Slant Six Forum
https://slantsix.org/forum/

who runs an overlapping cam profile on the street ?
https://slantsix.org/forum/viewtopic.php?t=45785
Page 1 of 1

Author:  USAJon [ Sun Jul 31, 2011 7:00 pm ]
Post subject:  who runs an overlapping cam profile on the street ?

while studying the flow issues on our Hooker Comp headers I found statements about an over laping cam can help with intake gas flow into the cylinder.I am wondering who runs one on the street, also any other info..compression/valve size/carb size or ?

I am not concerned about fuel economy on our 1968 Dodge Dart

any info would be good.

Author:  ceej [ Sun Jul 31, 2011 7:52 pm ]
Post subject: 

I take it you are talking about high overlap event timing. Even the most mild stock cams have some overlap. Effective scavenging doesn't work without it.
For stop and go traffic, or other urban use, using a cam with large amounts of overlap will be hard on economy.
Assuming an appropriate final gear ratio, economy out on the highway can be pretty reasonable, if not better. It's all about efficiency. If the torque is high at cruise, that's good. If cruise speed is under or over where torque is fairly high, or running at excessive engine speeds, then efficiency will suffer.
Other considerations would be converter stall, and weight. If you normally drive around with 600# of tools in the trunk, a big cam isn't going to be the best choice.
High overlap cams generally have pretty high lift, and may require higher valve spring rates. That results in higher loading of the valve train. This will result in shorter service life.

2¢

CJ

Author:  805moparkid [ Tue Aug 02, 2011 10:31 pm ]
Post subject: 

i do... 70* Erson .475 valve lift, 246 @ .050 duration, 106 LSA

now what issue of ""flow"" are you talking about with the hookers?

Author:  USAJon [ Wed Aug 03, 2011 5:41 am ]
Post subject: 

Quote:
i do... 70* Erson .475 valve lift, 246 @ .050 duration, 106 LSA

now what issue of ""flow"" are you talking about with the hookers?
they flow a lot, collector/cam overlap/exhaust tubing dia/length/muffler all add to the optium use.

Author:  805moparkid [ Wed Aug 03, 2011 9:59 am ]
Post subject: 

Quote:
Quote:
i do... 70* Erson .475 valve lift, 246 @ .050 duration, 106 LSA

now what issue of ""flow"" are you talking about with the hookers?
they flow a lot, collector/cam overlap/exhaust tubing dia/length/muffler all add to the optium use.
well thats not an issue... lol... just need to have a motor that flows enough and a cam profile to take advantage of the tuned headers...

and really from the collector back it dosn't matter... as long as its not restrictive and the correct diameter it will be fine...

now when you race, make a piece of tubing with just a flange so you can adjust your collector length for max power...

Page 1 of 1 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/