Rev Limit ?'s

[JMD0346]

I did a search on this. It brought up some things but not much. Ive noticed that some of you are turning your engines up pretty high. What is the limit of the stock valve train? My shut off is set at 6400 or so. The thing is its still pulling strong since I got the port. Should I raise my limit? If so How high?


Michael

 

[rmgtc01]

good question...bump.

 

[VirtualSVT]

Um. I guess it really would depend on a couple of things:

1. Where is your power peak? Ideally you want to shift within a few hundred of that.

2. Where do your cams "peak out" at? What RPM do your springs bind? Cuz you don't want that to happen.

I'd really go by your dyno sheet. Its almost useless to rev any higher than your peak power point.

 

[JMD0346]

Totally agree. Before I did the port I wouldnt have thought of revving any higher. Didnt need to. Now when the limiter hits its still pulling up. Torque is falling but HP is climbing. My last dyno was revved to 6200. I guess the only way to know is to raise the limiter and run it up. Thats the question. How far is too far? What is a safe limit for stock valve parts?

 

[VirtualSVT]

That would be a question to ask somebody with a little more knowledge than me on your cams.

There is a point where they become inefficent.

I shift mine at 7K but I know that the springs start to bind around 7100 so I'm careful but I know sh*t can happen.

Good luck and be careful.

 

[JMD0346]

Oh I am being carefull. Thats for sure. I just noticed that this hadnt been discussed too much. Thought it would be interesting to know. Ive got a 4lb on the way so my thoughts of upping the llimiter may change anyway. I dont know how the new setup will act.

 

[JMD0346]

Seems like Ive heard that you shouldnt go over 7000 on the stock valve train parts. Cant remember exactly.

 

[NY04snake]

I run my track tune with a rev limit=7150, street tune 6900. Powershifting can spike your rpms up a bit so even if you shift at 64-6500, you can bounce the rev limiter shifting into 2nd, if it less than 7K and if you do that, the resulting stumble will kill your run, that is why I have mine set to where it is. For the quickest times you have run beyond your powerband to increase the momentum of your flywheel and so that you are in the meat of the power in the next gear. Shifting at limit of your power band might be safer, but no way is it quicker.

 

[Black2003Cobra]

I'm not sure where the limit is, but I am certain that inertial forces on the piston pins, rod bolts, etc go as the square of rpm, so caution is well advised! In other words, if you increase the rev limit it 7k from 6.5k, the intertial forces go up close to 16%. Bump that up to 7.5k and those forces shoot up to 33% (relative to what they were at 6.5k).

 

[JMD0346]

Agree with both the last two post 100%. Thats why I asked the question. What is the limit? Surely somebody knows. Maybe one of the tuners/builders can speak up. I know my 97 and 01 could turn up to 7000+. The 03-04 motors have better internals so I would think they could atleast achieve that rpm safely. I do understand that higher rpm doesnt mean "better". Since I got the port I pull to redline. It feels like it needs a few hundred more rpm.

 

[turbocake]

good question...bump.

+1