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Haltech Elite injector size change/Auto VE temp compensation

Practical Standalone Tuning

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Discussion and questions related to the course Practical Standalone Tuning

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Pt 1:

Hello all, I have a question regarding injector size tuning on Haltech Elite. I started to learn tuning on an OE Subaru 16bit ECU using open source and cobb software, got interested and it's pretty much a hobby now. so went standalone for the convenience of not having to re-flash every time a change is made and flexibility. The tables related to fueling use pulse width such as "tip in enrichment", warm up, etc. being that they are based on additional pulse width you would put in your injector settings and some math for the percentage difference to reduce those values. obviously i know in the Haltech you input your injector latency and flow, in the base map the enrichment table values are based on percentage. i know you can change the axis to whatever method you want but i figured i'd keep percentage as it seems pretty straightforward. So if i were to change injector size does that mean that (given the VE table, percentages, and injector settings are correct) it would calculate how much enrichment is needed based on injector size and/or VE without having to touch the values?

Pt 2:

i feel like i'm chasing my tail getting my VE table all set, it seems every time i get it real close with low corrections it goes way out of whack like 5%+ corrections. i make sure it's not heat soaked while i'm trying to get it dialed in. how aggressive is the auto temp correction? whenever it gets heat soaked the short term correction starts adding loads of fuel, wouldn't it be the opposite? my temp sensor is in the intake manifold around 1 foot away from the valves. i don't know if it's just the sensor itself getting heat soaked and reducing fuel while the air is actually cooler and short term tries to correct it. i put a little insulating cover over the entire sensor to keep as much heat off of it. i want to try and use a composite bushing in the manifold for a long probe sensor to go into so it's insulated and well into the air stream

I did the same thing as you for a similar reason - I had a hobby background for tuning mine and my friends cars and writing my own software for working with emulators on old chippable nissans (even sold it to a few workshops) - and then after many years away from it - I got a k series honda and a haltech so i could "fiddle with things" to keep myself occupied and have nice datalogging :)

I found with the factory air temp sensor on the k series - and in traffic - the air intake temps would start to read up over 60c and the car would start getting stupid lean with its fueling with auto air temp compensation enabled and using ve tuning. I had to enable air temp compensation tables and add in a tonne of fuel as the sensor heatsoaked to keep the afr close to the target and the stft single digits.

I swapped to using the haltech air temp sensor - and lo and behold - the real air temps were actually closer to 40c in traffic and not the 60c that the factory sensor was saying - and the af ratio stayed way more accurate.

It turns out the factory air temp sensor on my car was a one piece casting of plastic - from the plug end to the sensor head - and the plastic would heat up in the position it was at in the engine bay and that would affect the temp readings. The haltech sensor in the same place in the engine bay didnt have that issue due to its different construction and design.

Touch your intake manifold after a fair drive through traffic - try and hold your hand on it and see just how hot it is - that heat will transfer to your sensor and if your sensor is plastic - then yeah - itll soak and affect temp readings.

There should be very little issue with you relocating the sensor to your intake plumbing before the throttle body and changing the sensor over to an aftermarket one - or if you want to spend the coin - the haltech one - and you should pretty much solve your sensor heatsoak issues.

That's my guess from my previous experience with exactly the same sort of issue as you are describing on my car - at the very least it may give you some ideas to on stuff to check and things to test that may improve your tunable consistency :)

After spending what you have on the haltech - spending a little more on some quality sensors is WELL worth it. Like Andre keeps saying you should never tune around a mechanical / physical problem - you can cludge things with compensation tables n stuff - but it wont be acceptable in the long run and will have its own set of issues. Or, as I've found the hard way - "garbage in garbage out"

As for the question 1 you had - sorry - I dont know the proper answer to that one as you have presented it - I can say that as my injector size changed from 380 to 1100cc I never needed to really fiddle with those tables for accel enrich / de-enrich stuff..... Well, I did fiddle with them anyways - but I didn't need to for drivability stuff they worked fine swapping between them and just updating the injector data.

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