how high can u rev safely and what would it take to get the 13b to do 9k-10k safely. or whats the max u take ur car

 

do not exceed the indicated maximum rpm's for your engine. 86-88 is 7K rpm and 89-91 is 8K rpm. any higher and you risk leaving chatter marks on your housings from wiggling apex seals and you run the risk of stationary gear failure. you do not make power above 7K rpm or 8K rpm (model year depending) so its actually a waste to exceed the redline.

 

k 7k it is

 

And to answer the second half of the question, building an engine that will rev to 10K requires balancing of the rotating assembly, lightening of the rotors if you want it to be reliable, oiling mods and hardened stationary gears. Of course, the stock porting and manifolds won't breath at that RPM anyway.

 

what happens if i mash my foot on my s4? will the needle bounce or will it just not go up anymore after certain rpm?

 

There is a rev limiter around 8K somewhere. I don't know the exact RPM but I'm sure it is in the FSM or training manual.

 

there is no rev limiter. the engine will run out of breath and will either no longer pull past a certain rpm or the engine will fail

 

There's no rev limiter on the S4 just an annoying beeping sound once you redline at 7k rpm. That's obviously the cars way of telling you to well.. Shift. Performance wise, if you wanna accelerate and shift well (in a non turbo) I've figured out it's best to **** into second right at 30 mph, into third around 60 mph, fourth gear around 85 mph, and fifth gear around 110 mph. Hope that helps any.

 

What?


s4 DOES HAVE a limiter, its around 7800. Lets get our facts straight



Contrary to this thread, I've read that 8000-8500 is the highest one should rev a stock engine(FC).

 

Oh haha, my bad. I've just never really rev'd mine up that high. Didn't think there was one.

 

if there were a rev limiter on an S4 (never took the engine past 7000 rpm), it would prevent you from revving the engine to 8000-8500 rpm on the high side. since the tachometer only reads to an indicated 8000rpm, there is no way to find 8500 on an S4 and doing so is just risky business. revving to 8000-8500 rpm can cause apex seal or stationary gear failure if done on a regular basis. on an older engine, 8500 rpm can mean certain death.

 

no. I have taken my car well past 7,800 it didn't do much of anything except probably shorten my engines life a bit

 

well this exploded. just wanted to know cause once im done on my rebuild over the winter its gonna be my weekend warrior

 

rev it till it wont rev any more. mazda did this so people like you dont screw the engine up.


there is no rev limit, more like a limit to what the ecu is capable of. wanna rev to the moon? put a carb on there and a distributor cap and have at it.

 

There is definitely a rev limiter on FCs. At around ~7800 on my FC (S4 n/a), there is a very abrupt "I just hit a brick wall" lapse in acceleration, usually accompanied by a large backfire.

Although, with the age of these cars and the known electrical problems, it would not surprise me to learn that the rev limiter has somehow stopped working on some cars. Just like how some cars have clocks and idiot lights that don't work right, wiper switches that don't work right, etc.

 

there is not a device to limit the rpm, or code in the ecu to stop the engine from revving. the simple answer is there is no information codded into the ecu after a set rpm. it hits the brick wall because the injectors arent told to fire or to not fire. they arent being told anything. or the coil packs for the same reason.

 

.

 

i can take mine to 7500 since thats where fuel cut is..(had my ports open up a little bit more since im running a full RB exhaust system(NO CATS OR AIR PUMP)

 

back when i blew my coolant seals and wanted to have the motor catastrophically fail(which it wouldnt do at all) i had the needle just stop moving at around 8.. pretty sure it went higher than that

 

My pops wanted to see if he had a fuel cut in his s4 n/a. Mashed on it to 8k then it fell on its face. There is fuel cut or rev limiter.