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93-LX-C
01-02-2004, 10:46 PM
What are the consequences to redlining your engine? How far can a stock h22 with an h22 tranny rev? Are there any benefits to redlining? Thanks for any responses.

ACCLUDE
01-02-2004, 11:46 PM
Good questions!

USDM redline - 7300
JDM redline - 7500

The redline is technically the maximum revs the motor can take before "motor go boom". However, mfgs have usually list the redline as slightly lower than what the motor can actually handle for their own protection. Also, you are able to take the motor past redline and hold it there for short periods of time. The motors can usually handle it without immediatly blowing, but I wouldn't recommend doing that. It puts additional strain on moving parts that could cause it to go immediately or cause damage that affects the long term life of the motor. For example, I had an old beater Prelude that had a redline of 6500. For shits and giggles, I revved it steady at 6800-7000 RPM for about 15 min. until the motor finally blew. Depending on the condition of your motor, it may last 30 min. being pushed past redline or it may last 3 sec. It's basically not recommended tho cause it doesn't really benefit you in any way. After about 6800 RPM the H22 kinda levels off the amount of "increase" in power. Meaning it hits its highest horsepower rating at 6800 and then kinda slowly drops in power as you either increase or decrease RPMs from there. The only bennefit taking it past 6800 is that it allows you to be in higher RPMs when you shift to the next gear. The beauty about the H22 setup is that if you take each gear up to 7500, then when you shift to the folowing gear you're right at the 5500 RPM range which is where VTEC kicks in. If you shift to each gear (2nd-5th) with VTEC engaged, the car will speed up much quicker. Honda designed that well. I would suggest not taking your car past 7500 unless you have a specific reason to like adding new cams, valves, springs, retainers which increase the redline.

93-LX-C
01-03-2004, 01:27 PM
I've seen adds for perfomance chips that raise the redline. Does it really raise the redline and if it does then does that mean it's ok? Also what changes affect the redline because I was visiting the 94-97 forum when I read about a guys engine that was going to redline at something over 10,000. Thanks.

ACCLUDE
01-03-2004, 11:07 PM
Those performance chips don't change the redline of your car...they change the rev-limit. There is a difference. The rev-limiter kicks in at a certain RPM to keep you from blowing the motor. The rev-limit is around 7800 on the stock H22 ECU. The performance chip you're talking about would change that to about 8000 or 8500 or even higher. That doesn't mean the motor can handle it, it just means that you have the option to take it higher than the stock rev-limit of 7800. That's a bad thing if you have a stock motor or just the usual bolt-ons. The stock motor can't handle 8500 RPM and will blow if you take it that high. So the redline still stays at 7500 even with those chips, just the rev-limit is set higher.

Now to increase the redline (maximum RPMs the motor can safely handle), you need to do internal work. The botom-end (crank, rods, pistons berrings) of the H22 are pretty solid and can rev higher than 7500 ok as-is but it wouldn't hurt to have them changed/modified either. Things like lighter pullies can also help increase red-line to the fact that the motor has to work less to move all the crap attatched to it and that means less stress put on the crank and everything attatched to it. The head and topend is where most of the attention needs to go to to increase the redline. Mainly the valves, springs, retainers, cam berrings & journals need to be modified/replaced to increase the redline. Chips and other electronic devices have no effect on redline. The motor itself needs to be modified in order to physically be able to rev higher.

H22Inside
01-22-2004, 12:08 AM
Since we're on the topic of redlining and such i had a question, maybe someone can answer it. I have an H22 swap and i've taken the rpm's up to about...8200 or so before the fuel cut-off. I've read that at that high an rpm the stock accord tach is not accurate. Is this true? It was stated that it's off by an amount of 400-500 rpms.

vasponger
01-22-2004, 06:09 AM
ive seen a guy hold an rx7 to 9k rpms for about 20mins before it cut off, only they forgot to put the coolant cap on so that was smoking and then exhaust pipes caught on fire

4thgenaccord
01-25-2004, 01:53 AM
Here is a good video to help with what you are taliking about. It's not a H22 (It's a Mazda rotory) but' it shows what happens when you do what you are talking about.

Kinda long. about 10 mins +.

Enjoy.

http://www.calinetworks.net/rez/movies/pop.wmv

(right click and "save as")