Tuning for increased supercharger boost

Hi Andre and everyone!!

I currently have a Toyota 86 with a Sprintex supercharger and I'm looking to decrease the pulley size to increase boost. What sort of things am I going to need to change in my current tune?

I assume I'll have to re-calibrate the MAF

Will I have to change fueling?

Will I have to adjust any timing to prevent knock?

Thanks in advance!

You won't need to recalibrate the MAF sensor to handle an increase in boost (provided you're remaining inside the MAF sensor's range). One of the advantages of a MAF based ECU is that the AFR should still track target pretty accurately as you increase the boost so there is little that needs to be done. As you increase boost you will end up in a different load range in both the AFR target and ignition tables. You will need less timing as you increase the boost but you will see that this is the natural progression in the ignition table anyway. It's simply a case of confirming exactly what timing the engine wants.

Just be careful with the pulley changes as the base sprintex kit is basically at its rated rpm limit as delivered. There's a very small window for boost increase before you exceed the recommended max rpm for the supercharger. We did a pulley swap on a sprintex kit a while back and saw almost no change in power (I think we may have seen an additional 3 kW atw max). so weigh up the cost vs reward.

Thanks for the reply! That makes the job seem a lot easier indeed.

In regards to the pulley sizing etc, I'm more so doing it as an experiment and I've been talking to the engineers over at Sprintex about it and we think it should be pretty fine as it's only "continuous RPM limit" that they worry about. And this is their SPS system which ships with the 69mm pulley as standard.

Thanks for the help and I'll be sure to post results!