Turbocharged S-5 mazda motor in a 124

ride65 · Post by **ride65** » Sat Apr 26, 2014 1:49 pm

A buddy of mine who runs a turbocharged RX7 at the track stopped by today to look a my collection and asked me if any of you "Spider People" had ever put a turbocharged rotary motor in in one of these "things". He said you could bolt a S-5 turbo motor(89-91) into a 124 with a little (he said probably less than for a V6) modification, and get 200 hp with a stock (turbo) exhaust. Has anyone ever heard of it being done?

v6spider · Post by **v6spider** » Sat Apr 26, 2014 3:15 pm

I doubt it would be little work.. the 124 trans runs a smaller diameter clutch than a rotary so widening the area where that goes through is a must.. the engine also is a rear sump so clearance of the cross member is an issue..not to mention the rotary is wider ...no it would certainly require as much as v6 if not more...imo
Rob

Holshot · Post by **Holshot** » Sat Apr 26, 2014 4:17 pm

While I agree that it would require a little more work like any custom engine install would be, I do disagree with v6 in the way it would fit. The rotary is overall slimmer not wider (not by much) then the stock TC motor and lighter. Of course assuming you don't run some massive single setup. Rotary motors are quite impressive when tuned properly especially the RB series motors found in the '93+ RX-7. Even with a really small t66 can easily put down 350-400 to the wheels and keep reliability on the stock apex seals. Since the motors are so short you may be able to push the motor/trans far enough forward to avoid any tunnel issues you may run into with the larger trans. Here are a few pics of one of my old builds for a reference of size...

ride65 · Post by **ride65** » Sat Apr 26, 2014 5:27 pm

Would pushing the motor forward create additional complications concerning the shifting linkage ? Also, he was suggesting sticking with a S-5 1989-1991 stock engine/turbo unit to make the initial install simpler vs a non-turbo unit and upgrading to a larger turbo later. I know the engine itself is extremely light, I stopped by his shop and there was one sitting on a milk crate(no exhaust or anything on it, just front and rear covers) I thought it was part of a heavy duty tranny for a truck, he told me to go ahead and pick it up, I could pick it with hardly any strain ( I think the smoke hanging out of my mouth was the problem). I'm just looking into this possibility while I carry on with more mundane tasks. It does sound feasible, 200 HP and a reduction in weight, just finding a complete parts/donor car to do it will be the problem, as I imagine a lot of little things need to be accounted for.

Holshot · Post by **Holshot** » Sat Apr 26, 2014 5:58 pm

If you're only looking for around 200hp that can be achieved in NA form so no need for the added expense, weight and hassle of FI (forced induction). That's is really pushing the limit though in a NA rotary and depending on your budget of course. Anywhere from 150 to 170 is fairly easy without having to get really crazy. As far as linkage is concerned you would have to start measuring. If sticking NA you'll have tons of room as you can see from what I posted above the turbo does add quite a bit of girth to the motor but a NA header is much small/compact. Also, take into account trying to ring out that muck power out of a Rotary in any form it will mean opening up the exhaust quite a bit and they are not known as being one of the prettiest sounding motors. They actually sound like shit to be honest especially in NA form, at least in a Turbo setup it is somewhat muffled and toned down some. Usually, either you love it or you hate it... So take that into consideration.

spidernut · Post by **spidernut** » Sat Apr 26, 2014 8:38 pm

Yes, it has been done. There was a car for sale about two years ago with the twin rotary installed. It was running and could be driven but wasn't completed....this is common with motor swaps.

I explored the same thing for grins but the turbo rotary is not known for its reliability or fuel economy. It has fair horsepower but is a bit low on torque from the specs I've read. I'm not a fan of motor swaps, but I'd personally go for the V6 for a multitude of reasons from parts, service, reliability, horsepower, torque, etc. No offense to the Wankel crowd (I'm intrigued by the design and built a visible Wankel as a kid), but the V6 is a superior motor all things considered.

All said, I'm a purist...I prefer keeping old cars stock.

v6spider · Post by **v6spider** » Sat Apr 26, 2014 9:04 pm

Spidernut I agree the v6 is better..I do love the Wankel though I've had a Cosmo and an rx7 and loved them both.. and they were very quick! But my first v6 powered spider ate them for breakfast...and handled better too... v6spider 2.0 will be a blast. I can't wait until it is on the road.

Rob

Daniel · Post by **Daniel** » Mon Apr 28, 2014 5:05 am

years ago i owned a turbo2 rx7 that thing handled really well i raced a porsche carrera 2 in some turns we were close
very close but i dont know if he was pushing his car as hard as i was? only mods i had KYB shocks and a air dam my rx7
car did 145 mph stock.

sptcoupe · Post by **sptcoupe** » Mon Apr 28, 2014 8:18 am

Years ago when we lived in the San Francisco area, a number of cars in the FIAT America club had rotaries in them. I also remember that someone had swapped one into an X/19.

btoran · Post by **btoran** » Mon Apr 28, 2014 8:23 am

the problem with doing this swap is that your fiat would go "hmmmmmmmm".

v6spider · Post by **v6spider** » Mon Apr 28, 2014 1:51 pm

You need to hear a rotary with just a straight header... it is deafening... sounds like angry hornets on crack.. LOL

Rob

btoran · Post by **btoran** » Mon Apr 28, 2014 2:35 pm

yup. was just referring to the old mazda commercials of my (long-past) youth.

ride65 · Post by **ride65** » Mon Apr 28, 2014 3:55 pm

"The Angry Hornets on Crack",

sounds like a good name for an NBA team or soccer club.

BERGFIAT · Post by **BERGFIAT** » Mon Apr 28, 2014 11:35 pm

Sorry, but the rotory would be one of the hardest motors to swap. Why? Because a rotory motor has a very high crankshaft centerline. If you are familiar with the RX7, you know that all generations have a very large transmission tunnel to accommodate this crank centerline. This is the main reason the RX7 remains one of the most popular swap vehicles; any current manual or auto trans will fit the tunnel w/o modification.

Daniel · Post by **Daniel** » Tue Apr 29, 2014 1:24 am

BERGFIAT wrote:Sorry, but the rotory would be one of the hardest motors to swap. Why? Because a rotory motor has a very high crankshaft centerline. If you are familiar with the RX7, you know that all generations have a very large transmission tunnel to accommodate this crank centerline. This is the main reason the RX7 remains one of the most popular swap vehicles; any current manual or auto trans will fit the tunnel w/o modification.

Interesting I've never heard of or seen another power plant in a RX7, RX2, RX3 etc not saying it hasn't been done
I've just always assumed why mess with a good thing.

Turbocharged S-5 mazda motor in a 124

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