Pistons in the Beloved FB?
 

Hey everybody...

First off- I know.
Second off- if youre going to flame, LEAVE NOW.

For the record, this has been floating around for a few weeks between a couple buddies and has really got me to thinking. Yes, believe me, I have defended our beloved Wankels tooth and nail, and I will not daily drive anything but my *rough* pride and joy- a '85 12A SP.

So, no- this hasn't been done- yet (at least not to my knowledge) but while sitting around with the guys over a few beers, we were admiring the body lines of my *rough* but beloved FB, and the comment came around "Why don't you put an SR into one?"

For those unfamiliar, the SR20DET is the fuel injected, 4-Cylinder, Turbocharged and Intercooled motor from Nissan that came stock in the Japanese Silvia's, Bluebird's, Pulsar GTi-R's. With roughly 200HP and 200FT/lbs, it would be nothing to sneeze at in our 2200 pound Mazdas.

With the introduction aside, I have searched and only found threads wondering about doing it, joking about doing it, and from those that possibly could have done it, (PAGING rotor vs. piston?) please come forward and discuss!

Other than the obvious mounting issues, having to run a stand alone, etc...what could be the pro's/ con's....this is sure to get somebody's blood pressure up so lets keep it clean, after all we're all adults here not louts...

i don't know much about import motors, but if you're gonna go to that trouble, why not just do a v8 or grand national v6 turbo? probably similar cost-wise but make WAY more than 200hp.

Actually, this conversation has reared its head in the Non-Technical section. Give that a look. :)

4G63 or 3S-GTE/4A-GE

spindoctor: yes, ironically that exact setup was also thrown out in the conversation, but among the crew there is an extra SR sitting in the garage that could be had for cheap and is readily available for measurements/shared cost for a "team car" -something we could all take to the track and beat around...while splitting the cost for economical (read as college) reasons...because a decent FB shell, as we all know can be had for cheeeeeeeap :)

85 FB: awesome...looking now.

i dont think it would be any harder than a v8 swap. jsut would need a lot of time to think plan measure twice cut once deal. I have been in a sr powered 240 and it was nothing to joke about it was a serious ride, with serious numbers. all in all though i guess if you wanted to do it go for it. I love it when people think outside the box but...for this project it would be kinda weird! After my current project of the turbo 12a i am gonna stuff a 12a or 13b in my 69 opel gt :)

Hmmm,,,, Opel Gt, the first "mini corvette"..lol I have been thinking about alot of different engines. I really want to do a swap because the numbers just aren't there with the 12A. But the 12A is running pretty good.

If you want to do it, then do it!!

Later,
Bill

The opel gt is one of the coolest cars ever made...it just looks sweet and it was made buy the guy who made the stingray :)

jeezus: the 4G63/ 3S-GTE/ 4A-GE are all formidable candidates but the availability of an SR for me...

yetterben and SSRx7: yea, two of the guys have SR powered 240's that are pushing right around the 300 mark, and are completely street legal and daily driven (reliably), thats what got the conversation originally started- power.

True. I forgot about the fact that you basically have one. I hate reading too fast :)

ha all good, do you guys know if rotor vs. piston did a write up on his? I have thus since concluded that he has done this swap (so much for the searching...wrong section) but yea it'd be awesome if I could get him to comment/add insight to this....

I wouldnt mind seeing that put in. While I love my rotary, I dont find anything wrong with exploring other ideas. If you have an engine like that, why not try? Though would it throw off the 50/50 weight of the car enough that it would make stock handling rougher?

Meh, my belief is that the RX-7 should have a Rotary based engine no-matter what... its what makes them such fun unique cars.

But an SR? Hmm.. I like the sound of it, but, you'll have some issues with the rear-end if you're going to generate that much power...

the SR swap has been done. search rotors vs pistons, he did it.

i researched this swap along with a 4G63 swap and a 3S-GTE swap. id go with either the SR or 4G. they each have their ups and downs. if it were me, id do the 4G. im holding off on a piston swap though. im tyring a boosted wankel first.

weight is an issue, thats why the SR in question is actually in question as opposed to the 1JZ sitting next to it ha...

anyways, DemonSpawn: your beliefs are welcomed although they should be checked at the door...j/k.. I'm right there with ya, it's not an "R"x-7 without a rotary! but for track/power/creative purposes, we're just in the thinking stage...yes! the rear end...good call. that was overlooked...

so if you are doing the sr20 thing, you dont need the weber and all... what would you want for it?

haha...nah this would be on a whole new car- a shell that would be stripped to nothing and built from the ground up. as of right now im running a Mikuni actually, while saving and tuning the weber, but same thing basically, if you're interested in the near future in a mikuni, doesn't look the best but runs pretty well...a little rich, but not bad at all...

Well, since you have an SR engine at your disposal, then go for it. I personally would never choose an SR over a domestic engine such as a V8 or strong V6. A 3.8L V6 from a mid 90's camaro or firebird would give you the same HP as a stock SR20, with much more torque, and easier to get a hold of parts. On top of that, that engine has a ton of aftermarket available, unlike the series 1 3.8. Turbo kits and everything are available, and you can even get a 6 speed for them easily if you find the right doner car.

I did a basic write up, it should still be here, not sure if it was lost in the move to new servers... I'll search tomorrow.

The 3.8 from the later camaro's are not a good choice for the 7. How do I know? I already tried and that's why I have the SR in it now. V8... I ran a SBC before I did the SR swap... and while there's nothing like the tunnel vision inducing power of a "built" v8 in the lunch box of an FB I'd rather drive the SR and do drive it much more than when I had the V8 in it.

As far as ease and availibilty I couldn't see going any other way than running the SR.

I'll check this thread when I get home from work... ask any questions you want answered after reading the small write up, let me know if you just can't find it though, and I'll do what I can to answer them.

Also, even when running the V8 I didn't have any issues with the rear end... stock GSL-SE

sweet...well I've got a few questions on youre set up:
Blacktop or Redtop?
How much power are you pushing?
Emissions?
Do you have any pictures of the final product? or the motor mounts/measurements?

Here's a link to his write up:
https://www.rx7club.com/other-engine-conversions-non-v-8-118/sr20det-swap-write-up-sort-587365/

also, are you running the factory S13 ecu or a stand alone? piggyback? how much boost? are you running the stock t25?

this is awesome. I'm getting so excited. wwaaaaaay too ahead of myself. scheister. I hate being the broke college kid....one day, oh one day I'll have a real job

...and a GARAGE! oh boy!

ha ha this is amazing me a few of my friends were talking about an SR swap on my 90 FC not 2 days ago. I was wondering if I had a engine and tranny already what would I really need to do a swap?

i was into the whole sr/rb engine thing that lasted about 1-2 years....but im all rotor now! :D anyways.... the sr20 is quite a light engine compared to the rb20/25/any v8..the sr has an alloy block..sr20s are extremely easy to get parts for in australia...(kos theres just TOO MANY s13's and 180sx's) the sr20det is 153kw @ 6000rpm, 274nm@4000rpm, compression is 8.5:1, NO DIFFERENCE IN POWER BETWEEN RED AND BLACK TOP SR20s in the s13s...the only difference is one is black and one is red...lol my n/a 7 will slaughter a sr20det silvia... sr20s can get really mental with the right mods...just make sure the conversion is legal b4 u start...hav a look to see if the transmission will fit too, ull probly need a custom driveshaft made as well....other than that have fun and good luck

damn dude, n/a 7 rockin the silvia's and the holdens?? that's impressive- what all you got done to it?! thats awesome!! show em whos boss! ahh West Oz..a hermetically sealed surfing culture, beautiful.

Anyways, I'm pretty sure there is a power difference between the red and black top SR20's- some came with a T25 and the later ones with a T28...boasting almost a 50HP difference between them...depending on the year of the motor. From 150Kw in the original Bluebird (redtop) to 183Kw in the S15 (blacktop)...you know, just for good measure...:)

I don't know how this is possible, for a brief 5K or so miles I had a 13BT swapped GSLSE. I attempted to drag race 5 times and broke 2 rear ends. Car couldn't have had more than 315-320 WHP. My buddy has a GSLSE with a 13B-RE making maybe 350-360 WHP and has also broken 2 rear ends.

And these are on no torque having rotary engines