Looking to select a cam that will create most AVERAGE HP and TQ gains not just peak power numbers. I'm running 12.98 at 105mph in the TX heat with a stock LT1 94 corvette convertible with shortie headers, ported heads and intake, and comp springs and 1:6 rollers with the stock LT1 cam.

I have in my arsenal an extreme energy Comp cam 230/236 at 0.050" with 555 lift but was thinking that it may be too large for my application and that an Accel 211 cam might be a better selection. Any ideas?

Thanks.

 

You have a couple choices, the 211 cam would make decent power over the stock cam. The 219 will make more peak power and will give the car a slightly lopey idle. Another choice is the venerable LT4 hot cam which is also a proven performer in the LTx engines. The 211 cam is by far the smoother of the choices and offers excellent drivability and economy as well as a decent SOTP gain in power. The 230 that you have is too big for what you are doing. It would offer decent power increases in the mid range and top end as long as you have the heads, headers and exhaust to support the cam. With the other three listed above, any of them can be used with stock heads and you won't run out of cam.

 

Thanks for the advice. I have run the 230/236 cam before and ran a best 12.44 at 111mph in 60-70 degree weather here in TX with the same combination that I have now. For the street, I prefer the feel of as much torque as I can generate but I hate the fact that I can feel the stock cam run out of juice on the top end with my ported heads. My LT1 heads flow 260 cfm intake and 210 cfm exhaust with 2.0/1.55 valves. What do you think about Comps Xtreme 218/224 or 224/230 setup? I ran the Hot cam before and it did not seem to pull very well in mid-range. How much HP and TQ can I expect to pick up with Long Tubes over shorties. I removed my cats with the shorties and picked up considerable TQ and HP and dropped .10-.15 in the 1/4 mile.

 

I initially ran a Comp Cams 212/224 521/536 112, it had great street manners and would run in the 12.3x's @115-116mph. About a year ago I changed the camshaft to a 224/230 605/622 112. The new camshaft's lower rpm hp/tq and street manners are almost identical to the old cam, but from 5500-6500 rpms picks up about 20 hp. I've yet to run the car with the new camshaft.

 

I'm kind of surprised that you felt your mid-range was lacking w/ the Hotcam. The only place I felt that it gave up anything was right off of idle, and not much at that. But after that it's always pulled strong, seemingly for further than I'd generally take it. I've used it with the stock heads and now ported ones that flow around 275 int. at the HC's .525 lift. I'll be curious to see how it performs with the stroker bottom now. I'm nearly done w/ that project, I hope to finish buttoning it up this weekend. I know I could have changed to a cam that would have utilized the added cubes better but ultimate power is not as important to me as mileage and driveability. Good luck with whatever you decide on.

 

Here's what I did.

A few years back when I was camshaft-shopping, for the umpteenth time, I opted to skip the off-the-shelf grinds and, instead, chose my lobes individually from the back section of the CompCams catalog.

While most folks generally only consider duration @ .050, valve lift and maybe Lobe Seperation Angle (LSA) when choosing a cam, I went one step farther and looked at the aggressiveness of the ramps.

CompCams has long touted how choosing lobes with more aggressive ramps will increase the area under the curve, resulting in more flow and power without the need of having to resort to more duration to achieve the same result.

CompCams calls the lobes CRC (from memory I believe translates to Constant Radius of Curvature.) Crane has a series they call Inverted Flank Rollers which are lobes ground along the same line.

To compare ramp aggressiveness I subtract the .050 duration from the advertised duration figure (usually measured at .006); the lower the difference the more aggressive the ramp. Grab one of CompCams' catalogs and compare, say, their CS3192 lobe with other lobes that have the same .050 duration; you'll see what I mean.

Also, selecting the LSA makes a difference in how broad or narrow/peaky the power band will be as the engine revs through its power band. There's a definite difference in how the same cam will perform if ground on 114 LSA as opposed to 108.

I chose CRC lobes 224/230, but my engine is a 415CID; 218/224 to me seems right for best all around performance in a 350ish engine.

Just my thoughts.

Jake

 

You could always bolt on an LT1 version of the superram, if you want more midrange torque.

I don't think this was very popular option for the LT1 crowd for some reason...

But seriously, I have no complaints with my Comp Extreme Energy 503 (224/230 112 lsa). Torque feels strong and flat from 2500-5000 rpm, and at least adequate below 2500 rpm.

 

You are giving up power with the shorties compared to LT headers. I basicially have the same setup except I have LT and the hotcam. See my signature for best times. By the way, I am surprised to hear you were disappointed with the hotcam on mid range. Heck, it was designed as a road race cam. Thats supposed to be its best area. (mid range)

 

STL94LT1,

What heads were you running? How about valve springs? I'm running Comp 986s and not sure what the maximum lift is with these springs? I'm surprised you did not have piston to valve clearance issues. 115 mph is strong. My other 94 only dynoed at 350 rwhp and 325 rwtq but I did not have LTs and the ECM was stock other than HYPERJUNK tuning.

 

Was just reading this for fun and had a question...im assuming you have an automatic...do you have the stock converter right now?
Ive learned with automatics,installing a slightly higher or better stall converter can help with the powerband of the engine,along with steeper gears in the rear.

 

93 ragtop,

116/117 mph is a great trap speed for an automatic with .409 gearing and the 1.66 60 ft. is awesome. I understand that Exotic Muscle, TPIS, and Stainless Works all make LTs for the LTx C4 Vettes. Are you happy with your EM's? Are you running cats? I'd be willing to bet you could attribute your wife's quicker time to the lighter driver : )

 

Bill's86coupe,

I have a ZF manual and 3.42 gears, however, I ran 4.09 gears in my other 94 ragtop.

 

I'm running CNC Cylinder Heads ported LT1 heads with Comp Cams 918 Bee Hive springs.

From what I've been told duration is a bigger threat to piston/valve contact than lift.

 

On the part about my wife being quicker? Ouch. :o yes, you are correct. I have her by about 90lbs. Course if you ask her, it is a combo of weight and driving skills.
I like the EM headers. The fit was perfect and they have never leaked. The only complaint I have had was there are specks of rust showing through the coating.
I have a seperate exhaust with these converters http://216.178.81.107/iwwida.pvx?;it...0%201?comp=ppe located where the resonator used to be. I put it on for emissions inspections.
What ever headers you go with I would not waste my money on the extentions to tie back into the existing exhaust. IMO they are overpriced and dont work well. I ended up getting 2 pieces of 3in exhaust pipe, cutting off my existing exhaust close to where the headers are, sliding it into the 3in pipe and welding it up. Course I used the band clamps on the header collector end.

 

I'll be trying the new XFI 467 Comp Cam 230/236 576"/570" 113 with ported AFR heads ( 290CFM@520"300CFM@ 600") , ported intake. The M6 car @ 130,000miles makes 313RWHP and 332RWTQ through LTs, Magnaflow Cats, Corsa Exhaust, 1.6 Comp Rockers, Alum Flywheel, elecWP and a home made ram air. It was good for 12.80s@110mph without DRs and a 3:73 gear.

I wanna try to break into the elevens on Drag Radials this summer and then next summer I'm going to use the same cam in a stroker motor build up.

I hope I can still make at least 320RWTQ@ 2600RMS like I do now with the new cam but I guess I'll wait and see in a couple of weeks.







I'

 

Does your wife know how to drive a M6? It sounds like she has the weight advantage and skills to get my car into the 11's.