Originally Posted by XDman
Im wondering if forking out the money to get my 302c dyno tuned and dizzy re-graphed will give me anymore performance? Its beginning to feel really slack.
Anyones thoughts on this would be great!
Dyno tuning with a strong game plan going in is the strategy that I like to use to save money and time. The last trip in to a chassis dyno, I had everything ready and the engine was freshly back from the engine dyno so I knew which directions to go in with regard to what I was trying to do with it.
The BEST thing that you can do is to write down/record every single change and make sure that the tuners are not overly aggressive or changing more than one thing per pull. I've seen crappy tuners who get some wild hair up their arses and think that they've got a clue about which direction to take in "tuning" an engine. The last guy practically snatched my carburetor off of the engine before I had a chance to even take the car down to the dyno. He was going to put some "serious" jetting in it. I asked him; "Whatcha doin'?" He said that he was changing jets. I told him that I thought that I had the jets right where I wanted them for at least the first pull. He asked me what jets were in it, I told him, 70/78. He told me that I'd need to go to at least 88 in the front and 92-94 in the rear. I told him that I disagreed. (He wouldn't stop fiddling with my carb.) I told him that I had a game plan and that I was happy with my prediction for at least a baseline jetting value. He would NOT stop on my carb, so I told him straight out. (All this time he kept telling me how I would go in so lean that I'd burn up the engine and that I'd just have to add more jetting and waste more time on the dyno, etc.etc.)
I told him that I was an engineer and the way engineers do things is that they make their best possible informed guess and then document their changes after verifying results from careful testing. I told him that I had my best guess in there already and that I wanted to see the results of testing so that I could better understand where my analysis failed, if indeed it would fail based on his predictions. (This same guy couldn't tell you what cam I had, the size of my valves or even what my A/F ratio was on my engine dyno testing, but he was able to spew forth like a mad man about where my jetting absolutely needed to be.) I finally told him to PUT DOWN MY CARB because I was going with the jetting that I SELECTED. He, bitterly, threw it down on the bench (much to my dismay) and retorted with "Well it's your money you're wasting."
First pull on the dyno showed the A/F at 13.2 across the board. Second pull confirmed it. The A/F was perfect. The car was in and out in 20 minutes including hook-up/disconnect time.
He did admit "Looks like the A/F is right." But he never once apologized for his own stupidity or insulting manner that included treating my parts like crap.
The moral of this story is the more you know about your combination the safer you are from all sorts of things.
I do strongly recommend dyno tuning whenever possible and that you have a better than fair idea what is going on with your engine. A reputable shop is a requirement wherever you go whether for checking the air in your tires or jetting your carburetor.