BlaCkPlaGUE

Im not talking about making power, but how exactly does the engine stop at say an 8000rpm redline? is it JUST fuel cut, or ignition as well?

What would happen if you removed these features and just stepped on the gas. Other than killing yourself what rpm does the flywheel explode at, stock? Has anyone actually seen this happen?

rs_1101

i think cake mentioned flywheel separation occuring around10k or something..

then there were the crazy boys who hooked up their blown motor and ran it at like 20krpm or someting.. interesting question, very ' bill nuy'

Makenzie71

harmonic balance is the biggest limitation to the 13B. With it's breathing abillity, the motor just didn't make power that high up, so mazda didn't feel the need to super-balance the assembly.

At about 10500rpm, crank-walk becomes severe enough bottom out the apex seals and/or allow the rotars to contact the housing walls.

I've seen a peripherally port 12A, built and balanced, that peaked at 254rwhp at 12,700rpm. I wasn't very impressed...except for the 12k part...

kontakt

I think they had it at like 10-11... it spun down a bit before the tach moved off of 9k, but not too much.

FB II

some college students once tested a 12a and it hit 22,000 rpms i think then practically melted inside ahhaha

Aaron Cake

iTrader: (1)

Off topic and useless posts cleared. Some of you should know better by now. Even most of the posts that are here aren't really that great. Please, answer the question if you know. If you don't know, don't post...

patman

iTrader: (3)

apparently, tho i havent seen it, there is a SAE paper which describes a mazda test of the s4 NA 13B, in which they revved it to 21,000 rpm on an engine stand with no load, only a flywheel, to see how long it would last. supposedly they eventually turned it off after it ran through several drums of fuel.

i personally have my rev limiter set at 9250, and have hit it several times under full power, without blowing anything up.

i also noticed that on several fcs i have owned, the stock revlimiter function doesnt work, and they will max out the tach if you let them.

Makenzie71

They didn't do that on a production 13b...the production e-shaft can not handle anything above 10.5...11k, tops. It wobbles too much and it will literally beat the interior to ****.

MountainTurbo

I know the 787B's motor could run to AT LEAST 10,500.

For racing they set the rev limiter to 9,000rpm for reliability reasons and made ~700 hp. After they won lemans some of the techs were playing with the car and took it up to 10,500 rpm where it made 930hp!

I can't even imagine how much fun that would be!

Whizbang

if you spend money you could rev to "insert # here"

1987RX7guy

iTrader: (3)

IIRC the R/c Engine that's been shown on this forum a few million times does around 30k RPM.

Makenzie71

maybe it's just me, but I don't find 9k for 5 minutes then catostrophic failure all that impressive...

patman

iTrader: (3)

hey mackenzie you ever seen a bridgeport race engine? ive seen one with a stock eshaft (except for oil mods) run 13k rpms.....

Makenzie71

Stock E-shaft? Ok. What about the rotars and flywheel? The e-shaft isn't the only part of the rotating assembly and it, alone, can travel to astronomical RPM...it's the rotars that make it wobble, not the shaft's imbalance.

BlaCkPlaGUE

So what prevents higher revs? fuel cut or spark, or both? what about 1st gen carbed cars? they don't exactly have an ECU to cut fuel, so what stops that from going above stock?

Tournapart

iTrader: (4)

the inablitity to provide fuel that high i suppose, not sure, just a guess