I have been watching you guys using all these formulas for DCR and SCR and realize that i still do not have a complete understanding of the proper way to use and apply the formulas to choose the proper duration/LSA and so on and may not for some time to come. I admit my lack of the full grasp of the knowledge at this point and thus i seek you guys help! I feel especially in this dept. no question is a dumb question so with that being said.....In looking at my mods in my sig what cam would you choose for me? I wish i had gone for a bigger/more powerful cam for my car.What I want of course is more torque and power. It is my everyday driver so I am not wanting to lose bottom end torque yet still be able to wind it out and not have it fall on its face(Like Patrick G's). I have built my car through TR and would use them for my cam choice most likely.The only mods I am thinking of in the DISTANT future is TSP prc ls6 heads keeping the stock compression ratio that the ls6 heads with a .040 cometic gaskets(about 11.1) ..I would appreciate advice on a cam for my setup as it is now.If someone could work the formulas for me as I cant seem to firgure them out just yet and come up with a general idea it would be MUCH appreciated! TIA for any help or suggestions. Craig

 

ttttt

 

Obviously, I feel that my current cam has the perfect blend of top-end and low-end performance. For thos who are shy about the high-lift LSK lobes, then the following cam is similar in performance:

228/232 .588/.592 110LSA +1 (Comp XE-R)

Thunder Racing can grind it for you.

 

Thanks for responding Patrick.So your current cam would work fine with my stock heads? If so that would be cool, because then when I do get aftermarket heads I wont have to worry about changing cams yet again! again thanks for your time! Craig

 

As long as you get really good springs (like Comp 921s or AFR 8019s) and shim them to within .050" of coil bind, you can run LSK lobes with stock heads no problem.

 

Ok good to know, those 921 are stout.Why do you have to shim them so tight? And also,no flycutting the pistons either i assume?

 

Shimming adds extra pressure, but even more importantly, eliminates spring surge, which can compromise your ability to rev.

 

AH spring surge.A new term i must learn. LOL The extra pressure i completly understand as i used to run a big solid lifter stick in my old 69 SS396 chevelle!

 

Spring tech has come a LONG way in 15 yrs! I'm QUITE sure I have experienced spring surge but not recognized the term to put it to what was happening!

 

Do you think it's worthwhile to use a higher lift LSK lobe on a stock 243 head? I looked on comp cams website and didn't find the LSK lobes.

 

I wonder...is the new LSK really harder on springs and valves than the 5-year old XE-R?

 

Patrick,

I see that you didn't mention PRCs. Will PRCs hold up well in a weekend street car?

 

TSP has been running LSK lobes with their dual springs and having success. You'll have to check with them to see how they're setting them up. If they work, it's a great way to save money. Those Comp 921s are $$.

 

Patrick,

Because, for me, it is not a DD I'm up to trying a few cams out on my bird. You made a post on one of the other threads about a cam that TSP should compare with the MS4. The cam I would like to know more about would be your 235/240 .646/.600 109LSA (+1) . Is this cam using LSK lobes? Would you have any idea about PTV clearances with worked heads. I would guess that the TSP LS6 SI heads would clear but how about Darts or AFRs? Just as well, would you recommend a tuner that could set up the valvetrain to handle a cam like this.

I, as well as the others, appreciate your input into these cams.

Semper Fi,

Rob

 

That cam has LSK lobes on the intakes and XE-R lobes on the exhaust (just like Thunder Racing's TRak cam and TSP's MS4). P to V clearance would be very tight (but doable with TSP heads running stock valve sizes and no good with Dart or AFR heads that have any kind of milling done to them.

If you're not willing to flycut your pistons, I'd recommend milling the heads to get the highest compression you can while running a slightly smaller cam. A smaller cam with higher compression makes more average power than a lower compression motor running a bigger cam.

For clearance, the TSP heads will be your best bet (unless you step up to the ET heads). Thunder Racing and TSP can give you a good mail order tune that can get you in the ballpark, but for supreme driveability, you probably want to tune it yourself.