Pirated copies of car parts..high performance N20 diverter valve

[Pbondar]

I’ve got a bad misfire at full throttle when running through the gears..appears first in 3rd at 4,000+ rpm and repeats in 5th / 6th etc

Changed just about everything that most people suggested ..fuel pumps, coils, plugs, injectors to no avail.

Further reading indicated soft failures of two other systems on pneumatic waste gated N20 engines…the boost control solenoid (unique to pneumatic waste gated versions ) and the turbo diverted valve (often referred to as a blow off valve)..ie no faults codes but not working properly.

Further reading suggested that the diverted valve cannot cope with the increased boost pressure of a re-map (moving from 18 psi boost to 22-24 psi boost ).

So yet more reading suggested that an upgraded diverter valve is called for not just a new one..

I selected a Go Fast Bits DV+ valve which is essentially a ‘servo assist’ upgrade that can be retrofitted to an existing OE diverter valve.

So I ordered one of eBay..the price was about half of the typical £120 ish of many vendors…too good to be true..

Looking at the OE supplier’s web site warned of fakes…

My version looked pretty authentic, however I bought a ‘proper version’ from an accredited supplier…

Comparing the two it was obvious that the one I had bought for £60 was a fake..wrong model code, wrong assembly instructions, different packaging etc..

Some people have said that for half the price they can live with it..

For me illegal copying of such a product that others have invested time and ingenuity into creating cannot be condoned so I’ve reported the seller to eBay..

Caveat emperor ..

[enuff_zed]

Good for you.
Whilst some simple parts will always have cheaper alternatives, something like this you're playing with fire.
And when it goes wrong and you then discover it's a fake......................

A related question if I may:
Are you saying all remapped N20s should be using this upgrade? Or does it become a factor over a certain limit (as per your stratospheric example)?

[Flyingfifer]

Whilst some simple parts will always have cheaper alternatives, something like this you're playing with fire.
And when it goes wrong and you then discover it's a fake......................

100% this, when tuning my cars in the past when it came to anything turbo or fuel i spent the extra cash, you done the right thing Peter!

Can I ask for a banana for scale on the pictures please

[Flyingfifer]

£113 from Demon Tweeks Clicky

[Pbondar]

The issue in the UK with the E89 N20 is we are in largely undocumented territory.

In the US there are many 1,2,3,4,X series N20 modified motors.

The issue on the N20 is that this diverter valve has a plastic valve as can be seen in the picture driven by a little biro class spring.

The primary purpose of this valve is to remain close until throttle lift off when some boost is present.

Then it is supposed to open to depressurise the turbo / intercooler to avoid back feed through the turbo as the normal route through the inlet manifold is now closed.

When pressure is down to zero it’s supposed to close then allow boost to build back up when the thrust re-opened.

The failure mode (which appears and is yet subject to verification similar to what I’ve been suffering from) is that as the engine ages and / or the engine asks for higher boost from a re-map and /or bigger turbo the valve doesn’t close as firmly or as positively when moving from open to close.

This then appears as a failure of delivered boost to fall short of what was asked for. It gets worse in most cases as the car chases through the gears.

I suspect (and it’s my theory) that in my case cause the tuner has run the top end very very rich to avoid heat induced failure of the pistons, and, the ECU is relying on the asked for boost not the actual boost to do its injection cycle calculation that the combination of sagging boost with what was going to be a very very rich fuel mix tips the resultant mixture into an unburnable mixture..hence the misfire.

So more generally my guess is that in part why we see different re-map results is that in many cars the diverter valve is getting tired and won’t maintain boost ..however this is case where what you see on a rolling road is not what you see on the road..

The chase through the gears gives the game away allied to data logging. A simple single run through one gear doesn’t really exercise the fault mode.

If you look at the chart the orange line shows the requested boost and the blue line shows the actual boost..you can see how the actual boost sags especially after the shift into 3rd..and in those cases where I persisted into 4th it goes badly downhill..

[Pbondar]

Whilst some simple parts will always have cheaper alternatives, something like this you're playing with fire.
And when it goes wrong and you then discover it's a fake......................

100% this, when tuning my cars in the past when it came to anything turbo or fuel i spent the extra cash, you done the right thing Peter!

Can I ask for a banana for scale on the pictures please

[enuff_zed]

Whilst some simple parts will always have cheaper alternatives, something like this you're playing with fire.
And when it goes wrong and you then discover it's a fake......................

100% this, when tuning my cars in the past when it came to anything turbo or fuel i spent the extra cash, you done the right thing Peter!

Can I ask for a banana for scale on the pictures please

Sorry dear, that's no banana, just my finger!

[Flyingfifer]

Sounds sensible to me, weak actuators were always a problem on the Jap cars, as we squeezed more boost from them they failed to seal correctly resulting in a loss of pressure even on recirculating systems like the Evo, if the map is based on assumed conditions rather than an actual condition that combined with a failure in pressure will result in some really nasty running conditions!
Personally I wouldnt be happy with that map, especially as you are pushing the envelope in terms of power extraction, really the car needs to be running on an awareness of itself not its expectations. Might be worth having an air/fuel gauge so that you are able to monitor it.

Thanks for the scale

[Flyingfifer]

This speaks volumes and also is a concern near the end where pressure should be atmosphere or vacuum and its not

[Pbondar]

100% this, when tuning my cars in the past when it came to anything turbo or fuel i spent the extra cash, you done the right thing Peter!

Can I ask for a banana for scale on the pictures please

Sorry dear, that's no banana, just my finger!

Sent wife out for bananas..thought I would keep up momentum

[Pbondar]

Sounds sensible to me, weak actuators were always a problem on the Jap cars, as we squeezed more boost from them they failed to seal correctly resulting in a loss of pressure even on recirculating systems like the Evo, if the map is based on assumed conditions rather than an actual condition that combined with a failure in pressure will result in some really nasty running conditions!
Personally I wouldnt be happy with that map, especially as you are pushing the envelope in terms of power extraction, really the car needs to be running on an awareness of itself not its expectations. Might be worth having an air/fuel gauge so that you are able to monitor it.

Thanks for the scale

Since actual boost is a lagging function the DME can’t really use it for WOT issues..long term fuel trims use the oxygen sensors on the N20 for cruise modes..maybe that’s why with up to 3/4 ish throttle it all runs peachy..just WOT the DME has to resort to standard lookup fuelling table which I guess is running around 10.5 ish to 1 to avoid melting piston crown syndrome allied to demanded boost and other real time variables like ambient pressure, temperatures etc..

[Flyingfifer]

Since actual boost is a lagging function the DME can’t really use it for WOT issues..long term fuel trims use the oxygen sensors on the N20 for cruise modes..maybe that’s why with up to 3/4 ish throttle it all runs peachy..just WOT the DME has to resort to standard lookup fuelling table which I guess is running around 10.5 ish to 1 to avoid melting piston crown syndrome allied to demanded boost and other real time variables like ambient pressure, temperatures etc..

Fair point, the AF gauge would read from the lambda sensor which I'm assuming A the N20 has and B the ECU uses anyway?

Strengthening the sealing components is always a good idea anyway even long term as (in the old jap cars anyway) they tended to weaken over time regardless.

[Pbondar]

Since actual boost is a lagging function the DME can’t really use it for WOT issues..long term fuel trims use the oxygen sensors on the N20 for cruise modes..maybe that’s why with up to 3/4 ish throttle it all runs peachy..just WOT the DME has to resort to standard lookup fuelling table which I guess is running around 10.5 ish to 1 to avoid melting piston crown syndrome allied to demanded boost and other real time variables like ambient pressure, temperatures etc..

Fair point, the AF gauge would read from the lambda sensor which I'm assuming A the N20 has and B the ECU uses anyway?

Strengthening the sealing components is always a good idea anyway even long term as (in the old jap cars anyway) they tended to weaken over time regardless.

Reading up about it seems that the issue with these babies is how lucky do feel punk ?

You can run a just slightly rich of max power stoichiometrically but apparently at those levels of boost you can meet pistons pretty quickly if it’s goes Pete Tong..hence why they run 10.5:1 type fuelling to help cool the pistons..we did something similar with old air cooled aircraft engines..

[Pbondar]

Sorry dear, that's no banana, just my finger!

Sent wife out for bananas..thought I would keep up momentum

Banana upgrade done..

[Nictrix]

Sorry dear, that's no banana, just my finger!

Sent wife out for bananas..thought I would keep up momentum

Banana upgrade done..

What size is the banana?
Can you picture it with an orange to see the scale of the banana?