Comp Cams

[RdHuggr68]

Originally Posted by WSSix

Pretty much! On an LS1/6 this cam will be dead down low ie under 3000 rpms and there are other factors involved that affect power band other than the cam. IMO, there's way too much overlap for a street car with this cam. However, everyone has mentioned how subjective streetable is and that's very true. You have to look at the total drive train and you're driving style. So what's the rest of the drive train look like on your car? What do you want power wise? I'm not referring to just the amount of power but where you want your power. What other engine mods, if any, do you have currently?

An example of a cam that I really like for all around street performance on an LS1/6, is a 228/232 on either a 112 or 114 depending on auto or manual trans. This was ground on Comp's XER lobe grind but they have changed their grind names so I'm not sure what new name corresponds. To me, this cam worked great on a stock LS1/6 with simply headers, exhaust, and normal gearing(ie mid to low 3.0s) but also would only get better with more mods like heads and intake. It was a simple off the shelf grind that works well for a street car. Nothing fancy or exotic. It just worked.

This cam is in a new LS3 with 11:5:1 comp. Diamond pistons,Callies crank 4" stroke Callies rods, heads milled and valve job. Fast FI intake.

[WSSix]

See, now the cam doesn't seem so bad. You're what 413 cu in now? That's a lot different than an LS1/6. You're actually on the small side for an engine this large. It will perform well, have good torque, a broad power band that starts low, and it'll be leaving a lot left on the table. Go bigger.

[RdHuggr68]

Originally Posted by WSSix

See, now the cam doesn't seem so bad. You're what 413 cu in now? That's a lot different than an LS1/6. You're actually on the small side for an engine this large. It will perform well, have good torque, a broad power band that starts low, and it'll be leaving a lot left on the table. Go bigger.

Thanks Trey, it is a 408ci and all new parts balanced ARP studs,should be sweet.
Kevin

[jwcarguy]

You didn't mention how you are going to use this engine/
But from asking "is this cam streetable" leads me to think that it will mainly be a street car with some track days? correct?
Auto or manual trans?
rearend gear ratio?

If so, also have to know if you Diamond pistons have valve reliefs, how much your heads have been milled, head gasket thickness and are you still running the stock 1.7 ratio rockers??
With that much duration (@ .050), you need to beware of what you ptv clearance is (piston to valve)

With the fist cam choice you have approx 13 degrees of overlap, which is high for a LS3 cylinder head (the intake valves are 2.165" compared to the exhaust valve at 1.59") that is why on these rectangle port heads, most cam recommendations have much more duration on the exhaust side to compensate for the size difference for proper exhaust gas flow

For my engine (LS2 6.0L w/ LS3 cylinder heads stock unmilled and intake setup) I contacted both "Pat G" @ Guerra Motorsports and "Spinmonster" from the Corvette world, both are some of the top LS EFI tuners in the country
Both of them explained about having too much overlap effects low end and driveability
here is a interesting read on the LS3 heads and cam specs vs performance/ driveability:
http://forums.corvetteforum.com/c6-t...-camshaft.html

My cam was custom ground by EPS:
226/234 .629”/.629” 113 LSA +2 advance (with 1.7 ratio rockers)
EPS ET/ET lobes on 8620 steel 3 bolt cam core
EPS26-2/EPS34-2 HR113 LSA +2 advance (111 installed intake centerline)

hope this helps,
Jeff

[WSSix]

Oh, it'll be sweet you're correct. I was planning something similar way back when. I might still but we will see. Jeff has some excellent points as well. Anyone you speak with about cam recommendations will need all that info and maybe more. Just be sure to always look at the total package and don't get caught up chasing dyno numbers. You don't register dyno numbers when driving down the road or sitting in traffic. How and where the engine makes it's power in relation to what you need will determine if the car is enjoyable to drive and performs for you. You've got a really good foundation started.

Case in point about not knowing dyno numbers while driving down the road. Have you ever ridden in a stock Z06? If not, I highly recommend it. I can honestly say I doubt I would do much of anything to that motor if I had one. It pulls like a freight train all the way to 7000 rpms. It's so smooth and linear. It's such a treat and thrill yet I've also built cars/engines that put more to the wheels than a stock LS7 makes. I'd rather have the LS7 with it's lower power because it's such a broad and smooth power band. It makes the power how and where I need it. I could care less what the dyno sheet shows in comparison to other engines.

[jwcarguy]

Originally Posted by WSSix

Oh, it'll be sweet you're correct. I was planning something similar way back when. I might still but we will see. Jeff has some excellent points as well. Anyone you speak with about cam recommendations will need all that info and maybe more. Just be sure to always look at the total package and don't get caught up chasing dyno numbers. You don't register dyno numbers when driving down the road or sitting in traffic. How and where the engine makes it's power in relation to what you need will determine if the car is enjoyable to drive and performs for you. You've got a really good foundation started.

Case in point about not knowing dyno numbers while driving down the road. Have you ever ridden in a stock Z06? If not, I highly recommend it. I can honestly say I doubt I would do much of anything to that motor if I had one. It pulls like a freight train all the way to 7000 rpms. It's so smooth and linear. It's such a treat and thrill yet I've also built cars/engines that put more to the wheels than a stock LS7 makes. I'd rather have the LS7 with it's lower power because it's such a broad and smooth power band. It makes the power how and where I need it. I could care less what the dyno sheet shows in comparison to other engines.

Well said Trey!!

You are correct!

When I had Pat G spec a custom grind cam for me and my application, I had to fill out a multiple page questionnaire, listing ALL engine, trans and rear axle ratios, tire diameters, driving style and goals of the car, etc.
Pat G is also the one tuning my car with a EFI Live AutoCal device
I bought the unit from Pat with my base tune, and have since sent him numerous data logs (recordings) of the engine idling, cruising at varied rpm's and WOT runs, I email him the files and he makes necessary changes and emails back new tune files, which I download into the EFI Live AutoCal and then "flash" program my pcm in the car

This is "real world" data running the car, in traffic, a/c on, braking and acceleration, etc. etc.
I am extremely happy with the results so far!

great driveability, without low speed "bucking and jerking" associated with high duration and large overlap cams! picture you driving around a parking lot looking for a spot to parking, but the car won't idle down or "cruise" at that speed, now you're on and off the gas & clutch, just trying to get the dam thing parked! A improper cam, may sound real good and work out great if you are racing all the time at WOT (mid to topend rpm range), but you will loose lowend and driveability

Just my opinion from everything that I have researched and spoken with top industry professionals

Jeff

[RdHuggr68]

Originally Posted by jwcarguy

You didn't mention how you are going to use this engine/
But from asking "is this cam streetable" leads me to think that it will mainly be a street car with some track days? correct?
Auto or manual trans?
rearend gear ratio?

If so, also have to know if you Diamond pistons have valve reliefs, how much your heads have been milled, head gasket thickness and are you still running the stock 1.7 ratio rockers??
With that much duration (@ .050), you need to beware of what you ptv clearance is (piston to valve)

With the fist cam choice you have approx 13 degrees of overlap, which is high for a LS3 cylinder head (the intake valves are 2.165" compared to the exhaust valve at 1.59") that is why on these rectangle port heads, most cam recommendations have much more duration on the exhaust side to compensate for the size difference for proper exhaust gas flow

For my engine (LS2 6.0L w/ LS3 cylinder heads stock unmilled and intake setup) I contacted both "Pat G" @ Guerra Motorsports and "Spinmonster" from the Corvette world, both are some of the top LS EFI tuners in the country
Both of them explained about having too much overlap effects low end and driveability
here is a interesting read on the LS3 heads and cam specs vs performance/ driveability:
http://forums.corvetteforum.com/c6-t...-camshaft.html

My cam was custom ground by EPS:
226/234 .629”/.629” 113 LSA +2 advance (with 1.7 ratio rockers)
EPS ET/ET lobes on 8620 steel 3 bolt cam core
EPS26-2/EPS34-2 HR113 LSA +2 advance (111 installed intake centerline)

hope this helps,
Jeff

Thanks Jeff, the pistons have valve reliefs and rockers are 1.7.The car will see some track time but street and highway too. Tremec 6-spd, 12 bolt with 373 gears. The engine was built for a gal who was putting it in an RX7 but she had to sell it before it was installed. I can change the cam out its stll not in car and has no intake on it, easy fix but I have to pick a cam out.
Kevin

[supremeefi]

A lot has already been said but just to add a thought or two.

That's basically an LS Thump'r. The reason it'll run up in rpms is because of the extra exhaust duration.
If you notice most of the LS stuff doesn't have that much stagger. That's because even with a much smaller exhaust valve an LS normally flows pretty well on that side. There is such a thing as over scavenging the engine.
Imo that cam is more for noise than hp/tq. You can do better than that.