9 replies to this topic

[Cruzer]

hey ive just bought a series 4 RX7 with a 13B NA. its gonna be my hobby car as i only paid 1200 for it. it needs a respray and interior work and i was gonna put a 13bt in it. ive had mixed reports about which engine to go for, be it the s4 or s5. any help would be appreciated

[sinister]

I don't know a whole lot about rotors but try this site...

http://www.ausrotary.com/

Or a USA based site

http://www.rx7club.com/

[Robbo]

$1200 !!! Series 4 !! Bargain!!!

The s4 and s5 argument isnt extremely releavent in my opinion. S4 motors have lower static compression ratios so they are a little more forgiving and better for high boost applications. S5s are newer and have lighter rotors making them a little more revable.

S4 and S5 turbos are also different, the main difference is that S4 turbos only have one very small internal wastegate flap, where as S5 turbos have two very small internal wastegate flaps. The S5 turbo obviously has a much better control over boost, and is less likely to kill a motor due to boost creep.

In my opinion I'd go for which ever motor you can find that has the most compression (as in compression test, not static compression), the lowest kays, and the cheapest price.

You should post some pics! I'd be very interested to see what a $1200 S4 looks like!

Cheers.

[Cruzer]

as soon as i get back from perth ill get the pics up. first thing ill be doin is strippin it, sandin it and makin it look pretty. it has an existing elec fault but who cares when im changin the motor neway. there are tiny areas of rust, but nothin that cant be fixed. should be a good hobby.

[cal-a-kid]

yeah definately a good hobby car ... Should be able to find some cheap parts for it and they don't look that bad either, if you could complain about anything it would be the weight...

I've heard series 5 engines are the way to go, although i've seen both blow up, go figure, its a rota.

Where did you get the car from???

Dean

[Rota Ash]

basically the newer the better, a S6 motor would be the go but they have longer gearboxes with different mounting points, out of the S4 and S5 go the S5, there is not much difference in price and as far as compression ratio's go there is no point in getting less compression unless u want to run huge boost (over 20) if u do plan on running big boost i think a rebuild would be a good idea, lol

[Robbo]

A good idea... or an inevitable fact of life!?!

Wheres the pics we were promised!?

[DUS12]

up and down not round and round ha ha... i recon bridge port so it sounds tuff

[50RCE]

In my opinion If your going to keep it stock it won't matter too much I prefer the series 4 cause of the lower comp rotors. If i was you I'd buy an import series 4 or 5 motor and get it rebuilt with extend ports, that way you know you have a fresh reliable motor, I'd definately go for a series 5 turbo and manifold over the series 4 one but.

Cheers

[Teddy]

yeah the s4 turbo isn't really suited to rotarys. Also remember that if you go 13bt you will want to run a turbo box and diff.

The s5 motor is slightly tougher just get it rebuilt