I saw this cam on NRP's site. It's for a 95 TA. It gives me 12* overlap, mostly centered about TDC (a little intake bias) which should build power past peak torque. I'm looking for a cam to run to about 6500 rpm. More interested in power under the curve than peak power. Not for a dd. Will see the track once or twice/year. Gives me about 10.2 SCR, 8.5 DCR. I realize I will sacrifice driveability, but once again, its not a dd. It'll probably be a pretty choppy idle. Thoughts? Any compromises or suggestions? Should I go for more lift? I could put it on a 1101+2 and get less lope.

Also, I got 280/285 @ .006. This gives me slightly less than XER lobes.(.006-.050=50) I was hoping for more aggressive ramp rate on closing than opening to push overlap even more towards intake. Using 66* overlap I came to 280* duration per David Vizard's formula. I then added to that to get 285* for exhaust. (Added only 5* instead of 6* split @ .050 to get a less aggressive opening ramp, again to help push overlap towards and a little past TDC.) The closing ramp and other finer details I would leave up to Futral, who will be doing the install and dyno tune. Again, thoughts and suggestions please.

 

Leave designing the cams to the people who do it for a living, these DCR calculators seem to make people think they are suddenly cam experts. This wasn't a personal attack against you, I'm just saying let an expert do it so you know it's right.

 

That's the responses I wasn't looking for(no offense to you) This was a cam designed by experts, I just changed the LSA and explained the processes and thinking and my goals in how I came to chose this cam. Now can anybody post up on what they see as positives and negatives to this cam and it's application in my set of circumstances. I would really appreciate it. Thanks!

 

the 12* overlap will give it a really choppy idle. I believe cc306s are somewhere around 8.5* overlap

XE grinds are considered a mild cam

8.5:1 DCR i believe will be pushing it on pump gas

 

306 is 13 degrees at .050.

 

I think you need to run more SCR. I'm only getting 7.9 DCR with that SCR, though. I never thought about a cam as much as you have. Seems like you've been doing a lot of reading! Good for you.

Speed Demon: Some people want to learn and you shouldn't discourage them for that. Trial and error is sometimes the only way, though.

 

I'd like to run more SCR but I'd have to do something to the heads or change the stroke or pistons or something major like that. I wish that were in the budget. If there are any simple, relatively inexpensive ways to increase SCR please let me know.

 

I'm not discouraging them from learning, but since cam installs are a big PITA trial and error won't exactly be a fun thing here.

 

I can't remember exactly what your setup was, but thinner head gaskets and milling the heads would do it.

 

With those lobes most likely it's not designed by experts, those lobes are a POS that are close to impossible to control past 5800rpm. A well knowledged person who understands cams would know that. Beyond that, LSA and advance reguardless of what you have read in places like LS1tech.com ARE NOT variables that make no difference performance. speed_demon can attest to that ;-)

PLEASE, PLEASE, PLEASE don't try and compare a lobe made for a SBC to a LS1 XER lobe, they are not even close. They can't be due to the larger journal size of the LS1 over the SBC/LT1.

speed_demon is right telling you to ignore the freaking DCR calculators. IF you want to change a DCR spec don't do it with the cam, you can chase that dog but it's better to not chase him and just add the SCR you can to get the DCR to the optimum level. Depending on the rest of the parts you have that can be 8:1 or 10:1.

Bret

 

Why are those lobes impossible to control past 5800? Thanks for the input Bret, but please tell me why this cam sucks not just that it sucks.

 

my friend had a 227/233 cam with similar lift numbers on a 112, but I dont have all the other info tho. long story short, he ran consistent 12.5's and 12.6's at 113mph with full bolt ons on drag radials down here in phoenix. the heads were never touched beyond the valve train. since then he sold that cam and put in a gm847 and no runs 12.8's @ 109....

 

A friend of mine has that FMS cam in his 1994 Firehawk, but it's on a 114. He loves it.

 

If it's the Comp Lobes I am thinking of they are just a very aggressive design that doesn't promote good valve control. Your better off staying away from them and running something else.

If it's a Cam Motion grind with those lobes then it's a different story. I don't have Cam Motion's lobe profile book so I can't say anything unless I had a Cam Dr readout.

Rasputins example is a good one on too much cam slowing you down. That cam is better than the 847 in that same example, but there are cams that are even better that will make the car a lot quicker down the track. Might be why he is running a Ed Curtis cam instead of the one you mentioned ;-)

Bret

 

What's your suggestion then? I'm not asking you to give away your secrets, just some .050 numbers would be nice. Those numbers don't tell the whole story, but it could give me a starting point. To answer your question the cam is ground by Comp from NRP, but I would be getting it ground from Camotion via Futral.