IFR effects on LTFT and WOT??
IFR will have a direct affect on LTFT's as well as you AFR at WOT. Do not change IFR at all unless you change to a different sized injector. Do tuning via VE and MAF tables.
so let's say you're mixing cement 
your shovel can move 1 pound of cement per second to the mixer (or whatever that's called) you supposed to mix cement and water in 1/13 proportions. you have a hose going in there that you believe delivers 13lb/sec of water. however, the hose is clogged, and you don't know about it, all you know is that your mixture despite your best effort is a bit off. so instead of checking what's wrong with the hose, you decide to grab a bigger or smaller shovel depending if your mixture is too watery or too solid.
did you get the right mixture in the end? yes. did you get the right amount of it? no!
this is exactly what IFR tweaking does to your engine. instead of looking at the source of the problem, you just try to make up for it somewhere else.
your shovel can move 1 pound of cement per second to the mixer (or whatever that's called) you supposed to mix cement and water in 1/13 proportions. you have a hose going in there that you believe delivers 13lb/sec of water. however, the hose is clogged, and you don't know about it, all you know is that your mixture despite your best effort is a bit off. so instead of checking what's wrong with the hose, you decide to grab a bigger or smaller shovel depending if your mixture is too watery or too solid.
did you get the right mixture in the end? yes. did you get the right amount of it? no!
this is exactly what IFR tweaking does to your engine. instead of looking at the source of the problem, you just try to make up for it somewhere else.
Originally Posted by RedHardSupra
so let's say you're mixing cement
your shovel can move 1 pound of cement per second to the mixer (or whatever that's called) you supposed to mix cement and water in 1/13 proportions. you have a hose going in there that you believe delivers 13lb/sec of water. however, the hose is clogged, and you don't know about it, all you know is that your mixture despite your best effort is a bit off. so instead of checking what's wrong with the hose, you decide to grab a bigger or smaller shovel depending if your mixture is too watery or too solid.
did you get the right mixture in the end? yes. did you get the right amount of it? no!
this is exactly what IFR tweaking does to your engine. instead of looking at the source of the problem, you just try to make up for it somewhere else.
your shovel can move 1 pound of cement per second to the mixer (or whatever that's called) you supposed to mix cement and water in 1/13 proportions. you have a hose going in there that you believe delivers 13lb/sec of water. however, the hose is clogged, and you don't know about it, all you know is that your mixture despite your best effort is a bit off. so instead of checking what's wrong with the hose, you decide to grab a bigger or smaller shovel depending if your mixture is too watery or too solid.
did you get the right mixture in the end? yes. did you get the right amount of it? no!
this is exactly what IFR tweaking does to your engine. instead of looking at the source of the problem, you just try to make up for it somewhere else.
Originally Posted by brad8266
IFR will have a direct affect on LTFT's as well as you AFR at WOT. Do not change IFR at all unless you change to a different sized injector. Do tuning via VE and MAF tables.
I don't agree with this of tuning the MAF table because it messes with timing too (indirectly).
I really prefer IFR alone.
Originally Posted by tici
Timing depends on G/cyl which depends on G/sec.
I don't agree with this of tuning the MAF table because it messes with timing too (indirectly).
I really prefer IFR alone.
I don't agree with this of tuning the MAF table because it messes with timing too (indirectly).
I really prefer IFR alone.
Last edited by brad8266; Apr 9, 2006 at 01:22 PM.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Originally Posted by tici
Timing depends on G/cyl which depends on G/sec.
I don't agree with this of tuning the MAF table because it messes with timing too (indirectly).
I really prefer IFR alone.
I don't agree with this of tuning the MAF table because it messes with timing too (indirectly).
I really prefer IFR alone.
as an additional perspective...
IFR is an easy constant to get right. VE can be tuned with a correct IFR, and MAF can be tuned with a correct VE and IFR. Now spark can be tuned because MAF, VE & IFR are correct.
IFR is an easy constant to get right. VE can be tuned with a correct IFR, and MAF can be tuned with a correct VE and IFR. Now spark can be tuned because MAF, VE & IFR are correct.
Originally Posted by joecar
And if IFR, VE, MAF are correct, then PE becomes 'what you see is what you get'.
Originally Posted by SSpdDmon
In EFILive, it tells us that timing comes from the GM.DYNCYLAIR_DMA pid. So, regardless of the MAF, timing is calculated this way. Not tuning the MAF is only going to lead to bandaiding the fueling to get your AFR's in line (just the same as "tweaking" the IFR tables).
Originally Posted by RedHardSupra
it's not THAT simple, but it is the idea. normally spark and ect has a lot to say about your real vs commanded afr. it is helluva lot closer than doing it using any other method, but the best part is that the only thing you have to change is PE, which doesn't screw up your normal driving, as it applies only to WOT.
Its great now that I got ve and MAf dialed in cause now I can easily do the division in order to quickly go in and change AFR. Every time I want to change AFR at WOT all it takes is a quick change in the PE table and its done.
Originally Posted by SSpdDmon
In EFILive, it tells us that timing comes from the GM.DYNCYLAIR_DMA pid. So, regardless of the MAF, timing is calculated this way. Not tuning the MAF is only going to lead to bandaiding the fueling to get your AFR's in line (just the same as "tweaking" the IFR tables).