Cams and rpm question...
02-01-2010, 10:08 AM
#1
Cams and rpm question... What is key specs on cam to let it still make power up to 7000rpm. Is it duration,lift, lsa?
I am hoping to very occasionally rev to 7000 in current build mostly for mph reasons in the quarter although would likely keep to 6500 99% of the time.
I have not had chance yet to go to dyno to see how my car and current cam does up high in the rpm range. My cam is gt7 and is very similar to later model z06 cam.I would think since the z06 can rev to around 7000 my cam would be ok for that as well.
Here is comparison specs from the z06 cam to my gt7. I am running 1.8 rockers for bit more duration and lift. Figure have around .590 lift with the 1.8s.
05-07 ZO6 cam 210/230 .561/.557 –120.5 LSA
Lingenfelter GT7 208/230 .554/.546 –121LSA
I originally thought needed low lsa like 112 to be able to rev and still have power up higher in the rpm ranges.Was this incorrect assumption.
I am hoping to very occasionally rev to 7000 in current build mostly for mph reasons in the quarter although would likely keep to 6500 99% of the time.
I have not had chance yet to go to dyno to see how my car and current cam does up high in the rpm range. My cam is gt7 and is very similar to later model z06 cam.I would think since the z06 can rev to around 7000 my cam would be ok for that as well.
Here is comparison specs from the z06 cam to my gt7. I am running 1.8 rockers for bit more duration and lift. Figure have around .590 lift with the 1.8s.
05-07 ZO6 cam 210/230 .561/.557 –120.5 LSA
Lingenfelter GT7 208/230 .554/.546 –121LSA
I originally thought needed low lsa like 112 to be able to rev and still have power up higher in the rpm ranges.Was this incorrect assumption.
02-01-2010, 05:59 PM
#2
A few things limit your your max rpm, valve springs,valvetrain weight and rod bolts.
With supporting bolts and springs can you run thatt cam to 7,000? Yes, but you power will have already dropped WAY off and all you'll be doing is putting more stress on motor parts... Best bet is to match your rear gears so your going though the traps at max SAFE rpms for the motor where its still making good power
With supporting bolts and springs can you run thatt cam to 7,000? Yes, but you power will have already dropped WAY off and all you'll be doing is putting more stress on motor parts... Best bet is to match your rear gears so your going though the traps at max SAFE rpms for the motor where its still making good power
02-01-2010, 06:09 PM
#3
I do have good parts..fully forged 408. callies crank, rods, wiseco pistons. arp main studs and rod bolts,head studs.titanium retainers on the afr 225s with 650 lift afr dual springs.So think engine wise no problems going to 7000 just to run thru traps very occasionally. And just read that near identical cam is spun to 7000 in the z06's. So would think it will still make some power up in that range? Of course power up there will also depend on my turbos being able to flow enough air and upgrading them shortly.
Would also think my afr 225s and intake manifold/tb are not holding things back up there either.
Guess just have to dyno the car and see what happens. Hopefully be doing that in a few months ,but for sure this season.
Would also think my afr 225s and intake manifold/tb are not holding things back up there either.
Guess just have to dyno the car and see what happens. Hopefully be doing that in a few months ,but for sure this season.
02-01-2010, 06:29 PM
#4
On a 408 that cam won't come close to carrying to 7K.....Duration, LSA and advance greatly influence when a cam makes power and where the power will be.... Then the rest of the valvetrain must be setup to handle it. Rodbolts too to make the bottom end last. After 7-7.2k you have to get even more radical
02-01-2010, 07:37 PM
#5
With the size and airflow needs of your motor I think you will need a lot bigger cam to hit 7k and hold power.
The best way to see is put her on the dyno and see where it starts to really drop off
The best way to see is put her on the dyno and see where it starts to really drop off
02-01-2010, 09:18 PM
#6
TECH Fanatic
iTrader: (4)
Join Date: May 2002
Location: Fairview Heights Illinois
Posts: 1,851
Likes: 0
Received 0 Likes
on
0 Posts
What is key specs on cam to let it still make power up to 7000rpm. Is it duration,lift, lsa?
I am hoping to very occasionally rev to 7000 in current build mostly for mph reasons in the quarter although would likely keep to 6500 99% of the time.
I have not had chance yet to go to dyno to see how my car and current cam does up high in the rpm range. My cam is gt7 and is very similar to later model z06 cam.I would think since the z06 can rev to around 7000 my cam would be ok for that as well.
Here is comparison specs from the z06 cam to my gt7. I am running 1.8 rockers for bit more duration and lift. Figure have around .590 lift with the 1.8s.
05-07 ZO6 cam 210/230 .561/.557 –120.5 LSA
Lingenfelter GT7 208/230 .554/.546 –121LSA
I originally thought needed low lsa like 112 to be able to rev and still have power up higher in the rpm ranges.Was this incorrect assumption.
I am hoping to very occasionally rev to 7000 in current build mostly for mph reasons in the quarter although would likely keep to 6500 99% of the time.
I have not had chance yet to go to dyno to see how my car and current cam does up high in the rpm range. My cam is gt7 and is very similar to later model z06 cam.I would think since the z06 can rev to around 7000 my cam would be ok for that as well.
Here is comparison specs from the z06 cam to my gt7. I am running 1.8 rockers for bit more duration and lift. Figure have around .590 lift with the 1.8s.
05-07 ZO6 cam 210/230 .561/.557 –120.5 LSA
Lingenfelter GT7 208/230 .554/.546 –121LSA
I originally thought needed low lsa like 112 to be able to rev and still have power up higher in the rpm ranges.Was this incorrect assumption.
Your cam looks good to me. You might see a little better top end power by retarding the cam slightly, adding a little seat pressure to the intake valves (if needed), and/or tightening up your sparkplug gaps a little.
Once you dyno you'll probably see your power start falling off well before 7000, but it might not be a sharp drop. When figuring shift points you want shift a good bit higher than your max power RPM so that your shift recovery is strong, and you see the highest AVERAGE horsepower between shifts (the fattest part of the HP curve).
As was mentioned earlier, you may have better luck either way by running less rear gear ratio - though I don't see what you have now.
Unless this is in a tank, a TT 408 with bottle doesn't really need any more than a 3.0:1 rear ratio, and I would run less myself. You may find your trap speeds improve greatly unless you blow through your converter.
02-01-2010, 10:53 PM
#7
Your cam looks good to me. You might see a little better top end power by retarding the cam slightly, adding a little seat pressure to the intake valves (if needed), and/or tightening up your sparkplug gaps a little.
Once you dyno you'll probably see your power start falling off well before 7000, but it might not be a sharp drop. When figuring shift points you want shift a good bit higher than your max power RPM so that your shift recovery is strong, and you see the highest AVERAGE horsepower between shifts (the fattest part of the HP curve).
As was mentioned earlier, you may have better luck either way by running less rear gear ratio - though I don't see what you have now.
Unless this is in a tank, a TT 408 with bottle doesn't really need any more than a 3.0:1 rear ratio, and I would run less myself. You may find your trap speeds improve greatly unless you blow through your converter.
Once you dyno you'll probably see your power start falling off well before 7000, but it might not be a sharp drop. When figuring shift points you want shift a good bit higher than your max power RPM so that your shift recovery is strong, and you see the highest AVERAGE horsepower between shifts (the fattest part of the HP curve).
As was mentioned earlier, you may have better luck either way by running less rear gear ratio - though I don't see what you have now.
Unless this is in a tank, a TT 408 with bottle doesn't really need any more than a 3.0:1 rear ratio, and I would run less myself. You may find your trap speeds improve greatly unless you blow through your converter.
So could play a bit with tire height mabye but not with gear ratio.
I was not really too worried to make power thru to 7000 in every gear just to be able to run the car out if need be in third gear for 1/4 mile runs. I guess have to crunch more numbers but for tires have et street 295/45/17s for track runs. I have no idea how much my yank converter will lose in the 1/4 runs yank said not to lock it at my power levels.
I guess I shouldn't worry that much as after the car hopefully hits its goals at track and it will hit them at non NHRA track likely since have no rollbar then it will get retired and just be a street toy.That was big reason went with mellow streetable stuff on the car. Fairly mild for a 408 cam. 3.54 as do like some gear off boost and car is mostly offboost around town.
4l80 makes it nice in traffic was sick of my t56 that had until end of season last year.
Car never went to track or dyno .Was waiting to get the 4l80 in and to get the dana 60 in and now to finish up the turbo upgrading and then track and dyno it. Hopefully this season.
I figured if the cam works in a ls7 then it should work in my build and lingenfelter was using that cam in just about every twin turbo build they put out and lingenfelter cars turned some pretty amazing times and were still known to be very streetable.As said the same cam basically is used in ls7 z06 with 7000 redline and of course its a 427.
So maybe since not really needed the power to go to 7000 but just wanted to run the car out to it in third it won't matter all that much about power drop off. I would be pretty happy to have the cam and power go good to even 6500 I think and in fact have it set to 6500 rev limlt currently and have shift points a bit under that.
