LSOHOLIC

iTrader: (3)

Hello there, I've been searching for a thread or post on LS engine lobe tech. And it seems there nothing out thread, so I figured I start one.

For me, I'm some what tech savvy but could still stand to learn more about the secrets of lobe dynamics. I'm freshening my top end and getting the heads worked. So in doing so I'm considering a cam change to take advantage of the new higher CR and improved flow.

And thats what is propting my curiosity in the lobe designs. There are so many to choose from, I will be using a top engine/ cam guy but still would like to be educated on the parts going into my engine.

1)LSL
2)LSK
3)LSR
4)XE
5)XER
6)XFI
7)EPS
8)HUC
9)ect...

Just to be clear, I'm only interested in hydr. roller cams.

My question is; has any one put these different lobe designs (with same; INT Open, INT Close,EXH Open, EXT Close, and with all other specs being equal ) in a cam doctor to check ramp rates at specific areas (.006, .050, .200, ect..).

I'm really interested in the new HUC lobes but theres not much info floating around.

Thanks...and I'm looking for an education..

GoatPilot87

Bump. I'd like to pay close attention to this thread, as I also would like to understand more about the ramp profiles, and lobe designs. If I read them I understand, but sometimes its just better to have "real-world" experience from some guys that have tried one or the other and might have dyno printouts to show changes in RPM band or so on. Good post. Looking forward to info. generated on this one.

LSOHOLIC

iTrader: (3)

HUC lobes, hello.....anyone outthere ??

LSOHOLIC

iTrader: (3)

I thought this was the advanced section ?? I'm just trying to understand ramp rates and lobe profiles not string theroy or quantum physics.

Hemi2Slo

Ha I've noticed on here that a lot of the folks that know a lot don't wanna share their knowledge, they just wanna say "do a search" or just don't post. I wouldn't mind to know about this either. I can understand your frustration. I saw a thread on lobe designs somewhere but I can't remember if it was on here or another site.

Hemi2Slo

Check out this thread, I can't copy and paste on my phone, but search for this thread, Camshaft Theory: Lobe Design. I don't know if it will completely answer your question, but it'll be a start I think.

LSOHOLIC

iTrader: (3)

Thanks for the lead...the lobes I'm reffering to (HUC) are some what new, I think. FYI, they are in the back of the new Comp. catalog.

LSOHOLIC

iTrader: (3)

And just FYI, I did a search but theres nothing definative on lobe tech (at least not in one thread). IMHO, there should be a sticky on ongoing data pertaining to lobe tech. Because inevitably thats what seperates the players from the wannabes (in terms of camshafts).

Thanks....and I truly understand how propriatary this info can be. But just wanting.....a little .

WKMCD

iTrader: (2)

Why only hydraulic lobes???

Some people run solid lobes with hydraulic lifters.

Don't even think about doing it they other way around.

A.R. Shale Targa

iTrader: (2)

Admittedly I'm not familiar with the new HUC lobes, however the trend of
agressivness continues. More rise over the run (faster lifter acceleration)
I would imagine that at some point the hydraulic lifter will become the
limitation. Apparently the LS engines intake valve closing point finds it's
sweet spot @ 43-45 degrees ABDC. My thought is this has alot to do with the
intake manifold and port design which GM tried to duplicate a stepped cross
sectional area similar to racing headers only on the intake side. It starts large
and gets smaller(area-wise) as it approaches the bowl to enhance velocity
and promote a blend of tumble and turbulance but not too much of either.
This is to keep the fuel molecules more like mist than droplets since until direct-injection becomes common the port has to flow air AND fuel.
Also the LS cam cores were a unique diameter 15yrs. ago it required retro
fitting other lobes like from Ford cams. However as this engine continues it's
hot-rodding popularity these companies are designing lobes specifically for the
application. Geoff @ EPS is very informative with describing how .050, .200,
duration #s and the smooth control of opening and closing rates (which can
differ on the same lobe) all plays a vital role in making power as well as
extending valvespring life.....hope some of this helps

Hemi2Slo

That was great info. That makes a lot of sense. I need to do some very extensive research looks like.

LSOHOLIC

iTrader: (3)

Whats going on Kevin ?? And thanks A.R. Shale Targa for the detailed break down.

Its been a interesting day, I've talked to Bullet, Cam Motion, LSM and Comp. about my current cam and lobes. After talking to Comp about lobes it seems the HUC is not really what I expected. They say it was designed for a lazy valve train, something that has heavier valves and in a marine application. The way the ramp designed was explained to me is, the lobe allows for the valve and springs to be "gently" sat down. A way of controlling a heavy valve train at higher rpm's. Sound like the opposite of the LSL's if you ask me, but I'm not a cam expert.

The reason I started this thread was to get a little insight into the lobe tech to see if it was worth a cam upgrade while the top end is off the motor. After talking to these gentleman it seems there would not be much gain if any from my current combo.

If anyone is interested I would be more than willing to spill the beans about the cam data to see if you guys think I should change cams to accommodate the new found CFM.

Again, thanks..

Stage7

iTrader: (1)

HUC lobes are not new. They work pretty well if the valve train is setup well.

LSOHOLIC

iTrader: (3)

OK.....whats not new ?? If I remember right Comp said they have been out like a year or something. Is there a newer lobe design out since the HUC's ??

Hey, Stage 7 whats your take on the HUC lobe as described to me by Comp. ??

Stage7

iTrader: (1)

I guess it's perspective. 1+ years isn't new to me. The engine in my sig uses HUC lobes. These lobes are very stable. I'm not sure what you were told regarding ramp rate, etc, but they were intended for marine based apps.

LSOHOLIC

iTrader: (3)

Stage 7...you have a PM.

01ssreda4

iTrader: (96)

what did Cam Motion say about their lobes when you spoke to them?

Wicked94Z

iTrader: (26)

I don't really dabble in the 55mm stuff, but just off the seat .050 .200 values, the HUC doesn't look to have that much area especially when you consider the base circle it will run. I've been running hydraulic lifters on solid lobes for the last 3 years with good success.

racer7088

HUC is not new at all like Stage 7 said, it just wasn't in the catalogue till recently.

Most of the faster lobes in that list are not that good unless you have ultra light stuff and don't turn too much rpm.

LSK for instance is one of the worst in general. I have seen that lobe lose over 40 hp across the top of some engines.

GIGAPUNK

iTrader: (2)

Erik, Is the 40hp loss you're refering to, generally when an LSK is used on a large intake valve AND over 7000 rpm? In your experience are the LSK fine on exhaust side under 7000 rpm?