Hi all- I'm still new to the forum and am trying to learn as much as I can about this most interesting motor and was curious about the compression ratios. Is it 1: possible to put NA rotors in a turbo motor, 2: is it worth the trouble to do so?

I've been thinking that since the combustion chamber 'enlarges' after spark, that the compression wouldnt put as much force on the seals/rotor as hard (as compared to a piston style engine). I figure you'd have to run lower boost to prevent detonation. Would the gain in compression be advantagous (while running lower compression). Any reasonable thoughts or ideas welcome.

Other question- what specifiacally is the difference between the NA and turbo rotors? (pics or a general explination. plz)

 

Yes you can use the na rotors. You'd need the counterbalance to go with them. However the higher compression would probably force you to run less boost, unless you went with a standalone. With the higher compression I think you'd need more accurate tuning than the stock ecu would allow. Just my thoughts. I'm no expert on turbo motors.

 

yeah its been done alot, and its a fun setup apparently, i was about to do it to my car, but now i'm waiting for my new one search you'll find stuff about it

 

I just built mine. 8psi feels like 12+ on my original motor. I have only chaged the rotors to high compression durring my latest rebuild. It pulls hard like a turbo, with the low end drivability of a NA. I think its great .

 

brent clement - That is not completely accurate but a safe analogy. There is absolutely no reason he can’t run 12psi on stock turbo with it.

You will spool faster and receive more HP at any given rate with a higher compression motor compared to a lower compression motor. The only thing at all that comes into play is that your detonation point is a little bit closer meaning the fuel can knock sooner. So just have the proper setup and you will be fine.

 

9.5:1, gt35r

 

so with a haltech standalone ecu, and a fmic, or just a more efficient intercooler, high comp would be ideal?

 

high comp will give you more power per boost level up to the point where the combustion pressure and heat get too high and you start detonating.

it's ideal for low boost (sub 14-17psi on pump gas) situations though...depending on the turbo size, among other factors.

 

I detonated and blew up my high-compression turbo setup, running 9:4:1 s4 N/A rotors... Not enough fuel, no way to retard timing...

If you're thinking about an affordable and streetable setup, at least get the R-tek 1.7 chip to retard the timing as the boost increases.

14psi only worked for a day...

On a positive note, my buddy who was running a nearly identical setup to mine, is having NO problems with his high-comp setup--he's using the R-tek chip at 12-13psi on the stock turbo, upgraded fuel etc.

If I were to do it again, I'd run it with a standalone ECU.

If you do it, just be careful and don't get TOO boost happy without the proper support.

 

i wouldn't even bother with high comp. without a stand alone...

 

megasquirt and turbo on my next car, i wonder if you can do timing retard per boost PSI with the megasquirt . . hmmmmm

 

Yes you can do boost retard with the Megasquirt n' Spark setup. It's fully programmable fuel and ignition control at that point.

 

that's what a stand alone is for...

 

^^
Yes, but if he was talking about Megasquirt by itself, then no it wont, that'll only control fuel. Not sure if he knows that or if he just didn't want to type out the Spark portion.

 

okie...

 

but back to my 35r with the 9.5 rotors mmmmmmm

 

I think I confused you. Megasquirt does fuel only, Megasquirt n' Spark does fuel and igntion control

For the people that want to control just fuel and either use stock ECU for igntion or a dizzy, these being the lazy people that cannot set up and tune it themselves, can use just the MS to control fuel rather than the MSnS. The only difference in the MSnS is that it has another connector and is slightly altered for ignition control.

And yes the MSnS now works with rotary thanks to muythaixbr (sp?). He finally got all the coding/programming worked out for it

 

Yah pretty sexy. I was reading about it in the FD section a while ago when Mazdatrix effed your rotors when they mailed them back to you after balancing the assembly, that sucked

And if I recall, the 9.5:1 compression was because you started with s5 9.7:1 rotors and polished them, right? And they tested out to 9.5 afterwards? Something like that if I'm remembering correclty...

 

yea, exactly....or at least as accurately as i can measure the meniscus. but the consistancy is more important than the actual number--which actually could be off. but who cares? it'll work

and **** mazdatrix

 

 

i think you read that post before i edited it because i hadn't read your post right above the previous one... i'm getting dizzy LOL

 

Oops... yep I must have, we're just too quick for each other I think.

 

bwahahahhahaha

 

For more info check the Rx8club. Those cars run even higher 10.0 compression rotors and are beging turbo charged succesfully. It's all in the tuning.

 

And are only able to run about 7psi with the stock ecu and e-manage or e-manage ultimate...

Most rx8 owners run about 4.5-5psi from what I've seen, with hardly impressive results. The greddy kit is a piece of junk and the characteristics of the car completely change from what I've heard, the powerband just completely changes and isn't as smooth.

And so far the other turbo kits out there are untested or hard to get ahold of, so there's not much available. There's some guy from puerto rico that's claiming a lot, but never posts pics or anything so it's all talk. Some of the supercharger kits might be better after some testings... The rx8 owners just need more ECU options for controlling everything, like going standalone but keeping the stock ECU to control the ports and such in the manifold.