Dyno tune with wrong injector dead time (lag time)

[Artem-makarchuk]

I built D16 Turbo, Vitara + Eagles, GT2871, Siemens Deka 830cc injectors and goes to dyno tune.
I had low power goal 275 Hp at 20 psi with 8.2 CR and misfire problem at WOT. Ignition system is OK, sparks BKR8E, new oem wires, new distributor cap.
Next day i had problem with start and idle on cold, alot misfire at WOT.
In calibration wrong dead time (lag time) for my injectors, now 0.45 at 14V, but for Siemens 830cc need 0.71 at 14V.
My tuner told me that all ok.

I need to retune with wright dead times ???

[Spunkster]

You should always tune with the correct dead times, or you w ill have to retune if you change the dead times later.

[crucian]

If the car is misfiring and not starting, the entire tune is NOT right and it's more than just the dead times. If the tuner is telling you that the car is ok and you feel that it's not. Try finding another tuner.

[Artem-makarchuk]

I retuned engine with right lag times and injector size, all Ok.
Engine had smooth idle, good cold start and good work.

But old tuner told me, that injector size, dead times and fuel pressure does not matter for engine tuning, because hondata have same calculation coefficient for all injectors, dead times and fuel pressures.

Is he right ???

[forevertrj]

that doesn't sound right at all, dead times are there because thats how they physically act in real life and were measured by the injector company hence the need for dead times ... and hondata as far as I know doesn't have a fuel pressure sensor, hence why you set the fuel pressure on your FPR with a gauge on the fuel rail, and dependant on your fuel pressure will change the base deadtime for your injector, less fuel pressure will normally result in a lower dead time, higher fuel pressure more dead time. if everything is running good I'd leave the dead times as the data sheet specified and hopefully the the tuner tuned the car with those values, you can always modify the AFR if it's off, street tune won't be as good as using a dynamometer but you can correct small variances easily with a data log.