Thread: Dyno Next Week - What to Test?

What's the basics of operating a car on a dyno? I dont mean strapping it down and hooking it up blah blah blah. I mean things like:

1) how long to wait in between runs
2) do you edit one cell at a time or do you edit a group of cells at a time
3) what is the plan of attack for tuning ignition without EGT

maybe i need my own thread..

I got a dyno at school that I get to use for free Wish I knew how to tune now haha

1.) I would wait at least 5 minutes, don't want the internals to heat soak, especially the intercooler. But that might be different once I get on the dyno and the guys tell me otherwise.

2.)Group of cells is probably the more efficient way to go. If you do one cell, then do a run, then another cell you'll be there all day. From what I noticed the timing maps and fuel maps mainly have similar number blocks.

Example, before say 50% load all of the fuel map will read 14.7, then at say 50+ load it goes to 10.1... So as long as you modify the whole block of similar map it should be good.

Timing is fairly similar at the top end of the load scale from what I noticed. Low end the timing does jump all over the place hehe.



LUCKY! Poor dyno is just being wasted

1. I dont wait a certain amount of time, I make changes and then just do another pull. We have stupid powerful fans on anyway.
2. I'll usually do quite a few at a time depending on where it needs fueling adjustments.
3. Timing = Torque. Watch your torque graph and see what the motor likes. It will tell you when you have too much, power will drop off. And of course pinging is bad

Setzer, so if I modify the timing for low end, I could possibly get more torque huh?

He means you should watch the torque curve when tuning timing (and tuning in general) because it will be easier to see changes in output compared to the HP curve. Dips and spikes in torque are easy to see and use for information, when usually the HP curve just climbs and climbs. All the information is identical in the two curves, it's just easier to see specifics in the torque curve and it's easier to conceptualize and understand what's going on with timing by using the torque curve instead of the power curve. The torque curve shows you what's going on for each combustion event (or group of 4 combustion events), the power curve has time/rpm mixed in there fogging the issue.

Makes sense, thanks for the heads up. This is my first dyno and tune event so trying to grab as much information as possible to make the best use of my money

So I assume you would advance timing in the ignition map until you couldn't make any more torque at a certain RPM, then retard it until you find that sweet spot where the rate of change first becomes zero.

Is there a way to do this just as accurately with EGT on the street?

I've tried in vain to find good resources online for tuning, but I haven't come across anything. Are there good books or online resources for tuning fuel injection on and off the dyno?

Close. First off, usually you can't advance until you stop making more torque. Detonation usually hits first. So you're usually advancing until you find detonation (although loss of torque or same torque for more timing is a good indication of detonation as well). Then you back off 2 or 3 degrees to be safe. You won't loose much power when you do this and you'll gain a lot of safe room.

EGTs can tell you general torque output and alert you of detonation in a similar manner. If you have a known good EGT at the pressure level you're running you can aim for the same EGT throughout the entire rev range and be relatively certain your timing is decent. I would find a guise to tuning with EGTs. They must be out there.

I haven't found a good place with the exact info you're looking for. There are tons of good books on tuning in your local massive chain book store. There's also decent guides online. I haven't found much that covered both street and dyno tuning though in the way you describe.

I recently got back from the dyno and got some pretty cool information. I will be posting this with dyno charts later on today.

All I will say is, 3 bar did a lot better then 4 bar. Seems like the injectors were not liking 4bar at all. It was like a 5whp difference.