ok so im not sure which redline is correct or not because in some pics i have seen 8k and on mine it reads 7k (rev limiter kicks in at about 7400 7500) which is correct? and while im on the subject has anyone cryo treated any thing on there fd? and if so do you like it? i was thinking of doing my 13b so i could rev higher and give it more reliablity

 

Don't remember where the stock ECU sets redline, aftermarket ECU's let you set the rev limiter. The engine on the stock twins doesn't make power way up top, raising the rev limit doesn't do anything for power. Cryo does ZIPPO!

 

do you have an auot?? on an X auto. They have lower rev limits.

 

I thought redline was higher? Oh well, i could be mistaken. Yeah and I hear cryo does nothing...

 

nope, redline for autos is lower (7.5k i believe). im 95% sure that redline for a manual is 8500rpm but our cars should not have a revlimiter installed with the stock ecu.

as for cryogening our engines, it might help a little if yoru going to the edge of performance (like teetering on the edge of popping yoru engien) but i doubt it really does anything. If you run lean and/or hit 20+psi boost (overboost) on the stock fuel system, your probally gonna pop your engine and nothing is gonna stop that.

what you might want to look in to cryogening is your brake rotors (there has some test which seem to suggest it does extend the life of your rotors) or possiblity of your frame (some have suggested it but i doubt its fesible).

good luck

 

I think its 8200rpm for manual....96% sure.

 

i heard that our belts fly off before our engine stops wanting to rev....

 

My rotors are cryo treated. The claim is they're 300% stronger, and disappate heat much more efficiently. I also got the pads cryo treated. They fade a lot less quickly.

Cryo treating the engine internals, as others have said, prob isn't the best use of your money, simply because our engines usually don't fail from excessive wear or cracked housings, etc. It's usually the apex seal that does it. And cryo treating won't to diddly for that

I would seriously consider cryo treating tranny internals when getting a new tranny, and maybe the PPF if you're an avid autocrosser, since it'll give the PPF greater strength (and hence you're less likely to crack it). The Mazdaspeed PPF is only 10% stronger than stock. That's def. not worth the money in my book. Cryo treat that junx!

 

stock ecu for 99spec manual has limits at 8K

 

Do NOT cryo treat a PPF. Cryo treatment improves strength at the expense of making it brittle. You'd rather have it bend than snap.

Engine rotors and housings may benefit, as may the tranny. See if you can get them to do hardness tests before and after the cryo to see if it made any difference. (It may not)

https://www.rx7club.com/showthread.p...hreadid=259845
Dave

 

Dave,

Not questioning your knowledge, just looking for an explanation.

Cryo treating makes parts stronger but brittle? I didn't know that...cuz I thought the whole point of cryo treating rotors was that drilled rotors can often crack, and this makes them much stronger and less prone to cracking. Are you saying they become stronger, but if pushed farther than their limit they'll just crack anyways? Cuz I don't believe rotors or PPFs usually bend on people, do they?

I know rotors may warp from excessive use, and PPFs may bend somewhat, but usually I hear of cracked rotors and PPFs snapped in half...

Could ya explain the difference a little more? (I did read your post in the other thread)