Cam recommendation needed. 5.3 tt 550-650whp range
03-24-2017, 08:12 PM
#21
Restricted User
Lol. I didn't even throw in the combinations of Micro, MS3x, and stock PCM (with and without 2 step box), or the list would have gotten out of hand.
By far my most complicated build ever, and I haven't even seen the car yet LOL.
Glad to see you finally settled on some boost, Jake. Addictive isn't strong enough of a word.
By far my most complicated build ever, and I haven't even seen the car yet LOL.
Glad to see you finally settled on some boost, Jake. Addictive isn't strong enough of a word.
03-25-2017, 02:12 AM
#23
Thats not really true. Throw a low lift cam in with mild duration and it will thump like a ****. The lope at idle is due to poor cylinder filling. Setup the cam events to provide poor cylinder filling at low RPM and you'll have lope.
Want a serious lope turbo friendly cam look at the 2215 edelbrock or howards version of the "GM hot cam" (actual GM hot cam is fine too but it's more expensive.).
Here is about 950 RPM cold with the 2215 edelbrock (220/220 @ 111 .510 lift) on a bone stock 4.8 long block. Once warm, I could drop it down to 800 ish and it would really lope. Still has -2* of overlap at .050. It was really snappy on my 4.8. I liked it alot. Also for what it's worth most decently sized twin setups don't need to worry about a "turbo friendly" low overlap cam. They should have close to 1:1 back pressure, so you can cam them aggressively like an NA application.
https://youtu.be/hXrbjDnz0J8
Want a serious lope turbo friendly cam look at the 2215 edelbrock or howards version of the "GM hot cam" (actual GM hot cam is fine too but it's more expensive.).
Here is about 950 RPM cold with the 2215 edelbrock (220/220 @ 111 .510 lift) on a bone stock 4.8 long block. Once warm, I could drop it down to 800 ish and it would really lope. Still has -2* of overlap at .050. It was really snappy on my 4.8. I liked it alot. Also for what it's worth most decently sized twin setups don't need to worry about a "turbo friendly" low overlap cam. They should have close to 1:1 back pressure, so you can cam them aggressively like an NA application.
https://youtu.be/hXrbjDnz0J8
Your incorrect partly. Yes "poor cylinder filling" otherwise known as exhaust reversion while idling causes lope, lift doesnt effect this. Its valve overlap while idling that does. A 220 220 thumps in a 4.8 cause a 4.8 is a small engine relative to that cam. Also remember you cant have a big cam with low lift, it just wouldn't work correctly. Bigger cams relative to engine size lope more because of more overlap due to bigger durations. Centerlines play a part in this as well. The more time both valves spend the same amount of time being open, the poorer the idle quality hence more lope. Oh btw no, hardcore NA cams dont work in turbo builds. Turbos HATE OVERLAP. Your bleeding out all that cylinder pressure with more overlap. Your effectively wasting the efficiency of your turbo and the intent of the motor as a whole.
Last edited by Bspeck82; 03-25-2017 at 02:19 AM.
03-25-2017, 03:44 PM
#24
Staging Lane
03-26-2017, 08:07 AM
#25
Your incorrect partly. Yes "poor cylinder filling" otherwise known as exhaust reversion while idling causes lope, lift doesnt effect this. Its valve overlap while idling that does. A 220 220 thumps in a 4.8 cause a 4.8 is a small engine relative to that cam. Also remember you cant have a big cam with low lift, it just wouldn't work correctly. Bigger cams relative to engine size lope more because of more overlap due to bigger durations. Centerlines play a part in this as well. The more time both valves spend the same amount of time being open, the poorer the idle quality hence more lope. Oh btw no, hardcore NA cams dont work in turbo builds. Turbos HATE OVERLAP. Your bleeding out all that cylinder pressure with more overlap. Your effectively wasting the efficiency of your turbo and the intent of the motor as a whole.
The earlier the intake event, the rougher the operation is at idle and low rpm. A late intake opening event does the opposite. The shorter the lift the earlier you can setup the intake event.
With a relatively tight 111 LSA, a 220/220 @ .490" and a 220/220 @ .650" will sound completely different. The lower lift cam will "lope" more due to the earlier intake opening event. Because of this you can run a relatively lower duration camshaft while maintaining a mostly turbo friendly negative overlap @ .050 and still retain the sound many are looking for. (which I'm not saying is optimal power wise)
You are correct the 4.8 is a small engine. That same edelbrock camshaft will have a healthy lope on a 5.3 or even a 6.0. Which is rare on a "turbo friendly" camshaft.
As far as your "TURBOS HATE OVERLAP" theory, this is incorrect. The turbo doesn't care how much overlap you have. Overlap will have zero effect on a turbo setup that operates at 1:1 (or better) exh. back pressure levels. An efficient twin setup or very large single setup will do this easily. Almost all "race" turbo setups are run this way and have very aggressive camshafts.
In most street applications where 1.5-2:1 back pressure ratios are common, yes... overlap is an issue. Which is why I mentioned the cam above. It maintains negative overlap @ .050 and will still thump like a large duration camshaft in the OP's 5.3 engine.
Same cam on a 5.3 (thru mufflers even)
Last edited by Forcefed86; 03-26-2017 at 08:22 PM.
03-27-2017, 08:51 AM
#27
Restricted User
He wants cam for sound alone.
I just don't see the point of running a 23x exhaust duration cam in a 5.3 turbo setup to make 550whp. Its a street car and needs usable torque, especially at part throttle. A cam that will end up with a peak-and-shift behavior works OK at the track but not so much here.
My cam has less than 220 duration on the intake and exhaust, and makes ~900+ ft-lbs at the flywheel before 4000 RPM on whatever junk 93 I can fill up with. I can cruise at 3-5% throttle and it takes 10% throttle to outrun a Honda from a stoplight. Sure, I'd make more peak power with a bigger cam, but it just wouldn't be anywhere near as nice on the street.
I had come up with ~4 different cam choices for this build over its many iterations.
214/214 on a 108 LSA.
219/228 on a 112 LSA. (Hot Cam)
222/222 on a 113 LSA.
222/225 on a 112 LSA.
Each with 4 degrees of advance ground in.
Turbos are twin GT35s with a truck intake. This thing will make 550whp on a stock engine at 14-16 lbs through an 80e and be able to run on 91. With even the smallest cam choice, 550whp will have come and gone by 12 PSI.
I just don't see the point of running a 23x exhaust duration cam in a 5.3 turbo setup to make 550whp. Its a street car and needs usable torque, especially at part throttle. A cam that will end up with a peak-and-shift behavior works OK at the track but not so much here.
My cam has less than 220 duration on the intake and exhaust, and makes ~900+ ft-lbs at the flywheel before 4000 RPM on whatever junk 93 I can fill up with. I can cruise at 3-5% throttle and it takes 10% throttle to outrun a Honda from a stoplight. Sure, I'd make more peak power with a bigger cam, but it just wouldn't be anywhere near as nice on the street.
I had come up with ~4 different cam choices for this build over its many iterations.
214/214 on a 108 LSA.
219/228 on a 112 LSA. (Hot Cam)
222/222 on a 113 LSA.
222/225 on a 112 LSA.
Each with 4 degrees of advance ground in.
Turbos are twin GT35s with a truck intake. This thing will make 550whp on a stock engine at 14-16 lbs through an 80e and be able to run on 91. With even the smallest cam choice, 550whp will have come and gone by 12 PSI.
03-27-2017, 09:26 AM
#28
TECH Veteran
900 ft lbs @ 4000 rpm 
03-28-2017, 12:02 AM
#29
I don't agree...
The earlier the intake event, the rougher the operation is at idle and low rpm. A late intake opening event does the opposite. The shorter the lift the earlier you can setup the intake event.
With a relatively tight 111 LSA, a 220/220 @ .490" and a 220/220 @ .650" will sound completely different. The lower lift cam will "lope" more due to the earlier intake opening event. Because of this you can run a relatively lower duration camshaft while maintaining a mostly turbo friendly negative overlap @ .050 and still retain the sound many are looking for. (which I'm not saying is optimal power wise)
You are correct the 4.8 is a small engine. That same edelbrock camshaft will have a healthy lope on a 5.3 or even a 6.0. Which is rare on a "turbo friendly" camshaft.
As far as your "TURBOS HATE OVERLAP" theory, this is incorrect. The turbo doesn't care how much overlap you have. Overlap will have zero effect on a turbo setup that operates at 1:1 (or better) exh. back pressure levels. An efficient twin setup or very large single setup will do this easily. Almost all "race" turbo setups are run this way and have very aggressive camshafts.
In most street applications where 1.5-2:1 back pressure ratios are common, yes... overlap is an issue. Which is why I mentioned the cam above. It maintains negative overlap @ .050 and will still thump like a large duration camshaft in the OP's 5.3 engine.
Same cam on a 5.3 (thru mufflers even)
https://youtu.be/zSq3dXwXCv0
The earlier the intake event, the rougher the operation is at idle and low rpm. A late intake opening event does the opposite. The shorter the lift the earlier you can setup the intake event.
With a relatively tight 111 LSA, a 220/220 @ .490" and a 220/220 @ .650" will sound completely different. The lower lift cam will "lope" more due to the earlier intake opening event. Because of this you can run a relatively lower duration camshaft while maintaining a mostly turbo friendly negative overlap @ .050 and still retain the sound many are looking for. (which I'm not saying is optimal power wise)
You are correct the 4.8 is a small engine. That same edelbrock camshaft will have a healthy lope on a 5.3 or even a 6.0. Which is rare on a "turbo friendly" camshaft.
As far as your "TURBOS HATE OVERLAP" theory, this is incorrect. The turbo doesn't care how much overlap you have. Overlap will have zero effect on a turbo setup that operates at 1:1 (or better) exh. back pressure levels. An efficient twin setup or very large single setup will do this easily. Almost all "race" turbo setups are run this way and have very aggressive camshafts.
In most street applications where 1.5-2:1 back pressure ratios are common, yes... overlap is an issue. Which is why I mentioned the cam above. It maintains negative overlap @ .050 and will still thump like a large duration camshaft in the OP's 5.3 engine.
Same cam on a 5.3 (thru mufflers even)
https://youtu.be/zSq3dXwXCv0
