Engine RPM Differences
05-03-2009, 11:25 AM
#1
5th Gear Member
Thread Starter
Join Date: Mar 2008
Location: Ohio
Posts: 2,994
Engine RPM Differences
What crucial parts in a "built" motor allow it to safely spin a much higher RPM than a stock motor?
The stock 4.6 red lines as like 6k right? Aren't some after market motors spinning 7.5k or better? If i were to build my motor, or put a built motor spinning higher rpms in my vehicle, is there a possibility of damaging any of my accessories by over driving them? What about a twin screw supercharger only made to spin at factory rpms? Could that be damaged as well?
Are there big benefits for be able to have a motor safely spin to higher rpms? Like more peak power or just a longer ranger of the same hp available?
Sorry if this doesnt make sense im not sure how else to ask my question here. I just want to see if it is really worth it to have a motor which is safe to handle a much higher rpm range, or if it would be smarter to keep it rev. limited to factory specs.
The stock 4.6 red lines as like 6k right? Aren't some after market motors spinning 7.5k or better? If i were to build my motor, or put a built motor spinning higher rpms in my vehicle, is there a possibility of damaging any of my accessories by over driving them? What about a twin screw supercharger only made to spin at factory rpms? Could that be damaged as well?
Are there big benefits for be able to have a motor safely spin to higher rpms? Like more peak power or just a longer ranger of the same hp available?
Sorry if this doesnt make sense im not sure how else to ask my question here. I just want to see if it is really worth it to have a motor which is safe to handle a much higher rpm range, or if it would be smarter to keep it rev. limited to factory specs.
05-03-2009, 12:09 PM
#2
5th Gear Member
Join Date: Mar 2007
Location: Cary/Charlotte, NC
Posts: 3,791
When you fully build an engine the rev limit can go through the roof, 10"Terror (Jim of Cushman Motorsports) has an engine spinning to a little over 11k IIRC, its a destroked 5.4l 4v.
One benefit of having a an engine that is capable of spinning higher is the potential to make more naturally aspirated power, assuming you can get heads and cams and vavlesprings that would support that at higher rpms. Otherwise you would run into massive power falloff problems or potential damage.
Another benifit you have with a high reving engine, assuming it makes linear power, is the gear longevity. For example with an 11k rpm redline engine on a stock geared Mustang, you could take first gear up to 74mph and because of that would scoot pretty quickly.
But you obiously couldnt keep all your low end torque because of a lack of, variavle valve timing, so that really wouldnt be feasible, but it is a neat idea.
As for the stock redline... I have cams and I have mine at 6250 I seldom take it up there but that is where my redline sits.
I would honestly leave it at 6k or 6.2k and shift at 5750.
One benefit of having a an engine that is capable of spinning higher is the potential to make more naturally aspirated power, assuming you can get heads and cams and vavlesprings that would support that at higher rpms. Otherwise you would run into massive power falloff problems or potential damage.
Another benifit you have with a high reving engine, assuming it makes linear power, is the gear longevity. For example with an 11k rpm redline engine on a stock geared Mustang, you could take first gear up to 74mph and because of that would scoot pretty quickly.
But you obiously couldnt keep all your low end torque because of a lack of, variavle valve timing, so that really wouldnt be feasible, but it is a neat idea.
As for the stock redline... I have cams and I have mine at 6250 I seldom take it up there but that is where my redline sits.
I would honestly leave it at 6k or 6.2k and shift at 5750.
05-03-2009, 07:53 PM
#6
3rd Gear Member
Join Date: Aug 2008
Location: Oklahoma
Posts: 912
05-03-2009, 09:29 PM
#8
Is it attached to a big tach?