You use the tq AND the rpm to find out what your HP at THAT rpm is. So if you have 329 tq at 3800 RPM then you have 238 hp at 3800 rpm.

And let me get back to your earlier question on exhaust/intake ratio. The WHOLE point is to get somewhere around a 75% ratio for best performance, period. If your head flow is less than that, say 69%, then you need a little bit more exhaust duration on the cam than intake duration to achieve an effective 75% ratio.

By going to a reverse split (230/224) you're only making the gap BIGGER, and its not going to result in more power. LS1 guys can run cams like that because their ratio is a lot higher.

 

Thanks for explaining Chris, now it makes sense to me. That explains why the exhaust side duration is higher on all the LT1 cams. So the cam I mentioned earlier would probably be pretty bad to use. Or cause a big bottleneck at the exhaust port.

It looks like your torque number is not much higher than mine. I would think with stage 1 heads and a cam it would blow me away. What gives? Do these things just level off after a certain point?

 

Well quite frankly the heads and cam are just too small. The stage 1's with a bigger cam would make quite a bit more HP, but the cc304 cam is just too small to make big power...it peaks at about 5400 rpm in terms of HP.

That is why the cam and heads are coming out...time to stop *****footing around and get serious about HP!!

 

Well I read through this entire post and Im still not really sure. Maybe one of you guys can help. At first I wanted to run the 224/236 just cause its a bigger cam. Of course Im not really educated with cams..hence-"bigger is better"..lol? Im not worried about emmisions at all. My car is basically a cruise/strip car. I will be spraying 100-125 shot on top of this. Would you guys recommend the 224/230 or the 224/236? The heads will be ported as well. thx

 

I'd say 230/236. The only reason I'd consider the 224/236 is if you are really limited with respect to emissions/driveability issues. If all that is out the window then there is no need for a 12* split on the duration. If the heads' exhaust flow really sucked then maybe it would be beneficial, but mismatching the durations too much is just giving up HP.

 

So then your saying the 230/236 even with the n20 will give me the most hp and tq out of all the cams. I just though the 224/236 would be better because its classified as a nitrous cam but if you think the 230/236 will be better ill go that route.

 

Well, I wasn't thinking about the nitrous. The 224/236 is a good N20 grind, but I'd get it with a 114LS or even 116 if I were going to spray, just to reduce the overlap some. I'm sure there are guys running the 230/236 with spray too...116ls would probably be good in that situation as well.

 

Which would be better? The comp 305 cam or the xe218/230?
The 305 has 220/230 w/ .510/.510 on a 114LSA.
The XE has 218/230 w/.495/.510 on a 113lsa
Does the XE make more power because of faster ramp rates or is the 305 better? I just want the most power with emissions.
Tom

 

I would go with the XE 224/230 over the CC305...they have very similar advertised duration, meaning they are the same size at very low lift, but once they start to open the XE grind opens faster, hence the larger .050 duration specs. The difference is even greater at .200 lift.

Its worth it to go to compcams.com and check out the specs for the various cam lobes. In their online catalog, p. 229 has the lobe specs for the Magnum series hyd. rollers (which the 305 is made from) and p. 230 is the XE series lobes. It is really eye opening.

 

You guys are sounding like me when I start thinking about cams

Lingenfelter has some cams thathave very fast lobe ramps too. 211*@.050 with .530" lift and 219*@.050 with .560" lift with 1.5 rockers are even faster than the Comp EX 319X lobes And apparently are stable enough to idle at 750. With his reputation, I would consider this cam if I weren't going bigger (and if the price weren't so high.)

After over a year of changing my mind DOZENS of times, I've pretty much narrowed in on what I'm going to use with my cam in my 350.

Comp Magnum lobes 3119 & 3122
280/290adv, 224/236@.050, 144/160@.200 with 1.6/1.5 rockers (.560/.570 lift) on a 115LSA. However, I'm STILL undecided on where to set the intake centerline.

I picked these over the XE 3300 and 3100 lobes for a few reasons.

Compared to the 3314, the 3119 more advertised duration and just 1* less duration @.200 so it should be easier on the valvetrain. But with the 1.6 rockers, it should be right there with it if not a little higher. I'm also liking the good bit more lift. With the 1.6 rocker, this will act like a 282adv, 226@.050, 146@.200 lobe

The 3122 has more adv and .200 duration than the 3316 AND a good bit more lift, so it should make more torque. But it will be easier on the valvetrain the the 3196 lobe.

I picked the 115 LSA because it give zero overlap @.050. That should be awesome for the accessories I will be spraying the car, and I would like to go with a blower someday. This cam would work great for either application (or even both together.)

For the intake centerline, I'm strongly considering 112. However I have also considered 110(which would be good for nitrous) and 115(which would increase the RPM range.)

I need a little help deciding guys (maybe even gals too)

For the rest of my car, I will have either stock impala heads with the slightly thinner .026 gasket or mildly ported aluminum heads with big valves and milled a bit for compression. I've got a Vigilante 3200 stall and 4.10 gears are going in early next week. The car weighs 4250# with me in it at the track. With the aluminum heads, that should drop to and even 4200. At the moment I don't have headers, but I was planning on putting them in when I do the cam. They will be long tubes with no cats.

My goal is 12.75@107.5mph on motor. Quicker or faster wouldn't hurt On the nitrous I'd be hoping to run 11.50@120mph with a ~150-175 shot.

By the way, I ran the ET in my sig on a 1.92 60ft with a burned out posi on ET Streets and 255rwhp/320rwtq at 4260# That math just doesn't add up, does it?

 

Oh yeah, Chris, have you finalized your decision yet?

I was considering the 3313/3315 lobes straight up on either a 110 or 112 which would have given me basically the same power and torque as the 224/236 115+4 BUT I wanted more lift AND the extra duration helps out with the volumetric efficiency Besides, that cam would have sounded too much like the LT4 Hotcam...

 

You guys are making me dizzy, and I have a fair amount of time with cams both the theory and the real world application. Here's a couple of points, which if kept in mind may clarify the issues a bit.

1. When you start talking about differences of a couple of degrees, it's insignificant.

2. You can't get serious about cam specs without head flow numbers as well as the more obvious stuff like static CR, fuel used, type of exhaust system, and the intended use of the car, etc.

3. The current trend toward steeper lobe profiles is excellent. Steeper lobes per se do not cause accelerated wear or parts breakage. The parts slected have to be up to the job though. The issue isn't the steepness of the lobes, it's the amount of spring pressure needed to control the valves. This is a function not only of the lobe profile but of the weight of the other valve train parts and most importantly, the rpm.

4. As you get into more extreme profiles, not only is parts selection important, setup is an issue as well. Verifying the installed height and seat pressures, checking for coil bind and piston to valve clearance, along with all the other traditional careful engine assembly techniques are what I am talking about.

5. No offense, but don't try to reinvent the wheel. It's really unlikely you will discover any "secret formula" that will be better than the other guys' on your first try. If you are quite knowledgable and use a sophisticated engine simulation package you may come up with soemthing worthwhile, but even the big boys actually try a number of cams on the dyno and/or the track before deciding what to use. That isn't to say that it's useless to try to understand this in order to select what will be best for your particular combo.

6. Also no offense, but picking one cam over another 'cause of how it sounds?

Rich Krause

 

Yeah the sound over performance issue has me too? Oh well some people look for sound over performance, no big deal to me. Im just looking for all out performance. My car may not sound like the best car in the world but as long as it gets me down the track faster then the next guy Im happy with that. There seems like there is a lot of nitrous guys in on this topic now though. It was brought to my attention that I may want to consider running the xe 230/236 cam on nitrous instead of the 234/236. Would this be a better choice. Also what lobe seperation should I be looking at for the cam. You talked about the importance of other mods such as exhaust too. I have hooker lt's that run back to true duals and are dumped before the axles. Then just basic bolts ons on top of that. Spraying 125 shot if I can ever get it hooked up with season....

 

Well since the first post asked for dyno #'s and track #'s of these cams I guess this is where I can post my knowledge. I have the 224/236 xe cam in my auto on a 114lsa. Peak power was 344rwhp and 343rwtq. Car still has the stock stall and stock heads w/ roller rockers and springs as the only mods to them. On my car peak power was at 6200 and by 6500 it had only dropped to 335. The tq stayed nice and flat from about 2600 till 5500 where it finally started to drop off (stock stall)

As far as track #'s go. Best run is in the sig on street tires. Which it fairly humid outside and about 60-70*. Car is stock suspension wise and weighs in at 3650 with me in it and half a tank of gas. Hope this could help someone out.

Joe

 

The 224/236 is, in general, better for N2O. Avoiding overlap with a larger LSA is not as much of an issue with nitrous as it is with a blower. I would use a 114. The 3192/3196 CC XE lobes are what I would pick, provided you are willing to use the right supporting components, as mentioned above.

I am not a shill for Comp, just familiar with thier products. Referring to their product line, you need the Magnum pushrods, #987 valve springs if you use 1.5 rockers or the #978 if you are using 1.6. I like aluminum rockers and have have good luck with Crane's, Comp pushes their Pro-Magnum steel rockers. If you plan to rev over 6,500rpm you will need the "R" type lifters and probably a stiffer spring like the #977. Other manufacturers have equivalent products.

Rich Krause