Hi all

Have just built a miata powered kit car, 1600 with a TD04H turbo interccoled running a MAXXECU, have been playing with efi megasquirts on NA motors for a number of years so new to the boosted world. i want to run two boost settings, 7psi and about 12 psi. yeah old school numbers....

A couple of question if i may.

I understand you switch between boost tables to get required boost levels

BUT

what about timing tables and fuel

seems to me 1 table for each will cover it, as the boost scale on the side goes to what ever you set, and if the boost is only using 1/2 the scale on one setting then the full scale on both, 2 tables are not required?

Can someone enlighten me please

cheers from NZ


Exocet kit

 

For fuel and spark I do something similar, 15psi wastegate and then a 20psi high boost setting I run a switch that just toggles the signal to the EBC (to be clear, it is always enabled in tunerstudio and the switch just interrupts the signal, when off its straight wastegate) and then my tables are scaled to 250kpa (about 22psi) and is tuned for the 205kpa (15psi) and the higher 240kpa (20psi)
works fine for me and boost can be instantly changed with the button. I found it annoying to have to cycle the power on the ECU to switch EBC maps so this was my simple solution

 

I setup dual boost in a previous car, an 1995 Escort GT that I turbocharged (1.8 BP). I know EBC is better but at that time, aftermarket ECUs were far and few between, nothing was plug and play and all were $$$. I'm just throwing this option out there that an extra vacuum solenoid worked well for me with MBC. I installed a switch near the boost gauge, down was low boost, up was high boost...I don't remember which energized the solenoid but it switched pathways in the vacuum hoses between wastegate which bypassed the MBC and air being forced to flow through the MBC. Low boost was 6-8 psi for rainy days or anybody other than me driving, and high boost was 13-14 psi for me on a tiny IHI VJ20 turbo from the Mazda 323 GTX.

I like Dr. Sep's solution to avoid power cycling the ECU. Once my built engine is installed and broken in, the next step will be installing EBC and tuning it. One question remains, Dr. Sep...does the switch also activate a second fuel and spark table? As pedronz mentioned, it seems if you're tuned for maximum boost and everything below, there should be no need to switch tables. It would only necessary for different fuel like 91/93 and E85 without having a sensor for blend capability, correct?

 

it does not change any fuel, spark, or EBC tables it uses 1 table tuned for both boost levels and the switch just interrupts the signal to the EBC

it is the most simple solution for having 2 on-the-fly switchable boost levels (that I've found anyways) and has worked without issue for me. Certainly not the most elegant, and probably "leaving some spool on the table" when running just wastegate compared to EBC assisted spool -- but eh, its just a street car anyways, the efr spools plenty quick without EBC cruising around