D Prepared Miata Build
- Thread starter aMaff
- Start date
Video to come after I get home, but suffice it to say that Nationals was a freaking riot. Tuesday went so-so. It was my 1st runs ever at nationals and I was inside my own head, and stunk it up pretty badly. But even my co-driver, who held his own in the car couldn't do much due to the point-and-shoot super high-speed into a pin cone nature of the East course. I was not a fan of the course, and it did not agree with my car.
We added 6 lb of weight in the morning, and rolled across the scales at 1700 lbs even on day 1. Min weight is 1695. *phew*
Peter was 12th and I was 14th of 16 after day 1.
We added another 9 lb of weight that evening for Wednesday's west course, which walked fun, and drove REALLY fun. The car was well set up for it, we made a small tweak which made it even better, and just had an absolute blast... until my last run when we found out we apparently burned a LOT more fuel than expected. The thing is acting like it's almost totally out of fuel. I've never fuel starved a miata before, but I guess there's a first time for everything. It happened to me about 4 times on my last run, but alas, live and learn. Even with that, that course was excellent. So much fun. Hang on as tight as you can and find out exactly how much you trust the car. Lots of sweepers and transitions.
Peter ended the day in 11th, and I was in 12th. After my utterly abysmal day 1 performance, I'm pretty pleased with that (1 of the places I gained was due to a Lotus with a dead throwout bearing).
All in all, a very successful 1st Solo Nationals for us. Lots of beer drank. Lots of 4 Square played in the Atlanta paddock.
Now, to trade my 4.3:1 diff for a 4.1:1... because damn do we need the gearing. It was better on the West course, but through the slaloms in the 1st couple sections I was just riding the limiter in 2nd.
And onward the project goes
I should probably get a little rest... we're getting up at 3am to pick up the trailer (with the car already loaded) from the event site for the 17 hour trek home. Fingers crossed that it'll be as uneventful as the tow up.
We added 6 lb of weight in the morning, and rolled across the scales at 1700 lbs even on day 1. Min weight is 1695. *phew*
Peter was 12th and I was 14th of 16 after day 1.
We added another 9 lb of weight that evening for Wednesday's west course, which walked fun, and drove REALLY fun. The car was well set up for it, we made a small tweak which made it even better, and just had an absolute blast... until my last run when we found out we apparently burned a LOT more fuel than expected. The thing is acting like it's almost totally out of fuel. I've never fuel starved a miata before, but I guess there's a first time for everything. It happened to me about 4 times on my last run, but alas, live and learn. Even with that, that course was excellent. So much fun. Hang on as tight as you can and find out exactly how much you trust the car. Lots of sweepers and transitions.
Peter ended the day in 11th, and I was in 12th. After my utterly abysmal day 1 performance, I'm pretty pleased with that (1 of the places I gained was due to a Lotus with a dead throwout bearing).
All in all, a very successful 1st Solo Nationals for us. Lots of beer drank. Lots of 4 Square played in the Atlanta paddock.
Now, to trade my 4.3:1 diff for a 4.1:1... because damn do we need the gearing. It was better on the West course, but through the slaloms in the 1st couple sections I was just riding the limiter in 2nd.
And onward the project goes
I should probably get a little rest... we're getting up at 3am to pick up the trailer (with the car already loaded) from the event site for the 17 hour trek home. Fingers crossed that it'll be as uneventful as the tow up.
Like I told my co-driver when we backed the trailer into my drive-way last night:
"This was a really, REALLY stupid idea. We should do that again sometime." (lol)
stevemhudson
Member
Nationals was a great and eye opening experience, and sort of like the 12 Hours of Sebring or the 24 Hours of LeMans (ok, it's nothing at all like those...), it revealed a few shortcomings and weaknesses in my car. 1st off was the diff. It's way, way too short. The 4.3:1 just won't cut it on short 13" tires. A 4.1:1 is going in today. If that's too short still, a 3.909:1 can be brought to bear, but I fear the gearing on that may be TOO long. A 4.1 will give us what we need for locals.
Unfortunately in pulling the diff, the end-caps on the axles (we're using 94-95 axles with stub-shafts) popped off, so now I've got to pull those and re-pack the inner CVs. New axle nuts ordered from MMD.
We found a LOT of difficulty changing into 3rd gear, something we'd not had trouble with in the past. Looking at the video, we're getting a lot of drivetrain movement. The shifter used to be pretty rock solid. It's jumping all over the place now. After about 5 or 6 years of nothing but autocross use, it appears that my Mazdaspeed motor mounts are on the way out. I've got a set of Delrin bushings coming to replace those.
I also figured out why on my last run at Nationals I kept getting fuel starve...
Oops.
So, hopefully the car will be back in business before our next points event.
Unfortunately in pulling the diff, the end-caps on the axles (we're using 94-95 axles with stub-shafts) popped off, so now I've got to pull those and re-pack the inner CVs. New axle nuts ordered from MMD.
We found a LOT of difficulty changing into 3rd gear, something we'd not had trouble with in the past. Looking at the video, we're getting a lot of drivetrain movement. The shifter used to be pretty rock solid. It's jumping all over the place now. After about 5 or 6 years of nothing but autocross use, it appears that my Mazdaspeed motor mounts are on the way out. I've got a set of Delrin bushings coming to replace those.
I also figured out why on my last run at Nationals I kept getting fuel starve...
Oops.
So, hopefully the car will be back in business before our next points event.
Goin' down the line:
I managed to get the worst of the OPR off the tires from Nationals. I'm thinking I may mold them into a set of Kart tires to sell to some schmuck lol
Got the "new" 4.1 rear end and the PPF back in.
Re-packed the axles with a good amount of new Moly CV axle grease, and put a couple dabs of RTV on the end-caps to help prevent them popping off prematurely in the future.
Te-did the anti-seize on the wheel studs because it was time.
Hit a couple of spots of surface rust that were under the diff that needed it with rust converter.
Left to do:
Still awaiting the motor mounts from Miata Roadster and axle nuts from Mazdaspeed.
The axles and prop shaft still need to go in. The RTV hadn't even begun to set so I figured I'd leave them at least over night, though I probably wont' be able to mess with the car until next week.
Since I had to pull the exhaust to remove the diff, I'm going to try running the exhaust without the big-heavy muffler. I know it's down low and the car isn't exactly under-weight, but I've got a turn-down that I've just never messed with that I want to play with at our next event since it's at Atlanta Motor Speedway, and not downtown Atlanta. Might as well give it a shot.
Aaaand I think that'll pretty much do it. Gotta love a big national event wrecking up your sh*t. Though it could have been far, far worse.
I managed to get the worst of the OPR off the tires from Nationals. I'm thinking I may mold them into a set of Kart tires to sell to some schmuck lol
Got the "new" 4.1 rear end and the PPF back in.
Re-packed the axles with a good amount of new Moly CV axle grease, and put a couple dabs of RTV on the end-caps to help prevent them popping off prematurely in the future.
Te-did the anti-seize on the wheel studs because it was time.
Hit a couple of spots of surface rust that were under the diff that needed it with rust converter.
Left to do:
Still awaiting the motor mounts from Miata Roadster and axle nuts from Mazdaspeed.
The axles and prop shaft still need to go in. The RTV hadn't even begun to set so I figured I'd leave them at least over night, though I probably wont' be able to mess with the car until next week.
Since I had to pull the exhaust to remove the diff, I'm going to try running the exhaust without the big-heavy muffler. I know it's down low and the car isn't exactly under-weight, but I've got a turn-down that I've just never messed with that I want to play with at our next event since it's at Atlanta Motor Speedway, and not downtown Atlanta. Might as well give it a shot.
Aaaand I think that'll pretty much do it. Gotta love a big national event wrecking up your sh*t. Though it could have been far, far worse.
stevemhudson
Member
Do you have a "torque arm" or whatever you want to call it to keep the motor from rocking? This one is a threaded rod with heim joints at each end and a tube over the rod just for looks. Sometimes when we have to shift to third, I've been known to hit fifth :-( We have a fifth gear lock out on the shifter.
When was the last time you replaced motor mounts? Missed shifts is a typical symptom of one or both of those being shot.
Though a torque arm like that is an intriguing idea...
Steve, I'm definitely interested in the 5th gear lockout idea, especially if it's easily reversible (we need to use reverse pretty frequently at our events to back into grid-spots).
James: It's been probably 5 years, minimum, since they were replaced. They almost certainly need it by now, just based on how much the shifter has been moving recently looking back at video from the last few events.
James: It's been probably 5 years, minimum, since they were replaced. They almost certainly need it by now, just based on how much the shifter has been moving recently looking back at video from the last few events.
Indeed.
I also noticed a difference after replacing the differential bushings (I used energy suspension bushings). They also serve to keep the whole PPF assembly from rotating. Just some food for thought.
Those are already Delrin and shouldn't be an issue. I just had the diff out last week and they looked basically new.
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New to this thread
Have been running in CSP moving to DP
Been running Hoosiers A6 225 cool/warm days 255 on hot days
Moved to DP last year
Plan to move to Avon in 2014 What 13 inch compound/width/diam?
Ride height?
Koni's can be rebuilt for spring rates and shortened (any experience?)
2014 changes for DP?
Any DP drivers coming to DC in April?
Have been running in CSP moving to DP
Been running Hoosiers A6 225 cool/warm days 255 on hot days
Moved to DP last year
Plan to move to Avon in 2014 What 13 inch compound/width/diam?
Ride height?
Koni's can be rebuilt for spring rates and shortened (any experience?)
2014 changes for DP?
Any DP drivers coming to DC in April?
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I'm pretty sure that aMaff would be happy to answer most, if not all of those questions. If he can't or won't you'll probably want to check out the autocross section of Miata.net as there isn't a lot of autocross discussion going on around here except for the thread in the Ohio section.
That said... I can answer a couple of your questions as long as aMaff doesn't mind cluttering up his thread a little. If he does, I'll remove these posts for him....
Shortening/rebuilding Konis: Yes, you're right. I'm guessing you have sports since you're mentioning shorting them. You're looking at $150 per shock for a rebuild/shorten plus any parts that are required. I had sports and I was looking into this but decided to upgrade to Xidas instead. There is a shop in Columbus (TrueChoice in Hilliard, Ohio) that does it. I would send them back to Koni NA though. Turn-around is usually a couple weeks.
2014 DP changes: Nothing significant that I've read. But I will add the disclaimer that I run STS, so I'm likely to not remember any minor changes that I read about. Most of the changes for 2014 revolves around what was formerly known as the stock class and the road tire classes.
April DC: I assume you're talking about the ProSolo at the end of April... Like I said I'm not a DP driver, but assuming I can get my car put back together in time, I'm planning on coming down and run the Pro.
I'm not going to speculate on ride height, alignment, or any other setup stuff being an STS guy on (relatively) narrow street tires.
BTW, here's a link to the Miata.net forum that contains a wealth of autocross knowledge that relates specifically to Miatas: http://forum.miata.net/vb/forumdisplay.php?f=13
Let me know if you make it up to Ohio for any of the national events in my neck of the woods.
That said... I can answer a couple of your questions as long as aMaff doesn't mind cluttering up his thread a little. If he does, I'll remove these posts for him....
Shortening/rebuilding Konis: Yes, you're right. I'm guessing you have sports since you're mentioning shorting them. You're looking at $150 per shock for a rebuild/shorten plus any parts that are required. I had sports and I was looking into this but decided to upgrade to Xidas instead. There is a shop in Columbus (TrueChoice in Hilliard, Ohio) that does it. I would send them back to Koni NA though. Turn-around is usually a couple weeks.
2014 DP changes: Nothing significant that I've read. But I will add the disclaimer that I run STS, so I'm likely to not remember any minor changes that I read about.
Most of the changes for 2014 revolves around what was formerly known as the stock class and the road tire classes.April DC: I assume you're talking about the ProSolo at the end of April... Like I said I'm not a DP driver, but assuming I can get my car put back together in time, I'm planning on coming down and run the Pro.
I'm not going to speculate on ride height, alignment, or any other setup stuff being an STS guy on (relatively) narrow street tires.
BTW, here's a link to the Miata.net forum that contains a wealth of autocross knowledge that relates specifically to Miatas: http://forum.miata.net/vb/forumdisplay.php?f=13
Let me know if you make it up to Ohio for any of the national events in my neck of the woods.
