LS1Formulation

iTrader: (13)

Any reason why this cam won't work? I want a cam that peaks around 6200 RPM and lopes hard at idle with strong midrange. According to PianoProdigy's calculator, it'll have an 8.41 DCR and 14 degrees of overlap. Even with that much overlap, it should come on strong around 2000 RPM. I haven't seen too many people use sub 110 LSA's and I think it's the way to go on cams with short timing (under 228*). I don't believe this cam would work in an automatic car, I designed it to be a stick only cam. Narrowing the LSA is going to narrow the powerband but increase the power output within that range, which is an ideal situation for a close ratio 6-speed trans. Also, to add to my combo - the car will be getting an LS6 intake, ported TB and LTs/ORY at the same time. What do you all think?

LS1Formulation

iTrader: (13)

I must design cams too crazy to be commented on, lol.

s346k

iTrader: (4)

i think it depends on the use of the vehicle with this cam. a 6 spd + 342 gears and that cam? are you looking for a cam that lopes and peaks early? what are your goals?

redtail2426

iTrader: (10)

i say have it ground and install it,it makes sense that it should do what you stated,strong midrange and nasty idle..Just be sure to get it dynoed if ya do it,i would be interested in the grapf and how it looks.

jlashley2001ss

iTrader: (5)

im interested in what the cam guru's say about this cam spec. I bet this **** would "cam" hard!

LS1Formulation

iTrader: (13)

I have 4.10's, so I am not too worried about how "cammy" it will be at low RPM. I basically want a cam that rips in the midrange and peaks early, around 6200-6300, yet has a nasty lopey idle. It has 14 degrees of overlap, which would definitely give it a rough idle. To compare, a TSP 233/239 cam on a 110 has 15 degrees of overlap which if any of you have heard, sounds nice and mean. The big difference is, the 233/239 cam only has 8.02 DCR (installed on a 108 ICL) and mine has 8.41 DCR. My design will "come on the cam" a lot sooner than a 233/239, peak a lot earlier and produce better midrange, while still possessing the lumpy idle I'm going after.

LS1Formulation

iTrader: (13)

Any "cam guru" opinions on this cam?

pdd

iTrader: (3)

it will peak earlier than that. 38 ABDC is kinda early if you ask me. if you want to use that cam id go 107+1 and have BTDC 7 ATDC 7 39ABDC, but still too early for me, but to each his own

PREDATOR-Z

38 IVC with LS6/Fast intake will peak in the 5800 rpm neighborhood on a 346.
Also, not enough exhaust split for shorties. and it will die fast after peak.

No matter how you slice it, that is the dilema of running the stock SCR with regards to DCR.

I found the easiest way to beat it is to run a thinner head gasket (200$ cost if you get Cometics)
Run a .040 gasket and a 224/228 will be pleasant.

224/228 109/108 (LSA/ICL)

4>IVO
40>IVC
44>EVO
4>EVC
110>ECL
8* Overlap

Peak around 6000, carry well after peak for 6500 shifts, mega trq in midrange, 8* overlap for good power and nice rumble.

~10.69 SCR and 8.49 DCR (just by swapping gaskets)

LS1Formulation

iTrader: (13)

I think you missed in my first post about me adding LT's to the combo when I get the cam. That's why I only chose a 4 degree split. I also don't want to shift over 6200 -6300 rpm for fear of the stock rod bolts failing. I guess I should have been clearer about power peak compared to shift points. I already shift at 6K with the stock cam and it doesn't feel like power has dropped off significantly. I don't want to tear into the engine any farther than I already am because I can't afford to. When I can afford a set of heads, then I will, but the work involved just to swap head gaskets is too much. So far, it seems like this cam will do everything I want it to do, unless someone else can point me in a different direction with it. I looked at other cams that are popular, like the TR 224/224, and in my eyes, they don't seem optimum for a stock SCR engine. The TR 224 only has 8.28 DCR and that's on a 112+4 LSA. It's not going to make the torque down low that my design will.

PREDATOR-Z

It will only have ~8.21 DCR, stock compression is ~ 10.1 not higher, it will bleed off too much due to the size of durations and amount of overlap. It will be too peaky. You need to be able to use the most average power between shifts.
Not to mention it is gonna be a serious pain in the *** to tune due to the type of intake design we have. (surging and bucking)
But sometimes curiosity has to be satisfied.

LS1Formulation

iTrader: (13)

I was going by Piano Prodigy's calculator, which puts stock compression at 10.37 for some reason. Even so, that still makes a TR 224 even worse for DCR and that's a cam people swear by. I guess I hadn't taken into account the intake design when designing this cam, my experience has been based mainly in carburated gen 1 small blocks which behave quite well with narrow LSAs. Given that I don't want to spin the engine over 6300 rpm and the fact the engine is stock compression, I think the 226/230@.050 duration will work well, it's the LSA and ICL that are giving me fits. I honestly do not know what is going to work best. I want a cam that idles like a musclecar (more overlap) but pulls hard from 2500-6000 with a 6200-6300 shift point. I also want it to not be a total dog under 2500, but I do understand there are tradeoffs when it comes to running narrow LSA cams. What about setting it up with a 108+4 or a 109+4 LSA?

PREDATOR-Z

108/107 if you are dead set on those durations

6>IVO
40>IVC
44>EVO
6>EVC
109>ECL
12* Overlap

speed_demon24

iTrader: (6)

I'de run it.

jlashley2001ss

iTrader: (5)

look into a 110+2

LS1Formulation

iTrader: (13)

I think 110 is too wide an LSA for what I am doing here. I've been reading through David Vizard's book on camshaft theory over and over again and I really think having an unconventional (read: narrow) LSA will be beneficial. I think I am going to go with what Predator-Z said and have it ground on a 108+1 LSA. I will be sure to post up dyno graphs once I get it ground and installed, which probably won't be until April or May due to budget constraints.

GOaT Cheese

The tight LSA in the past was to mask poor flowing heads. The LSX heads flow so well that you can take advantage of a wide LSA (read low end torque). And why not shift over 6300? I know of about a dozen stock 6.0 GTO's shifting at 7000, with only a tune. Any doubt about the LSA question can be argued with the LS6 and LS7, those are very high output engines that spin to 7K+ and are on 118- 118.5 LSA's.

Ragtop 99

iTrader: (7)

14* of overlap is not going to make for great torque at 2000, even with 38* IVC.

I'd consider pulling it back a bit. A 220/224 108 108 will be dead by 6300 and have a better low end. Even a 220/224 109 109 might be a better choice.

LS1Formulation

iTrader: (13)

Try a 140K stock shortblock with marginal rod bolts. I am not rich. If my engine comes apart, I am screwed. I'm trying to keep it together for a longer period of time. Stock 1998 heads do not flow all that well and regardless of headflow, a certain amount of overlap is good for midrange torque production, which is what I am aiming for. Wider LSAs broaden the powerband and extend it, but at the expense of torque production across the board. It's a proven phenomenon. OEM's need to have those wide LSA camshafts for emissions reasons and to reduce harshness. Not many aftermarket camshaft manufacturers use such wide LSAs because they're not needed in most cases.

Ragtop 99 - I decided to have it ground on a 108+1, which has 12* overlap.

GOaT Cheese

Not trying to be an ******* here, but you are wrong about how the numbers affect torque. The wider LSA traps more cylinder pressure and generates alot more torque across the curve. The reason aftermarkets still use tight LSA's is for one simple reason...To sell camshafts. The tighter LSA have a radical idle, which sounds cool, but is killing low end performance, if you spend $600 on a new valve train, and it sounds exactly like the stock cam, despite huge power gains, you as a consumer will not be happy. The "lopey" idle that you hear with a tight LSA camshaft is the engine running so poorly at low RPM it can barely stay running, the cylinders are firing at erratic power levels.