Reverse split cam

[daves8]

I was chatting to a tuner yesterday and was mentioning I was considering a cam for my Calais.

in order I want

1. no pushing against brake
2. Relatively smooth / mild idle, no shaking or pig rooting
3. Power delivery down low and mid range over top end dyno queen

the tuner recommended a reverse split cam - 228 / 224 on a 116 lsa with about 610 lift.

what would be the benefits of a reverse split?

I understand it might help low end torque as the air is being jammed in, but exhaust is not as free flowing this low end will improve but top end sacrificed.

he said ported heads will make it the complete package.

thoughts?

 

[harrop.senator]

Nothing. The only time a reverse split helps is when you have a bad intake and you're attempting to cheat it.

I would never run a higher intake duration then exhaust in an LS. Intake manifold and intake port are great on them. There's a reason almost all cam manufacturers for an LS run a longer exhaust.

With the cubes of a VF and the rectangular ports you want a bit more exhaust split on them. 6-10 degrees apparently works really well. I think a little 222/228, 219/228 , with around .600 lift will do what you want.

 

[Deuce]

As above, unless you have an oversized - super high flow exhaust system that you are trying to hold back, then I can think of no reason to reverse split an LS motor since they are known for a really good intake system.

 

[07GTS]

all LS heads are in comparison exhaust restricted, exhaust has to be able to get out so it dosnt contaminate the next intake cycle, a smaller exhaust duration or too late opening point restricts torque, IMO a too late closing intake can be worse then a longer exhaust duration on drivability, as has been said always go a longer exhaust to offset the poor LS exhaust port compared to the intake

 

[shane_3800]

I was chatting to a tuner yesterday and was mentioning I was considering a cam for my Calais.

in order I want

1. no pushing against brake
2. Relatively smooth / mild idle, no shaking or pig rooting
3. Power delivery down low and mid range over top end dyno queen

the tuner recommended a reverse split cam - 228 / 224 on a 116 lsa with about 610 lift.

what would be the benefits of a reverse split?

I understand it might help low end torque as the air is being jammed in, but exhaust is not as free flowing this low end will improve but top end sacrificed.

he said ported heads will make it the complete package.

thoughts?

You really need to have the heads hand ported for something like this.

I would advise against it and just go for a even cam and the head porting and new valves but don't back cut the exhaust and do a 45° seat with standard cuts on the exhaust try and push over 15° into the 20's with seat angles on the exhaust and it will act like a reverse split cam but better.

 

[daves8]

Thanks for your replies guys…

let’s scrap that idea!

how would 216 / 224 / 114lsa fit my requirements I listed?
Another shop suggested this with Higgins heads

 

[shane_3800]

Thanks for your replies guys…

let’s scrap that idea!

how would 216 / 224 / 114lsa fit my requirements I listed?
Another shop suggested this with Higgins heads

Would go okay but you could get more if you went more duration. 216/224 is not a very big cam.

Small cams don't make more torque 99% of the time.

 

[daves8]

Would go okay but you could get more if you went more duration. 216/224 is not a very big cam.

Small cams don't make more torque 99% of the time.

My biggest priority is not pushing against brake with stock stall and minimal lope. I want a stealth cam with low down driveability

 

[shane_3800]

My biggest priority is not pushing against brake with stock stall and minimal lope. I want a stealth cam with low down driveability

Dude you can have more duration and do that lol.
Look at brian tooly cams.

 

[crew chief]

I have seen people getting good results with the Super Stock 2 from GM Motorsport its a 219 235 118lsa.
I run a 216/ 228 and in hindsight wish I went for the slightly bigger one