TurbochargedBerserker Posted October 22, 2004 Report Share Posted October 22, 2004 So I ran a little experiment to see if my VE table results mentioned in the other thread (getting 60-80% VE using the SD method) were screwy because my IFR values were too rich. Makes sense, right? VE is very low hence IFR is too rich... Anyway, I made two runs -- one with the stock ve table and IFR of 5.44 (old value was 5.15), and another run with the stock ve and IFR of 5.75. The first run's results are almost identical to the 5.15 setting, and the second run is closer to ideal, but still shows -10 LTFT in many areas. I cleared the LTFTs in both runs and tried to avoid boost. Why didn't the 5.75 setting make the LTFTs lean? It certainly would with the MAF plugged in. I arrived at the 5.15 IFR by computing new inj size / old inj size * old IFR. I've also talked to about a million people who say that the 42# stubbies are around 5.2 IFR. Thing is, at 5.15 the truck seems pretty rich (AFR gauge is 2 leds into rich). At 5.75, the AFR gauge is right at the top of stoich, but also crashes out the o2s every now and again (and I mean crashes... they go to < 10 mv). Looking at a graph of the o2s, 5.75 is really sleepy most of the time, 5.44 is kinda sleepy, and 5.15 is still a bit sleep at times. Is there an exact formula for calculating IFR based ONLY on the injector size (and not on the old value, etc.)? Link to comment Share on other sites More sharing options...
SSminneapolis Posted October 22, 2004 Report Share Posted October 22, 2004 the only IFR calculations that i have seen take into account your stock injector size. not sure what to say about that one... might be time to kneel down and pray to the tuning gods...or you could call whomever you got your injectors from and see what they normaly are set at in tuning applications...they should know...but then again you never know. Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted October 22, 2004 Author Report Share Posted October 22, 2004 This ends up being the problem of not having the IAT sensor working. Fixed. Link to comment Share on other sites More sharing options...
deezel Posted October 23, 2004 Report Share Posted October 23, 2004 FYI the 42lbs injector rating is supposed to be 42 lbs/hour (at the rated fuel pressure). The value in Edit or HPT is grams/second. Just a metric/units conversion... Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted October 23, 2004 Author Report Share Posted October 23, 2004 FYI the 42lbs injector rating is supposed to be 42 lbs/hour (at the rated fuel pressure). The value in Edit or HPT is grams/second. Just a metric/units conversion... <{POST_SNAPBACK}> Really?? (smacks head with hammer) That's too easy... I can't believe the mess on the internet about IFR. My injectors are rated at 43.82 lb/hr @ 58psi on the racetronix flow bench which is 5.52 g/sec 42 lb/hr is 5.292 g/sec Link to comment Share on other sites More sharing options...
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