fishman wrote:
u r saying you have a camshaft that will give me 30 more hp without turning the motor any harder........the car does seem to really lag the last 100 feet or so......a little more hp and a bigger cam will straighten that out...thanks
Yep,
I based my calculations on turning the engine 7,300-max.
Been awhile since i replied to this post...but since then i have taken the torque out sent it in and got it loosened up from stalling at 4900rpm now to 5800rpm.....i am going to leave it this way and run the car and see what it picks up and then go from there......i have another question without changing the cam and going to 1.7 ratio rockers on the intake...(.i have 1.6's on intake and exhaust right now) i will pick up roughly .040 lift on the cam so the cam will be around .674 lift..........changing 8 rockers is not a big dollar but how much of a gain will see like 15 horse?..........thanks for the input...........been batting this around in my head is all
bigjoe1 wrote:Unless you get the rockers for free, it is not worth the trouble.
JOE SHERMAN RACING
Joe you don't see any gains going to a 1.7 rocker on the intake valve.........theoretically speaking by gaining .040 lift you would think that i should see 10-15 horse..........hummmmmmmmmmm
It depends on a whole buch of things, but you only have about a 50--50 chance of a noticable gain-- Last year I have a real good running engine and when it came in for a freshen up, he had to get the new high ration rockers for the intake-- I went from 1.55 to 1.709 Shaft setup) at a cost of over 500 dollars..-- It did not gain even ONE HP-- it did not loose, but it did not gain---500 dollars
bigjoe1 wrote:It depends on a whole buch of things, but you only have about a 50--50 chance of a noticable gain-- Last year I have a real good running engine and when it came in for a freshen up, he had to get the new high ration rockers for the intake-- I went from 1.55 to 1.709 Shaft setup) at a cost of over 500 dollars..-- It did not gain even ONE HP-- it did not loose, but it did not gain---500 dollars
JOE SHERMAN RACING
That is weird hey.....cost me around $200 for 8 rockers, not a big cost...not sure if i am going to change them anyways, going to wait and see how the motor reacts to the converter being opened up 900 rpm...my gains might be enough, as all i want is to run single digit numbers and old combo ran 10.13 at our track and 9.81 at sea level...........it's a long winter over here in alberta....we have probably 4 inchs of snow already and the temperature high today was around 30 degrees Fahrenheit.........to much time to think now and dream about spring which is opening day at our track is around end of april
The only way I would see it gain is if your intake lobe was to small for what you are doing. It not only will pick up lift but will also increase your dur. numbers at .050 about 1.5 to 2*.
3V Performance
" ENGINES WITH AN ATTITUDE "
980-222-7230
" It not only will pick up lift but will also increase your dur. numbers at .050 about 1.5 to 2*."
That is what I was wondering with Joe's test. The motor may not have made anymore peak horsepower in that case but what about the horsepower curve in the lower rpm ranges?
1989TransAm wrote:" It not only will pick up lift but will also increase your dur. numbers at .050 about 1.5 to 2*."
That is what I was wondering with Joe's test. The motor may not have made anymore peak horsepower in that case but what about the horsepower curve in the lower rpm ranges?
I,m sure it hurt some in Joes case because he run's such HUGE cams in everything.
3V Performance
" ENGINES WITH AN ATTITUDE "
980-222-7230
The cam I was using was a 484 lobe lift, so the valve lift went from 750 to 822, and made no differance at all-- ( In this case )In other engine builds, I just go for the big ratio intake right off the bat-- Most of the time you can not afford to buy several seta of differant ratios, because it cost too much
theoretically how close do you think these rocker ratios are compared to the advertised numbers? i'm sure when you are running .822" lift you use really good brand.
would he gain anything putting 1.5's the exhaust? would it lose anything? what about advancing the cam 2*? at his altitude would a 1/2 point in compression help? as if he changed to thinner head gaskets? would he pick up using a 2" spacer instead of the 1"?
3v performance wrote:" It not only will pick up lift but will also increase your dur. numbers at .050 about 1.5 to 2*."
1989TransAm wrote:That is what I was wondering with Joe's test. The motor may not have made anymore peak horsepower in that case but what about the horsepower curve in the lower rpm ranges?
More rocker arm ratio on the same lobes will hurt the low end.
You don't find more power with more rocker if you already have enough lift to satisfiy the motor and if you add in valvetrain problems. More rocker means more force the pushrod sees so it can deflect and cause control issues and the power will not increase even if the motor needs more lift.
Larry Meaux's PipeMax program is a good way to find how much lift you actually need or can get away with.
Bret
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[i]Those of you who think you know it all are particularly annoying to those of us who do[/i]- Penske garage sign @ Indy circa '71
