Custom Cam...

[Superdave]

(For the Cam gurus)

How does this sound for a custom grind for a P&P'd 3400...


@cam 306 in/310 ex
@valve 490 in/496 ex
Dur @ .050 216 in/228 ex
110 LSA

It's similar to the H272-2 but i changed a few things to keep the lift down since i'm using LS1 springs. From what i've seen the stock LS1 cam lifted .496 at the valves (depending on years).

thanks for any feedback.

[geoffinbc]

Myself I would widen the LSA to 112. It will get you more vacuum and a smoother idle witch the EFI system will thank you for. Also it will be a little better for driving.

Otherwise looks good. If you ever plan to boost it then widen the LSA even more to 114 or 116

[Superdave]

Myself I would widen the LSA to 112. It will get you more vacuum and a smoother idle witch the EFI system will thank you for. Also it will be a little better for driving.

Otherwise looks good. If you ever plan to boost it then widen the LSA even more to 114 or 116

No boost in the future.. just N/A.

How hard do you think it'll idle @110? I wouldn't mind a nice lope.. haha


the XR270HR i have in my 355 is just a little larger with a little more duration and a 110 LSA and it's not by any means smooth idling but it's not bad at all.. i don't have any vacuum problems either.

[geoffinbc]

Yea but its not EFI. EFI relies alot on a steady vacuum signal especially at idle.

So you could do it but you may find the engine hunting at idle. Its not such a bad thing just more of a thing you need to live with. ECM tuning will be a must for any cam with that much duration. A good tuner will be able to really make a cam like that work well.


Oh and I think you should upgrade your valve springs even further.

[jp_grasshopper_007]

Re: Custom Cam...

(For the Cam gurus)

How does this sound for a custom grind for a P&P'd 3400...


@cam 306 in/310 ex
@valve 490 in/496 ex
Dur @ .050 216 in/228 ex
110 LSA

thanks for any feedback.

how about:
Dur @.050 220 in/228 ex
Lift .515 in/525 ex
106 LSA

If you are going to stay n/a and can find someone kickass at tuning
(sappyse107/Ben) that would be a sick cam. With LSA that tight you wil get alot more power and unreal rev. speed.

[Rhedalert]

I've got a mild regrind in my 3400 .460/.460 lift at the valve, duration @ .050 210/218 with a LSA of 112, and I still have a lopey/hunting idle. It's liveable but can occasionally be a hassle when first starting the car (may stall)

[SappySE107]

Odd enough, the simulations in dynomation seem to like 105.5 LSA. I figured I had something screwed up but I haven't figure out what if anything. Before it was showing good with 112 on my laptop but I haven't messed with the program in a while since ive been busy with heads.

I read that it was best to use flow numbers with the intake manifolds on and exhaust manifolds but that has been showing me 3400 hp stock power of about 120 hp. Yeah...um..sure?

[Scott_68B]

Re: Custom Cam...

@cam 306 in/310 ex
@valve 490 in/496 ex
Dur @ .050 216 in/228 ex
110 LSA

Just curious, is this possible to achieve with a regrind if the LSA was left at 112?

-- Scott

[geoffinbc]

Odd enough, the simulations in dynomation seem to like 105.5 LSA. I figured I had something screwed up but I haven't figure out what if anything. Before it was showing good with 112 on my laptop but I haven't messed with the program in a while since ive been busy with heads.

I read that it was best to use flow numbers with the intake manifolds on and exhaust manifolds but that has been showing me 3400 hp stock power of about 120 hp. Yeah...um..sure?

Ben whats your IC on that thing? an LSA of 110 and an IC of 105.5 would be belivable. But a 105.5 LSA and (im asuming) an IC of 105.5 sems very narrow and would suck big time on the torque curve. It would make torque but only for a short time. Also what is the duration? Same as posted above?

[Superdave]

I've got a mild regrind in my 3400 .460/.460 lift at the valve, duration @ .050 210/218 with a LSA of 112, and I still have a lopey/hunting idle. It's liveable but can occasionally be a hassle when first starting the car (may stall)

Do you have any sound clips or video of it?

@cam 306 in/310 ex
@valve 490 in/496 ex
Dur @ .050 216 in/228 ex
110 LSA

Just curious, is this possible to achieve with a regrind if the LSA was left at 112?

-- Scott

You could get close... IIRC about 470-480 would be about max on a regrind because of all the material that's gotta be removed. it's too bad the stock cam is hollow...

I talked to Milzy and he said he could grind me this cam, but the price is a little over my budget. I may just go with a smaller regrind. I just need something to compliment my port work and headers. :P

[SappySE107]

I dont know what any of the specs were in the simulation anymore. Ill try it again later this week if I have time.

Regrinds can get you well over 500 lift. Check out GPSE3400's thread about his 14.9 run. He lists his regrind specs and im sure its like .53x lift. Crane did his regrind and its a hell of a lot less than a milzy (cammotion) cam.

[SappySE107]

Crane Cam regrind. IN.524, EX.539, duration@.05 I230, E236.

That is what lorenzo runs.

[Superdave]

Crane Cam regrind. IN.524, EX.539, duration@.05 I230, E236.

That is what lorenzo runs.

nice...

so i guess i could have Crane grind my specs into the stock cam then. I'll call them tomorrow and get a price. :P

[AaronGTR]

I wouldn't go with a 110 LSA either. A bit too low for EFI. You'll need tuning anyway, but with that low an LSA you'd probably need to increase idle to like 1000rpm to keep it happy.

For valve springs I also would recommend something stiffer than LS1 springs. They are only a tiny bit stiffer than stock LA1 springs. You have to remember that there's more than just lift. If you're increasing the duration a lot you are going to have much faster ramp rates and that is what really is going to make the lifters jump off the lobes and make your valves float, especially at higher rpm. I'd get LS6 springs or comp's.

[Superdave]

Well, since it's a regrind it'll have to stay 112 LSA. Moonwell and I ran a symulation in Desktop Dyno and it showed about a 40-45 HP gain.. i'm gonna run it again because i realized i forgot a few things (headers) so we'll see..