Miata Turbo Forum - Boost cars, acquire cats. - NASA TTU Miata: Round 4 @ Mid Ohio, Jul 7-9

NASA TTU Miata: Round 4 @ Mid-Ohio

Another weekend of spectacular weather and racing awaited us at Mid Ohio on, site of the upcoming NASA National Championships and one of the finest road course venues in the country. We've been campaigning The Fish, one of our in-house turbo Miata projects, in Time Trials Unlimited this season in an effort to push the envelope of what can be done with the first gen chassis in a road course environment... while still being able to drive the car to and from the track.

We were greeted with four other competitors, all of them Z06 Corvettes save for Christie Clark's Porsche 993 entry. My good buddy Buzz Korth was rolling one of the Vettes, his newly acquired toy to replace his bad arse but now defunct 454 powered C5 which blew up at the last event at BeaveRun.

Changes to The Fish included a mild tweaking of the suspension; we installed a set of 99 upper shock mounts on the rear, as well as a set of 275lb. springs in lieu of the 400lb units that came with our mystery Ebay coilover kit. To top it off, we replaced our wasted cantilevered Hoosiers with a set of 225/45-15 R3S06s which indeed are narrower, but not by as much as you might think, plus they have much more positive feedback than the cantilevers. All this is in an effort to curb power oversteer in the twisties.

Turns out that would not be an issue this weekend, as we also installed a standalone Link engine management system that had not been tuned yet... my butt-dyno estimate is that we were down ~30 or so horsepower compared to the less-sophisticated yet well-tuned piggyback arrangement we had before. Regardless, it would prove to be an interesting weekend on a number of accounts.

In the turns, the car was extremely manageable (finally!) The car was very hooked up, I could come into a turn hot, trail brake to rotate the car and then get right back on the gas, a'la Spec Miata. It was a thing of beauty! Finally the turbo car was planting down... so much that it would actually lift the inside front tire in the Keyhole! To be fair, it has yet to be seen whether the setup can withstand the full amount of power the car can generate. We did get the Link somewhat tuned in however. But what nobody anticipated was the stunning performance of Danny Popp and his C6 Z06 Corvette...

Saturday results:
1 Danny Popp Corvette Z06 1:34.541
2 Shane Benson Turbo Miata 1:41.095
3 Don Michaels Corvette Z06 1:42.003
4 Buzz Korth Corvette Z06 1:42.621

Sunday results:
1 Danny Popp Corvette Z06 1:33.696
2 Rick Kaplan Corvette Z06 1:41.736
3 Buzz Korth Corvette Z06 1:42.031
4 Shane Benson Turbo Miata 1:42.211
5 Christie Clark Porsche 993 2:38.834

You read right, he was 7.5 seconds (!!!) faster than the next best time all weekend (ours). And I mean to tell you, this car is crazy bad! Fully race prepped, at the very limit of TTU and nearly in TTR. I knew sooner or later this season we would run into one at this level of prep, and the difference is amazing. It would be interesting to see what a Miata prepped to that level could do... guess we should start looking at that sort of thing!

It was a mixed weekend, pulling down 2nd on Saturday but only managed 4th on Sunday. The car is definitely down on power; previously we were a good match for a modded Z06, but now they're walking us hard core in a straight line. Our last visit to Mid-O the car topped out in 5th gear, up against the rev limiter on the back straight, but this weekend we could only manage 130 MPH. To make things worse, the car felt as if it had actually lost power over the weekend. Maybe our salvage yard Escort block is finally starting to give up the ghost...

Regardless, we did beat our fastest lap from the previous visit by 1.5 secs (1:41.095 versus 1:42.490) which is a sign that we are headed in the right direction. If we can get the missing power back I'm confident we'll dip into the sub-1:40 bracket... but I seriously doubt we'll have anything for Danny if he manages to get qualified for the Nationals, unless we suddenly have a windfall of time and money at the shop :) Keep in mind we've built this car for less than an entry level Spec Miata.

Next round is at Autobahn South in Joliet, IL in two weeks... we hope to get to the bottom of the power issue and get the Link tuned out, but a new engine might be in The Fish's near future...

More information can be found at www.nasa-tt.com and at our website.

Shane
AIM Tuning