[Tim M]

Looking at a camshaft for our soon to be supersized LT1 (416) with a ported LT4 blower at ~8 psi.

The OEM cam will be round filed to mainly eliminate the DOD aspect with a side benefit of providing a bump in performance to our project.

We had upgraded the valve springs with the supercharger addition, employing PSI 1511 beehive springs (.625 lift limit). Although still seemed to run into a valve float/crash issue at 6550 rpm.

Very likely we will purchase a Cam Motion camshaft. Unfortunately, the only one they offer under .600 lift is:

Titan 1 NA cam:
218/228-114+5
Duration at .050": 218/228
114 Lobe Center Angle with a 109 Intake Centerline
Lift with 1.8 Rocker Arm Ratio: .594"/.585"

The also offer a Positive Displacement cam (mildest), but exceeds .600 threshold:
220/236-118+4
Duration at .050": 222/238
116 Lobe Center Angle with a 112 Intake Centerline
Lift with 1.8 Rocker Arm Ratio: .621"/.612"

The question is how much benefit would we really receive from the specialized camshaft? It would also be right up against the limits of the selected valve spring (which means we would likely have to find another option).

For comparison, the OEM LT1 cam is:
200°/207°
116.5 Lobe Center Angle
0.551 in/0.524 in

Lastly, we are giving serious thought to going with the OEM Ti intake valves to further reduce valvetrain weight and gain a few hundred more rpm (if this is indeed the issue).

Acknowledge this is not an optimum combination - stock exhaust, small blower, no E85, but believe it will still out-perform this driver's capabilities. :-)

Thanks.

Image for fun:

[SSUNDVL]

Are you only looking at off the shelf cams or have you talked to them about a custom grind?

Also the lt4 really drops power in the higher rpm range, a cam helped me quite a bit in the higher rpm range. I would probably discuss with Cam Motion and your tuner as to what specs will be best for the 416 and lt4 setup you have going for track use before pulling the trigger to get their advice based on all the setups they see.

I wouldn't be deterred from a higher lift cam either, but if you are driving it in Germany outside of tracking I would imagine a big cam could be a bit sketchy. Alternatively skip the cam and put money into cooling.

[LT1ornothing]

Did you lower the compression on the 416? You said you were getting knock and having to utilize octane booster on the old set up. The port work reduces heat and definitely helps but the benefits of porting are seen when the blower is spun at higher speeds.

As for camshaft, your "mild" positive displacement blower camshaft option would absolutely make a big difference. Is there a reason why you cannot have a custom ground camshaft with slightly lower lift so that the valvetrain does not have endure such excessive loads?

[Joshinator99]

Agree with SSUNDVL. Reach out to CamMotion and have them do a grind for *your* build rather than off the shelf IMO.

[Tim M]

Appreciate the replies.

CR will be dropping to 10.6 or so (wish it was a bit higher, but piston availability...) to reduce the knock tendency and remove the octane booster requirement. (Kpt turning my plugs orange! j/k)

I will be replacing the camshaft with an aftermarket - figure at the very least, 10% increase in displacement dictates 10% increase in cam timing...not looking for a torque engine!

I do have a note into Cam Motion about possibilities, but do wonder about availability and gather they won't like my combination and insist on headers, etc.

Another note between the Cam Motion cams is the PD cam requires locking out fully the cam phaser on the engine, while the NA model only requires a 4 degree 'block.' It would be nice to keep a portion of that functionality since this is 90% street and a smooth idle is required.

I've watch a few Richard Holdener videos and find it interesting that he describes the secret that any cam is a turbo/blower cam. What the engine curve does NA will just be further exaggerated with a power adder. Certainly there are likely situations this is not true, but he provides data several times to support.

I forget who discovered it on this forum, but the OEM LT5 camshaft appears to be a non-DOD version of my OEM NA LT1 cam. Admittedly, not all the specs are known, but the published duration/lift is exact. If the same, a bit odd that even GM chose this option - realizing emissions, fuel economy likely has a higher priority than what we prefer.

SSUNDVL: Your reference to cooling is for the supercharger? I've had no issue with the engine temps - very consistent and with Germany is a touch cooler overall...

Thanks for the discussion.

[s346k]

id think you'll want an aftermarket camshaft simply for the fuel lobe. if i were in your shoes id contact btr or cam motion directly and have them spec you a custom grind, i think they are only something like $25 more. well worth it.

[laynlo15]

I had the Btr Stage 1 cam in my Camaro with a Maggie 2650.

[KingLT1]

Originally Posted by Tim M

Appreciate the replies.

CR will be dropping to 10.6 or so (wish it was a bit higher, but piston availability...) to reduce the knock tendency and remove the octane booster requirement. (Kpt turning my plugs orange! j/k)

I will be replacing the camshaft with an aftermarket - figure at the very least, 10% increase in displacement dictates 10% increase in cam timing...not looking for a torque engine!

I do have a note into Cam Motion about possibilities, but do wonder about availability and gather they won't like my combination and insist on headers, etc.

Another note between the Cam Motion cams is the PD cam requires locking out fully the cam phaser on the engine, while the NA model only requires a 4 degree 'block.' It would be nice to keep a portion of that functionality since this is 90% street and a smooth idle is required.

I've watch a few Richard Holdener videos and find it interesting that he describes the secret that any cam is a turbo/blower cam. What the engine curve does NA will just be further exaggerated with a power adder. Certainly there are likely situations this is not true, but he provides data several times to support.

I forget who discovered it on this forum, but the OEM LT5 camshaft appears to be a non-DOD version of my OEM NA LT1 cam. Admittedly, not all the specs are known, but the published duration/lift is exact. If the same, a bit odd that even GM chose this option - realizing emissions, fuel economy likely has a higher priority than what we prefer.

SSUNDVL: Your reference to cooling is for the supercharger? I've had no issue with the engine temps - very consistent and with Germany is a touch cooler overall...

Thanks for the discussion.

That was yours truly on the LT5 cam. Another member got a hold of one and measured the fuel lobe and it's identical to the LT1. GM likely opted for that because the LT5 uses Port injection along with Direct injection so they don't need the bigger fuel lobe and the LT1/LT5 cam is a little bigger then the LT4. Evidently they didn't need to worry about specific emission requirements with that limited production engine so they opted to use the larger cam of the LT family with no AFM.

I agree with others that I would have Cam motion spec you out a cam. I wouldn't worry about locking vvt. The larger cubes will negate needing to advance the cam down low for more torque. It should still be able to idle smooth depending on the cam profile. VVT doesn't really have anything to do with that. GM used it to be able to advance cam timing down low to improve low end torque since the heads have large intake ports and retard it up top to carry power. That is how the LT1 was able to achieve much more torque below 3k rpm then the LS3. Adding stroke combined with small PD supercharger will more then make up for that. You will likely be looking for ways to reduce the low end torque because it's going to be a tire frying machine.

[Spaceme1117]

What are the goals for the car? That will dictate the cam.

A supercharger cam can help to maximize the gains from the supercharger.

[JANNETTYRACING]

Originally Posted by Tim M

Looking at a camshaft for our soon to be supersized LT1 (416) with a ported LT4 blower at ~8 psi.

The OEM cam will be round filed to mainly eliminate the DOD aspect with a side benefit of providing a bump in performance to our project.

We had upgraded the valve springs with the supercharger addition, employing PSI 1511 beehive springs (.625 lift limit). Although still seemed to run into a valve float/crash issue at 6550 rpm.

Very likely we will purchase a Cam Motion camshaft. Unfortunately, the only one they offer under .600 lift is:

Titan 1 NA cam:
218/228-114+5
Duration at .050": 218/228
114 Lobe Center Angle with a 109 Intake Centerline
Lift with 1.8 Rocker Arm Ratio: .594"/.585"

The also offer a Positive Displacement cam (mildest), but exceeds .600 threshold:
220/236-118+4
Duration at .050": 222/238
116 Lobe Center Angle with a 112 Intake Centerline
Lift with 1.8 Rocker Arm Ratio: .621"/.612"

The question is how much benefit would we really receive from the specialized camshaft? It would also be right up against the limits of the selected valve spring (which means we would likely have to find another option).

For comparison, the OEM LT1 cam is:
200°/207°
116.5 Lobe Center Angle
0.551 in/0.524 in

Lastly, we are giving serious thought to going with the OEM Ti intake valves to further reduce valvetrain weight and gain a few hundred more rpm (if this is indeed the issue).

Acknowledge this is not an optimum combination - stock exhaust, small blower, no E85, but believe it will still out-perform this driver's capabilities. :-)

Thanks.

Image for fun:

I think you need my Terminator cam it was designed specifically for road race applications and has 7000 RPM capability.

That little blower will be the Restrictor plate on a 416 no matter the porting or speed you turn it.

Heck it is too small for a 376.

HP comes down to 1 thing Air flow, 1 lb. a minute makes 10 HP.

does not matter if it's a 283 or a 600 cube engine.

The larger cubes will just lower the peak torque RPM capability of that blower.

The larger supercharger raises the Peak Torque RPM range which turns in to HP.

Ted.

[Tim M]

Ted,

I acknowledge the OEM blower might be considered too small, I'm ok with that.

My preference is a mild camshaft for reliability, smooth idle, and able to rev to 7000 rpm (even if on the downside of the curve).

I'm already set up for the single beehive 1511 springs, is your Terminator cam compatible? Is the camshaft available separately as I will be using Katech/Johnson lifters / OEM exhaust?

I don't see this cam on your site, is this the same as smooth/rough idle cams?

Thanks.

Cam Motion did provide a few options after I provided all my restrictions...end result was:

224/238 Duration @ .050''
120 LSA, 116 ICL (120+4)
.594''/.594'' Lift with 1.8 rockers

Seems like a logical option.

I will be making a decision soon as my OEM cam is a DOD and must be replaced...

[LT1ornothing]

Originally Posted by Tim M

Ted,

I acknowledge the OEM blower might be considered too small, I'm ok with that.

My preference is a mild camshaft for reliability, smooth idle, and able to rev to 7000 rpm (even if on the downside of the curve).

I'm already set up for the single beehive 1511 springs, is your Terminator cam compatible? Is the camshaft available separately as I will be using Katech/Johnson lifters / OEM exhaust?

I don't see this cam on your site, is this the same as smooth/rough idle cams?

Thanks.

Cam Motion did provide a few options after I provided all my restrictions...end result was:

224/238 Duration @ .050''
120 LSA, 116 ICL (120+4)
.594''/.594'' Lift with 1.8 rockers

Seems like a logical option.

I will be making a decision soon as my OEM cam is a DOD and must be replaced...

Those camshaft specifications look perfect for your build. It should idle very smooth. Your valvetrain will thank you for the lower lift on the camshaft.

[JANNETTYRACING]

Originally Posted by Tim M

Ted,

I acknowledge the OEM blower might be considered too small, I'm ok with that.

My preference is a mild camshaft for reliability, smooth idle, and able to rev to 7000 rpm (even if on the downside of the curve).

I'm already set up for the single beehive 1511 springs, is your Terminator cam compatible? Is the camshaft available separately as I will be using Katech/Johnson lifters / OEM exhaust?

I don't see this cam on your site, is this the same as smooth/rough idle cams?

Thanks.

Cam Motion did provide a few options after I provided all my restrictions...end result was:

224/238 Duration @ .050''
120 LSA, 116 ICL (120+4)
.594''/.594'' Lift with 1.8 rockers

Seems like a logical option.

I will be making a decision soon as my OEM cam is a DOD and must be replaced...

My Terminator cam is available separately if you so choose.

It falls somewhere in the middle of smooth and rough Idle.

It requires better springs and 3/8 pushrods

Ted.

[EDFHOBBIES]

If the LT4 makes 650hp w 10.1:1 compression on 9lbs of boost and isn't all that great when it gets hot at the track, why are you messing around with a supercharged setup if your hp mark is so low?

Both katech and LME offer NA stroker motors that make 600 to 800 hp. If your building an all around car that sees track time and little league roll races I can dig it. PS you can mimic there build you don't have to spend 26k however most of LME power is in that 5k buck NA manifold want to say it worth close to 50 hp over the LT1s.

NA build: most would suggest raise the compression, switch to all E, cam easy on valve train, Jesel rockers, morel or johnson lifters.. Some great heads like edelbrock or cid. 650 to 680 na would kick but over the SC guys after a 15 min session every time..