Cam guys i need some help
06-03-2017, 11:28 AM
#1
Cam guys i need some help I built a 416 lsx twin 67/66, 4l80e, yank 3400stall, 10.38 comp. 6bolt genx 255 heads holley low pro intake,
My cam is custom grind solid roller 252 260 699 701 116 staight up.
went to the track last weekend first time on new set up the car will not get out of its own way in 100ft, 1.82 60ft.
At 4000 rpm the car is nuts, just kills 28 14.5 tires like they are street tires,
Stagging car on 2step/tbrake the car will not spool up pass 2900rpm only makes 2.8psi of boost. 2step is set at 3600 the car will phisically not rev pass 2900-3000 rpm, gets up aginst the converter and will not rev.
I have tuned my own car for the last 6yrs,car has been 8.43 on a alot smaller engine combo, i have tried throwing a **** load of timing at 2step rpm and i have tried -17 deg to try anti lag, not happening.
cam guys is the cam way to big?? if i adv cam to 110 center line will this fix my issue?
Im hoping the car traps low 170s once i get it lined out should put me at 7900rpm with tire/gear set i have,
what do you guys think I should do?
My cam is custom grind solid roller 252 260 699 701 116 staight up.
went to the track last weekend first time on new set up the car will not get out of its own way in 100ft, 1.82 60ft.
At 4000 rpm the car is nuts, just kills 28 14.5 tires like they are street tires,
Stagging car on 2step/tbrake the car will not spool up pass 2900rpm only makes 2.8psi of boost. 2step is set at 3600 the car will phisically not rev pass 2900-3000 rpm, gets up aginst the converter and will not rev.
I have tuned my own car for the last 6yrs,car has been 8.43 on a alot smaller engine combo, i have tried throwing a **** load of timing at 2step rpm and i have tried -17 deg to try anti lag, not happening.
cam guys is the cam way to big?? if i adv cam to 110 center line will this fix my issue?
Im hoping the car traps low 170s once i get it lined out should put me at 7900rpm with tire/gear set i have,
what do you guys think I should do?
06-03-2017, 12:15 PM
#2
TECH Regular
Join Date: Sep 2014
Posts: 433
Likes: 0
Received 0 Likes
on
0 Posts
My guess is it'll need a higher stall converter to get that combination balanced and working the way you want it to. However, take that with a grain of salt... I'm not a drag racer.
With your projected trap RPM, I don't think I'd choose a shorter cam over increasing converter stall.
$0.02
With your projected trap RPM, I don't think I'd choose a shorter cam over increasing converter stall.
$0.02
Trending Topics
06-15-2017, 10:50 AM
#10
TECH Fanatic
Advancing the cam would be a good idea. That motor should make a good amount of torque given its size so if you can't get it to rev on the converter I would suggest loosening it up.
06-15-2017, 10:57 AM
#11
If that were mine, I would put the camshaft on a 111-112 degree intake centerline and try that. It will certainly make it spool faster. If I were to have spec'd the camshaft, it would be about 8 degrees smaller, but I would try it if I already had it.
06-15-2017, 11:12 AM
#12
FormerVendor
iTrader: (1)
Join Date: Nov 2008
Location: Santa Ana, CA. USA
Posts: 2,157
Likes: 0
Received 16 Likes
on
16 Posts
Turbo vs N/A Cam Duration Hi "9" YES the cam is very LARGE for your RPM band, change this, a Regrind ?
There is a difference of thirty (30) degrees in Torque Band for Turbo vs N/A cam selection.
YOUR N/A "spec" is 282 Intake Duration (252+30), like an Indy Car with 12K RPM.
The account, your account, states this with a 4K light off.
Lance
There is a difference of thirty (30) degrees in Torque Band for Turbo vs N/A cam selection.
YOUR N/A "spec" is 282 Intake Duration (252+30), like an Indy Car with 12K RPM.
The account, your account, states this with a 4K light off.
Lance
06-15-2017, 01:07 PM
#13
Thanks for more input.. I have a very good relationship with the shop that does all my machine work/help order all these parts for this build. he knows every part of the car to relay to erson cams.. I really do not know why they cut the cam so big.. i have the old cam that went 8.43 on the 365 engine. dont quate me but was around 238 242 620 620 116+6.. if im going through the trouble of deg cam up. will i just be better off going back to old cam with this cubic inch.. again thanks for the inputs
06-15-2017, 11:42 PM
#14
Cam is currently installed/degreed at 116 ICL? I would record compression test result at 116 ICL and move cam +/- 2* increments and see where peak compression is recorded. This can help map out motor response to cam timing and give you some insight on what to do. I won't be surprised if advance 4-6* yields highest compression result and best motor response.
06-21-2017, 12:28 AM
#16
pulling front of the engine tomorrow night to adv cam.
thanks again guys will post results fri night.. i just need that lil bit to get up on the 2step. never thought about comparing comp. from straight up 116 vs putting it in at 110, will definitely be taking notes to compare
thanks again guys will post results fri night.. i just need that lil bit to get up on the 2step. never thought about comparing comp. from straight up 116 vs putting it in at 110, will definitely be taking notes to compare
06-22-2017, 03:12 PM
#19
it shouldve been in the motor on a 111 to begin with.
You'll pick up 40 psi of cranking compression moving the cam. its going to make a big difference. between that and getting the valve event relationships correct.
You'll pick up 40 psi of cranking compression moving the cam. its going to make a big difference. between that and getting the valve event relationships correct.
06-23-2017, 12:16 AM
#20
ok guys i adv the cam tonight,
starting compression was 175-180psi across all holes. adv 4deg popped off 210psi and advanced it 6degs and jumped up to 235psi.. the springs that are on the heads my lil spring compressor tool will not smash them down to get my p/v checker springs on. so i went back to the 4deg advanced. not know my p/v clearances, i put the front of the engine back on and went out and tested.
the car responded better down low but still could not reach my 3600rpm 2step. 3200-3300 all she could do, but it did make 4.5psi on tbrake more then the 2.8 before,
so when i was sitting on tbrake up against the converter building boost as boost started climbing my afr started dropping 0psi 13.5afr 2.5psi 12.8afr 4.5psi 11.5afr at this point the engine went from 3200-3300 rpm to 2900-3000rpm. this all within 3-4 sec on the tbrake. how lean can i get the engine to keep it spooling higher. this was all at 31deg of timing on the tbrake.. I feel this was major improvement from the start. with out knowing p/v do i push up to the 6deg adv or try leaning it out first?
thanks again guys,
starting compression was 175-180psi across all holes. adv 4deg popped off 210psi and advanced it 6degs and jumped up to 235psi.. the springs that are on the heads my lil spring compressor tool will not smash them down to get my p/v checker springs on. so i went back to the 4deg advanced. not know my p/v clearances, i put the front of the engine back on and went out and tested.
the car responded better down low but still could not reach my 3600rpm 2step. 3200-3300 all she could do, but it did make 4.5psi on tbrake more then the 2.8 before,
so when i was sitting on tbrake up against the converter building boost as boost started climbing my afr started dropping 0psi 13.5afr 2.5psi 12.8afr 4.5psi 11.5afr at this point the engine went from 3200-3300 rpm to 2900-3000rpm. this all within 3-4 sec on the tbrake. how lean can i get the engine to keep it spooling higher. this was all at 31deg of timing on the tbrake.. I feel this was major improvement from the start. with out knowing p/v do i push up to the 6deg adv or try leaning it out first?
thanks again guys,
