mdscole

The car: 2000 Corvette coupe. Normal LS1: 853 heads, crappy intake. Mods to date: Blackwing air cleaner, Corsa exhaust (catback only).
The use: Daily driver. occasional road race events.
The why: Bored. 300rwhp is about it.
The goal: more power... hopefully up to 400 rwhp. Smooth across the rpm band, no surging.

Looking at the first time modifying the internals of an LS1. Going with 799 heads, LS6 intake. Stock bottom end. LS7 lifters while the heads are off. Stock exhaust manifolds for emissions testing reasons. The heads are as-cast with only a pushrod and spring upgrade to PAC 1218s. Throttle body is stock early ls1 (2000 C5).

I've been doing all the research on here about cam choices duration, lift, lobe choices and LSA. It's way more than I thought.

While most people are completing the above with long tube headers, my scenario is going to retain some of the exhaust restriction due to the stock exhaust manifolds. The reason for this is 1. money, and 2. emissions inspection program in Kalifornia.

Anyway, in this instance, I'm under the impression that a split duration with emphasis on the exhaust will yield better results than a straight up cam. This additional time allows for more opportunity for the exhaust to make it through the restriction. i.e. going with a 224/228 vs a 228/228 or a 224/224. This is also a pattern I see with all of the stock cams.

Am I correct?
Is the power difference insignificant?
Does it need to be a larger difference between the lobe durations? i.e. 220/228?

Darkman

iTrader: (2)

I have an LS6 build using stock exhaust manifolds. The custom cam, spec'd by PatrickG, uses 218/230 durations and EPS lobes.

mdscole

Interesting. That's a significant split. Questions:
Is the only mod the cam? (Stock intake and heads)
What's the LSA?
Are you subject to a sniffer and if so, how did it do?
What is the power level?

I would expect that this cam drives close to stock with lots and lots of torque?

Darkman

iTrader: (2)

https://ls1tech.com/forums/generatio...sions-cam.html

https://ls1tech.com/forums/generatio...s-reprise.html

Paul57

I think you are right by going with a wider (than usual) split because of your stock exhaust manifolds and Pat G knows his stuff.

99Bluz28

iTrader: (35)

Don't forget you need to stick with a cam with at least -4* overlap, and yes the wider split is necessary with the stock manifolds.

PM sent.

Example: 220/228 114lsa = -4* overlap, or with a 115lsa = -6* overlap.

disc0monkey

iTrader: (10)

your lucky you can use z06 exhaust manifolds, you should def use them and go with a 222/230 for power or 218/230 for a stock idle or passing sniffer maybe smaller

nobreaks254

iTrader: (50)

Just for reference. My car; 03 Corvette Coupe. LS6 intake, Blankwing air cleaner, comp 220/224 on 114 cam, AFR 205 heads, stock manifolds and Ti catback made 386 rwhp. All work was done by previous owner from California.

mdscole

After all the positive comments about Patrick, it really seems worth the $25 to get his specs. (really, what's another $25 at this point!)

Thanks All!

Paul57

That is pretty much how I seen it when I was looking too.

DMM

The Thunder Racing CheaTR V3 cam (219/230 .607/.604 117 LSA) is a great DD cam that was designed to work with stock manifolds/exhaust and maintain stock idle and drivability while making great power everywhere. There are a lot of write ups and YouTube idle video's to help make your decision.

If you notice, this cam looks very similar to the one that Pat G recommends by EPS. I believe the current owner of EPS previously owned Thunder Racing and designed the CheaTR cam. I'm sure someone will correct me if I am wrong though.

Send the heads to AI or TEA and you'll be set.

mdscole

is there a link to AI? not a very googleable (sp?) term.

2QuikTA

http://www.advancedinduction.com/index.php

mdscole

That's too much lift for beehives. These stock heads don't really do much past .550, so beyond that - it's just money in valve train. Thanks for the thought though.

99Bluz28

iTrader: (35)

Not so, PAC 1518's are good to .650" lift.

Paul57

My thoughts exactly!

Paul57

And, you may not see significant gains going over .550 like you do as you approach it but there are gains for sure!! If you are looking for a particular amount of power it takes duration and lift. If more duration puts you out of the powerband or shift point you were looking for the only other option is lift (all other things being equal).

DMM

...Hence the AI or TEA statement. You're going through all the trouble, do it right the first time. You will be leaving power on the table, which has no emissions consequences. In a CA build that has to pass a sniffer, this should be a priority IMO.

I think that you will find that most of the streetable cams that make good power while staying in emissions compliance are in the .6xx lift range.

01ssreda4

iTrader: (96)

This, and send the heads to AI and it'll be right when you get it back together

mdscole

now all I need are some heads. They cost so much to ship! Would be nice to find a local set.