Topic says it all. Where is a safe redline to shift at? I know the older 84-87 Si motors could handle up to 8500rpms. If I want to rev the d16a6 up that high, what will need to be done?

Mind you, I won't be living at that rpm...it will just be in case I need to go there for autox and hold a gear out a little longer.

 

I take my crx si up to 7200 when I race it, and no problems yet.

 

Yeah, that's about stock redline. I know it can handle that, but how much more?

 

My question is why would you want to rev any higher stock? I mean, they don't make much power past 7k rpm.

 

Answer: Autox. Those few hundred extra revs past redline is better than shifting to the next gear or banging the limiter. Think about it...you're losing time by shifting or sitting on the limiter, and autox is won by tenths of seconds, sometimes less.

 

Ya, I wouldn't want to be sitting above 7krpm for very long, the valves start to get overlap past 6krpm, and things start to get a little scary for the motor, you may as well shift into the next gear, be in your powerband to come out of a corner... etc. It makes no sense to sit above 7krpm, go and practice some heel toe shifting for your corners, and you'll have your problem solved. The key is not to stay at the highest rpm, the key is to keep it in your powerband so you always have acces to the most power possible.

 

You don't want to be shifting or hitting the limiter going through the timing lights, and I've been on many a course where that happens. Extra revs = better time.

 

more revs doesnt always mean a better time. if you have more rpm and arent gaining speed and dont have as much available power because you are out of your powerband then it is pretty much worthless. look at the dyno charts for your car your max power is like 1k r's below redline and top torque is a little less than that. you dont want to stay at the top of your revs you want to stay in the range of those 2 so that you have more driving power.

 

Trust me on this people...it is quicker to stay in a gear for a little longer than shift to the next gear or ride the revlimiter.

Say you're 50ft from the finish in the top of second gear about the hit the redline. Do you 1) shift to third 2) Short shift earlier 3) bump/ride the limiter 4) have a limiter that comes on 500rpm later and continue to accelerate through the finish, even though you are out of your peak power?

Answers:

1) shifting takes far too long to do and you going to third won't be a benefit so close to the finish because you'll have no time to get into the power.

2) Short shifting is not a solution either because shifting = time unless you can shift in a place where you won't be accelerating anyways.

3) riding the rev limiter is not accelerating.

4) even though out of the peak powerband, you are still accelerating and hence not losing time.

But if I can go to third and make use of the gear, then by all means I'll hit third. This isn't an option in this scenaro though.

 

Good scenario, I run into that all the time on the auto-x track. I think upping it to 7500-7700 SHOULDN'T be too terrible. 7500 is the most I personally would go.

 

According to Z-dyne, the stock ECU on a CRX can only handle a max of 7800rpms, above that and ECU does not control the injectors. I imagine with an upgraded valve train (stiffer springs) 7800rpms is perfectly reasonable. I race autox and was thinking of doing the same as well....

 

The engine itself can handle 8k....the injectors however will get stuck open at that high of RPM

 

Ya man, it all depends, I mean, you can have the rev limiter raised or taken off. But, you just don't want to spend too much time up that high with the stock valve train, like I said, it becomes more and more inefficient above 6-6.5krpm. So the answer to your question is difficult because you are asking for something you can't have, but you would be smarter to go about it the logical way. ie, strenghten your valvetrain. Than, raise your rev limiter and rev happy, but than, you could come back and ask the same question, and you may want a higher rev limit because you don't want to shift.... that would be my scenerio. I mean, where do you draw the line... right???? I'm not trying to tell you that you are wrong, I'm trying to say, if you want a higher rev limit, or you want to be able to keep your motor at high rpms, than invest a little money to make it so the engine won't hate you when you do it. If you don't, than there is little sense changing anything. I mean, these are the facts man, you have to pay to play, you know that, I know that. You have two choices as I see it right now, bounce or shift. Every motor has its limit, these arn't F1 cars. If you learn heel toe shifting in a corner that will save you a lot of time. Instead of risking injury to your motor, practice your driving skills and become that much better to shave the tenths off. No one is perfect, even though we'd all like to think so.

To answer your question directly your motor will safley handle between 7-7.5krpm, no more the way it is. If you want more, do the work.


[Modified by cottagecreep, 7:01 AM 1/3/2002]

 

speaking from experience your motor can handle revs up to 8500. Ive taken my d16a6 motor past 8500, on a stock valve train. It really helps when you need to shift that high, but its useless if you dont have the power band that NEEDS high revs. I had a JG race cam along with a Prospeed ECU (9500 redline), that's power started above 5600. Although, the stock injectors had a really tough time above 8500, with my car just stalling a few times. I wouldnt dare taking it past 9000. In conclusion i think the motor is capable of handling rpm past 8000, provided that it is taken care of and tuned right. If you really cared about your motor, its better to set your limits. Go high only when you NEED to, and stick with the stock redline most of the time.

 

Yes, going past 7200 is not something that I'll do on a daily basis. It is more of a tool that I'd use only if I absolutely needed it.

I always heard the D16a6 would handle rev in excess of 8K, so it's good to know that the motor will hold if I go there one time in its life.

 

Get a D16z6 8k shoudnt be much of a problem.

 

Todd, I'm one of the few that understood you first post, you can goto 7500-7700 with ease. I would only wanna do it once per run though, and not in first gear.

Running out second gear to 7600 on our backstretch was .3 sec faster that shifting into 3rd then right back second. Also less footwork which means less chance of missing the brake pedal and going off course.

I know, I did!