How does the stock crank fail under sustained 8K operation? Just wondering. I'd take a guess and say it's an oiling issue that results in a crank issue tho. Just asking

 

carefull andy. he might think your making an ASSumption

(second hijack..sorry)[the block has no scores. its good to go]

 

8k..blah. I like my hp in the 5000rpm range. Put a flat six in there. How about real high compression and big valves. or more valves, then bigger...then turbo it since its an n/a.

 

well. if you turboed it and sized the turbo for the job. you should have torque all the way up in the 8k range. but, you need the bottom end for it.

 

porshaowner, could you please explain to the group why you are so obsessed with 8000 rpm? The engine is what it is. It's good for about 6500 rpm. Can it be made to run at 8000 rpm? Sure. If a nascar team can make a pushrod v8 run at close to 10,000 rpm then 8k from this motor shouldn't be a problem. It will require head work. It will require a different cam, heck a completely different valve train. It will require a different oiling system. It will require stronger internals. It will require a lot of money for engineering work and development. But what's the point?

 

8000 rpm seems alot easier to get to than 9000 let alone 10000. Whats the point? there is no point. Why not just throw ideas around for when somebody wants to build a go fast na engine. Of corse its gunna take alot of money and brains. If it was easy there would be alot of powerful 944 na's, not just a few.

 

if you could build a 2.5L na engine that ould fill the cyclinder enoughto make good torque at that rpm would i even have to say that you would dominate?

 

Ideas are useless and probably not right without building it. Reason is that one can talk all they want, but unless you actually know what forces and issues happen you can't know what it takes.


Now if someone was actually looking to build a motor like this for a specific racing class and had the funds to see it through, I would be VERY interested in it. But if it just bunch of uneducated talk (and it will be without experimenting) that is something I can do without.

 

Then stop reading this thread if it is beneath you. I like swapping ideas, that always makes for a better final product. If I can learn one thing out of 100 ideas, that makes me better. Thats all I'm trying to do is develop my and hopefully someone elses car education.

 

You're a troll.

Don't feed the trolls folks.

BTW, bigger valves would decrease the rpm limit of the engine.

I seriously doubt the crankshaft would have issues (other than oiling) over 8k rpm.

 

[
BTW, bigger valves would decrease the rpm limit of the engine.
.[/QUOTE]


Is that because of the weight of the valve? I thought that the head can only flow so much and if the valve was bigger then it would flow more into the cylinder right when the valve started to open increasing efficiency. Thats why I'm asking questions, because i want to learn, not because I'm a "troll"

 

Then you could go about this a little better.

The limitation is a matter of harmonics. I admit to only knowing this at the most rudimentary level. To raise the harmonics (and allow higher rpm), one method is to reduce weight. Larger valves, all other things being equal, lower the harmonics and limit safe rpm operation.

Another way to control the harmonics is with the valve springs. Most people just install stiffer springs which will raise the harmoncis, but spring maeterial can also affect this.l Jim Wolf Technology offers valve springs made of near unobtainium (only available from one source in the entire world) that will increase hp output by 2 hp (documented and reapeatable on the dyno) in an otherwise stock Nissan SR20DE engine, such is the improved valve control, yet they are barely stiffer than stock. They also use these very same springs with their uber radical cams for the engine such is their effect on harmonics at 8k rpm, even with radical cams.