reving to 8k safely
May 17, 2007, 10:54 AM
#18
Evolved Member
Join Date: Feb 2006
Location: Seattle
Posts: 1,123
Likes: 0
Received 0 Likes
on
0 Posts
like scorke said a flash is only thing holding you back from 8k
the bottom end of the engine is going to be good stock to well over 8,000 rpm no problem. its your valves, and what cams you have. determining if your even going to make power or break your car. upgrade the valve train to rev higher than IMO 7,800. (some go up to 8,000)
the bottom end of the engine is going to be good stock to well over 8,000 rpm no problem. its your valves, and what cams you have. determining if your even going to make power or break your car. upgrade the valve train to rev higher than IMO 7,800. (some go up to 8,000)
May 17, 2007, 02:26 PM
#20
Evolved Member
iTrader: (-1)
Join Date: Jan 2006
Location: So. Cal (LA County)
Posts: 574
Likes: 0
Received 0 Likes
on
0 Posts
RPMs kill engines.....
https://www.evolutionm.net/forums/sh...9&postcount=17
The rod ratio of the stock 4G63 is not condusive to high revs. I'm sure some people have pushed the limits of the stock bottom end and valvetrain....but i don't recommend pushing it too far over stock.
On the stock turbo, i run 7800rpm on the stock bottom end and stock valvetrain. Once i install my HKS 280 cams, i will NOT raise my revlimiter at all over 7700-7800 rpm on the stock valvetrain due to aggresive ramp rates, which will only exacerbate valve float issues. Although, the stock bottom end should be able to handle the piston acceleration @ 7800rpm.
CJ
https://www.evolutionm.net/forums/sh...9&postcount=17
The rod ratio of the stock 4G63 is not condusive to high revs. I'm sure some people have pushed the limits of the stock bottom end and valvetrain....but i don't recommend pushing it too far over stock.
On the stock turbo, i run 7800rpm on the stock bottom end and stock valvetrain. Once i install my HKS 280 cams, i will NOT raise my revlimiter at all over 7700-7800 rpm on the stock valvetrain due to aggresive ramp rates, which will only exacerbate valve float issues. Although, the stock bottom end should be able to handle the piston acceleration @ 7800rpm.
CJ
RPM kills bearings not motors.
A poperly assembled motor will handle RPM without a problem.
My 408 has a 6.126 rod and a 4" stroke thats a 1.53 ration it turns 8600 rpm through the traps on nitrous.
thats 4000ft/min @ 6000 rpm
5000ft/min @ 7000 rpm
5667ft/min @ 8500 rpm
.
May 17, 2007, 02:44 PM
#24
Evolved Member
iTrader: (-1)
Join Date: Jan 2006
Location: So. Cal (LA County)
Posts: 574
Likes: 0
Received 0 Likes
on
0 Posts
A better question is how many times will i be able to shift at 8500 rpm without destroying my synchro's.... First missed 1-2 or 2-3 shift at 8500 rpm and you can kiss that shift fork and syncro good bye.
May 17, 2007, 03:15 PM
#27
Evolving Member
iTrader: (1)
Join Date: Mar 2006
Location: this old house
Posts: 265
Likes: 0
Received 0 Likes
on
0 Posts
Well I feel a must have or a good thing to have is a valve train that can handle the 8krpm and some rod bolts. I mean you spend a few hundrad now and save a few thousand later. That's my 2 cents.
If you are not gonna build the block and head at least do rod bolts and the right valve train.
If you are not gonna build the block and head at least do rod bolts and the right valve train.
May 17, 2007, 03:17 PM
#28
PLease re-read.
RPMs do kill engines that were not built for high revs, like the stock 4G63. Again, re-read my post and stop trying to bust somebody's ***** without reading exactly what they said.
Thanks
CJ
May 17, 2007, 03:22 PM
#29
Former Sponsor
iTrader: (6)
Join Date: Jan 2007
Location: long island
Posts: 1,840
Likes: 0
Received 0 Likes
on
0 Posts
7800 is the recommended rev-limit for a stock 4g63's valvetrain. surely people rev higher and lower, time is the only thing keeping the engine alive depending on the tune and or who tuned the car.
cams+springs+retainers will allow you to rev higher. for instance fully built 2.0 race engines are usually around 9000-9500 rpm rev limit.
fully built 2.3's usually do not exceed 8200 rpm.
cams+springs+retainers will allow you to rev higher. for instance fully built 2.0 race engines are usually around 9000-9500 rpm rev limit.
fully built 2.3's usually do not exceed 8200 rpm.
