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SR86 shift strategy and RPM limiter

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Hi Team,

This question is more directed towards Andre in regards to the shops SR86. I have just finished watching the whole build series and update videos and have a similar problem with the head.

At the start of last year I sold up my turbo 86 track car to a mate and bought a already modified s15. Its 2.2L stroker with a P11 head, oversized valves, kelford beehive springs and Ti retainers, Turbo X-trail cams, hypertune inlet, GT35-x gen 1 turbo. The car also runs a Tractive sequential gearbox. The ecu it came with was a older haltech sprint unit and was out of inputs and generally past its time to run this car to where i wanted it.

Over the last year I've changed the wiring loom, ecu, added a dash, bosch motorsport throttle body, added wheel speed sensors as they had been removed and whole bunch of other sensors so everything can be logged and monitored. I went with the Motec M150 GPRP package and a C127 dash. The car has never been setup for flat foot shifting with the old setup and the old owner just used the box like a regular manual with clutched shifts, which i wanted to changed and use it to its full potential.

There was no way i am confident enough to tune the car so I had it tuned by someone i trust and am happy with the results and the overall job in the setup. I took the car out for some laps around the block after we had setup the flat foot shifting and traction control and it felt great. Now being new to these engines and not knowing how delicate they can be when it comes to rpm limiters and shift setups, when i came back from the drive it seems its dropped a shim!!

After watching your whole build series and seeing what happened to you guys with the dropped shim i checked out how we had setup the RPM limiter and unfortunately we had it setup via ignition cut. After watching the webinar on RPM limiters I now know we need to change this to be Fuel cut only to avoid this issue again.

My question is regarding the shift cut side of things. I asked my tuner how mine is setup and he said the gearshift strategy starts by throttle reduction to 50%, retarding the timing about 35 degrees and goes into a closed loop ignition and fuel cut strategy based on how effectively the engine reduces power and RPM for the next gear.

How have you got the SR86 setup in this regards? I really want to try not let this happen again as you already know how costly and time consuming it can be when it happens. Also like you guys i was booked in to be at the track next week but that wont be happening now lol.

Thanks for the help,

Bret

If you want Fuel Cut rather than Ignition Cut, set the Gear Shift Engine Speed Limit Fuel Margin to a negative number. Have a look at the Help for Engine Speed Limit Default Fuel Margin for a more detailed description of it's operation.

Ok thanks mate i'll have a look at that. Much appreciated.

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