sounds good Joe i bet your well chuffed with the results so far?

So fare so good Paul

Yah... but why would that help you? You still have the same sensor and hence it will still limit on excess airflow. What you need is something that throws out less volts for the same airflow, so it can cover all the range you need, *and* you need to look at the airmass -> injector period maps...

That is, it needs to tell the ECU that there's about half the air going through that there actually is - so it doesn't flatline at boost - and then the ECU needs to spit out twice as much petrol as it expects (plus adjustments for timing, load, temperature etc).

It may well be that the 20vt MAF can be used in place of the VIS unit but five terminals worries me; it may have completely incompatible controls or perhaps extra functionality - e.g. thermistor - in there also.

Might be simpler to look at the default behaviour of the out-of-range response, and just throw excess petrol in such a circumstance.... not as elegant, though.

Neil

Could you increase the size of the MAF housing, or is this a no go on the VIS?

The problem is the 5 wire VIS MAF sensor itself Paddy, the parameters that it's design to work within is totally different to the 20vt.

... actually, that's not such a bad idea. If you can flow more air past the sensor without affecting the sensor - i.e. a larger diameter tube with the same sensor - it would logically read a lower value for the same mass of air.

Which is what you need, coupled with increased injectors, fuel rail pressure, and/or mapping tweaks.

(Note that doubling the fuel rail pressure only increases the flow rate by 141% and is probably limited by fuel pump parameters anyway.)

Yes I think this is the idea that Ogri is having with increasing the induction pipework and moving the MAF position so that it's after the inter cooler, but he did say it may come down to patching in a standard 20vt MAF and wiring loom, but this would be either costly or time consuming.

Hmmm, like you say some good news and some bad. I didn't realise you hadn't connected the fuel return Joe, you are effectively running off pump pressure so I'm not suprised it is overfueling! I assume the VIS uses a normal MAF i.e. hot film/wire sensor, if so I agree with Barnacle in that I can't see how placing it further up the intake tract can make any difference other than the change in air temperatures. If you run a larger MAF housing then this will give better resolution. I currently run a much larger MAF housing than the standard 20vt which allows me to fuel for 2bar, 1.5bar and less with good resolution. The problem is the timing must be compensated, it's certainly not a bolt on mod but I'm sure Ogri knows this.

Any news on the VIS affecting low down torque?

Oh I will be offering a "Big MAF" conversion to 20vt owners, you need to be boosting big to make it worthwhile though

forms a queue......

Might've known you'd be in there, Nigel!

Joe, some excellent spannering going on there. As Jimbo said, nice to see a completely different projet going on and as with all projects for the first time, there are loads of problems and niggles, but i'm sure you will get it sorted and running well

any more updates on this Joe

Little update on this.

I brought the Hybrid back to the unit tonight from Reddot and took it for a quick spin before I parked it up.

We'll it boosts very well and drives much like a 20vt, the plenum is desperately in need of plastic welding as I'm sure I could hear pressure leaking past the gasket, so this as well as the fuel return line are first on the list when I get a chance to work on it again, then I'll start looking at the MAF issues but overall I'm very pleased so far

Great stuff Joe

thanks for the update Joe, looking forward to the inlet plenum getting welded and the fuel return sorted, then we can see what she can really do

It must be time for another update on this?

i believe the inlet plenum still needs to be plastic welded and the maf/fuel return needs to be sorted...he has been busy fixing my cars

Any update on the project Joe?

Well I've had a chance to get the hybrid up on the ramps this afternoon seeing that Bristol Italian Auto Moto Festival is only 3 weeks away, I thought it was about time I finished off the couple of issues it needs before getting the car remapped and hopefully running at 220bhp.

So I've now changed over the fuel lines so it now has a return and in line filter system, the weekend I'm trying a reinforced plenum to see if this stop the seals being blown out, hopefully I'll be turning the boost up to what it should be

What happened to this project Joe? I just thought of it and looked in the Coupé Projects forum expecting to get an update...

...and the coupe soft top

It would just so happens that I brought the Hybrid back up to the unit this morning for phase 3 of " Try and seal the plenum again" you must me spying on me Trappy

Rob from Carlisle has kindly sent me some stronghold 902 adhesive so fingers crossed I'll be able to bond this bugger so it doesn't pop again, I'm only looking for standard boost pressure so if this doesn't work I think I may have to build a plenum out of Alloy and fit the standard plastic internals so that the VIS system still works, but hopefully I won't need to worry and I'll be updating the forum Sunday

As for the soft top, well I think I might of found the perfect 20v n/a for this project, just got to get it collected first, another job on the list.

To bring an old thread back,what ever happened to this coupe?

Mr CC has been very busy lately so the hybrid has been put to one side until he frees up some time.

Well, you've had over a year now Joe, have you finished yet?

bump, updates on the plenum?

Its nice an sunny...

20v SoftTop Joe?

I'll be throwing the dust sheet off this project again soon so hopefully I'll have a new progress report

By soon I hope you mean today lol . What a great read and a lot of good work by yourself Joe.
Jason