RE Suzuki

Recently I've recieved a rx7 magazine from my parents in japan and one of the article talked about placing a US 13b N/A rotors onto the 13b rew. The N/A rotors have higher compression rate to accomodate the power and torque compared to the turbo engine's rotor. (US 13b n/a rotor: 9.7 | 13b turbo 9.0 ) This is being done at a store called "KKM". They say by changing the rotors to n/a rotors, you can obtain better response+thicker torque from the low to high ends. This is being managed by power FC by they way.

Has anyone in US tryed this?

MR_Rick

iTrader: (7)

it would be a bad idea if you plann on doing this.
1. you're in cali 91 octane would suck for that. In Japan they get better gas than we do.
2. they weight more so they can't be rev all the way to 8k rpm (from what have heard).

busy13b

iTrader: (5)

Bzzz.. It is not a bad idea to use the higer compression rotors at all.

FYI, the series 5 N/A rotors and the 13B-REW rotors are the same weight - 9.54lbs.

See what Mazdatrix has to say about the weights: http://www.mazdatrix.com/faq/rotorwgt.htm




RE Suzuki: Engine builders do this frequently. Search the "general rotary tech" threads for details on using the high-comp. rotors. Ralph from Xcessive Motorsports has many posts on the subject.

You have to be more careful when tuning as the higher compression will lead to easier detonation. Not to say that is reason enough to stay away from this type of motor build. Not even to say that lower boost should be run. But tuning needs to be spot-on.

FDreaming

It's a great idea it's been done to a much more extreme degree in the piston world. For example they are getting some great results running as high as 11.5:1 with all forged internals in Honda motors and boosting on that. Essentially your peak possible numbers go down, but your low end comes up and your using less boost/fuel to create the same amount of power. It's a great idea for the more power band minded individual.

MR_Rick

iTrader: (7)

Thanx for the info. I was thinking 86-88 was the same as 89-92. but .7 jump on the compression ain't much either so I actually think it won't be a bad idea. I take back my comments.

RX7WEEE

iTrader: (16)

Xcessive hase high compression rotors in his FD, he is crazy though :P T72... lots of boost

31psi i think....

Sesshoumaru

iTrader: (1)

FD guys don't like the idea..........

FC's do it alot more since they are a bit more do-it-yourself builders.

I personally love frankensteins

https://www.rx7club.com/showthread.p...ght=9.7+rotors

i would be running a set in my engine but i got f*&cked and never got the rotors.

It's all about application

you actually save money doing that. S6 rotors are stupid expensive.

Elysian

heh i got a set of S6 rotors that i had in my 88 TII when i still had it, paid 300 for em both... but due to a poor build by a crappy shop, the front rotor was hosed, excessive bearing clearance made the side of the rotor slap against the front plate and ruined a side seal and the rotor, as well as spun the bearing... a real mess.... i couldn't even afford to keep that car, went to a 84 GSL and a 74 REPU lol... oh well... i personally would be kind of wary of the higher compression... unless as stated, your tuning was spot on, but dyno tuning isn't the same as real world, so spot on tuning is kinda tough... oh and i hear atkins sells S6 rotors for 300 a piece or so, so yeah they are generally retarded expensive lol... i guess i got lucky at the same time as i got unlucky:|

Sesshoumaru

iTrader: (1)

pisser

hoped they swapped couter weights from a S5........that could have done it too......

the s4's are different weights (heavier).