Marv

convertibles do not need a new bracket?

DigitalSynthesis

Convertibles DO in MOST CASES need the new bracket as well. SOME convertibles (seems to be the earlier '88 and '89 models) have both, but MOST do not have both brackets. Caveat Emptor, check before assuming.

gonzz

I had to make a bracket on my 90 vert 5 peed conversion i did a few months ago

doridori-rx7

iTrader: (3)

Semi resurection from the dead..
But I have to say i cannot believe the number of people slamming the guy , not 'offering' up comments but slamming him. No wonder people don't take the time to do write ups. Who the hell wants a bunch of punk *** kids 2nd guessing you at every corner AND being ****** at the same time.

As with all fab. work it's an evolving process, as was demonstrated by the upgrade to 1/2" from 1/4" this is what all the people that are thinking to do this SHOULD be paying attention to. One design can lead to more improvments, it's a natural progression. Those peple that 'ONLY' use the OEM brackets becuse that's the 'way it should be' are the people who can't really design and be creative on thier own.. I've seen 4-5 diferent ways to improve on the OEM parts easily in just a few min. and on his design.. but it's a good starting point to jump off from. But I'm not going to flame him or slam him for not 'towing the line' and not thinking for himself, it's a good bit of kit. and well made.

As for the whole ' go out and cut it from a parts car ' that may work for a small percentage of north america but I'd like to see ANY parts car, that is sold/yarded in Canada or anywhere in a wet climate actually have mounts that are useable, LOL not going to happen. So you have two chioces buy a frame that has been weather protected in which case might as well buy a whole replacment car or you make due and be creative , modify and adapt. As much as I like mazda ALL car companies build for profit and for ease of build what you get OEM is almost always going to be a compromise to those two factors. Upgradeing the eng. of ANY OEM car part on 95% of the worlds cars takes very little effort to do.

inflatablepets

I agree 100% Brought this back up to add my own comment to this and to have this thread handy to use for refrence. The best way would be to use the factory brackets, which I will probably do. The other home-made setup looks like it would function in a satisfactory manner for most people.

Bluewind

iTrader: (16)

This sounds like a pain with this bracket issue. It seems that I, a person who doesn't yet own a rx-7, should buy a manual and do a T2 swap instead of an auto to manual T2 swap. I personally would rather buy an auto and later convert it to a manual, but this sounds like a pain. Or is it?

JamesBong

It is, if you don't have the tools. I had an Auto, and bought a 5sp parts car. I moved all the good stuff off the auto on to the 5sp. Now the auto is the parts car.

alexdimen

iTrader: (13)

thanks for the write up, but i'm having some problems with your adapter design.

i'm using 1/2 inch thick steel bar 1.5 inches wide instead of what you suggest (i have to champher the outer edges where it mounts to the body for fitment), but the width shouldnt cause the problems i'm running into.

1. the mounting bolts are only 10mm, so why drill the holes to 1/2 inch? that leaves a lot of play.

2. this could be because my car is a S4 but i doubt it... the brackets were made per the directions exactly and i'm having to grind back the welds closest to the crossmember. there is no way the part can fit if the B part is mounted to on the car / orig. auto mounts. also, you obviously have the longer A part bolted to the original mounting points and the B part bolted to your crossmember in your pictures, contrary to the instructions.

from what i'm seeing, it would have been better to make both pieces 5 inches long with a 1 inch overlap... your design brings the edge of the longer piece too close to the mounting points. they would have been reversible and in my case not need to be modified.

please tell me if i'm crazy, but this isn't working.

alexdimen

iTrader: (13)

one more thing, i'm posting this here cuz i can't post in the archive... and this shouldn't be archived as it is.

in the beginning of this write it up claims that a series 4 conversion is similar. this couldn't be farther from the truth. series 4 manual transmissions mount to the crossmember in a completely different way (a series 4 mount (the part between the trans and crossmember) looks like a wide T with flared up ends while a series 5 mount looks like a Y), so the series 4 manual transmission can not bolt to an auto crossmember (which accepts only the y style mount) as a series 5 manual can.

i didn't realise this would be a problem until i had made really nice mount adapters out of some expensive 2024 aluminum stock and already had the series 4 transmission bolted to the car. i'm currently working out another mounting method, but if i had it my way, i would have held out for a series 5 trans.

now you see how misleading the statement "86-88 similar" can be. the post in the archive should be updated to say that a 89-91 transmission with a Y shaped mounting point is the only thing you can use for this particular conversion method. as it is, the write up mentions nothing about what year trtransmission this is intended for.

i'm trying to save other people from losing time and the disappointment i faced when i thought my conversion was finally coming together.

inflatablepets

Well, I've had the brackets made. I got them for free at a Wesco machine shop. I had to build a furnace room and bathroom and did a couple extras for free that got me the parts. I used 1/2 inch thick steel and had them weld all sides. I simply gave them a couple drawings. I don't see any issues with strenghth here. I think other things will break first.

inflatablepets

No, you're not crazy, I see this as well.

skylinekin

So if I use a S5 Transmission and crossmember on my S4 will this mounting kit work?

alexdimen

iTrader: (13)

yeah you need a series 5 transmission and you use your old s4 x-member (get new mounts too if you're gonna go through all this trouble).... and mind what i said about the bracked deign.

i did it with an s4 trans but i basically did 2x the fabrication and strayed far from the instructions.

hit me up for wiring instructions... these won't work. basically there's no way you can have a working clutch interlock and have it idle properly. basically what you do is trick the car into thinking it's always in the park/neutral position (bridge 2 pins on the s4 auto trans harness) and just put a bolt in place of the clutch sensor on the pedal. then all you need to do it hook the reverse switch to the 2 reverse pins on the s4 auto harness.

slpin

iTrader: (9)

the rotary resurection write up shows a stronger transmission bracket design.

it uses a C channel rather than a bar that could be bent with ease.

slpin

iTrader: (9)

alexdimen,,, if you made it out of aluminum, it hink you are crazy

inflatablepets

My design works fine. It's similar to the one in the article.

slpin

iTrader: (9)

i didnt doubt it works...
but i am saying the one from rotary resurection will be stronger in both structural deisgn and in laternal movement.... and definately could withstand wheelhop/etc better.....

alexdimen

iTrader: (13)

hehe. well first off i doubled the thickness. the part was cut out of a solid block of inch thick 2024 alloy stock... the stuff is extremely hard and i expect it to outlast the car by far. it was just scrap my father had at his shop and is expensive normally. there are probably better choices that are cheaper.

what i did was make two 9 inch stepped down (or up depending on how you look at it) pieces and drilled clearance holes a little bigger than 10mm. the pieces are as wide as will fit. hole spacing as per the other direcctions but not unequal lengths for each end of the bracket.

i actually have the adapter bracket stepping down on the car to allow room for another piece that makes the s4 trans mounting point like the s5 manual/ all autos (HUGE PAIN TO MAKE). this allows you to put auto x-member on the s4 manual. that's only necessary if you're using a s4 trans, as the s4 trans x-member is unique to s4 manuals and will not bolt onto your adapter brackets because it isn't straight.

these are as the x members would look from the rear of the car

s4 manual x-member

''''''''\__.__/'"'''\ <---- angled mounting point to chassis

s5 manual and all auto x-member

""""""\__/"""""" <---- flat mounting point

alexdimen

iTrader: (13)

from the materials suggested by this write up, i agree a c channel is stronger. what i don't agree on is that it's as stable.

using the c channel method eliminates the transmission mounts and can easily move side to side. there is only 1 bolt on each end of the c channel in those plans.

this has all been talked thru before and yeah the best way is to weld in mounting points, but i'd bet that at before MY adapters break, the sheet metal frame would be bending.

slpin

iTrader: (9)

I see EXACTLY where you are coming at, and believe me, I had the exactl same doubts. That is exactly why I decided to weld the C-Channel cirectly onto the cross member. After that, it feels alot more stable, and I remember I even throw it straigth against the concerte floor a few times (to test it), and it was fine with no brakage or anything. The drivetrain substained quite a bit of wheel hop and it lived.....The welding onto the C Channel elminated the side to side movement, adn the C-Channel design itself elminated any wheel hop and transmission holding capicaicty or bending problems... overall, in my opinion, the c-channel is just a better design... not as optimal as the stock design, but it is better than this design...

alexdimen

iTrader: (13)

hahaha, ultra low budget R&D

well to each his own... but i'm sticking with my set up!

skylinekin

so can someone show me, or do a write up on a series 4 manual conversion? I want to know the size etc. of the custom mounts I would have to make for everything to work on a s4 engine and tranny.

slpin

iTrader: (9)

^^^ i swear, sometimes, the noobs are THAT retarded....

i mean geez, i could swear someone said something about a c-channel... or was i high at the time????

classicauto

iTrader: (3)

play nice

skylinekin

thanks for nothing