Ya has more than 10 race hours on the turbo. I even feel comfortable ditching the trailer.
Laguna Seca: 1:43
Thunderhill West: 1:25
Thunderhill East: 2:02
Car holds up well. I legit throw in 100 octane and just run 255whp.

 

Very nice! I just picked up an NB1 with plans for a similar setup. I just want a fun HPDE car. Appreciate your thread and sharing info! You mind sharing what your oil and coolant temps are? Any issues with temps getting hot after a long session?

 

The only tracks I have issues with is Thunderhill West on 90F+ days. The 3 slow turns don't yield enough airflow to cool everything off. After 12 mins my coolant comes to 240F then I back off. On other tracks, Sonoma, Laguna, Thunderhill East, I do not have any cooling issues, constant high speed yields enough airflow. Highest oil temperatures I've seen is 240F on those tracks, water is nice and comfy at 200 sending it for the full 20 minutes. I could resolve the issues by ducting the radiator to the bumper but rather I just have some shrouding that "helps".

 

Wow 240 water temps is getting up there but if it's only at a specific track with very hot temps that's awesome. 240F oil is on the cool side for a turbo car on track. That's impressive. I would've thought the hot air coming off the radiator would've resulted in warmer temps but I'd say a 25row setrab is probably on the large side for a ~250whp car. Well done man!

 

As the purpose of this thread is to demonstrate the reliability of a turbocharged Miata in HPDE, I'd like to report the first issue with the car, which is a blown 5-speed transmission. Trying to set a personal best, I gave the transmission less mechanical empathy, resulting in the loss of 3rd gear. Now, the transmission sounds like it's full of rocks. 3rd gear grenaded itself while the motor was producing peak HP. I will install another 5-speed and see how long the second one lasts! At least I set a personal best that day.

 

Transmission had roughly 40 hours, 12@255whp.

 

Tiger.

For.

Punishment.

 

Thanks for reporting back. Nice to get some real world numbers on how long things last. That's not too bad. Some people make it sound like the 5 speeds are made of glass. I guess results vary though.

 

Paging @Fireindc , your trans has outlasted another competitor.

In all seriousness, bummer, but thanks for keeping the thread updated! Depending on your timeframe, I might explore the route of procuring a 6 speed. Yeah, they're three times as expensive as a five speed but if you blow another five speed, you're going to be looking to upgrade anyways...

I was going to add, maybe it'd be prudent to bump the power down to around ~240whp for track use, just to be nice to the bottom end in addition to the trans. Then I saw you said "trying to set a personal best" and realized I've been there before haha. Mechanical empathy be damned when I'm chasing that last 0.2 sec. Just gotta be prepared to own the consequences.

 

How do the 6 speeds compare to the 5 speeds shifting wise? I've read in a bunch of places that the 6 speeds don't shift as nicely and are notchier than the 5 speeds but I guess that's the tradeoff for holding more power.. I wonder how long a 5 speed will last on low 200whp. I was told by one person they can last a while.

 

I personally don't get all the hype about the 5 speed vs 6 speed shift quality. On the street with stock shifters on both, my 5 speed had a marginally more positive shift feel than my current 6 speed. I liked the shift feel on my 6 speed with MR short shifter better than both the 5 and 6 speed with stock shifters.

I'm having issues downshifting into 4th on track on my current 6 speed but I think that's just because I was used to the short shifter on my previous 6 speed. Also worth mentioning is that my 5 speed had 207k miles on it when I removed it, whereas my current 6 speed has a claimed 70k miles on it (came from a retired JDM car). So maybe that's swayed my opinion on the matter a bit.

I had no problem running my 5 speed at 210whp on track with 200k+ miles. Got about 15 track days on it, half of which were turbo'd and it never gave me an issue. The 5 speeds do seem to have less consistency in regards to the power level they fail at, though. Fireindc's been running his at 300+whp for a while without issue, but I've also heard of people grenading them at 200whp.

 

Y'all need scramble boost buttons.

 

If I turn up the boost for a few seconds then switch it off, can I fool the trans into thinking I never turned it up?

 

No but you could reserve high boost for later in the powerband and maybe prevent some drivetrain stress...?

Look I don't know if it'll help but I like buttons.

 

Cool good to hear. Ya some people are really not a fan of the 6 speed and I'll have to drive one one day to compare. I thought in Fireindc's thread he said he really only does a few hotlaps at a time..? So that's not 20+ minute sessions of stressing the trans so maybe that's how his has held together?

 

Oh shucks. Sorry man, I thought you were joking at first, hence my response haha. My e85 map actually scales boost up like that. Starts at 13-14psi at 4k and works its way up to 16.5 at redline.

I think he also usually or always runs low boost on track. That might be helping as well.

 

Another data point for high torque 2560 wiping out a gearbox! My theory is that with my lazier turbo, and full spool closer to 4400rpms helps with the gearbox issue. it also ramps up slower in between gears.

Not that any of that is a good thing per say, but it's definitely softer on ze gearbox! That said, I also don't track my car at full power. Generally at the 240-250whp level is where I track it, and leave the kill mode for fun wheelspin and the streetz.

And yeah, a time attack session is 5 laps at a time. I get about 5 of those sessions per "event". Of course I've done some HPDE kinda stuff here and there as well, but all low boost.

 

Most definitely, I don't flog my car as hard as a lot of the track rats. The shorter sessions we do in T/A don't get nearly as much heat in the drivetrain. Hoping to do some more HPDE and different formats this season though.

Funny enough this is what I plan on doing to squeeze out some more power on the straights. I already have high/low boost maps, high boost is triggered by grounding the tableswitch pin (on a toggle switch), but I was thinking I could have a sweet scramble button on a momentary switch inline with the existing switch to do that when I want.

 

lol, I know modern ECUs handle progressive boost better than a button but scramble boost triggers nostalgia for me!

 

I love it.