NefMoto

I was playing with getting high levels of boost working on a GT3076R with an external gate. Now being external the duty is extremely linear already. We wanted to push boost up from 20psi to 25psi flat from about 4k-7.5k and found duty of about 57% worked a treat.

So I set CWMDAPP originally to 1, then setup KFLDRAPP with our desired duty. Obviously I had all torque monitoring turned off and idle etc were issues. But I went on to change CWMDAPP to 8 and the car with a bit of duty tweaks drove extremely well.

So I know that running CWMDAPP as 1 isn't ideal and i've researching a number of topics on here. But what are peoples thoughts about using CWMDAPP = 8 permanently for open loop boost control.

Are there any other negatives, or is there anymore positives to go back and attempt to run openloop using KFLDRL?

Bearing in mind I've not yet been successful in attempting to port the 5 bar hack to the Vauxhall's yet so am unable to pursue closed loop at the moment.

Hello Rabbid
I asked myself the same question. What has been your experience with use CWMDAPP = 8 permanently over the last 10 years?

Here's 7 negatives:

1. Do two back to back runs. One on colder exhaust, one on hotter exhaust. The 2nd run will have way higher boost. If you do 3 runs, then it will be even higher.
2. If you hit a little worse fuel and have more timing retard -> more energy in exhaust gas -> higher boost -> more knock etc.
3. Altitude. You will have different boost at every altitude. The higher you go the less boost you will have.
4. IAT - cold vs hot temperature. You will have severe overboost with denser air.
5. Shit spool. Instead of going to 100% duty and then regulating as the boost goes up, you have a perpetually laggy car when flooring in midrange.
6. Different boost in each gear, laggy in low gears.
7. Throttle controller constantly fighting with the turbo in midrange.

Really, really stupid idea for people who can't tune for shit.

If you just need a little more boost, say 2 bar instead of 1.5, and you lack the brain to do a 5120 mod, then just fit 3 bar sensor(s) and underscale everything by about 17% where ECU thinks that it has 2.5 bar but actually has 3 bar absolute.
Adjust the ambient pressure sensor linearization as well so that with ignition on both more or less match (by reducing multiplier and increasing offset) or turn off the cross check diags.
This will work just fine until 3 bar or so without any big complications, and even though not ideal, it is still better than grenading your engine and the car driving like shit.

Wow, I'm impressed. All the things that would go wrong... :o Thank you for your explanations.

How to eventually destroy everything with one value change