Electronic boost controller Vs. Mechanical boost controller

[andyleaves]

OK apart from the obvious;
Which is better for my legnum? Or more effective?

Would I need to upgrade the BOV at the same time?
(I know this is really sad, but would to get a BOV that made the same sound as the original Dump Valves from the Sierra Cossie, , what can I say grew up in the time, when they first came onto the rally scene and just loved the ay they looked and sounded???)

[Turbo_Steve]

With the best will in the world, dude, have you searched - there is an ENTIRE FORUM dedicated to boost control, and the information you're after is covered in there many, MANY times over.

Rally cars don't run dumpvalves - the sound you hear is either wastegate chatter (the squeaking) or turbo stall (chufffufufufuuffff). It sounds great, but our sleeve bearing turbos won't last long under that kind of abuse.

VTA dumpvalves also compromise the cars driveability somewhat, and further increase fuel consumption.

[andyleaves]

Ouch Steve!

[aboo]

I'v had a MBC & a VTA BOV for over a year now with no problems.
No probs at RR & 1/4 mile time talks for its self & fuel consumption has'nt changed that much unless I rag it.

[Turbo_Steve]

aboo - try putting the factory one back on for a long journey. I did, and was truly shocked at how differently the car behaved. I've had similar on several Evos - fitted VTA and enjoyed the noise etc, but had issues with gentle throttle changes - especially as boost starts to build. It's absoloutely the same flat-out though.

You MIGHT be fine - it's one of those maybe / maybe not things, but it definitely affects the MAF readings, and definitely causes you to use (a bit) more fuel.


The argument for electronic boost control is that you will have less of a spike and more stable boost control. As you will be fighting against the ECU's fuel cut, this can let you get a bit closer to the 'bleeding edge' before you get fuel cut.
The argument against it is that, for the money you spend on an EBC, you could buy a Nutter_John ECU and have the same / better results.
I know where I'd spend my cash.

The Mechanical boost controller tends to have a small spike as boost builds, then settle down.
This means you need to stay a bit futher from fuel cut - i.e. slightly lower boost. (maybe 0.5psi?)

The net result is probably 3bhp less and a slight narrowing of the power band. An MBC cannot be beaten bang for buck - it's a must have cheapo mod for the VR4.
However, I would suggested getting a remapped ECU is probably the best 'bang-for-buck' you'll see.

[Wodjno]

You MIGHT be fine - it's one of those maybe / maybe not things, but it definitely affects the MAF readings, and definitely causes you to use (a bit) more fuel.

Totally agree with the above

(And i'm being totally Un-pedantic) The compressed air that the BOV is dumping to the atmosphere has been measured by the MAF, thus is expected in the cylinders.. The ECU will dump in the expected amount of fuel which will give a rich moment and also can dump unburnt fuel into the hot exhaust causing an explosion and maybe resulting in some nice flames

[swinks]

The argument against it is that, for the money you spend on an EBC, you could buy a Nutter_John ECU and have the same / better results.
I know where I'd spend my cash.

Not really...
You still need a EBC unit to control raised boost level.
But must agree, that's the best money spend on.

[Turbo_Steve]

I thought that the NJ ECU elevated the boost as well?

[swinks]

Yes, up to 1.1 bar at max, but you'll need any EBC to make ecu happy and hold upped boost.

[aboo]

Is it just me or is this Ecu of Kinkynutter inc sounding more expensive as it go's on.

Sorry for the thread hijack.

So you'll need a EBC & some sort of AFR gauge?

Sounds to me like it would be easier getting a map2?

[Turbo_Steve]

No. You should have an AFR gauge with any ECU / aftermarket tune.
Presumably an MBC would be as effective as an EBC?

I was under the impression the ECU raised target boost - not just fuel cut.
Ergo, the factory solenoid will attempt to bleed to 1.1Bar?

[aboo]

No Steve. John said in the other thread that MBC could not be used.

I agree that you should have AFR gauge though.