tommycompton

iTrader: (1)

Ready to put my final parts list together. I have my engione tear down started, and almost complete, now I need to consider what to do for a cam.

I'm not looking to push the power from the cam, I figure the whipple will do that just fine. But I figure I could get a more efficient cam over stock for FI.

Here are some options,

I could leave he stock ls2 cam in

or something like these

Lingenfelter GT2-3 camshaft
207/220 .571/.578 w 1.7 rocker 118.5 CL



ZR1 cam:

211/230 .558/.552 122.5 CL

Thunder Racing Custom Camshaft
"Split Pattern" - 224/227 .563/.569 114 LSA

Let me know your opinions.

-T-

iTrader: (2)

Are you forged? The theory to the cam selection can be in many areas. Increasing cylinder pressures via dynamic compression, increase boost via ICL changes. I don't want to say its the easiest, but your dynamic compression calculations need to be determined to judge where your improvements can be from your current setup to obtain your goals- whatever they may be. The ZR1 cam is proven and low risk. But is it the avenue you want to travel? A lot of guys want uniqueness with their mods.

tommycompton

iTrader: (1)

No I'm not forged. I'm in the process of installing lower compression heads, because my compression was too high to run without race gas or be reliant on methanol. Low risk is where I want to be. Lowering my dynamic and static compression is my goal. I don't need a cam to give me more power, Ican easily push the limit of bottom end with the blower alone. I'm looking for something to compliment the blower, somthing boost friendly.

itsslow98

iTrader: (18)

Until you forge the motor id leave the stock cam in there. Its a relatively good cam for boost and when that bottom end goes you'll likely be taking whatever cam you put in now out for something better. Throw some good valvesprings in there and run it the way it is.

DMM

Oh boy...here we go again...LOL! What is your exact combo at the moment? If you have a Maggie, you'll want to stay with a higher LSA such as the LS7 or LS9 cam (exact same profile, LS7 is 120 LSA and LS9 is 122.5 LSA) in order to keep from bleeding off boost. The 112 is really too small for the 5.7 - 6.0, so there is truth in the wide LSA theory.

If you are using something larger, you'll ultimately make more power with a little overlap. Search for threads regarding blower cams by Predator Z in the GEN III section, he has a proven cam profile that works well.

You're going to get a thousand responses here.

BTW - The GT2-3 cam is the exact same as the stock '02-'04 Z06 cam...there are no gains to be had there.

Edit: You're running the Whipple...there will be nothing lost there. What kind of drivability/idle characteristics are you looking for? And, you're going to stay stock cubes, correct?

98cobra

iTrader: (32)

I have a low mileage gt9 cam coming out if you want it.

VeryWhiteDevil

iTrader: (9)

I have a CTS-V2 cam we pulled for 50 + shipping if you want

tommycompton

iTrader: (1)

Alaways good advice. It's one of those while I'm in there things. Right now I'm leaning towards the Ls9 cam, because they are cheap, or just staying stock.
My current set up consists of 3.3l whipple, and supporting fuel upgrades. I do have methanol plumbed in, that I want to rely on for cooling purposes only.
AFR 72cc 230 heads to lower compression, I'm beefing up the valve train, timing set and oil pump. Also have headers.
I've been torn between forging the bottom end on this block with stock cubes, or driving it with above mods, and building a second block.
I definitley want somthing fairly reliable and easy on the valve springs. I'm not trying to push wild untill I go forged.
Not sure if I'm interested in used, but do you have the specs? It could be a viable cheap alternative and better suited than the ls9 cam.

punishmentcycle

iTrader: (6)

i have the ls9 cam and couldnt be happier. drivability is perfect. and i used the ls9 springs,cheap and matched to the cam so it was a no brainer.

imo the whipple will love it and because its a caddy drivability was my main concern

tommycompton

iTrader: (1)

More agressive than I would like, thanks though. It would probably be my choice if my engine were up to the task.
Thanks for the insight, that's what I need to hear.

raven154

iTrader: (14)

Used really isn't a problem on roller cams unless they trashed a lifter roller and trying to hide it. Chances are it's a pull out of a low mile V that had a cam upgrade. I wouldn't be worried the least as long as there is no visible damage.

punishmentcycle

iTrader: (6)

only thing i see about the lsa cam is that its even smaller than an ls6 cam. kinda going backwards there

DMM

Curious as to how you arrived at 230cc heads. FI doesn't require good flowing heads (Grand National is a perfect example here) to make big power. I would forego the cylinder heads and concentrate on a forged motor as you'll likely make just as much power from the increase in spark advance.

I plan on staying stock cubes as well, and am looking at worked over 317 heads, which have the same ports as the 243/799 heads and can be ported by AI or TEA for 300+ cfm flow on the intake while lowering SCR by 1 full point.

No need for large cams over .600" lift as the boost will do the work, you'll find power in the duration and lobe design...which I believe LXL are preferred for boost. If you are staying with the 347, I would not go over 117 LSA as it will put the powerband too high in the RPM range.

tommycompton

iTrader: (1)

That's just it I'm not looking to make big power, I needed to lower compression on my LS2. The 72cc heads is what I needed to do that, the 230 heads match my 4.00" bore.
Plus I can carry the heads over if I decide to go bigger bore. The whipple was causing detonation on pump gas with 10.9:1 compression of the stock ls2 364.
The 230's with 70cc chambers should drop me down by a full point, into the boost friendly zone.

Btw I've had the heads sitting in my living room for the last 6 months

vmapper

iTrader: (8)

I like the idea of high flowing heads with FI, it lowers the boost pressure, easing stress on all the parts. SkyDivers V is a good example. ~12.5psi ... still has big power.

I am using 230 AFR v2s, but the 65cc chamber and thinner gasket to increase quench.

This static compression idea is not really important, what is, is the dynamic compression and this is set by the cam choice. You could possibly keep 10:9 static but have a 7.5:1 dynamic set by the cam. (example)
With that being said, DMM makes a good point, and I agree. "I would forego the cylinder heads and concentrate on a forged motor as you'll likely make just as much power from the increase in spark advance. "

tommycompton

iTrader: (1)

Cylinder head foregoment is moot point, I already own them. I have two choices, I slap this sucker together with all the top end done and drive it for a season or two while I build another bottom end. Or I get a forged rotating assembly and put it in this block.
Ideally I would prefer an Iron block for boost, so building a seperate bottom end build would prefered, then I could strip the heads off and put them on the iron block
If i was to do a cam now I would be going a cheaper route with say an LS9 cam, because I probably wouldn't be carrying it over to my next block.

I know I'm doing some of this backwards, but this is kind of how it worked out.
Bought whipple, need to get it to work, then bought heads to get it to work.
Really should have done a forged set up first, but that's not how it happened.

Money is a tad of a factor because my plans on an 8.8 rear before spring is a must.

punishmentcycle

iTrader: (6)

he already has the heads! plus good heads on an fi set up is never a bad idea. the problem your gonna run into with that whipple is the manifold is very small. thats why there is heat and detonation issues with them. only real way to make big power with that blower is to get the bigger manifold and change hoods. thats why i passed on the whipple and kept my 112.

DMM

Sorry about that, I was unaware that you had already made the purchase on the heads. Anyhow, just for the sake of the thread, the 317's also have a 71cc combustion chamber, which is also about 1 SCR point lower. The AFR or Trick Flow chambers are much more advanced though, and resist detonation by design.

VMAPPER made a very good point about DCR, which is what I was going to bring up as well. It is important to factor boost into the DCR calculation in order to get an accurate idea of what cylinder pressures you will be running. Cylinder pressure is an exponent of DCR, it will change if the contents of the cylinder are already pressurized before the compression stroke begins...it's important to know this when you design your build b/c things get very expensive if you're off.

You can get 8.0:1 DCR on a N/A motor with 11.0:1 SCR, but not an FI motor since you also have to calculate the boost in the equation as well. You will have to know your bore/stroke/rod sizes and what static compression (SCR) you will have in order to get an accurate DCR calculation. Stock conn rod length is 6.098", BTW. Only use the "IVC ABDC" numbers, NOT THE 0.050" NUMBERS!

Here is a very detailed DCR calculator: http://www.wallaceracing.com/dynamic-cr.php

Here's a good one for getting your SCR: http://www.wallaceracing.com/cr_test2.php

Here is a link that has the OE cam spec's (LS6, LS7, LS9, etc) so that you can enter them into the calculator:

http://www.superchevy.com/technical/...e/exhaust.html

It's best to keep DCR in the 9.8 - 10.0 :1 range at most for pump gas motors. Enter your current (stock) combo in the DCR calculator and see what you come up with. You'll know why you have maybe 12* total advance (at most) with your current tune.

Also, last thing..once you decide on a cam, you can fine tune the DCR by advancing or retarding the cam (which will advance or retard the IVC by as many degrees).

tommycompton

iTrader: (1)

Believe me, with the hassle I should have went with an edelbrock e-force.

DMM

LOL! We're in the same boat my man! That's why i'm looking at the 317's right now. I need to get my SCR down as well.