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4D Tuning with Haltech Elite 2000 on a RX7-FD

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I found japaneese documentation about the fuel modeling on RX-7 FD and was surprised to learn that the OEM ECU works in Alpha-N until 27% TPS and above that with Speed Density. I am running only Speed Density at the moment and realised through datalogs that i have a few Cells (kPa) that i can hit with varying TPS positions. For example: as i hit 120kPa with full throttle right on the Lambda target, in can hit those 120kPa also with only 20% throttle opening and as a result, the fueling is around 8% too rich.

The question now is, what would be the best way to get an OEM like behavior for the fueling? I’ve seen the TPS+MAP Tuning for ITB Turbo Webinar and although the car has a plenum with single throttle body – this falls kind of in the right direction. The thing i don’t know though is, if the Elite 2000 would act just like the Link. Should i try and set the primary fuel load to TPS and let the AFR Target Table do it’s work for the MAP side of the fueling? Another suggestion is to leave it at speed density and set up a generic correction table to correct for TPS.

I appreciate any input!

OE manufacturers do a lot of unusual things for a variety of reasons we're often not privy to. The throttle body setup on the FD is also a little unique with the three separate throttle plates and the fact the bottom plate begins opening prior to the two upper plates. SD tuning generally gives great results that are more than acceptable under most conditions however it won't accurately estimate airflow under all conditions. While it adds a little complexity I generally find that even on single throttle/plenum engines you can see more accurate control of the fuel delivery.

You can still do this perfectly on the Elite. For this system you'd just use TPS as your load axis for the main fuel table and use MAP for the axis on the AFR target table. MAP of course is still used on the load axis of the ignition table. In the main settings under 'Fuel' you can enable a 'MAP Correction' table which provides a background compensation for manifold pressure in the background. The way this is set up is to have it set to 0 at 100 kPa (no correction), -100% at 0 kPa, and 100% at 200 kPa etc.

This should then allow your fuelling to track changes based on manifold pressure and your target AFR.

Using tps & map can become more important on a factory throttle setup where there is significant difference in port timing on the secondaries too.