sburkett

Disclaimer: I don't want a short shift kit. I had the Mazdatrix one and it made things worse. Stop reading if you are going to tell me about short shift kits.

I race an SCCA EP 1st gen, 12A. Ran it in IT with a stock transmission in 2001. Last year I ran a Miata center section with factory close ratio gears and stock RX-7 bellhousing and extension housing/shift linkage.

The problem I have is the VERY slow, vague shift from 2-3 or 4-3. I have tried a short shifter (as I mentioned) and it made matters worse - more blown shifts. I have also had more experienced racers drive the car, and its not just me.

I can't afford a dog ring box this season, is there anything that will substantially improve shift feel in the mean time? I tried backing up the 5th gear select spring with washers, also the detent ball springs. Maybe springs that are even stiffer?

Any help would be appreciated. My competition all went out and bought $8000 PBS boxes, and I want to shift faster too.

Thanks!
Steven

p.s. I'm not afraid to spend money, just not $8K - anyone have a used dog box for sale?

kaiesr

I'll be interested it an answer too. I have a 1st gen CSP RX7. I've always had a problem shifting from 2nd-3rd. I tried a "cheater" Mazda Motorsports trans mount, to no help. So I took it out. Any help?
Later
Steve

Adsy01

have you got 5k???




gurumotorsports.com

sburkett

Actually I just ran across the gurumotorsports stuff last night while searching for options - I'm going to order a scatter blanket from them.

I get the impression from their website that you have to install their kit in either a Turbo II or FD case, which would mean I still have to come up with a bellhousing conversion. But I'm going to ask them about it when I place my order. 5K is still on the steep side, but getting closer to "attainable".

Thanks!
Steven

Adsy01

up the fit the tII or FD casings, but those belhousing should be a straight fit.

Ive seen the Scatter blankets first hand,, there as good as in the pics.. there a ust IMO if you like reving high,, and don't we all

RacerX7fb

Try pulling out the shifter and pouring in some synthetic MTL in there (if its dry) then lightly greasing the bushings that hold the shifter in place before popping it back in. Ive done this with all my trannys and they shift nicely.

851stgen12a

Switch over to Redline Shock Proof Gear Oil. I switched over and the entire tranny is ,Quieter, and shifts a whole hell of alot smother.... $8.00 Quart..
www.redlineoil.com

Rx7carl

As stated, check, clean and relube your shifter. Especially check the plastic bushings. Since you put a miata center I assume you are sure that the syncros are good? Good syn oil in the box is the ONLY way to go. And believe it or not, an engine torque brace helped mine out alot too. It keeps the tranny and driveline rock straight so your shifter stays steady.

Chemical

What about harder (solid?) engine mounts? That should help shifting a bit...

Sterling

I don't think that would matter with a brace. And I don't think it would be nearly as effective as the brace.

I gotta say- "Redline is yer pal." (I cut a deal with them- Even though I'm not a racer, if I can prove I said that just 500 times, then I get a whole free QUART!)
Expensive, but worth it. I tried something else (synth)-can't remember what, Maybe Castrol. But she whined like Carl after a qualifying run.
The shifter gismos should all be cleaned first, and then lubed up.

I have never missed a shift*.

...*totally lying.

sburkett

Thanks to everyone for the help. I'm going to try a full synthetic gear oil and engine torque brace (I have one sitting on the shelf uninstalled) and see how that works.

Thanks again,
Steven

rx7 Nut

This may sound like a wierd solution but anyway today I had to bleed the clutch line and set it up so the pedal has about half its travel of play. So far I find that my shifts are a lot faster. Just an idea.

djmickyg

wouldnt this be the same as just pressing the clutch in half way, just past the friction point?

rx7 Nut

No becuase the clutch doesn't start to engage until half way down. If it was set up normally and you pressed the pedal down half way the clutch would almost be fully engaged.

inittab

I didn't think the clutch travel could be adjusted. How exactly did you do it?

rx7 Nut

To be honest i'm not really sure. I just stopped bleeding the line at that point becuase I liked the way it felt. I'm sure someone else on here knows more about this.

suntzumd

Nobody, I mean nobody listens to me! Try some GM syncromesh transmission fluid. When I first got my GSL-SE I would grind gears all the time going into third. I put some GM Syncromesh in and it shifts smooth as silk now! Many race specific tranny rebuilders require GM syncromesh use in their trannies.

racermike

"Free play" in the clutch is adjusted with a rod between the clutch pedal arm and the master cylinder.

mwpayne

Ok, I'm convinced, GM (or pennzoil) syncromesh!!

Now WHERE CAN I GET IT????

Rota_Motor

sorry, a bit off topic, but what casing do you use to use ther miata centre section? is it a 1st gen casing with the miata centre section, or a T2 type box? as I would desperately love closer ratios in my RX-7 even though it is only street driven.

MikeLMR

theresa website somewhere that tells you what interchanges between Rx7's an Mx5's IIRC its just the gear set its self that you swap into an RX7 casing

Its a pity you can't use the entire transmission really as Mx5's have the best gearchange of any car i've been in so far (well except the ford focus wrc )

Rota_Motor

Mike, or anyone, any idea what that website is? as Im really interested in the miata/MX-5 gearset for my 7

sburkett

If you use a gearbox from an early (1.6L) miata, its easy.

The center section and gears can be bolted to either the Miata or RX-7 bellhousing or tailshaft. If you want to use the Miata shifter and tailshaft you'll have to fabricate new transmission mounts and you *might* have to modify your driveshaft length, but I'm not sure about that.

I know there is at least one EP driver using the Miata shift linkage, so it can be done.

In any case, the Miata input shaft must be shortened and the chamfer re-cut. I don't remember the exact dimensions, I just laid the transmissions side by side and worked it out. Cost me about $50 at a local one-off machinists.

Everything else just bolts together. I agree that even with stock Miata gears this would be a great mod. I paid $500 for a low mileage box from a '91 Miata, even the synchros were like new.

Steven

Rota_Motor

so the miata input shaft has to be modded to suit?

do you have the ratios used in the 1.6 miata? because I may just go with an early 626 five-speed gearset into my casing if the ratios are similar, I know the 626 ones are closer than RX-7 gears. but not sure if miata is closer ratio again.

thanks for the help.

nopistonsforjoe

has anyone else had problems with the short shift kit? also, sburkett did the short shift help at all? did it make all your shifts worse or just the one from second to third? you should try reinstalling it after you put in synthetic fluid to see if you get better results. sorry if this is off topic...hehe