L67 camshaft choice discussion

[vHell83]

As the subject states, I'm in the market for a new cam.

The engine is an l36 bottom with l67 top swap.
Blower is ported internally and externally with u bend porting and ls1 tb and maf with 4" intake.
3 inch pulley with plans to drop down later on.
E85 and 5 speed manual.

Now the question is out of the cams listed which is going to be the best one to use with boost and why? I'm not good with cam specs just yet so forgive me if I sound a little silly.

This Is my current cam


And the ones I'm looking at

Xp hotcam aka mace stage 2 605 with 1.7 or 1.8 rocker ratio (unsure what one would be better)


The Clive cam grind


The camtech grind


At first, I wanted something very lopey hence the 108 lsa, now I want performance and efficiency over lope.

[vlad01]

I think the XP looks best suited, the 2nd last clive is a big cam, though its suited for full out NA race engine, looks to a be saloon series specs.

cam tech is meh, mild NA cam

Your cam isn't bad if the LSA was only wider, say 113-116º and dialed in center line.

[The1]

depends how you want to drive it as well and where you want peak torque.

[0081]

I run the XP Hot cam, not a bad cam and I'm making decent power with it.
If I had to choose a cam again i would have gone something that would make a bit more power

[madmaxisback]

Check this site out: https://zzperformance.com/3800/supercharged-cams-1.html
Their XP Hot cam would be fun I think!
Or nasty NIC cam:
https://youtu.be/Zx32S-dz18o
(note it didn't start first pop)

I agree with Vlad if picking from that list you have.

The specs you want vs. what your engine wants is most important when choosing a suitable cam. Big lumpy idles with boosted combos tend to be a bit of a pain to tune and keep happy, this will probably equal lots of fuel being used at idle... Gotta weigh up what you want the engine to do and where it will end up going mods wise before pulling trigger on the right one I think.

[vHell83]

Check this site out: https://zzperformance.com/3800/supercharged-cams-1.html
Their XP Hot cam would be fun I think!
Or nasty NIC cam:
https://youtu.be/Zx32S-dz18o
(note it didn't start first pop)

I agree with Vlad if picking from that list you have.

The specs you want vs. what your engine wants is most important when choosing a suitable cam. Big lumpy idles with boosted combos tend to be a bit of a pain to tune and keep happy, this will probably equal lots of fuel being used at idle... Gotta weigh up what you want the engine to do and where it will end up going mods wise before pulling trigger on the right one I think.

That's the cam I posted the specs to. Zzp xp hot. Friends use the cam and run tiny pulleys uncooled with e85.

The next question after a xp hot would be what rocker to bundle it with, some say 1.8 is too big for the cam and that 1.7 will work better. I've got .610 lift atm with my cam and I just find that down low it can be a little sluggish at times.

My current cam is nastier than the nic and it always starts first go every time. I found with too much crank fuel it would pop and start like crap where with too little it would take forever to fire over and need throttle to fire up. With the right fueling at all temps it was first turn, so I took a little out at cold so it could crank for a bit and build oil pressure.

[vlad01]

imho that lift is pretty excessive, even good ported heads don't flow that well at those lifts and would be loosing velocity as its entering the cylinders at low rpm.

On the other hand completely reworked ZZP alloy heads do though But I mean completely reworked, they are pretty shithouse out of the box but at least better than moderate to a good (but not all out best) cast irons ones. The factory buick heads when fully developed well outperform the best ecotec factory heads despite having much smaller valves, just the nature of ecotec/L67 heads, not the best factory design of the V6 family.

I would go for 1.7 but even 1.6 will work nice. Huge rocker ratios aren't good for valve train reliability and longevity.

Mid to high 500 thou is as far as I would go for good reliability and best power, going over 600 is minimal gain for a lot of compromise. Key is getting enough lift before gains dry up and working on the right duration, relationship of the lobs and overall timing.

[vHell83]

imho that lift is pretty excessive, even good ported heads don't flow that well at those lifts and would be loosing velocity as its entering the cylinders at low rpm.

On the other hand completely reworked ZZP alloy heads do though But I mean completely reworked, they are pretty shithouse out of the box but at least better than moderate to a good (but not all out best) cast irons ones.

I would go for 1.7 but even 1.6 will work nice. Huge rocker ratios aren't good for valve train reliability and longevity.

Mid to high 500 thou is as far as I would go for good reliability and best power, going over 600 is minimal gain for a lot of compromise.

Yeah I Been thinking about 1.7s too over the 1.8s. If rockers weren't so expensive I'd love to put them both on and see the figures produced on the dyno, atm I've got 1:98:1 rockers.

[immortality]

Work out what rocker ratio gets you closest to your current total lift. A good roller rocker really would be a must at higher valve lifts to negate wear issues.

XP lobe lift is .325/.335 so with a 1.8 rocker you would end up with .585/.603 valve lift.

You current cam is probably a bit sluggish because it's a n/a cam with relatively tight LSA so you end up blowing a fair bit of boost out the exhaust valve on overlap.

[madmaxisback]

Check this site out: https://zzperformance.com/3800/supercharged-cams-1.html
Their XP Hot cam would be fun I think!
Or nasty NIC cam:
https://youtu.be/Zx32S-dz18o
(note it didn't start first pop)

I agree with Vlad if picking from that list you have.

The specs you want vs. what your engine wants is most important when choosing a suitable cam. Big lumpy idles with boosted combos tend to be a bit of a pain to tune and keep happy, this will probably equal lots of fuel being used at idle... Gotta weigh up what you want the engine to do and where it will end up going mods wise before pulling trigger on the right one I think.

That's the cam I posted the specs to. Zzp xp hot. Friends use the cam and run tiny pulleys uncooled with e85.

The next question after a xp hot would be what rocker to bundle it with, some say 1.8 is too big for the cam and that 1.7 will work better. I've got .610 lift atm with my cam and I just find that down low it can be a little sluggish at times.

My current cam is nastier than the nic and it always starts first go every time. I found with too much crank fuel it would pop and start like crap where with too little it would take forever to fire over and need throttle to fire up. With the right fueling at all temps it was first turn, so I took a little out at cold so it could crank for a bit and build oil pressure.

Yep. Same same.

Mostly suggested the link as there is some good info on that site about rocker ratios, what works and what doesn't etc.

Sounds like your onto it mate. I personally like my engines to rev hard and fast without any delay and choose cams that give me that.