Aftermarket Boost Management

[prj]

ahem ,
I run a greddy boost controller with 2 bars plus of boost.
If the car is mapped for the boost levels correctly, it's reasonably safe. motronic will pull timing should det occur.
if you dont have an afr gauge it will be risky playing with a boost controller.

You contradict yourself in your post.
If motronic is mapped properly, there is no need for a boost controller

You can run 2.2-2.3 bar boost (and probably more) perfectly fine on motronic as well. BTDT.
Also, if you get lean running due to any number of reasons and heavy knock, pulling 3-4 degrees of timing will not save you.

Anyway, why do you need a boost controller with stock engine management?
If you want switchable boost profiles, that's already there. If anyone remotely knowing what he does maps your engine, he can map any boost profile and boost behaviour you ask.

And all the decent aftermarket ECU's have boost control built in.
To me a separate boost controller on a car with that facility already present is like a piggyback. I don't like piggybacks.

[Faheemo]

ahem ,
I run a greddy boost controller with 2 bars plus of boost.
If the car is mapped for the boost levels correctly, it's reasonably safe. motronic will pull timing should det occur.
if you dont have an afr gauge it will be risky playing with a boost controller.

[irish]

will do , should be sorted by xmas, let u know then

[prj]

The ECU might be as well.
If you need someone to "remove all the sh*t" from there as well, I might be able to help

First try how it drives after the hardware modifications have been removed though.

[irish]

hey

thanks for info lads, i have taken car to place where he says he can remove all sh*t that was put in, so maybe it run as it should when done, as long as ecu is not doctored

[prj]

it's fair to assume that the car is running 95RON. if we assume the wastegate is closed at what RPM would the compressor make 1.45 bar? I know that will depend on load etc

If wastegate is fully shut you will instantly make 2+ bar and break your engine.

On stock spring the wastegate opens due to backpressure at about 1.6 bar @ 3000-4000 rpm and 1.1 bar at 6000 rpm from my experience.

[s2_wot]

Retarding timing alone does not always save you. That is why motronic pulls boost as well.
The timing retard is mostly so, that you can run on 95 RON fuel. The boost cut is to save people from destroying their engines.


Yep, this happens on stock AAN past ~1.45 bar. And without the possibility to pull back boost no amount of timing retard will save you

it's fair to assume that the car is running 95RON. if we assume the wastegate is closed at what RPM would the compressor make 1.45 bar? I know that will depend on load etc

If the car must be driven I suggested no aggressive accelerating and not passing 5000 rpm but I have no real technical basis for this.

[prj]

Whilst you do loose the (factory) safety factor with an aftermarket set up would the knock sensors not retard timing prior to the heavy knock you describe..

Retarding timing alone does not always save you. That is why motronic pulls boost as well.
The timing retard is mostly so, that you can run on 95 RON fuel. The boost cut is to save people from destroying their engines.

My concerns were mostly about the knock detection and also perhaps the car is running lean with more air than the ecu is prepared for.

Yep, this happens on stock AAN past ~1.45 bar. And without the possibility to pull back boost no amount of timing retard will save you

[s2_wot]

I would be concerned about the fuelling too, if they did the boost management the dirty way god knows how they went about adapting the fuelling to suit. If it were me i would rip all that crap out and revert to stock. No point messing around with a stock setup. The real question is did they do anything to the ECU?

The ECU was played with, damaged and put back to stock.

if the guy just wants a non-dodgy car again, rip that sh*t out, go back to stock ECU and get it properly remapped.

I think the route he'll have to take is pull those aftermaktet modifications out and get a safe chip put into the ecu. Then enjoy the car for what it is safe in the knowledge that any other problems could be sorted.

[Dan]

VEMS is great for what it is, but if the guy just wants a non-dodgy car again, rip that sh*t out, go back to stock ECU and get it properly remapped.

[newsh]

Is there a good place to buy these from? Roughly what would they set you back?

Google Vems Round

[mcandmar]

I would be concerned about the fuelling too, if they did the boost management the dirty way god knows how they went about adapting the fuelling to suit. If it were me i would rip all that crap out and revert to stock. No point messing around with a stock setup. The real question is did they do anything to the ECU?

[HMS-S6]

I would think the obvious ones that can be checked are AFR, Boost and EGT through after Market gauges.

Is there a good place to buy these from? Roughly what would they set you back?

[s2_wot]

My concerns were mostly about the knock detection and also perhaps the car is running lean with more air than the ecu is prepared for.

I'm no expert but the car feels like the wastegate is closed all the time. With any of these cars I've driven / been a passenger in if you got to full throttle or close to it from low rpm you car hear and feel the wastegate fluttering via the N75.

With this car it feels more progressive once it begins to come on boost and there seems to be nothing to restrict or cut the boost to suit the fueling.

Maybe someone put a 1 tonne spring into the wastegate or something like that. When you come off the throttle there is a tissss noise from a dumpvalve that was fitted too.

[Dan]

My gut feeling is it's kinda risky - you don't know what this black box is doing / trying to do and as prj says, could just be holding on boost regardless of knock etc.

Far better to run through the ECU/N75 and have it mapped properly.