Need Patrick G's advice on cam selction
 

Hey Patrick,


I was going X3/MS3 style but after reading all this stuff about low DCR and power under the curve Id like to optimize my cam choice. I could have a custom grind there is no problem with that.

I have a 2003 zo6 which is stock internally, but externally she has a intake and set of TPIS Longtubes. I am also using a TNT f1 kit and spraying a 100.

My ulimate plan is to have a heads and cam FORGED internaled 346ci motor.

Would like to make 500rwhp (with a set of AFRs or ETPs) or close to that with all the boltons and spray a 200 shot.

But for this season I am just upgrading the cam and vavletrain but leaving the motor stock. I would do the rest (heads and lower end) next season or so.

So what would be your recommendation on a cam that would work for me well.

Not a daily driver but driven alot. Dont want a drag only setup. But want something aggressive that will make me big power and under the curve and also on the bottle.

Thanks for you time and advice :)



-Zee

If you're leaning toward a drag setup and don't mind giving up some street manners, I'd recommend a high lift version of the T-Rex:

239/247 .649/656" 109LSA +1

....................... 0.006 0.050 0.200
Intake Duration - ID 289 239 164 2130 LSK Lobe .649 lift
Exhaust Duration - ED 297 247 171 2132 LSK Lobe .656 lift
Lobe Center Angle - LSA 109 109 109
Intake Centerline - ICL 108 108 108

Intake Valve opens - IVO 36.5 11.5 -26 BTDC
Intake Valve closes - IVC 72.5 47.5 10 ABDC
Exhaust Valve Opens - EVO 78.5 53.5 15.5 BBDC
Exhaust Valve Closes - EVC 38.5 13.5 -24.5 ATDC
Exhaust Centerline - ECL 110 110 110
Overlap..................... 75 25 -50.5 degrees

Thank you!
But would this work well with heads in the future?
I dont want to fly cut pistons.
If I wanted slightly better drivability?
Its definetly more of a street car than drag car.

Those specs soundbut badass maybe a little to big?
You tell me how a cam like that would work on the street for driving. Surge below 2k?
Where would this cam bring my DCR up to.



Others can input what they feel also.

Thank you!
But would this work well with heads in the future?
I'm recommending this cam based on future heads more than current stock heads.
I dont want to fly cut pistons.
You mentioned forged internal in future. Forged pistons typically come with valve reliefs. You won't need to flycut with stock heads, but with ported heads, big valves and small combustion chamber, you'll definitely need valve reliefs.
If I wanted slightly better drivability?
You can so smaller, but you may want to give up your goal of 500 rwhp with 346 cubic inches without a power adder.
Its definetly more of a street car than drag car.
Seemed more drag oriented by your first post.
Those specs soundbut badass maybe a little too big?
You tell me how a cam like that would work on the street for driving. Surge below 2k?
It would be OK with a very good speed density tune. I wouldn't want to drive it every day. It's more for a weekend toy and race oriented car.
Where would this cam bring my DCR up to?
With 11.5:1 static compression, your DCR would be around 8.6:1. Perfect for lots of area under the curve.

Ok thanks alot for you time again. Very much appreciated.

If you were to go with the same idea but wanted a little more streetability what would you use then?
I am willing to give up the 500rwhp for a close to # with more streetability.

I see with your street cam your at 470+rwhp.
Would it be the cam your using now or is there something in between you could spec out. ;)

239/247 .649/656" 109LSA +1....

This cam would fit under 243 heads w/out notching the pistons???
that split in duration sure would love some nitrous...

Can you get the cam you mentioned on LSK lobes?

the higher lift version of the trex patrick posted is on lsk lobes.

so why can more lift be used with lsk lobes and not xer lobes?

The LSK lobes are ground with a more aggressive ramp rate after .050". They're just more aggressive...and not for everybody.

hrm, i must be missing something then. i thought max lift was exactly that - max lift, regardless of the ramp rate or duration, lsa, etc...the valve would only actually lift .x inches from the head...?

i am guessing the valve closes faster with these aggressive ramps? is that what you're telling me? which would technically allow it to hang open - farther - longer?

judging by those specs (and others), if i custom ground a 238/246 .620/.625 on a 108+0 using lsk lobes, i would have no ptv issues on a stock headed motor?

Well the faster ramp rate means that the valve will open and close quicker which allows for the piston to be down far enough so that the valves wont crash.

That cam is going to be tight with a stock head, but it should fit. The exhaust is the main thing I'd be a little worried about.

Thats a bigass cam. I run an F13 and I wouldn't want to go much bigger than a 232/236 after driving this around. But then again I value drivability more then a magic number.

500hp on a 347 is not a super drivable combo. Unless you put some big money into the setup, that is not something you can just slap together and drive 60 miles a day and enjoy it. JMO.

And yes, Patrick did it, but he also didn't throw that combo together ;)

so all this being said considering the ramp rate, how large of duration and lift would one be able to go without PTV issues?

PM feature not working ?
:jest:

i don't want to get into the cam argument...but i am concerned with the cam's performance between 5-7k, that's it.

you had more lift and more duration on the other cam...so i assume the lsa is now becoming an issue?

what kind of springs would go along with that cam with such high lift? 921's?? how long would they last as well??? those lsk lobes sound bad ass

Ordering cam...
want something in between yoru current cam Pat and this monster!

????

Street Street/Drag Drag
your 228 cam ? 239/247 high lift.



Im thinking something along lines of 23x 23x with high lift #s...

i'll have some numbers of my cam her in a few days, i'm running a 227/231 on a 112 + 2 on lsk lobes. Tho it ended up specing out to a 229/233.

A 231/235 on a 110 would be a reall mean cam using LSK lobes.