ssbandit158

iTrader: (3)

I ordered a comp cam and they sent me a 224/224 .581/.581 112lsa ---- They got everything right but the lift. I needed a .550/.550 due to the fact I have 1.8 rockers so the end result was suppose to be a .581/.581. Im in the middle of a turbo set-up and was wondering what the effect of my lift being 615/.615 now with the 1.8 rockers... Would I have clearance issues, driveability issues or would this be ok? I have 317 heads on a stock ls1 block and springs that can handle .650 lift. Thanks for any help in advance.

XtraCajunSS

iTrader: (2)

If you are stock heads, gaskets, and pistons, you will be fine. Maximum lift is NOT the determining factor when checking P to V. Duration and acceleration on and off the seat are the determining factors. The only issue you will probably have is valve float depending on what lobe family you are using, how much boost the back of the valves will see and which rockers you are using. Those sound like XE-R lobes which will be fairly hard to control with the 1.8 ratio especially when you add the boost to the equation. At this point it all depends on what kind of RPM you are shooting for.

Shane

ssbandit158

iTrader: (3)

This is just an XE lobe not XE-R, so hopefully thats ok. My main concern with .615/.615 lift is how my car will run/drive and where the power will be coming in. Im not planning on running the RPM's past 6500 and Im just curious as to what the performace characteristics are between a .581/.581 lift cam and a .615/.615 lift cam on a turbo set-up. Thanks for the help.

PREDATOR-Z

Shane is correct, I agree with him.

.581 lift is XE-R, lobe 3722
.534 lift is XE low lift,lobe 3753
.568 lift is xe high lift,lobe 3715

With those lifts and XE-R ramp rate I do not recomment 1.8 rockers (especialy in boost situation). Ramp rate is too harsh to do that and valvetrain instability is imminent.
Either change cam or rockers, personaly I say rockers.

ssbandit158

iTrader: (3)

The lift I ordered was .550/.550 which I was told is an XE lobe. They sent me the wrong lift and Im assuming wrong lobe, So with that much lift the 1.8 rockers will do what to hurt my performance? I guess I will be sending this cam back to get the correct XE lobe..

PREDATOR-Z

Do you have a cam card? Can you post a pic of it!

I think that by now we understand that you ordered a 224 cam on .550 lift.
We are telling you that .581 lift is XE-R lobes (very agressive). They do not work with 1.8 rockers
I posted above the lobe numbers for XE.
THERE IS NO XE LOBES WITH .050 lift, it is either .568 or .534

Seing that you are boosted, with 1.8 rockers, I would use the .534 lift.

THAT IS LOBE # 3753 (Both intake and exhaust).

Please do not ask what it will do for your performance again.
.581 lioft XE-R DO NOT WORK WITH 1.8 ROCKERS IN BOOST SITUATIONS>

IS THAT CLEAR.

(Sorry I think I just lost my )

vettenuts

iTrader: (4)

Personally, with the parts you have in hand and your planned installation, I would send the rockers back.

PREDATOR-Z

Exactumundo....

XtraCajunSS

iTrader: (2)

Stock 1.7 GM rockers are your friend...

Hope this helps.

Shane

ssbandit158

iTrader: (3)

Sorry about all the questions, Im in the middle of a build and new to turbo's and just want to do it right the first time instead of just slapping parts together. I didn't realize that 1.8 rockers and XE-R lobe wouldn't work together at all, which is why im glad you chimed in on that. I just re-ordered my cam on a .534 xe lobe, so hopefully everything will work out good, thanks for the input!