Ramp rates advice please

[weSS1LEy]

Trying to spec a cam, said I still want it to have decent street manners. Comp recommended a mild cam because he said most big cams “beat the hell out of the valvetrain”.

So does the lobe profile determine the ramp rate? Is it possible to get a bigger cam that won’t kill my valves?

He recommended a 222/234 .566/.576 113

I was hoping for bigger than that

[0331Marine]

Talk to GPI. Their SS3 is people the top selling cam out there.

[acammer]

Originally Posted by 0331Marine

Talk to GPI. Their SS3 is people the top selling cam out there.

Agree - GPI is responsible for well over half the N/A cars on the SBE fast list - that's not a coincidence. I have an SS3 going in mine next month - looking forward to making some strong NA power.

222/234 .566/.576 113 is fairly mild. It would be a noticeable gain over stock, but leaves a lot on the table. Cam selection really needs to be a working backwards process where the cam choice comes last - define your goals, consider all the other parts in the build and then back into what cam suits the rest of your parts, and your goals.

For me, I want to make as much as N/A power (as evident by trap speed, not dyno numbers) as I can without pulling the heads. The GPI SS3 is about as much as you can hope to reliably get away with in the PTV clearance area, and the track results speak for themselves. And once you get a taste of the service you get from Aaron, Ryan, and other guys at GPI, you'll never want to give you business to anyone else.

They do have an SS1 and SS2, which are a little less aggressive while still offering outstanding performance.

[weSS1LEy]

My tuner says he likes comps lobes/ ramp rate. What does this mean? I’d ask him but he’s a one man shop and hard to talk to.

[acammer]

Originally Posted by weSS1LEy

My tuner says he likes comps lobes/ ramp rate. What does this mean? I’d ask him but he’s a one man shop and hard to talk to.

Ramp rate talks about how aggressively the camshaft accelerates the valve train, in all directions (opening the valve, stopping the valve open, starting the valve closed, and stopping the valve on the seat). You'd have to ask your tuner what he likes about Comps ramp rates - I'm guessing by the initial comments he finds them sufficiently gentle as to not be a concern for premature parts wear or failure.

I would posit that many of what are considered the more aggressive cams currently available (ie. GPI SS3, TSP F35, BTR STG4, etc) are still ground in such a manner that keeps a properly upgraded and maintained valve-train pretty happy. We don't see a big rash of lifter or spring failures that would be indicative that these cams are terrorizing the valve-train. There are a lot of guys on the forum running these units in daily driven cars that have put tens of thousands of miles on them.

It's important to understand that a cam with what's considered a lot of duration and lift (ie. 23x/25x in the low-mid 600's) may be fairly aggressive in the duration and lift department, but still have reasonable ramp rates that make it a good choice for something that still sees lots of street miles.

There is some good reading here about ramp rates:

https://ls1tech.com/forums/generatio...cam-lobes.html

[acammer]

Again - you need to work backwards from what you want out of the car. That will dictate the type of cam you should be looking for. 222/234 .566/.576 113 would be a fairly mild cam. It would make more power everywhere and have pretty decent manners. But there are definitely other options out there that would make substantially more.

[weSS1LEy]

Thanks very much acammer, my tuner likes comps lobes because he can tune them easily he says. I’ll have to have a better consult with him. Also Aaron at gpi has been very helpful considering I haven’t bought anything yet. Seems like he knows what he’s talking about!

[acammer]

Originally Posted by weSS1LEy

Thanks very much acammer, my tuner likes comps lobes because he can tune them easily he says. I’ll have to have a better consult with him. Also Aaron at gpi has been very helpful considering I haven’t bought anything yet. Seems like he knows what he’s talking about!

Aaron is the man - he genuinely cares about the people he's serving, and shoots straight with you. Those guys over at GPI are really right out on the cutting edge of LS3 cam design. They continually update and enhance their cam specifications as they learn more and more. Again - there is a reason they are comfortably situated as the majority on the fast NA list - they've got a few things figured out ahead of their competitors.

Happy to help - I love this stuff. This thread had me take a much deeper dive into ramp rates over the last 24hrs. I don't think I learned too much I didn't already know, but it's been enlightening.

[racesloth]

Cammotion lobes are easy on the valve train. Stay with something in thee 226/227 deg intake to help maintain low end torque....

[acammer]

GPI cam's are on a proprietery Cam-motion lobe. They discuss it in a little more detail in this thread.

http://www.camaro5.com/forums/showthread.php?t=486079

[frankwjr]

Pat G.'s https://www.guerragroup.com/motorsports custom lobe designs are better than Comp and ground on Cam Motion cores by license...even with high lift the valve train stress is less. And the cam is spec'd to YOUR car...for $25 not a bad deal.

me thinks your tuner needs to open their eyes a bit...sayin u can only tune a specific ground cam is weird.

good luck OP...peace.

[DRKS1D3]

Here is a video of my car. It's a custom ground cam from Lunati, installed by CSP in West Chester, PA. Solid street manners (slight bucking at low RPM), great cam lope and a linear power curve. 227/235 .619/.626 114 +3 455hp/435 torque

Good luck!

[frankwjr]

Originally Posted by DRKS1D3

Here is a video of my car. It's a custom ground cam from Lunati, installed by CSP in West Chester, PA. Solid street manners (slight bucking at low RPM), great cam lope and a linear power curve. 227/235 .619/.626 114 +3 455hp/435 torque

Good luck!

nice...what's the rpm idle? tks!....peace

[DRKS1D3]

Originally Posted by frankwjr

nice...what's the rpm idle? tks!....peace

Once warmed up, she idles at ~800 rpm.