226/230@.050 .585/.592 107+2 Lsa
#1
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Joined: Apr 2006
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From: Grand Rapids, Michigan
226/230@.050 .585/.592 107+2 Lsa
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?
#4
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.
#6
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Joined: Apr 2006
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From: Grand Rapids, Michigan
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.
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#8
Originally Posted by LS1Formulation
I basically want a cam that rips in the midrange and peaks early, around 6200-6300,.
Last edited by pdd; 12-31-2006 at 08:28 PM.
#9
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)
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)
Last edited by PREDATOR-Z; 01-01-2007 at 02:57 AM.
#10
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From: Grand Rapids, Michigan
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.
#11
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.
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.
#12
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Joined: Apr 2006
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From: Grand Rapids, Michigan
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?
#16
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From: Grand Rapids, Michigan
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.
#17
Originally Posted by LS1Formulation
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.
#18
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.
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.
#19
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Joined: Apr 2006
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From: Grand Rapids, Michigan
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.
Ragtop 99 - I decided to have it ground on a 108+1, which has 12* overlap.
#20
Originally Posted by LS1Formulation
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.
Ragtop 99 - I decided to have it ground on a 108+1, which has 12* overlap.