Rpm maximum

Question,I have a 1915cc with two Weber 40's and a 383 rear. Since I have owned it I have never taken the engine over 4000 RPM. It has just occurred to me I might not be getting all the engines potential at that rmp. What is the general consensis of a maximum rpm without harming the engine?

steve,

disclaimer: the following has not been tested/proven or validated in any shape or form.
further more, no aniamls were hurt using this system, but don't try this at
home.

i know people like gadjets and watching redline, idle speed and other indications. but
from personal experience i've found it best to listen and feel your engine. drive the car
and you'll "feel" the moment when spinning the engine any faster loses any futher advantage/omph. spinning beyond this point is a waste of time and eventually
(who knows when) could lead to trouble (big bang). your engine is under "load" and
when you spin past that point things kinda "freewheel" and can get slightly out of control.
sorry i couldn't give you an answer/number.-bruce

Steve, I think that what the maximum safe RPM is would be a function of the quality of the components going into the engine build and the skill of the builder. If you are unsure about this, trust your senses to avoid the "big bang" Bruce mentioned. I don't think you want that.

If you go to www.cbperformance.com/dyno/dynocharts.html , you'll see some dyno results from CBPerformance engines. Most Hi perfomance VW motors don't make peak Horsepower or Torque until about 5000 RPM.
I'm not saying a pushrod motor is happy running at peak all the time, but the charts will give you some idea what to expect from a worked over type1.
Greg B

rpm redline depends alot in valvetrain hardware, cam etc do you know what you have?

I think 9000 to 9500 is a good redline. May not be for everyone, but I like the "R"sssssssssss

You know that is a good question. I normally try to run (normal) at or just below 3000rpm, But when I shift 1 to 2 I run to 4000 or just above. There is a power curve on or around 4000 that is nice and doesn't seem to create any squeals or shimmy.

An Aircooled engine needs close to 3000 in order to cool properly.

On my previous 1776, I found that sweet spot that Mike just mentioned between 38-4200 Rpm for spirited driving without abusing it. It all depends on your build, cam, carbs, heads, exhaust... That 1776 was a nice mid level build, but with the ICTs It just wasn't that strong after 4600,4700. I think with some IDFs it would have barked a little better.

I expect this CB 2110 to be a bit more of a Rev'r. (after I break it in.)

(Mike, good to see you back on. Where in the "World" have you been? Surfer's Paradise?)

I wish I was mate....Wednesday I was skiing and at the end of a double-diamond which I was skiing short radius turns I was cruising at medium speeds towards the chair when a snowboarder creamed into me and took my tibia off the knee. I was operated on Thursday and home Friday. 7 pins and one plate later. I will be imobilized for 2-3 months. There goes the ski season. I might make it to Surfers where my friends live in July to go to NZ and ski.

Bummer..... ^%$# snowboarders and I am level ski instructor to boot.

Ouch! Man, that had to be a big time hurt... I mean, SOB, that sucks. My sincere wishes for a speedy recovery!

Jim

Steve, what cam and crank is in your engine? My first motor was a 1776, with a counterweighted 69mm crank and mild cam (can't remember model #) Motor ran out of hp after 5000. It would rev to 6000, but it was all noise and no go. The 2110 I had put in next (forged crank and much hotter cam) would pull all the way to 6500! So, if it's a near stock motor, going over 5000 is a waste of time. If it's a stock crank going over 5000 might be the last time you do it. Having said that, I had a 1970 Beetle (stock, except for dual carbs and header) that, on many occations, saw 5000 rpm. Sold that car (still running fine) with 115,000 miles on it.
Ron

Thanks for all the input guys. I don't know the internals, it came out of Vintage.

If that's the case Steve, your engine is pretty much stock except for the pistons and the add-ons (carbs).

Nice post TC.... informative and funny.

When we were kids we used to put vac. gauges in the cars so that we could tell when a buddy was lifting his foot and chickening out on turns and stuff. If you really want to know, after you get the specs and approximate where your power band and max horse power lies, fit a vac, gauge to the car, just temporily, and hit the highway with your foot in it. When the engine maxes out the gauge will move from full pegged position, ever so slightly, then more and more. Mark the rpm minus two or three hundred, clock the tach and leave it in that position.

The closer you get to "12: 00" the closer you get to armagedon, think of your tach as a nuclear clock.

Luck,

TC

Thanks Jim ! :)

Even though my wife thinks of me as a grumpy old man, I think that I must have been a funny kid at some point, or just the usual stupid one.

TC - Hey! I've seen your V-8 VW panel truck......I think the funny kid turned into a riotous old man!!!!

gn

When to shift? Easy, go to a hot rod shop with a rear wheel dynomometer. You see them on various TV car shows all the time. For $60 to $80 you should get two rear wheel horsepower pulls at full throttle. This should not hurt your engine in any way, it only measures your real world power at the rear wheels - the only place it counts! You should be presented with a graph showing torque and horsepower curves versus the engine's RPM. Armed with this knowledge, you are in a better position to decide how YOU want to drive YOUR car. Enjoy the ride.