Injector Latencies

UTEC/Hydra/MOTEC? STi, WRX, EVO, Legacy, R32? Come on in!

Moderator: Moderators

Post Reply
User avatar
Phibs
DCAWD Groupie
Posts: 1197
Joined: Tue Dec 21, 2004 7:00 pm
Location: Sterling, VA
Contact:

Injector Latencies

Post by Phibs »

Looking at the map I have from jeff my latency table is as follows:

7.81, 2.81, 1.65, 1.18, 0.78

The nasioc archive for my injectors recommends:

850 cc 3160 PE 850cc 2004+ STi Fuel Injectors 9.80, 2.70, 1.80, 1.50, 1.30

Which are right??
Bryan
2012 WRX 5-Door Limited
User avatar
zaxrex
DCAWD Founding Member
Posts: 6350
Joined: Mon Sep 06, 2004 8:00 pm
Location: asiandale

Post by zaxrex »

Latency is a physical characteristic of an injector. If you know the latency for the injectors that you are using under a defined voltage and fuel pressure, then you can scale them to make sure that you are having the ECU open them long enough for the right amount of fuel to flow in. But that is if you are having a fuel problem.

What are your AFRs? If they are within reason, and all the other parameters are good, then I would not worry about latency tuning.

If you are still having issues that don't show up as a log number from the engine, maybe your style of driving needs to match the new mechanical ability of the hardware that you installed.
Patience is the ability to idle your motor when you feel like stripping your gears
User avatar
Phibs
DCAWD Groupie
Posts: 1197
Joined: Tue Dec 21, 2004 7:00 pm
Location: Sterling, VA
Contact:

Post by Phibs »

zaxrex wrote:Latency is a physical characteristic of an injector. If you know the latency for the injectors that you are using under a defined voltage and fuel pressure, then you can scale them to make sure that you are having the ECU open them long enough for the right amount of fuel to flow in. But that is if you are having a fuel problem.

What are your AFRs? If they are within reason, and all the other parameters are good, then I would not worry about latency tuning.

If you are still having issues that don't show up as a log number from the engine, maybe your style of driving needs to match the new mechanical ability of the hardware that you installed.
What would be the symptoms of too much fuel flowing in? I am getting about 180-190 miles per tank after the modifications and I am not driving any differently than I did before, when I got ~ 300.
Bryan
2012 WRX 5-Door Limited
User avatar
zaxrex
DCAWD Founding Member
Posts: 6350
Joined: Mon Sep 06, 2004 8:00 pm
Location: asiandale

Post by zaxrex »

Phibs wrote:What would be the symptoms of too much fuel flowing in?
High AFR readings, or AFR "hunting" at cruise. Your tune was for the small period of time when you are pushing it. For the rest of the time IRL, you won't be able to tell from your organic posterior accelerometer. You may be able to smell more of your exhaust, and your pipes will soot up faster than before.
Phibs wrote:I am getting about 180-190 miles per tank after the modifications and I am not driving any differently than I did before, when I got ~ 300.
Once you have the off throttle AFRs fixed, it would be a good idea to adjust how you drive to make the most use of all the things you replaced.

When I "got bigger", I found myself mashing on the gas a bit harder down low b/c there used to be torque down low and I was expecting it. When the bigger turbo comes in, everything shifts to the higher RPM range and you have to change the way you drive.

My mileage was bad, but I got it going back up again as I learned how to have the engine and gearing matched up.
Patience is the ability to idle your motor when you feel like stripping your gears
User avatar
Sabre
DCAWD Founding Member
Posts: 21432
Joined: Wed Aug 11, 2004 8:00 pm
Location: Springfield, VA
Contact:

Re: Injector Latencies

Post by Sabre »

Phibs wrote:Looking at the map I have from jeff my latency table is as follows:

7.81, 2.81, 1.65, 1.18, 0.78

The nasioc archive for my injectors recommends:

850 cc 3160 PE 850cc 2004+ STi Fuel Injectors 9.80, 2.70, 1.80, 1.50, 1.30

Which are right??
Leave them where they are. Jeff probably adjusted them so that your idle was smooth.
Sabre (Julian)
Image
92.5% Stock 04 STI
Good choice putting $4,000 rims on your 1990 Honda Civic. That's like Betty White going out and getting her tits done.
User avatar
gsx-lex
DCAWD Groupie
Posts: 699
Joined: Thu Dec 16, 2004 7:00 pm
Location: Columbia
Contact:

Post by gsx-lex »

Are you able to log your long term and short term fuel trims? if so, make sure that the ECU is adjusting as little as possible (This may be hard to do with the recent weather change). As Zarex mentioned, what are you AF trims doing at Idle and partial throttle?
Have turbo, will spool.
I <3 Lesbians
Image
Post Reply