Hey all. My brother is putting together a turbo kit for his 85 MR2. We have access to a used turbo from an 87 fc RX7. I was wondering if there are any links to compressor maps or such we could get a hold of. The motor is a 1.6 4A-GE that will be revving to 7500 rpms or so. We're planning on running, for now, 5-6 psi without an intercooler. Also, if I remember correctly, the rotor turns at 1/3 the speed of the drivetrain, so if the fc revved to 8000 rpm, the rotor would be turning at less than 3000 rpms, and with 1.3 liters of displacement, that isn't much flow out of the turbo, compared to a piston engine. Do I have that correct? Any help is much appreciated.

 

a rotary motor forces just as much air in as a piston motor.. there are no differences from a piston turbo to a rotary turbo... they are identical.... lbs. of boost are lbs. of boost... so if im boostin 14 lbs of boost..... its the same exact amount of air that a piston motor boostin' 14 lbs. has going in it... i dont have a map for the turbo.... but it should be sufficent for what you want... im not an expert, so im helping the best i can.... dont take this info as a concrete statement

 

You have the rotor vs driveline relation flipped. The rotors actually spin at 3 times the speed of the driveshaft, as 3 rotations of the rotors equals 1 engine revolution. As for the rest, I can't help you, sorry. I wish you and your buddy luck with this endeavor.

-=Kenneth=-

 

actually.... the rotor itself spins at 1/3 the speed of the ecentric shaft.... everything else spins at the same speed as the ecentric shaft

 

no, you've got it flipped. C'mon, if you don't know the correct info please don't post. You'll wind up confusing others! :-P
-John

 

 

So, now that we've got that figured out, can anybody tell me anything at all about FC turbos?

 

No valve or head to get in the way for the exhaust on the rotary engine and the exhaust is pushed out by the next event.

Figure twice to three times the output of a 4A at its exhaust port for the exhaust volocity and volumn.

 

dont you just love rotary

 

That turbo would be way to small. IT would run out of steam way to early. The 1.6 Turbo would be way outside its efficiacy range by like 3psi. The rotory needs amlost twice the CFM of that turbo. Think Saab 9000 or other V6 based turbos. The OEM turbo for the 13b is pretty large compaired to every 4 banger turbo I've seen. When properly sizing a turbo for a car its all about CFM.

Plus you can get your hands on the OEM turbo for cheap.

Anyone have the max CFM of the OEM Turbo?

 

i can't find the cfm's , but i do know that mazda engineers re-designed the turbo's
(hitachi ht18s-2s) for the s4's to work with a minimum of turbo lag. the turbo's are designed for a rotory engine can't say it would give you the results you may be looking for though.

 

bump

 

The stock turbo is a bit too large for a 1.6 piston engine. If you are looking at cheap OEM turbos, I'd look into things like the T25 from SR20 guys upgrading, or a T3 from a Z31 300 ZX (.60 compressor, .48 exhaust) or from a Turbo Ford (.60 compressor, .48 OR .63 exhaust)