I'm Back! '90 GTUs

[project86]

Planning to black plastic dip my side mirrors. Id rather them be black then the nasty faded red that they are now. I actually had one started but it got knocked over and messed up. So I'm going to have to peel it off and start over.

I went ahead and placed an order today for a Mazdatrix short shifter, new shift boots and a 93 knob. I took the shift panel off to find all the inner boots missing. Next thing i do will probably be exhaust so i can drive it in peace lol.

[project86]

Alright so I have the mirrors done. Im not really a fan of black/red combo. But i like them black better than i like them faded.

Also, I just ordered the S5 black off plate kit.. so just the ACV and BAC. I've read mixed things about removing the pump on the S5. I removed all the emissions on my S4 and just wired the 6th ports open and didnt experience any issues. I'm assuming i can do the same on this car.

I've also located my vibration problem... The split air tube is like 9 miles long and isnt anchored to anything so it just bounces around down there. You can also see how shoddy this exhaust is. A full RB exhaust is on the list to do after i have the coolant system flushed.

One more thing... I believe i mentioned in the opening post that i was getting some shuddering in 1st gear (after I'm off the clutch). Anyone have any insight as to what could cause that? The rest of the gears feel fine.

[MolotovMan]

Originally Posted by project86

One more thing... I believe i mentioned in the opening post that i was getting some shuddering in 1st gear (after I'm off the clutch). Anyone have any insight as to what could cause that? The rest of the gears feel fine.

Whats the total mileage on the car? The first thing I'd look at is the driveline mounts. I'd guess it would be the trans mounts, diff mount, or the driveshaft has some slop.

Congrats on the GTUs, in a bout of sacrilege I parted out my '89 GTUs a few months ago. I stalled on the project and was never going to get it on the road in a reasonable amount of time.

Hands down the best mod I did to the car was having an NB Miata gear set put into the S5 N/A case. It made the car so much more fun to drive.

[project86]

Originally Posted by MolotovMan

Whats the total mileage on the car? The first thing I'd look at is the driveline mounts. I'd guess it would be the trans mounts, diff mount, or the driveshaft has some slop.

It has about 135k on the body. The engine has around 30k (supposedly). With the way the gear shift feels (like a floppy sausage) my guess is that the trans is original to the car. Is there any reason why it would be limited to just 1st gear?

Originally Posted by MolotovMan

Congrats on the GTUs, in a bout of sacrilege I parted out my '89 GTUs a few months ago. I stalled on the project and was never going to get it on the road in a reasonable amount of time.

Hands down the best mod I did to the car was having an NB Miata gear set put into the S5 N/A case. It made the car so much more fun to drive.

Thanks man I'm really excited about it. Im ready to kind of run it hard but i want to get the coolant flushed first and maybe have the trans fluid done too. Why the miata gears though? The gearing in this car is already shorter compared to the other models.

[infernosg]

Originally Posted by C. Ludwig

.756 od

You're right. I was thinking of the Miata gear ratios.

Originally Posted by project86

Thanks man I'm really excited about it. Im ready to kind of run it hard but i want to get the coolant flushed first and maybe have the trans fluid done too. Why the miata gears though? The gearing in this car is already shorter compared to the other models.

Only 5th is shorter in the GTUs. The Miata gear ratios are closer together than the RX7 ratios, even the GTUs, but 1-3 are taller. Source:https://www.mazdatrix.com/g1.htm.

[project86]

Originally Posted by MolotovMan

Hands down the best mod I did to the car was having an NB Miata gear set put into the S5 N/A case. It made the car so much more fun to drive.

So you just sourced Miata trans and had someone do the input shaft mod for you? Does the fc shifter still fit the same way since it's just the internal parts being changed?

[infernosg]

Originally Posted by project86

So you just sourced Miata trans and had someone do the input shaft mod for you? Does the fc shifter still fit the same way since it's just the internal parts being changed?

The mod is essentially putting the Miata gears into the RX7 transmission housings so the rear housing and shift linkages are still all RX7. Though technically you could swap some Miata stuff over so you could run a Miata short shifter if you wanted. They're much cheaper for some reason. It sounds straightforward but it's a pretty complicated task. You have to completely disassemble the transmission to get to remove the input shaft. I posted a how-to on here a while back detailing the process per the FSM.

[knonfs]

Originally Posted by project86

So you just sourced Miata trans and had someone do the input shaft mod for you? Does the fc shifter still fit the same way since it's just the internal parts being changed?

Originally Posted by infernosg

The mod is essentially putting the Miata gears into the RX7 transmission housings so the rear housing and shift linkages are still all RX7. Though technically you could swap some Miata stuff over so you could run a Miata short shifter if you wanted. They're much cheaper for some reason. It sounds straightforward but it's a pretty complicated task. You have to completely disassemble the transmission to get to remove the input shaft. I posted a how-to on here a while back detailing the process per the FSM.

A good local standup guy (in Northern VA that is) is selling a NA FC trans with the Miata gears on it. I don't want to cross post threads, but if you are interested, I can get you in touch with him (or pm you his FS thread)

[chibikougan]

I have those injectors and new connectors if you want them. You cover shipping and they are yours.