2.5 race motor
#20
Originally Posted by porshaowner
So all the magic is in the cylinder head. With proper porting, larger valves, and a cam that works, 8000rpm is a reachable goal. Will both of the timing belts withstand this type of rpm? or is that not an issue? Since this wouldn't be a throwaway motor I think I would keep the balance shafts. Other than the weight would there be a draw back to keeping them?
#21
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.
#23
Originally Posted by porshaowner
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.
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.
#24
Originally Posted by M758
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.
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.
#25
Originally Posted by porshaowner
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.
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.
#26
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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"
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"
#27
Originally Posted by porshaowner
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"
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.