Area under the curve(avg horsepower)

[Unobtainium]

I've seen a ton of dyno graphs and positive reviews on cams, but have any of the shops actually taken the time to see which cam delivers the best power curve, and not just the best number? I know the Mustang dyno's always show average hp, which would be a good indication, but has anybody really looked at this? I realize there are tons of variables, but cars with the same mods and tires with different cams would show a lot.

[Avenging Orange]

Generally the smaller cam will produce all its power under the curve. My '04 LS1 GTO had a Thunder Racing TR220.........Only laid down 335rwhp, but it was all under 5500rpm. My '06 had a Comp 228/232, didnt start pulling till 4000rpm.
Lesson from our Aussie brothers.........keep it small, keep it tight. They would run like 216-220 duration with tight lsa (108-110).
Also, check out GM High Tech magazing...they often do LSx cam comparisons

[Bad70supreme]

Yep, keep it smaller... these guys are putting to large of a cam in there cars in my opinion, to much weight and not enough gear! My 217/228 on 112 is going in tomorrow! Should pull hard all the way through to about 6400.

[InfernoSS454]

So your saying any cam bigger than that is a waste on this car.

[newmoon]

Originally Posted by Unobtainium

I've seen a ton of dyno graphs and positive reviews on cams, but have any of the shops actually taken the time to see which cam delivers the best power curve, and not just the best number? I know the Mustang dyno's always show average hp, which would be a good indication, but has anybody really looked at this? I realize there are tons of variables, but cars with the same mods and tires with different cams would show a lot.

Good to see somebody is paying attention

[Bad70supreme]

Originally Posted by InfernoSS454

So your saying any cam bigger than that is a waste on this car.

Yes and no... if you are going with 4.10s and a drag tire setup, and or big stall for an auto then no point. If your are staying with stock gear for a few years to come, mabey just some drag radails, mostly street car then keep it small. The hole point is to match your setup... stock heavy weight car, heavy 20" rims, and 3.42 gears and running a big cam is a big missmatch of parts!

Why do you think so many guys have a hard timing running solid times with these big cam's... they dont have anything down low to get moving.

[Anthony @ LG Motorsports]

Sure, yes, no, and 100%. or something like that.


Being a company that has been focused on road racing for most of our time, we have to focus in on making power in the RPM ranges we operate in, and for a road race car that is a much broader area than say a drag only car.

Also, and this would have to do with power under the curve as well, is when doing upgrades you have to think about where YOU drive the car. If you spend most of your time idle to 4500 RPM, then there is no point in putting a big cam that is 3000-7200 RPM because you'll never see any of the benefits of it. At the same time....if you are a mile runner...why would you want to worry about anything under 3500 RPM? If your never there...no point in focusing in on that range.

....this not only is related to cam profile but also modifications in general.

I thought you would find this interesting.....when dealing with forced induction and power under the curve.

To make this even more biased towards a centrifugal I chose a LS7 vs LS9 so the ATI has a bigger stroke and cube engine to start with. The E-force cars I have done so far have been auto cars (manual car on the lift right now getting one). The LS9 uses basically a very similar TVS setup to the E-force unit, so it was used to compare.

LS7 (blue curve)

• LG 1 7/8 Headers
• LG G7X3 cam
• RPS clutch
• 8 rib drive, 8 psi boost

LS9 (red curve)

• LG 1 7/8 Headers
• stock cam
• lower pulley 11 psi boost

Same tire size, same diff ratio used in both cars (3.42)



You can see how the blowers make boost in different ways. Almost 200 ft-lbs toque difference. Notice the LS7 ATI setup pulls more top end HP, just not the low end...even with the longer stroke and bigger displacement.

[nycoupe11]

I went with a VVt-2 cam and once i put a converter and gears in...the thing will flyyyyy

[Bad70supreme]

Unfortant that most people dont understand that, big cams sell... people always want to go as big as possible and dont understand how it all works. I dont know everything but I after years of trying different things I think I have a pretty good idea of how to choose a cam. These 230-240 duration cams dont start pulling till higher RPM, they make big numbers and they work, but without all the supporting mods they are going to run slower in short burst on the street, no power under 4000k and not going to run big numbers at the track like they should. These cars in basicly stock form should be setup with a cam that will pull from hard from down low and rip real hard from say 3000-6500 in my opinion.

If you look at some of the G8 and GTO guys, some of the most respectable cam only times are ran with small cams and actaully run good MPH.

[axis]

This is where VVT has it's major advantages. Gives you the "under the curve" numbers and also highend as well. It doesn't give the same highend as nonVVT but you get a good combination of both.

[InfernoSS454]

So all cams have their place and a 230/240 duration with a big stall will still haul @$$. Right?

[Unobtainium]

Thanks for all the replies, and thanks to LG for the graphs too.
I certainly see the benefit of the positive displacement blowers. I always worry about IAT's after a long pull though.
I really don't want a car that doesn't have any fun factor under 4000, and I think that's what these big cams accomplish. The blower is an interesting case though. Will a smaller cam be worth the overall cost? Ultimately the car will be TT, and not 1000whp.
Hopefully there is a company that sells a milder cam that will work good for turbo later.

[Bad70supreme]

If your TT then you are limited to a point, the TT will make sick power! I would suggest talking with a vendor about running a smaller cam that will work with a TT later, They can cook something up for you I am shure.

[black79ta]

A manual can handle more cam, if you can handle the loss in low end torque.