| mtsbirch |
When you build a highly modified engine using a combination of polished and balanced stock parts and some aftermarket parts, how do you figure out the redline RPM?
Some cars rev to 8000 and some rev to 11000 so how do you figure it out for a particular engine?
I've heard theres a max piston speed somewhere around 4-5000 fps but then how can 2 engines with the same stroke have different redlines?
I've asked this question in other boards and I haven't received a good answer yet so I was hoping there were some professional engine builders on here. |
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| SplineZ |
well.. The reason one can rev higher with the same stroke is probly related to the materials used in the motor. The lighter they are, the faster you can rev'em...
Also valve springs make a large difference in weither or not you can rev an engine. Valve Float will destroy things very quickly.
Mass of the engines valve train. One reason why pushrods dont arent as rev happy as DOHC is because there is more mass in the valve train. The more energy you use to move your valves/cam/whatever, the less you will be putting down..
Tighter tollerances.. Ballance of the internals, etc.
There are far more, I dont know them tho :)
James Z |
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| midnite |
quote:
Originally posted by mtsbirch
I've heard theres a max piston speed somewhere around 4-5000 fps but then how can 2 engines with the same stroke have different redlines?
having a longer rod/stroke ratio will put less stress on the sidewall, and having a closed deck will give it more strength for higher rpm's.
lighter valves and higher rated valve springs will allow you to rev higher without having valve float. |
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| Pro Drag |
quote:
Originally posted by mtsbirch
Some cars rev to 8000 and some rev to 11000 so how do you figure it out for a particular engine?
Build the engine the way you want. Strap it down to an Engine Dyno, tune it, then set redline slightly after the Horsepower begins to drop off below tolerable levels.
It is an art and a science. The best practitioners are usually found in F1 and other high levels of motorsports. |
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| mtsbirch |
quote:
Originally posted by Pro Drag
Build the engine the way you want. Strap it down to an Engine Dyno, tune it, then set redline slightly after the Horsepower begins to drop off below tolerable levels.
It is an art and a science. The best practitioners are usually found in F1 and other high levels of motorsports.
Does it have to be done on an engine dyno, or will a chassis dyno be accurate enough?
So if you want to rev higher, weight and balance are the main parts choice criteria?
A balanced rotating assembly will help with this too, correct?
On that subject, any opinions on a good machine shop in Edmonton for 4 bangers like a Toyota 4AGE? |
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| Pro Drag |
quote:
Originally posted by mtsbirch
1.Does it have to be done on an engine dyno, or will a chassis dyno be accurate enough?
2.So if you want to rev higher, weight and balance are the main parts choice criteria?
3.A balanced rotating assembly will help with this too, correct?
4.On that subject, any opinions on a good machine shop in Edmonton for 4 bangers like a Toyota 4AGE?
1.I would prefer,in a perfect world, to tune the engine on an engine dyno, that would help to calculate optimum gearing options for different applications.
2.Weight, balance and STRENGTH.
3.Balancing the rotating assembly will help, when done properly.
4.I would recommend Bel Engines and AMS (Automotive Machine Service). |
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