RB25DE NEO with Haltech ECU

[Haggerty]

I seem to the be only person that is using a Haltech 2500 on an NA motor, I've installed a Bosch DBW throttle body to the OEM intake manifold and am having problems maintaining AFR even with the wideband o2.  It will run extremely rich at idle and up to redline, but under load it will go extremely lean in the 20s and i'm essentially having to rev it over 4k and feather the clutch to get it up to speed.  I've read a few other threads of about the butterfly, it seems removing the vacuum to it is supposed to have it remain open, i've noticed no difference under 4k with the vacuum line to it plugged. 

I'm hoping someone here has had luck using the NA manifold with Haltech, and if they happen to have a tune for it.  

[MBS206]

You very likely need to get it on a dyno and tune it.

My assumption is, you've got an RB25DET tune in it, which has a different manifold, different injectors, and different cams as a minimum.

What O2 sensor are you running?

 

When you say it runs extremely rich from idle all the way to redline, is this just free revving it you see that?

[Haggerty]

Yep, the closest base tune available was for the GTT, I went with that and made all the logical changes I could find to convert it to Naturally Aspirated.

It will rev fine in Neutral to redline but it will be cutting nearly 50% fuel the whole way.  If I let it tune the fuel map to start with that much less fuel it wont run right and has a hard time applying corrections.  These 50% cuts are with a fuel map already about half of what the GTT tune had.  I was having a whole lot of bogging when applying any throttle but seem to have fixed that for no load situations with very aggressive transient throttle settings.

I made the corrections to my injectors with data I found for them online, FBCJC100 flowing 306cc.  I'll have to look to see if I can find the Cam section.

I have the Bosch 4.9 from Haltech.

My manifold pressure when watching it live is always in -5.9 psi/inHg

Edited yesterday at 01:43 PM by Haggerty

[Murray_Calavera]

@Haggerty This seems silly to ask, but are you confident in your ability to tune the Haltech?

 

[GTSBoy]

Shouldn't need a "base map" for anything other than guidance to ignition tuning. You just need the engine capacity right, the injector size right, and something, almost anything, for a VE map.

On an NA engine, fuelling is almost completely a function of load signal & rpm. It should run and drive with a completely flat fuel map. It will be too lean under load, but that's easily fixed.

We used to tune all ECUs without any base map. There were no such things (until someone had tuned a near stock engine on one, and then they had a "base map".

[Kinkstaah]

For fuelling the Haltechs have O2WB fuel controllers. Very useful for helping tuning VE and correcting for *small* mistakes.

Of course if your injector/cam/trigger/sensor data is just wrong (or for a GTT which is not a GT) then you will get impossible reactions to things.

I am sure you know this already but the reason people don't typically put haltechs (or any Aftermarket ECU) on GT's is because there's practically no real gains to be had - So this knowledge won't be commonplace.

[Haggerty]

As far as I can tell I have everything properly set in the Haltech software for engine size, injector data, all sensors seem to be reporting proper numbers.  If I change any injector details it doesnt run right.   

Changing the base map is having the biggest change in response, im not sure how people are saying it doesnt really matter.  I'm guessing under normal conditions the ECU is able to self adjust and keep everything smooth.  

Right now my best performance is happening by lowering the base map just enough to where the ECU us doing short term cut of about 45% to reach the target Lambda of 14.7.  That way when I start putting load on it still has high enough fuel map to not be so lean.  After 2500 rpm I raised the base map to what would be really rich at no load, but still helps with the lean spots on load.  I figure I don't have much reason to be above 2500rpm with no load.  When watching other videos it seems their target is reached much faster than mine.  Mine takes forever to adjust and reach the target.

My next few days will be spent making sure timing is good, it was running fine before doing the ECU and DBW swap, but want to verify.  I'll also probably swap in the new injectors I bought as well as a walbro 255 pump.

 

[Haggerty]

I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor.

When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.