|
Author
|
Topic: another cam q
|
Dubz
Gearhead Posts: 243
From: Manitoba Canada
Registered: Oct 2002
|
posted 02-07-2003 01:54 AM
   
comp cams labels their cams as having an operating range, is this the only range they work in, or they are just the most efficient in this range------------------
1974 Gran Torino, 351W Just a young buck
IP: Logged |
D&S Induction Systems
Gearhead Posts: 118
From: Columbia Heights Mn U.S.A.
Registered: Feb 2003
|
posted 02-07-2003 02:35 AM
Lets say you had a cam with an "operating range" of 2500-6500. And you also had the ideal heads and intake etc. to match it.Put the engine on the pump and you would find the engine make more HP per RPM with in 2500 to 6500 rpm range. I dont know these guys but, here is a dyno sheet I found on the net.  From the looks of it this engine has a cam with an "rpm range" from about 4200 to 6000. There is alot more to the big picture and I know I didn't explane it all that well but it's the best I could do in a forum.
IP: Logged |
Fastymz
Moderator Posts: 9095
From: Reno Nv USA MEM#1240
Registered: Apr 2001
|
posted 02-07-2003 12:18 PM
So you pick the range the motor will in most the time.And find the cam that matches that range?
------------------
SCOOP
oddly obsessed with big scoops on little Mustangs 2.26 60'S
14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede. https://mustangsandmore.com/ubb/Fastymz.html
IP: Logged |
Dubz
Gearhead Posts: 243
From: Manitoba Canada
Registered: Oct 2002
|
posted 02-07-2003 01:35 PM
so i pick a cam i'd want for cruising, and then i can still give her hell and get the rpms up there....allright, that's all i was asking
IP: Logged |
D&S Induction Systems
Gearhead Posts: 118
From: Columbia Heights Mn U.S.A.
Registered: Feb 2003
|
posted 02-07-2003 07:07 PM
quote:
Originally posted by Fastymz:
So you pick the range the motor will in most the time.And find the cam that matches that range?
Yes, thats one way of looking at it. See, dirt track, and NASCAR engine builders have a harder time finding the correct cam to use than drag race and truck pull engine builders. In a drag race you may launch at 3000 rpm's and shift at 6200 rpm's. You're not going to be slowing down to 4500 then up to 7000 down to 6100 then to 7150 and so on. Another example: We just got through doing a 302 stroker (347) for a close freind of mine. This thing pulls HARD! from about 3800 to 7500. We used TF heads and comp cams 305H.
Now he wants to street this thing (wich is fine) but the thing goes through ALOT of gas and the rpm's are always 2800+. Any lower than that and the engine is going "lumpity lump" shaking the car to all over. It's a stick wich makes it even worse. We could have stuck a smaller cam in with less overlap (wich would help the idle) but at the cost of top end power. It's all a trade off. As far as "streeting" high rpm engines... It's all in the owner.
IP: Logged |
Dubz
Gearhead Posts: 243
From: Manitoba Canada
Registered: Oct 2002
|
posted 02-07-2003 07:13 PM
so the range is then the "happy range" for the cam, not the limits of operation
IP: Logged |
Toronado3800
Gearhead Posts: 191
From: St. Louis, MO
Registered: Jul 2001
|
posted 02-07-2003 10:53 PM
Yeah, it won't just turn off at 6501 RPMs or nothing, it just isn't as efficient. D&S is right on the money for making your parts match. First time I bought a cam I spent hours looking at Jegs and Summits charts to see who claimed what RPM ranges. What all parts do you'all consider RPM performance sensitive? Like Torque Converters have a guestimated stall, heads have an RPM band, Intakes...exhaust, in a way. Dubz, what kinda 351W you trying to build?
IP: Logged |
Dubz
Gearhead Posts: 243
From: Manitoba Canada
Registered: Oct 2002
|
posted 02-08-2003 03:21 PM
a nice lively street strip car, will get driven fairly often on the street, but will also see track use fairly often. A 1300 - 6800 rpm range, if possible. My car will be a pro-street when it is all done, so it need to have some decent power, and be able to rev nice and high------------------
1974 Gran Torino, 351W Just a young buck My Page
IP: Logged |
Mustangsandmore Forums
UBBFriend: Email This Page to Someone! 
