"6th Year" Silver Supporting Member
Loc: The Texas Hill Country
07-17-12 08:16 AM - Post#2249057
I recently read with interest, an article in the Sept 2012 Car Craft magazine.It was a comparo test of heads under $1,000.
After looking at the numbers over and over, I just have to ask, why don't these guys use cam advancement to put the top end numbers and torque into a more useable range for the average hot rodder?
I've seen the Pro engine builders do this time and time again with a lot of what I would consider, street success. Is this a viable option for a big cammed street engine these days, or is the object to just buy it and install it and have an eratic idle. I'm so out of it, I don't have a clue. Thanks
| Wife: "Don't race the Police car, Stan!" |
Loc: Katy, Tx, USA
07-17-12 09:06 AM - Post#2249071
In response to 4dr 57
While advancing or retarding the cam does what it's supposed to do in terms of tilting the power and torque curves, the amount of change is not all that big.
So if your intention is to compare cams and heads, it's just a side exercise that usually has the same result.
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Loc: FLORIDA USA
07-17-12 09:37 AM - Post#2249077
In response to Rick_L
on average Ive found advancing or retarding a cam a full 4 degrees moves the whole torque curve about 150rpm on most of the engines I build.
now horsepower , is calculated as torque times rpm, divided by 5252
so lets say an engine makes 400 ft lbs of torque at 3800rpm and 370 ft lbs at 5500rpm
thats 387 hp
retard the cam 4 degrees
you potentially could get 398 hp or a gain of 11 hp but you also tend to loose about the same on the lower end of the power band, and because the lower end is almost always used far more than peak power its rarely a huge benefit, thats one reason why most cam manufacturers tend to have cams degree in 4 degrees advance on a dot-to-dot instal.
keep in mind port cross sectional area restricts flow rates as rpms increase, so your frequently not going to get the full potential benefits
| " " IF YOU CAN'T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK !" |
Edited by grumpyvette on 07-18-12 06:25 AM. Reason for edit: No reason given.
"7th Year" Silver Supporting Member
Loc: laurens sc
07-17-12 08:04 PM - Post#2249282
In response to 4dr 57
i'm with grumpyvette. i tried the advance/retartd route on my el camino's 327 and could not tell enough difference to make it worth while. a friend who had a 63 impala with a 427 with a rather large cam told me many moons ago that putting a really big cam in a street car would diminish the fun factor because it would be temperamental to drive.
i took him at his word and went with a smaller cam that still sounds good and makes good power in my 62 with a 427. i have not regretted that decision. it may not have the "rumph rumph" of some,but it is fun to drive and gets reasonable gas mileage.
| 56 bel air ((since 2002)|
62 impala ss (since 1965)
65 el camino (since 1969)
66 nova (since 1987)
67 malibu convertible (since 1981)
72 el camino ss454 (since 1985)
83 gmc 4wd (since 1991)
95 impala (new)
11 malibu (new)
Loc: North Carolina
07-27-12 05:47 PM - Post#2252805
In response to 62chevy427
I enjoyed that article too. Remember being slightly amazed by how inexpensive cast aluminum heads are getting now. There's some real value there.