Ls2 Injector Flow rate?
Thread Starter
Drifting
Joined: Jan 2005
Posts: 1,827
Likes: 301
From: Tucson Arizona
St. Jude Donor '08
Ls2 Injector Flow rate?
What are the correct 0kPa and 80kPa flow rates for a 2005 C6 with stock injectors and why would a tuner change those settings from stock (33.1-36.2) to 31.2-34.2? Cold air intake? Thoughts?
Drifting
Joined: Apr 2006
Posts: 1,276
Likes: 5
From: Ambler Pa.
6% less fuel, leaner puts you right around 12.4 , which is a good , safe ratio for E10 gasoline. [ equivalent to 12.9 for straight gas ] IMHO
Melting Slicks
Joined: Oct 2000
Posts: 2,235
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From: Herndon VA
Don't have my tuning laptop in front of me, but the only reason to change the IFR table is if you put different injectors in. If he changed it for any other reason, he's a hack.
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
4.168335
4.194336
4.219848
4.245849
4.271240
4.296630
4.321655
4.346923
4.371826
4.396606
4.421142
4.445556
4.469848
4.494140
4.518432
4.542358
4.566040
or
33.082501
33.288861
33.491346
33.697706
33.899222
34.100738
34.299347
34.499894
34.697534
34.894206
35.088940
35.282705
35.475502
35.668298
35.861094
36.050984
36.238937
2005 Corvette E40
You don't adjust IFR to set PE. You adjust IFR when you change injectors.
Elmer
Last edited by eboggs_jkvl; Feb 11, 2011 at 12:42 PM.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
This was a common technique years ago before tuners learned how to tune the right way.
The PCM injector duty cycle is based on the time needed to inject a targeted amount of fuel from a the IFR. By putting in a lower IFR, the PCM duty cycle will be longer thus it makes its richer.
If the tuner is trying to make it richer for E10 fuel, then he should be changing stoich not IFR. If he is trying to make it richer for any other reason the VE, MAF, and PE tables are there to do that.
I agree, if the IFR is different than the actual injector rating, its a hack.
Thread Starter
Drifting
Joined: Jan 2005
Posts: 1,827
Likes: 301
From: Tucson Arizona
St. Jude Donor '08
Bad news
A previous highly respected Forum Vender speed shop did the original changes to the IFR along with MAP, and a present highly respected Forum Vender made changes to those same areas including IFR all around 2007. Neither used the factory settings.
1. Were both in error or out of touch?
2. Done this way because it was an email/street tune?
3 Thought the factory settings were incorrect.
By the way, the first tuned cost and second was for free.
Thoughts? Anyone want to explain why this is a legitimate tune and that I don't have to start all over resetting the IFR to facrtory settings as their are no mods requiring larger injectors. They run 77% at wot.
1. Were both in error or out of touch?
2. Done this way because it was an email/street tune?
3 Thought the factory settings were incorrect.
By the way, the first tuned cost and second was for free.
Thoughts? Anyone want to explain why this is a legitimate tune and that I don't have to start all over resetting the IFR to facrtory settings as their are no mods requiring larger injectors. They run 77% at wot.
Safety Car
Joined: May 2006
Posts: 4,016
Likes: 93
From: St. Louis, MO
Tech Contributor
It's called idiocy. Hack jobs tune by pushing the IFR around to compensate for fueling error because either their software is inadequate or they just don't know what they are doing.
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Just wanted you guys to know many tuners take short cuts.
Common things they do is change the PE table to command a much higher A/F ratio during open loop/WOT to delivery what they want.
To put it another way, suppose its 30° outside your house and you want your house inside to be at 70°, but you have set set your thermostat at 80° because your thermostat is out of calibration. Yes, you get 75° but the right thing to do is get your thermostat calibrated. What happens if the outside temp goes down to 10°? Do you have to reset your thermostat to 85° to get it at 70°?
The right way is to first recalibrate the IFR, MAF, VE tables to deliver the commanded A/F ratio. Then add/subtract fuel via the PE table which deliver the right amount of fuel so the actual A/F ratio equals the commanded A/F ratio. Otherwise as conditions change, the A/F ratio will not be right. This takes more time than some tuners want so they go directly to the PE table and rape it.
Go read Greg Banish's books or take one of the classes.
Common things they do is change the PE table to command a much higher A/F ratio during open loop/WOT to delivery what they want.
To put it another way, suppose its 30° outside your house and you want your house inside to be at 70°, but you have set set your thermostat at 80° because your thermostat is out of calibration. Yes, you get 75° but the right thing to do is get your thermostat calibrated. What happens if the outside temp goes down to 10°? Do you have to reset your thermostat to 85° to get it at 70°?
The right way is to first recalibrate the IFR, MAF, VE tables to deliver the commanded A/F ratio. Then add/subtract fuel via the PE table which deliver the right amount of fuel so the actual A/F ratio equals the commanded A/F ratio. Otherwise as conditions change, the A/F ratio will not be right. This takes more time than some tuners want so they go directly to the PE table and rape it.
Go read Greg Banish's books or take one of the classes.
Last edited by Mez; Feb 19, 2011 at 11:06 PM.
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Safety Car
Joined: Feb 2008
Posts: 3,712
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From: TEXOMA
St. Jude Donor '08-'09
Many, Many, 'Pro" tuners are scared to goto the hptuners forum, because there tunes get tore up if posted.
Safety Car
Joined: Apr 2004
Posts: 3,932
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From: Hayward California
What did you pay for the tune(s) and did it involve a dyno or driveability tuning?
Thread Starter
Drifting
Joined: Jan 2005
Posts: 1,827
Likes: 301
From: Tucson Arizona
St. Jude Donor '08
If my memory serves me, it was $150 for the first and free for the second. After each of several tune changes, I would do a driveability scan and forward to the tuner.
