Silverhawk_02TA

Now that I've got heads installed I want to ditch the Torquer I have and move to a custom cam. So, I've been looking around and doing some research. The first thing I wanted to do was get some more detailed information about the cam I'm currently running. When I bought the cam back in '04, the specs were listed as 233/233 .589/.589 112+2. I called TSP to see if I could get some more info on the lobes. They were able to tell me that it was a Lunati grind, but that's about it. They also said it has .595 lift instead of .589. Just to make sure I wasn't crazy, I went back and searched and sure enough, it's posted on the boards as having .589 lift in every instance I could dig up.

So, I called Lunati to see if I could get some more info on the lobe profile. I was able to get an advertised duration from them (278), but they told me that the lift was actually .575, and not .589 or .595... So, who knows where it's at. When I got the cam it did not have a cam card. Has anyone here actually had a V.1 Torquer Cam Doctored? It's not really a big deal to me at this point, but I am curious as to what the lift actually is.

But anyway, here are the numbers I come up with for my setup with the Torquer (I estimated .200 lift duration):



Static Compression Ratio - 10.64
Dynamic Compression Ratio - 8.18

My goal is to increase power under the curve, which is a big reason I went with a small runner head in the first place. With those numbers it doesn't appear that the Torquer is helping me reach that goal.

My preliminary thoughts on a custom grind is to run Comp XE-R lobes spec'ed out at 228/232 .588/.595 110+4, which calculates out to:



Static Compression Ratio - 10.64
Dynamic Compression Ratio - 8.49

What are everyone's thoughts on this? I'm not exactly a cam guru, so all comments and criticisms are welcome. Recommended changes?

WOTFMAN

iTrader: (3)

Whats the point of advancing the lobe? The whole point of using a 110 ICL is to bring the torque and horsepower graphs closer together. Run that cam installed straight up on an XFI lobe and you will see the power you are looking for under the curve. Look at the .200 numbers if you want to see the difference in lobes and how they correlate to power under the curve and what not. The only problem you will have is a tuner that knows what the hell they are doing.

Also somethings you will hear on tight LSA's is that they dont run in the HIGH rpm ranges. Thats false brother. I have a 236-242 on a 110 installed straight up with no advance on the lobes. P to V is tight but thats when things run the hardest. Some people say not to run p to v tight on the street...thats the guys that are constantly struggling to be at the top. Its always smart to run p to v regardless. Just know that its tight and that your valvetrain should constantly be checked and always under control. Lightweight parts help in that area.

Silverhawk_02TA

Installing that cam straight up and without any advance ground into it moves the ICL from 106 to 110, and correspondingly the IVC from 40* to 44* ABDC. The end result is that the DCR drops from 8.49:1 to 8.22. From what I understand, this should be counter-productive to low-end or under the curve power. Am I missing something?

I looked at the XFI lobe profiles, and I like the slightly higher lift, but the lobes aren't as aggressive. What's to be gained by going with a higher lift, less aggressive lobe versus a lower lift, more aggressive lobe?

BIG_MIKE2005

iTrader: (116)

Get in touch with Patrick G, he is the cam guru around here.

dyls1

iTrader: (11)

+1 From what I have read here, for 25 bucks, he will spec a custom cam for you. And if you go with the grind he specs you get a discount from the supplier of the cam and I *think* it ends up being about the same price for an off the shelf cam. I could be wrong, if I am somebody please chime in and correct me. Good luck!

Silverhawk_02TA

Yes, this is true. There's no denying that Pat G knows his stuff, and I'd love to hear his input in this thread. But the fun for me lies not in the end result but in the journey. It's much more satisfying (for me at least) to do the research and dig into the tech and theory and come up with something on my own than to just pay someone to do it for me. If I was just concerned about end results than trust me, I would have already filled out my info and sent it to Pat!

Ragtop 99

iTrader: (7)

I question whether Lunati gave you the correct advertised duration and suspect your DCR calc for the Torquer 1 is incorrect. You have just 45* between .006 and .05. That's pretty damn fast and probably overstates the DCR. I'd bump it back up to the same 49* you are assuming for the comp.

Anybody ever put one on a cam doctor?

Also, I don't believe that is enough of a change to do a cam swap. You could put an adjustable chain on the torquer and pick up another 2* advance. For your suggested cam, use an LSK lobe to get some extra area under the curve. Cut the LSA to 108 and install it straight up. Otherwise I'd move to a 231/231 109 107 LSK/Xer combo.

Just saw that. Should I delete the above cam specs?

Silverhawk_02TA

I wouldn't be at all surprised if I got incorrect numbers from Lunati. When I called it took them quite a while to locate the info I was after, and I kinda got the impression that it was a "best guess". I had pretty much the same reaction you did when I saw the .006 duration numbers. It's a considerably faster ramp than an XE-R. If I plug in your suggested .006 numbers that takes the DCR down to 8.0:1. Tossing in 2* advance brings the DCR up to 8.18.

What makes you believe that it's not a big enough change to make a swap worthwhile? I'd assume that going to a cam with .5 more DCR would net me a solid gain.

I didn't try to spec out an LSK lobe because I couldn't find any info about the lobe profile. It's not even listed in Comp's lobe catalog. Is there any info out there on the LSK lobes that would allow me to run some numbers through the DCR calculator?

Lastly, would you care to elaborate on why you would recommend that 231/231 109 107 LSK/XE-R combo? In specifics? Remember, I'm tech-whoring.

WOTFMAN

iTrader: (3)

How do you figure the XFI isnt aggressive. 153 degrees at .200 on 236 duration is pretty radical IMO..200 is where you should be concerned anyway...Not .050


Play with ICL until you get the numbers you want.

DaveX

Your SCR and resulting DCR are a little low. What thickness gaskets did you use?

Those heads with .040 gaskets + that cam on a 110 + 0/1 will give you a SCR of 11.3 / DCR of 8.6-8.7. This is where you want to be for a 346 torque monster street car IMO. Could even go a bit more on the cam, say 230/234 or 232/236 but keep the DCR @ 8.5+.

Silverhawk_02TA

What I'm getting at is that the XE-R lobes have a faster ramp rate than the XFI lobes. I wasn't meaning to imply that the XFI lobes are not aggressive in their own right.

Due to time constraints during the head swap I was not able to order and wait for Cometics, so I had to pick up some MLS gaskets from a dealer. According to the DCR calculator going to a .040 Cometic would put me at an SCR of 11:1 and a DCR of 8.75:1.

Going with a longer duration drops my DCR down from 8.5:1 on my current setup, no matter how much I play with LSA and ICL (within reason). However, if I swap out the MLS for a .040 Cometic I can see the point of upping the duration a bit. I'll play with the numbers and see what I can come up with.

WOTFMAN

iTrader: (3)

What are you basing your faster ramp rate conclusions on?

Ragtop 99

iTrader: (7)

LSK lobe profile is in the cam sticky.

As to why it is not a huge change that you are proposing, you are moving your power band around, but not really adding more power. That's why I suggest the lower LSA version.

The 231 can use the LSK lobe on the intake. The exhaust really should be the 232 Xer lobe. With headers, true duals, and I'm assuming no cats, you don't need much extra exhaust duration. The 109 LSA will add some overlap for power and 107 ICL gives you an earlier IVC without having to advance the cam so much.

5.3LJimmy

iTrader: (10)

Comp Cams LSK lobes
Lobe#, Dur. @ .006", .050", .200", & Lift w/1.7 rocker
2124 265 215 142 .629"
2125 269 219 145 .632"
2126 273 223 149 .636"
2127 277 227 153 .639"
2128 281 231 156 .643"
2129 285 235 160 .646"
2130 289 239 164 .649"
2131 293 243 168 .653"
2132 297 247 171 .656"
2133 301 251 175 .660"
2134 305 255 179 .663"
2135 309 259 183 .663"
2136 313 263 186 .663"

Silverhawk_02TA

From the difference in duration at .006 and the duration at .050.

This is directly quoted from Comp's 2007 lobe catalog, referring to the LS1 XE-R lobes: "The XE-R designs are our most aggressive hydraulic roller ramps to date."

That's actually mostly what I'm after. If I didn't gain any peak power from the swap I wouldn't care. I'm trying to bring my low end torque up. This is why I'm trying to raise DCR and keep duration moderate. Any peak power I gain would just be icing on the cake.

Now that I can run the LSK numbers (thanks 5.3LJimmy!) I do indeed like that 231 lobe. Now I'm leaning towards 231/232 .639/.595 with a 109 LSA as you suggested, but with the ICL moved back one more degree to 106. This puts my DCR at 8.6:1 (but only if I move to a .040 gasket). Seem solid, or is that still a tad too much advance?

Another question also comes too mind. Since the flow data I can dig up on the Dart heads shows flow dropping off after .600 of lift, is there really anything to be gained by going to an LSK lobe over an XE-R?

Ragtop 99

iTrader: (7)

For what you are trying to do, 106 ICL would be fine.
Put an adjustible chain on. Then you can advance or retard as you desire.

I guess the only question I should have asked is: How low is low end for you? If you want a big power increase at 2000 rpm, adding overlap isn't going to help. If you want power gains at 3000 then we're on the right track.

Silverhawk_02TA

Yeah, around 3000 is what I had in mind when I said "low-end".