Hello yo

I'm planing RX-7 200HP. The old 13b non turbo died
so decided to make some SWAP

MY PROJECT

engine FROM MB 190E AMG 2.3 16V
stock 6) Mercedes Benz 190E 2.3 16v 185hp@6200-235Nm@4500


McPie mazda rx-7 project


















main question

how to stick MB eingine with with FC3S gear BOX and fd3s lsd differential
any ideas?


Regards
McPie

 

Dont waste your time with a FD LSD... get a KAZZ or a S4.

Im personally going with a 2.3T from a ford. half as many valves, but its not necessary - if I really had to Id just modify a volvo head for it

That said, you could try to get a custom bellhousing and pilot bushing made, or either modify the input shaft or the crank of the benz engine.. but that would cost a lot of money.

It would probably easier to get the benz tranny and just bolt that in with a crossmember under the car and get a new D/S cut.

Interesting swap! Definitely a one of a kind... but you're gonna be on your own here.

 

You could simply have an adapter plate made, as opposed to a whole new bellhousing. Was there a reason to not use the MB tranny?

Definitely an interesting swap. I was actually thinking about putting an LS1 in a 190E as a winter car, you kinda went the other way.

 

there is a possibility of creating plate and stick mb engine with rx gear box.
and there is one but:






the part wich marked in red after stick is to short that means I have to make a bit thiner plate(aproximate 12mm) and take of some "skin"(aproximately 5mm) gear box bellhousing. In this type I think conncetion will be weak and drags, drifts, other fun will be not avalable


If I take MB egine MB gear box and Fd3S differential, that means very short shifts.

RPM=7000

TopSpeed / RPM drop
1 gear 49,8 / 2676
2 gear 80,6 / 2083
3 gear 114,7 / 2017
4 gear 161,2 / 1444
5 gear 203,1 / -

5 gear - 87km/h@3000rpm, 130,6km/h@4500rpm.

some people suggest me to take mb differential and make custome conects between drive shaft and diferential.

main question:
If plate with is ~10-12mm and from RX gear box I'll take of 5mm will the conection will be enough strong for drags burnouts drifts ect.

by the wy wheels R16

Regards
McPie

 

If you're going to use the Mercedes engine, make sure you use the Mercedes gearbox with it. If the gearing is too short, just change the final drive ratio in the diff. This would be a much easier way to go.

 

I agree for your opinion, easyest and better way: mb engine, mb gear box, mb diff.

but I want to save some money and stick mb to rx transmition, that is only 10-12mm plate (between engine and gear box) and take of 5mm from rx gear box front. IS THIS CONECTION STRON ENOUGHT ?

 

mb dif ratio 2.81
rx-7 gen III dif ratio 4.1
rx-7 gen II non turbo dif ratio is 4.2

I'd like to believe that plate with 12mm width will be strong enought to stick mb and rx

what width of plate you would suggest to use in my swap? and wich metal beter to choose
which is stronger and not afraid of rust?

 

FINALY all calculation were unsecfull and came to decision:

MB egine with MB gear box MB cardan MB diff and rx-7 customised driveshafts


maybe someone is intrested in RX-7 FD3S/Fc3S LSD DIFF ?

 

theres no reason to use the MB Diff right now.

IT would be very difficult to set it up to work with the stock IRS, unless youre capable of and still interested in modifying it or putting in a MB rear end.

People have used a ford 8.8 diff before, same for the chevy corvette C4 differential.

And, anyway, you could make a driveshaft to fit the MB Transmission up to the RX7s rear end anyway

 

corect my mechanic will rebuild fc drive shaft and fit it to mb diff

I could attach file with rezult of mb gear box and rx diff gears are very very short
5th gear 3000RPM and speed is 87km, very sad.

I'm intrested fully modify my rx-7, speed, traction, handling, torque and just want to keep real/original interior and body.

I think after 2-3 month will place there DINO rezults still Patiently waiting for it

 

You're going to have to weld and modify the rear subframe to accept the MB Differential and also modify either the differential or the mazda axles via broaching to mount up to eachother, and you might have to make tweaks to keep the alignment and geometry true.

Im not saying it hasnt been done, Im just saying its not going to be EASY.

 

Yea it's true but I have a good mechanic and he has good equipment all I need id patient & money