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Can you use a NA Miata trans for the FB? I think the mazdatrix site conversion spec's NB unit.
yes! the miata 5 speed has like 3 iterations. 90-93 is single synchro on 2 and 3, 94-2005 is double synchro. 2006-2015 has a different case, but the same guts as the previous.
So it looks like anything 94 or up is what I want to look for in a Miata transmission? I don’t know anything about Miata’s so I have been poking around looking at what people recommend and like most things on the internet the info can be conflicting…
So it looks like anything 94 or up is what I want to look for in a Miata transmission? I don’t know anything about Miata’s so I have been poking around looking at what people recommend and like most things on the internet the info can be conflicting…
its really weird, the Rx7 has a book, an SAE paper, and the workshop and service training manuals for every iteration, but the miata doesn't have anything. its almost like its made by a different company or something, very odd.
i just looked in the parts catalog, and i think the synchro change might have happened before 94, i think midway through 1991. anyways, if you look up the parts, the NB uses the same transmission, to 2005, and then the main guts stay the same all the way up to 2015, although the case changes in 2006 for the NC.
The advice I got from Charlie Clark at KC Raceware is to avoid transmissions from the 1.6L Miata because Mazda does not stock parts for them anymore. So to play it safe I went with a 99 transmission. Visually the 99-2005 has a different looking tail shaft than the earlier 1.8L transmissions.
Overall, I think the Miata conversion makes a positive difference to the way the car works off of slow corners. Really important if the slowest corner starts the fastest part of the race track. Most of the tracks in my area have this characteristic and it sucks waiting on the engine to catch up on a long straight.
Doing this over, I would spend the money on a REM type finish on the gears. Also money spent on magnaflux inspection to catch cracks.
As a fellow SCCA member and newbie IT-7 racer, I love this build and it's given me a number of ideas to improve on my car.
I probably know the answer, but what's the possibility of removing the dash pad with the rollcage installed?
Here is the airdam that came with my car which is pretty sturdy (tested with a 4 wheels off excursion in practice). I hope to update it to an airdam more like what you have built.
Just finished up my first winter project - a lug pattern change from 4x114.3 to 4x100. I am doing this for several of reasons. 4x100 wheels are lighter than 4x114.3 wheels at very attractive prices. Next,15x8 4x100 wheels can be found with a +35mm off set which will help me tuck the rear tires up in the rear fender wells. So now I can lower the back of the car more.
On the rear the change is pretty straight forward - I had the rear axles drilled for the 4x100 pattern. The back side of the axle flange also had to be machined a little to accommodate the wheel stud flanges. To finish up I had the 4x100 pattern machined into the 5 lug Turbo 2 rotors. I say machined because this was done on a 2 axis CNC mill.
On the front the same mill was used to make a pair of lug pattern adapters using 25mm thick 6061 material. While I was hesitant to use adapters like this, I determined it is safe. Actually the 25mm thick spacers help make using +35mm wheels possible on the front of the car.
Are 4 X 100 really that much easier to find than 4 X 114.3? The 200TW manufacturers have been going all out and there are some 245-40-15 tires on the horizon, no way I am going to be able to run those on my 15 X 7 wheels. Searching around I was able to find lots of choices in both s bolt patterns in 15 X 9 wheels. It would be much easier for me to convert to 114.3 since I could just remachine the axles and hubs with a larger hole to use some larger diameter press in studs. Plus I designed some hats for Wilwood that fit a first gen and use 4 X 110 and 4 X 114.3 so they will fit both first gen patterns, I can easily redesign my hats to use 4 X 100 but that is probably not what most people would want to do.
Are 4 X 100 really that much easier to find than 4 X 114.3? The 200TW manufacturers have been going all out and there are some 245-40-15 tires on the horizon, no way I am going to be able to run those on my 15 X 7 wheels. Searching around I was able to find lots of choices in both s bolt patterns in 15 X 9 wheels. It would be much easier for me to convert to 114.3 since I could just remachine the axles and hubs with a larger hole to use some larger diameter press in studs. Plus I designed some hats for Wilwood that fit a first gen and use 4 X 110 and 4 X 114.3 so they will fit both first gen patterns, I can easily redesign my hats to use 4 X 100 but that is probably not what most people would want to do.
There are allot more 4x114.3 options than there used to be. But you have to consider how many popular sporty cars use a 4x100 pattern....like a Miata. I learned a long time ago that being able to play in the Miata world opens up allot more possibilities. Cheap possibilities.
One of my goals this year was to reduce un-sprung weight and lower the back of my car. Also I wanted to do this with wheels that have the same offset front and rear. To do this I either needed to triple my wheel budget or work with stuff that is commonly available. Switching to 4x100 wheels will save me about 4lbs per corner and allow me to narrow my rear track by 42mm while using 15x8 wheels I can rotate front to back.
Winner Winner Chicken Dinner.
Last edited by mustanghammer; 04-14-16 at 10:00 PM.
Being able to rotate front to back is an absolute requirement for me doing endurance races. I am slightly less concerned about weight, I want a light wheel but it has to be able to survive the occasional rub or curb jump since you spend 90% of your time fighting your way through traffic. For the new generation of 225 and even 245 tires on the market I need a 15X9. Turns out those are not as hard to find as you would think due to the hellaflush crowd, I stumbled across a video of how to install a 165 tire on a 15X9 wheel when I was searching LOL. For right now I will stick with my 15X7 Rewinds and 205-50-15 tires, the car seems to handle great on them and I have other priorities like getting an MS3 Pro system up and running.
I am not sure what you are allowed to do in Chump/Lemons/WRL but a lighter flywheel with a good sprung hub clutch would help with longevity. Before I started my build I ran my car with a 215mm light weight steel flywheel with a Center Force dual friction clutch; downshifts were like butter! Way smoother than with the stock boat anchor flywheel with the same clutch or the 7.25" dual disk clutch I have now.
Hold on here. So a lighter flywheel will INCREASE transmission life? I just rebuilt my 13b in my gsl-se endurance racer and left the stock flywheel alone under the thinking that the heavier flywheel will increase transmission life as it serves to more or less dampen the change in forces going through the transmission during deceleration/acceleration/shifting.
Being able to rotate front to back is an absolute requirement for me doing endurance races. I am slightly less concerned about weight, I want a light wheel but it has to be able to survive the occasional rub or curb jump since you spend 90% of your time fighting your way through traffic. For the new generation of 225 and even 245 tires on the market I need a 15X9. Turns out those are not as hard to find as you would think due to the hellaflush crowd, I stumbled across a video of how to install a 165 tire on a 15X9 wheel when I was searching LOL. For right now I will stick with my 15X7 Rewinds and 205-50-15 tires, the car seems to handle great on them and I have other priorities like getting an MS3 Pro system up and running.
And here I thought racing was a non-contact sport!
Hold on here. So a lighter flywheel will INCREASE transmission life? I just rebuilt my 13b in my gsl-se endurance racer and left the stock flywheel alone under the thinking that the heavier flywheel will increase transmission life as it serves to more or less dampen the change in forces going through the transmission during deceleration/acceleration/shifting.
Am I totally off base here?
Yes.
A heavy thing spinning at high RPM is harder to slow down and speed up than a light thing. It was allot easier to match revs for smooth downshifts with the light flywheel.
If you want to dampen drive line shock, use a clutch disk with a sprung hub. But also use a proper performance/racing clutch. For me the Center Force dual friction setup was perfect when I had to run a stock clutch.
Being able to rotate front to back is an absolute requirement for me doing endurance races. I am slightly less concerned about weight, I want a light wheel but it has to be able to survive the occasional rub or curb jump since you spend 90% of your time fighting your way through traffic. For the new generation of 225 and even 245 tires on the market I need a 15X9. Turns out those are not as hard to find as you would think due to the hellaflush crowd, I stumbled across a video of how to install a 165 tire on a 15X9 wheel when I was searching LOL. For right now I will stick with my 15X7 Rewinds and 205-50-15 tires, the car seems to handle great on them and I have other priorities like getting an MS3 Pro system up and running.
My daily driver is running a BFG Rival S 225/45-15 (probably one of the best square configuration sizes for the FB) on a 15x9 (4x100 Lug Pattern) Jongbloed Racing Wheel. Is it heavy? No. Is it the lightest on the market? Hell no! But it'll last a LONG time and they are flow formed cast wheels @ $120/ea shipped. I can live with weight knowing that they are STRONGER. Ohh, and they look amazing.
This is what I ended up with - Kosei K8R +36mm in 15x8. These are flow formed and weigh 12lbs.
I have a set of 15x7 Drag DR-21s for rain tires that I picked up on sale from Discount Tire.
I am not sure if there is enough real estate behind stock fenders for 15x9s. Doesn't matter because the rules limit STU to 8" wide wheels and fender flairs are not allowed.
Where is a good source to search for wheels? I have checked out eBay and found a few interesting possibilities, and Tire Rack has chosen to make it impossible to search wheels so where is a good source?
Scott, that's a bitchin' setup! Exact same thought process.
As for where to get wheels? Umm, these days I deal with a lot of local designers who manufacture overseas and stay on top of their quality control (GD&T!) throughout the build process. Jongbloed Racing owner, Ryan, comes out to your house, takes measurements, and starts designing your wheels for you and your application. For racing, you could go slightly heavier for durability and strength. Just a badass dude to deal with.
MANY companies are replicating replicas without actually testing their products, which is why even the best stuff on the market is only a 500kg JWL rating, which is OKAY for street, but don't expect them to last long. My wheels were 550kg JWL rated (Jongbloed 15x9 +36 offset), and previous 5zigen FN01R-Cs were 690kg JWL rated for a 15x7 +42 offset.
Rota, of all replica companies, has become a "GOOD" wheel. Ugh. You just have to shop around.
650, I have searched eBay, Phils Tire Service (for Jongbloed), Goodwin Racing, Discount Tire and Tire Rack.
eBay has the best selection of 4x114.3 wheels which is a big improvement over 6 years ago when I started working on my car for STU.
The trick with the Tire Rack is to identify a car that has the lug pattern and off set options you are looking for. Also keep in mind that their fitments are conservative so some times you have to think outside the box. Like searching for RX8 wheels that can be used on a Mustang with the right wheel spacers.
While I was trying to decide whether or not to go with the 4x100 pattern, I called the Tire Rack and spoke with a sales person. He was very helpful and provided offset, weight and pricing information that made the decision easy. From there I ran searches for a 87 VW Golf GT and a 97 Miata. This returned what I was looking for. Once I confirmed hub bores (I need 73mm hub bores) I pulled the trigger.
I was also impressed by the options at Goodwin racing for Miata fitments.
Last edited by mustanghammer; 04-19-16 at 08:29 PM.
Looks like I am going to be copying you on this one, converting my car over to 4X100. I plan to drill my axles for a new M12X1.5 screw in studs just as I have now, and machine a new set of hubs from some stock front rotors that I will cut the rotor off and machine it for M12X1.5 studs on the 4X100 pattern. I have a design for Wilwood brakes that use existing 4X100 hats or if I don't have time to get the Wilwood system up before my next race I will drill a set of the second gen rotors that I am using now.
For now I plan to use Jongbloed wheels, they are pretty light, strong and priced really well. I am leaning towards a 15X9 over a 15X10 for now, with the 10 inch wide wheel I am pretty much limited to the 245-40-15 which only has one tire available for now. With 9 inch wheels I can still run the 245 it just won’t be quite as optimized as it would be on a 10 inch wheel, and I can run 225-45-15 tires which will be pretty much perfect on that wheel.
Looks like I am going to be copying you on this one, converting my car over to 4X100. I plan to drill my axles for a new M12X1.5 screw in studs just as I have now, and machine a new set of hubs from some stock front rotors that I will cut the rotor off and machine it for M12X1.5 studs on the 4X100 pattern. I have a design for Wilwood brakes that use existing 4X100 hats or if I don't have time to get the Wilwood system up before my next race I will drill a set of the second gen rotors that I am using now.
For now I plan to use Jongbloed wheels, they are pretty light, strong and priced really well. I am leaning towards a 15X9 over a 15X10 for now, with the 10 inch wide wheel I am pretty much limited to the 245-40-15 which only has one tire available for now. With 9 inch wheels I can still run the 245 it just won’t be quite as optimized as it would be on a 10 inch wheel, and I can run 225-45-15 tires which will be pretty much perfect on that wheel.
Sounds like a plan! Post up some photos of your work, would love to see it.
What kind of diff and gear are you running in this? I was running a custom Torsen with 5.38 gears and 24 spline axles until I recently went to a quick change. Now I am sitting on the holy grail of First Gen setups and I have no idea what I am going to put it in.
I wonder how close I can run the rear tires to the inner fenders and not have rub when the body rolls? On my car with the 9 inch wheels and 245 tires I have to make the front adapters ridiculously thick since the tires I have now are already almost touching the struts, but on the back I can tuck the tires in quite a bit.
09-04-15, 11:40 AM
