Tin Indian

Whats your opinion of this hypothetical cam selection in a stock block, your average 2.02" 1.57" valved Stage 1 heads, LT headers/w Cats car.

Two cams... Both 220 duration, both 114 LSA

One with the new fast ramp/high lift "XE-R" .565"+ lift cam vs the same cam with the older "Xtreme RPM" .530" lift.

My thought is that the [high lift/fast ramp] cam will produce maybe 5-8 more rwhp at the top of the rpm curve, but loose maybe 10-15 Ft Lb torque in the 2,500-3,000 rpm range to the [lower lift cam].

If I am correct, do you believe the lower lift cam may be a better selection for a daily driver NA-no NOS heads/cam/header car?

And, how about valvetrain longivety (ie: springs, stock rockers) between the two cams?

Ron,
(Korea)

WILWAXU

iTrader: (6)

Ron.. this would do better in Internal Engine (Cam Experts) <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Tin Indian

Thanks John
I thought I was in the "internal" section. Old age makes me very very confused sometimes! Time to take my nap...... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

LS1derfull

Kimchee and rice, higher lift cam would not trade torque or power over smaller lift cam, the only real exception to this would be if Hi lift ramp had larger seat duration(unlikely). I am running .578"/.578" and 220*/220* on a 112* with 918 springs and i dont believe there will be any reliability issues with it.

Tin Indian

LS1derfull......

Well, from what I have read from previous threads, I certainly respect your input.

Deep inside, I agree with you, but something keeps telling me that these .560" + lifts are going to play hell with the valvetrain somewhere down the road.

I am torn between a lobe #3752/3752 CompCams 218/218 .527/.527 cam and the MMS 218/218 .561/.561 (both on a 114 LSA)

Maybe in my "perfect world", I could get CompCams to grind something in between. How bout a 218/ 218 .540"/.540" 114 LSA? <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

And, valvetrain noise would have to be much noisier with those big lift cams. Dont ya think?

I dont know, but I just have the feeling the big lift cams ain't going to give trouble free service for 80,000 miles + like the cam I have talked myself into using.

Hell, maybe I am wrong......

Ron,

LS1derfull

Ron, my valvetrain is acceptably louder with my custom grind Comp cam. I think what you have to realize is with lS1 cam size(lobes and journal) the design doesnt really have to work that hard to achieve bigger lifts and its ability to distribute load on larger components builds in reliabilty. You cant judge against old style SBc cam grinds when comparing with these Gen 3 cams.

LS1derfull

The only valvetrain reliability issue that concerns me is the way stock rocker arms lose the end retainers occasionally on ls1. I believe its from valve float and too much spring pressure. The valves and other components are featherweight on Gen 3 motors and i think many over spring their set ups. Sideloading and deflection is what kicks retainers off the sides of rockers IMO.

LS1derfull

Ron for what its worth my lobes have seat duration of a 224* at .050" Extreme grind and i would say my cam is not compromising low speed power or rough at idle, if you went 224 0or 226* on a 114* you could expect the same with more top end than me.

TimZ28

The XE-R lobe is going to have less duration at 0.006" than the other cam and will have more area under the curve. It will make more torque than the other camshaft assuming everything else is equal (intake center line and lobe separations).

Tim

MyLS1Hauls

iTrader: (2)

Kimchee-

How about this CC setup...218*@.050" 267*@.006" .537" I dont have the lobe numbers, but comp can give you that info. I think that the .537 lift is perfect. Right inbetween safe and maybe sorry.

Brad

Jason99T/A

iTrader: (21)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by TimZ28:
<strong>The XE-R lobe is going to have less duration at 0.006" than the other cam and will have more area under the curve. It will make more torque than the other camshaft assuming everything else is equal (intake center line and lobe separations).

Tim</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Tim is exactly correct. This is why the TR224 (and other fast ramp cams) are making more power everywhere compared to cams with smaller duration at .050 lift. Even though they are bigger at .050, the are actually smaller at .006. This helps with driveability, etc. The valve is staying on the seat longer, thus building more cylinder pressure.

VINCE

iTrader: (1)

What they said.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

SStrokerAce

iTrader: (2)

CC 220 Lobes

Adv .050 .200 Lift Lobe
274 220 134 .530 Xtreme RPM
273 220 138 .564 LS1 High Lift
269 220 143 .581 XE-R

I would go with the middle one.

Bret

VINCE

iTrader: (1)

Why would you go with the middle one? Lift too high or something?

SStrokerAce

iTrader: (2)

The cam is seems to be what he is looking for. The XE-R lobes are very steep and need extra maintenence to keep them going. The best comprimise is the middle one.