Which Cam are you using?

[Shawn's 78]

Hey everyone - I'm assembling my winter wishlist and want to know what everyone is using for a cam?

I have a stock L48 w/4spd that has a stong lower end (140-150 compression). I plan on dumping the 2-1-2 exhaust and going to true duals (chambered) and adding a performer maniforld with the stock Q-Jet.
I'll do all the work myself.

Your thoughts?
Shawn

 

[rpounds]

What rear gears are you running? Your final drive ratio should be taken into consideration when selecting a cam. Your compression ratio is fairly low, which is another factor to keep in mind when selecting a cam.

Low compression ratio + tall rear gears (even with a stick) + smogger heads + big overlap cam = huge disappointment.

A stock L-48 can be given pretty good grunt by sticking to a cam that is designed for the lower compression ratios and that keep the HP/torque band in the lower RPM range.

If you wish, I can run some numbers for you in Desktop Dyno, just to give you a rough idea of what might work for you.

Ron

 

[Shawn's 78]

Ron,
I'm running stock 3.36 gears.

I hear you on the set up. Even with a change to true duals and an intake swap, it looks like i'm very limited. Summit has a cam (k1102) that might work: 204/214 .420/.442. I think that might be might limit unless I change out the heads.

My thought "is it worth the extra work for this change?". I quess my next question is what is my stock cam #'s? The spec manual is very confussing :crazy. Know where I can find these numbers?

Desktop dyno - sounds cool! Sure, run the numbers and let me know - any info is appreciated.
Shawn

 

[rpounds]

I have run several different cams in mine. I'm currently running the Summit 1101. Awesome low end. I'm running 3:08s and a TH400. I would bet that a 1102 would be a screamer with your 4 speed and 3:36 rear end, especially in the RPM range that you probably normally run.

Just for fun, here's some DD2000 numbers with this cam and your engine, assuming a stock engine other than the cam:

Compression = 8.5:1
Smogger heads
Stock exhaust
Summit 1102

Max torque = 342 lb/ft @3000 RPM
Max HP = 254 @ 4500 RPM

The emphasis here is on the torque curve. Very flat out to 4500 RPM, retaining 296 lb/ft at that speed.

Add a set of AFR 190's with this same setup and use 64cc combustion chambers to up your compression to ~ 9.5:1 and it looks like this:

Max Torque = 375 lb/ft @ 3000 RPM
Max HP = 314 @ 5000

Use the same AFR heads and run an XE268 Cam and you look like this:

Torque = 372 @ 3000
Max Torque - 375 @ 3500
Max HP = 324 @ 5000

Now for comparison to these, we'll use your stock set up with the XE268

Max Torque = 337 @ 3000
Max HP = 261 @ 4500

So, if you retain all of your stock components and only change the cam, the 1102 is a pretty good choice.

All this for what it's worth. I sometimes shy away from chipping in too much where cam selection is concerned, mostly because there are so many differing opinions as to what's best, so folks tend to get a little testy if the specific cam they love isn't on the list of recommendations. However, I have been disappointed on occasions because I insisted on over camming an engine that simply didn't have the static compression and breathing ability to match the cam.

Personally I think that if all you are going to do is change the cam, you have made a good choice with the Summit 1102.

My 2 pennies . . .

Ron

 

[Shawn's 78]

Ron,
Thanks for the "bucks" worth of infor!

I appreciate the other Dyno info on some other cam and setups. I also am considering the xe268 and it was good to see you added that to the list.

I respect the opinions of the CAC members and (IMO) this is what makes this the best forum on the internet! :smile No one telling you "your wrong or stupid". Just lots of "pennies" worth of info to help steer you in the right direction.

Thanks again :bar
Shawn

 

[rpounds]

Shawn,

I couldn't agree more. This is by far the best forum to which I subscribe from the stand point of courtesy, friendliness. Lots of good information and everyone behaves themselves. I subscribe to a number of different forums, but this is the one that I ALWAYS come to first. Great bunch of guys and gals here. I'm proud to be a member of CAC!!

Ron

 

[Ganey]

Shawn

That's not enough cam for a Corvette 4spd. True duals rec., but the chambered is restrictive- not. rec.. A good min. is XE256 & more is rec. like XE262 if you drive hard. REC.!
More cam can be used.


:cool

 

[Blue82]

I run the XE262 with 114 LSA (for the map sensor) and really like it. If you go with the XE256 or XE262 you won't be disappointed. You will need more compression though.

 

[rpounds]

"You will need more compression though"

Thank you . . . exactly my point. Use more cam only if you are willing to do something about the compression. Dynamic compression goes south with cam overlap, which will kill the low end.

 

[MoeJr]

I like the Summit 1102 cam the best for Shawns application. I have used that cam in an L48 with 4spd and it runs like a scalded dog. I also think the chambered exhaust is a good idea. I put one on a customers 74 vert and it ran alot better than the true duals he had. Chambered exhaust is very free flowing. With the aluminum intake you will wanna richen the secondaries of your QJet. It is very easy to do as it is a simple rod change that takes all of 30 seconds. Keep us posted

 

[sscam69]

Use the same AFR heads and run an XE268 Cam and you look like this:Torque = 372 @ 3000
Max Torque - 375 @ 3500
Max HP = 324 @ 5000

Thats what I am shooting for but in baby steps. I just installed the XE268 cam with smog heads with a mild port job. I also have

-True Dual exhaust 2 1/2" Flowtech 2 1/2" In/Out 2 Chamber
-Headers
-Performer RPM manifold
-Holley Avenger 670 (The Quadrajet felt stronger no more responsive)
-M4 w/ 3.08 diff (soon to be 3.8)
-Dual electric fans
-On a diet

I have a few bugs to work out, like #6 pinging BAD!, but as far as performance is concerned its there with Heads and a compression ratio that compliments it. The low end is alright but you might want to consider the differential because with that cam the car doesn't like it to much.

Future plans
-3.8 differential
-AFR 190 heads w/ 64cc chambers (CNC ported)
-Lil bit of laughing gas for fun before I tear her down for the body off resto.

Ron I think that those numbers are really conservative. And thats good IMHO. I have run the sims and the real life engines tend to have higher numbers for the most part. With the AFR's and the XE268 400hp/400ftlbs can be achieved on a very streetable setup.

I also have a mag somewhere around here where they used that exact same setup and made close or more that 400hp. I will dig around and find the articles for everybody.

Oh BTW happy holidays Ron, and everybody else for that matter. I hope everyone has a merry christmas and enjoys time with their familys!
:bar

Frank

 

[Blue82]

Frank, the article you are referring to is in the Sept. 01 Chevy Hi-performance. You can find the article on line in the tech articlles/engine/ 7 Spicey Combos. The engine combo is the Medium Rare Mouse and it made 409hp/427 torgue using Vortec heads and a XE268 cam. The bottom end was GMPP.

I built my engine off this this one, but used the XE262 cam and a 454 TBI. These combos are a great starting place for serious performance ideas.

 

[jetech]

I am planning to keep my engine close to stock. Comp cam techs recomended the XE262h-10 for stock eng with or without performer manifold. I have heard this will boost the hp close to 300 but I don't know for sure.

 

[Blue82]

Jetech, I don't know what your hp numbers will be, but you will get a good lope with the 110 LSA. If you go with a 112 LSA on the same cam you will not get quite as nice a sound, but you will have better cylinder pressure and low end torque.

The XE262 has good low end torque but it operates best above 3,000 rpm. It is my understanding that the lower the LSA, the higher the operating range.

Just a thought...