| Track Junky |
06-24-2013 08:58 PM |
Quote:
Originally Posted by Ron in SoCal
(Post 489083)
Gaetano any insight on the changes to your motor and the difference in dyno numbers, other than timing and different dynos/days? That almost looks like you changed/advanced your cam...
|
The motor definitely pulls harder down low now. After that little burnout video Vince posted I was curious on why the car launched so hard and left such dark marks on the asphalt. I checked rear tire air pressures and they were at 15 lbs. Obviously due to the car sitting for so long.
Thinking back, when we dynoed at NYES we only spent about 30 minutes on the dyno. Dont think those guys wanted to spend the time tuning other than playing with the distributor and we made two pulls. Cam was degreed with #1 intake at 106*. We made a pull with the timing at 37* and the other at 39*. When I told Joe about that he said that was way too much timing for a large C.I. small block which kind of made sense to me because my 350's always liked 36* and the 383 liked 34*.
The most recent dyno session the first thing Joe was looking for was where the motor liked total timing and after a few pulls Joe said 32.5. Then we started playing with cam timing. Pulls were made with #1 intake at 104, 106, and 108. All this did was move the power curve up and down the rpm range but it pretty much stayed the same so I opted for retarding cam 2* from where NYES originally set it to 108 which kicked peak torque to a lower rpm but left peak hp at 6300 rpm. Figured that I might pull harder coming out of the corners which is where I want to pick up my lap times. It only kicks peak torque in 300 rpm sooner. Not sure how much difference this is going to make yet and I may not even notice. One thing we didn't do was make a pull after rechecking valve lash at the end of the day. The lash grew quite a bit and Joe readjusted lash .002 smaller than cam specs recommend so the cam was probably alot smaller during the pulls which makes me think the motor is making a touch more power judging by the torque numbers. I should have pushed for another pull after we reset lash but after 6 hours I think Joe accomplished what he wanted to and was ready to get out of there.
He says he's built a similar motor before and can get me another 50 hp with a smaller duration cam but I'm not sure I need to go there. I'd rather not add work to the valve train and I honestly dont think it is hp that wins the race as opposed to reducing weight, tuning the suspension, and spending a little wheel time. |
