Dyno tuning question

[Mikz86ta]

So I read somewhere, that when they do a dyno run they get to 45MPH and then they go WOT. Plus I seen a dyno run or two in my day and noticed they get going before they 'hit it'.

Why 45MPH?
Also in a manual situation, would you be in 3rd or 4th at 45 before you WOT? I know at 45 and if auto is in 4th it will likely downshift itself. But manual you gotta be in that lower gear so you are not in higher gear and put a lugging load on the engine.

Just curious

[ScarabEpic22]

Its the MPH at which the converter locks in 3rd gear (for 4spd autos, 3rd is 1:1). You can change this to make it lower, adjust the values at which the TC will unlock at WOT to be really low and force it to lockup at an earlier MPH. Then you can get into 3rd and have the converter locked at a lower speed before you hit it, and when you do, it will not unlock the converter.

[Mikz86ta]

Oh I see. So on a manual what would you do?

[minytrker]

There is no magical mph to Dyno something. There are a lot of variables on deciding when to start your Dyno pull and even what kind of Dyno your on. I personally go off rpm and not mph. You want to Dyno in what ever gear is close to 1:1 as possible.

[ScarabEpic22]

There is no magical mph to Dyno something. There are a lot of variables on deciding when to start your Dyno pull and even what kind of Dyno your on. I personally go off rpm and not mph. You want to Dyno in what ever gear is close to 1:1 as possible.

Exactly, I was trying to explain that in my last post (and failed miserably). Pick the gear that is as close to 1:1 and use it, with a manual, just get into that gear with the vehicle moving and the RPMs at a certain point (Ive heard some people like to start at 3000rpms, really personal choice) and go from there.

[Mikz86ta]

Gotcha. I kinda figured it out from ur 1st reply Erik. Basically what u guys just said....at 1:1
My NV3500 5speed is that in 4th gear
I guess its good to figure where ur stock powerband is or where it should be in case u have different engine configurations. I may play this weekend in 4th at 3000 or little lower and see how it does on the scanner. Redhardsupras info on the scanning HP and Tq (street dyno)

[hog]

Its always nice to see at which rpm your peak hp occurs at for torque converter selection. I like to see the torque curve build, so I prefer graphs starting at 2000rpm. But lots of the newer GEN engines are still building at 3000rpm. I also like to compare locked and unlocked TC values.

It also matters if you are using nitrous oxide as well, I wouldnt start the squeeze until after 3000rpm.

I dislike seeing mph graphs, that info is meaningless unless you are figuring shift points, or gearing or some such scenario.

peace
Hog