I couldent think of a better place to post this and i hope that no one thinks of this post of as just technical musing...

I was readign about the science behind high reving engines and the biggest factor is a short stroke.

Is is posible to build a 4g63 with a shorter than stock stroke, in addition to other modifications, so that the engine might spin up to 9 or 10 thousand rpm? This is "the key to big horsepower" as one article said. If i had the thousands of dollars i know this woudl coast i woudl do it in a heart beat. How cool would it be, not to mention having a car that suunds like an F1 racer...

You can already rev a 4G63 to 9k with 2.0L.

It's De-Stroke by the way not unstroke.

You can get the engine to spin to whatever RPM you want. The problem is you couldnt get the tranny to go into gear at that RPM. You can barely get it to shift at 9k let alone anything higher.

Dogbox course thats not a stock tranny

There are many engine shops that can stroke or destroke a crank. Revving high can make more power but there are so many other factors that need to be addressed. The higher you rev the more stress is placed upon everything. Plus to really maximize efficiency in the ultra high rpm range you need to have properly designed cams, intake, etc. Its just not as easy as revving to 10K. If you dont make power up there and cant keep the engine up in its power band you are just wasting your time.

oh your so right i know i was jsut asking aoub that... yeah i read about valve float and the devilry that occurs if it happens.... i have an auto btw, and you really can rev to 9000 wih out ruing the engien? you have to remove some limiter right? different cams deffintly, and is it shourt or long tube intake manifold that is better for high rpm? BMW managed to get 19000 rpm out o their f1 engine so relialby 9 or 10 out of a 4g63 shoudl be somewhate fesible.... if the trany can keep up... it woudl sure own an s2000.

"There are many engine shops that can stroke or destroke a crank."
- would this also involve shorter rods and a shorter bore?

Oh and one more thing how many rpm can the stock block physicaly handle?

Man if i had like a billion dollors i woudl walk in to Mitsubishi and make them build an F1 engine... or think EVO PIKE'S PEAK HAHAHAHAHAHadsafadfa

Originally posted by focusedrage
oh your so right i know i was jsut asking aoub that... yeah i read about valve float and the devilry that occurs if it happens.... i have an auto btw, and you really can rev to 9000 wih out ruing the engien? you have to remove some limiter right? different cams deffintly, and is it shourt or long tube intake manifold that is better for high rpm? BMW managed to get 19000 rpm out o their f1 engine so relialby 9 or 10 out of a 4g63 shoudl be somewhate fesible.... if the trany can keep up... it woudl sure own an s2000.

"There are many engine shops that can stroke or destroke a crank."
- would this also involve shorter rods and a shorter bore?

Oh and one more thing how many rpm can the stock block physicaly handle?

Man if i had like a billion dollors i woudl walk in to Mitsubishi and make them build an F1 engine... or think EVO PIKE'S PEAK HAHAHAHAHAHadsafadfa

Click to expand...

Please use proper punctuation and spelling.

Originally posted by focusedrage
oh your so right i know i was just asking about that... yeah i read about valve float and the devilry that occurs if it happens.... i have an auto btw, and you really can rev to 9000 with out ruining the engine?

Click to expand...

Dude your spelling is painful. Take 30 extra seconds and compose your post in word then copy and paste.

Now to answer your question. Yes you can really rev that high occasionally. The only real place you would do that is in 1st gear with a big turbo to keep it spooled for the 1-2 shift. Most DSMs on the stock intake manifold start loosing power at 7k. If you have the right valve train yes you can do it without damage.

(this is an edit of a PM i sent focusedrage)

The only real way to shorten stroke is to reduce throw on the crankshaft. i.e. reducing crank throw by 5 MM will reduce stroke by 10 MM. Using shorter rods will only result in lower compression ratios.

Besides switching to a competely different crank, with V engines it's common to regrind the crank to a smaller diameter at a tangeant to the original diameter: smaller circle towards the crank center reduces stroke, away from center increases stroke. The available leeway of the new center is determined by final desired strength of the crank. Of course you need different rods if you go this way. I'm not sure if rods are even available for doing this in DSMs.

Reducing the stroke also decreases the compression ratio, which you can offset with different pistons or rods, or possibly severely decking the block (severe decking is not usually an option with V engines). Unfortunately the big HP you mentioned usually happens at much higher rpms, so you should really go with lighter and higher flowing valve assemblies to both allow and complement the possible high rpms.

Originally posted by focusedrage
oh your so right i know i was jsut asking aoub that... yeah i read about valve float and the devilry that occurs if it happens.... i have an auto btw, and you really can rev to 9000 wih out ruing the engien? you have to remove some limiter right? different cams deffintly, and is it shourt or long tube intake manifold that is better for high rpm? BMW managed to get 19000 rpm out o their f1 engine so relialby 9 or 10 out of a 4g63 shoudl be somewhate fesible.... if the trany can keep up... it woudl sure own an s2000.

"There are many engine shops that can stroke or destroke a crank."
- would this also involve shorter rods and a shorter bore?

Oh and one more thing how many rpm can the stock block physicaly handle?

Man if i had like a billion dollors i woudl walk in to Mitsubishi and make them build an F1 engine... or think EVO PIKE'S PEAK HAHAHAHAHAHadsafadfa

Click to expand...

It appears I wasted precious keystrokes replying to your original post.

A formal appology.

Sorry, I know my spelling is horrible, but I am often so excited about things I am in a fervor to write them. I should know better, especially since I am able to post on this forum.

Clearly such a project as I am discussing is expensive, but would be amazing. I don't know if this falls in to the "How about a quad turbo set-up" or not, but I thank you for the advice.

De-stroke a 4G63 sure why not, you can do whatever you want to any engine so long as money is not a factor. To shorten the stroke you could A: buy a custom crankshaft of your desired stroke length (a lightweight one of course). B: Purchase some custom lightweight pistons with the correct pin height, and compression ratio. C: Buy some good custom connecting rods preferbly with a longer center to center length (to aid in V.E. since the intended use is in a higher rpm range), oh yes have them made in titanium, or maybe a metal matrix composite.

Since the idea here is increase power with less displacement, then you should be thinking more like 14,000 to 16,000 rpm's. Which would be roughly a forty% increase in bangs per minute. At these speeds you will also have to make some serious reductions in friction as it increases exponentialy with RPM. Also conventional valve spring technology will be pushed to its limits at those speeds, so you may want to concider a pneumatic valve spring arangement preferably a constant pressure one, as it will aid in frictional losses.

Keep in mind that high rpm F1 engines do not use timing belts. Everything is gear to gear (that is where alot of their unique sound comes from). So you may also wish to modify every driven component on your 4G63 for a gear to gear set-up, wet or dry?

This is just the tip of the iceberg, so you should think seriously about what you are trying to achieve and why. rdrkt is correct about the transmissions not shifting very well at high engine speeds, so you may also want to concider a electronicly shifted semi-automatic gearbox (like the one in the Ferrari ENZO or F-50) of course you will have to modify it to the 4G63 motor.

The driving force behind F1 engines is more power and less weight, money is no object. When everything else is taped out you need more power stokes per minute. To do that you need to increase engine speed. (More bangs per minute) Or you need a new idea? Like electro-pneumatic valve actuation, I.E. no camshafts, or something else.

CRAZY... I haven't even heard of such a valve arrangement... awesome. Wow you definitely told me how to "do it right" and it seams i might as well just wait and hope for a career in cart. thanks.

c.a.r.t. doesnt allow pneumatic valve actuation.

How did this stupid question get in this forum?

Originally posted by BatmanGSX
How did this stupid question get in this forum?

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And with that I think this thread has run its course.

Thread Closed.

You forgot to close it.

Nevermind I replied right as you were closing it