aaron's simply running a PTE no star based VVT reclass, which allows enough points to run the wing and air dam. It's a well built and setup car with a great driver. I had a couple hp on him, but there were also a couple near 100mph sweepers at NCM that really benefited the aero cars.

Tires certainly got a little greasy, but not terrible considering it was 96 degrees out and I was driving as hard as I could to catch him (and keep away from Chris and Cody)! Not sure why the video looks like I sit far away, I sit very close actually.

Somebody help me peer pressure Cody, Chris, and Aaron into coming to east nationals! If we got Cody a few more hp and Chris runs some newer tires we would have 3 more very competitive cars. It's a shame to see such great cars and talented drivers only run couple of events each season! ;)

Has anyone built a 2600lb PTE* Miata yet?

<p></p><p>&nbsp;</p><p>I haven't...but I am seriously considering a points NB1 build if I could magically get about 8k&nbsp;;).</p>

I'm debating it, It'll come down to how much power my motor makes once I'm finished with it. I can go up to about 2670# with the cage I have in my car.

I don't remember if he is PTE or PTE* but Jeff in NASA-MA is 2500lbs+

Gret racing at NCM this past weekend by all 4 of us.

Jason- we plan to come to the autobahn and mid-o weekends at the end of the season. Then next year probably run a lot more since it sounds like we will have a lot more "regulars"

The whole idea of driving the heaviest miata sounds great until you have to corner the car. I'm at 2500# and its a pig to drive. Im going to drop almost 100# and retune for what i think is a "better" reclass as far as drivability goes. Id also like to say that it was my first weekend in E. Im glad I made the jump here, hopefully I can dial in the set up on my college kid budget and hang with the gang.

Every 80bs you add to the car is ~5whp. You forget really fast about the extra 160lbs when you've got 10whp more than the guy behind you. Nobody ever said a 2600lb PTE Miata with 1000/400 springs and stock sways was going to be fun/forgiving to drive, but I'm looking for fast, not fun.

I see.

The number of lapping days I do compared to the number of races I do is probably 10:1. - so I'm not too concerned about having a car that is going to be fast. I'll take a fun car over a fast car any day of the week.

I think it was proven this weekend that a lot of different set ups are competitive at our regional level and it boiled down to who had the car set up the best out of the bag. And that was clearly Aaron.

Set the car up so you can add ballast easily. I drilled 1" steel plates and bolted them into the passenger floorboards. You should be able to put ~200lb of steel down pretty easily. Bolt a Coolsuit in on top of that and you're at 250lbs. From there it's an ECU map change and you're on the way.

The suspension is a little harder, since nobody wants to swap springs/sways on a regular basis. The 1000/500 springs are a little tough to get used to, but not awful - I'm still running them as a leftover setup from 2013. I do plan to put 800s and a FSB back on the car, but it's not bad enough to make it a priority.

For the the few customers I shipped 1000/xxx Xidas to, I tell them it's a bit more sensitive to setup and driving style but still fast. 800/500 with the big sway bars is much more forgiving. You have to be more precise with your inputs on 1000's. Not for a toss-and-catch or back-it-in driving style.

On some tracks, it's actually faster than an 800/500 setup.

Im making a few set-up changes that will help accommodate the 240lbs of ballast I have in the car now. Im still on a used Spec miata set-up with stock sways. But I'm going to run 700f/450r and I think it will actually help me quite a bit. I also don't think I had the car high enough so it was bottoming out the shock on really leaded corners.

Last year I was jumping between Thumper with 700/400 Gen1 XIDA, and Rover, which has 1000/500 and Gen1 XIDA with digressive rebound (upgraded by HVT). The best word to describe it is "forgiveness". Even with the trick-er DDP shocks, Rover didn't tolerate a sloppy turn-in point since pre-apex steering corrections, even tiny ones, had huge impacts on the yaw of the car. If you got it right, there was virtually no difference, but you had to get it right every single time with the 1000# fronts. Thumper could be rolled in a little early, then corrected at the apex slightly, and it would take it all in stride.

I really noticed the 1000s at Sonoma a couple of months ago. Rover would take this big hop right as we started up the hill into T2 that would push the car towards the right side of the track by about a full car width. It's also why I went off in T10 - a little too much speed, front end hopped a bit, and away she went. I drove Thumper (new owner asked me to shake it down briefly) and it was a pretty night and day difference there.

At SMMR, much less of a difference. That track is so smooth and has minimal elevation, so the stiff springs don't hurt. I still had to be careful with inputs, but I doubt the 800s would have been faster.

I would do 800/500, especially if you plan to run SM7s or R7s. Even at 2300lbs the sticky tire will want the higher rates, and it will REALLY want the higher rates at 2500-2600lbs.

Cody's been trying to convince me, I might have to consider PTE next year.... Sounds like a lot of fun and who doesn't like having a larger class?

Or you could race SCCA STL, 20+ car fields and serious Mazdaspeed/Hoosier contingencies if you finish on a podium.

That is if you want a large class that's not SM...

PTE beats STL for me because you can win (definitely regionally, usually nationally) with an unopened junkyard motor. NASA's dyno system is definitely frustrating but it does help keep costs down.