Suggested rev limit on my build?
07-30-2010, 10:38 AM
#1
Suggested rev limit on my build? I have quite short gearing in my kit car which runs a weber race engines new ls6 block, stock (new) GM crank, carillo rods, JE pistons. heads are stock 241ls1s, springs are comp cams 918s, pushrods are comp cams, as are the retainers so all slightly better than stock, but on stock ls1 rockers.
very mild cam, 220/220 with lowish lift, so i dont expect to have to ring every last rpm out of it, but am currently revving to 6300rpm which comes up like lightning. i have a proper breather system and a dry sump so great oil pressure, via a 2 stage dry sump system and uprated oil pump.
power curve seemed to show the peak was about 6300 rpm anyway so no real point in going a lot higher, but maybe taking it to 6500rpm might make the gearchanging less frequent?
or is that just pushing the valvetrain too much for the sake of it?
any thoughts appreciated. car is only used on trackdays and sprints so gets caned but does very little actual mileage as not road driven.
currently the car is very very quick and great fun but 6,300rpm seems very low and its on the rev limit continually in all the first 4 gears. gearbox is out of a porsche 911 carrera4 so not a cheap option to alter gearing or box unfortunately.
very mild cam, 220/220 with lowish lift, so i dont expect to have to ring every last rpm out of it, but am currently revving to 6300rpm which comes up like lightning. i have a proper breather system and a dry sump so great oil pressure, via a 2 stage dry sump system and uprated oil pump.
power curve seemed to show the peak was about 6300 rpm anyway so no real point in going a lot higher, but maybe taking it to 6500rpm might make the gearchanging less frequent?
or is that just pushing the valvetrain too much for the sake of it?
any thoughts appreciated. car is only used on trackdays and sprints so gets caned but does very little actual mileage as not road driven.
currently the car is very very quick and great fun but 6,300rpm seems very low and its on the rev limit continually in all the first 4 gears. gearbox is out of a porsche 911 carrera4 so not a cheap option to alter gearing or box unfortunately.
07-30-2010, 12:27 PM
#3
TECH Junkie
iTrader: (17)
Join Date: Aug 2006
Location: Rapid City, SD
Posts: 3,161
Likes: 0
Received 0 Likes
on
0 Posts
^^ this. I rev my stock valvetrain minus PAC 1218 valvesprings (good to .600" lift) on my Patriot cam with .580/.590 lift all day long to 65-6600.. My power peaks right before 6500 though, so it makes more sense for me.. Your car would still be great to pull to 6500 because it'll bring the rpm's higher up on the next shift.
07-30-2010, 03:44 PM
#6
not actually sure what my gear ratio is as there were 2 or 3 ratios available in the year my box was made and the guy i bought from didnt know either!
rear tires are a bit limited (car runs 335-30-18s) so i think i will need to try upping the rpm maybe 100-200rpm max.
i didnt want to overload the valve train too much as the springs are only mild but then again the cam isnt massive lift and doesnt need massive seat pressures. the pushrods were measured out at 7.375" if i remember and there isnt any noise/ticking issues in the valvetrain, it runs very sweet. i have ls6 lifters in also. engine was run in for 20mins as per instruction from weber, oil changed and then run hard. has seen full rpm since about 50miles on the engine and the first oil change!
rear tires are a bit limited (car runs 335-30-18s) so i think i will need to try upping the rpm maybe 100-200rpm max.
i didnt want to overload the valve train too much as the springs are only mild but then again the cam isnt massive lift and doesnt need massive seat pressures. the pushrods were measured out at 7.375" if i remember and there isnt any noise/ticking issues in the valvetrain, it runs very sweet. i have ls6 lifters in also. engine was run in for 20mins as per instruction from weber, oil changed and then run hard. has seen full rpm since about 50miles on the engine and the first oil change!