Webinar 133 | How to tune a turbo engine

Hi there. I understood most of what was covered in this webinar and it made a lot of sense to me. My main question from this webinar is on boost control. In an engine controlled by non-electronic boost control, is the only way to control boost limit going to be by changing the external wastegate spring? There is no point setting boost limits on the ECU is there? There is no solenoid inputting boost values to the ECU to cut fuel or ignition for safety im assuming. The reason I ask this is because in this webinar, Andre does show a boost control table and talks about boost soft cut.

The turbo and ECU set up I am using is a Precision Turbo 6266 Ball bearing turbo and the ecu is a MAXXEcu Race. This set up uses a 46mm external wastegate (before the turbine housing inlet) that has no electronic function whatsoever; and no other extra boost control solenoid will be used.

Basically, I will not be having to use any of the boost control tables in this ECU as it is all mechanical, right?

Secondly, how do we control our turbo spool simply based on our fuel and ignition mapping? Does retarding the ignition timing produce faster spool because of the higher exhaust gas temps?

also, are you controlling the RPM (at 2500rpm and 4000rpm) by pressing break to hold engine speed but increase the load by pressing on the accelerator at the same time on the dyno at the 32-34 minute mark when showing the fuel correction process?

also, you mentioned "tuning at multiple boost set points"; can you elaborate on what you mean by "boost set points"?

Apologies for the slow reply. If you have no electronic boost control then you're obviously not going to be able to influence the boost inside of the ECU but you do still want to set a boost cut for safety in case something goes wrong like a line to the wastegate blowing off. Without electronic control you can still vary the boost without changing springs. It requires a pneumatic bleed valve that allows you to bleed air off the wastegate which raises the boost. If you do want to vary the boost though I'd suggest you consider adding a 3 port solenoid and wiring it to the ECU. There's plenty of advantages in using electronic control of your boost.

The dyno we are using is a load bearing dyno which has an eddy current power absorber. This means we can tell the dyno to hold a fixed rpm and as we increase the throttle opening the dyno will apply more load to the rollers. If you're running multiple boost set points that can be selected with a boost map switch through the ECU, you want to make sure that your fuel and ignition timing are correct at each of these points while doing ramp runs.

Hi Andre. Thanks for the reply. Noted on the pneumatic bleed valve. I'll do some research on that. Regarding the boost controller, do you recommend any? Also, the installation of boost controllers are abit confusing to me, do you go through that in any of the webinars?

Noted on the dyno; that makes sense now. Still don't quite get what boost set points are. Do you go through this in the "boost control" course?

Boost set points are specific RPM points at specific engine load that you choose to build up your boost curve...

Hello the boost control webinar covers all of your questions too

Regards Ross

alright great. thanks guys