4722 replies to this topic

[Nev]

I've just had some council estate kids round in my garage... look what the little buggers have done !!!

Edited by Nev, 15 February 2011 - 07:55 PM.

[techieboy]

Here's one to haunt you for the rest of time.

Why are people so obsessed with how their engine bay looks, surely there are more substancial things you can do with your time.

[VXT Tim]

Here's one to haunt you for the rest of time.

Why are people so obsessed with how their engine bay looks, surely there are more substancial things you can do with your time.

Too much forum knowledge Matt!

[Nev]

I know Tim, shame on me !! It's just that Im so bored waiting for parts. Well, at least its gonna be a unique VX engine bay and hopefully the engine will be functionally superior, even if it looks like its come off a council estate ! Im just about to add some more pics of it, with the parts mounted up onto the engine (get your sunglasses out!).

[VXT Tim]

Chav at heart. You'll be slipping a sub and amp in behind the seats before you know it

[Nev]

What an excelent suggestion Tim I dont think a stereo will be any good, the noise from the engine bay is going to be overwhelming, seeing as there isn't a shred of sound proofing and that fat turbo will be literally 1 inch away from the bulkhead at ear level.

[VXT Tim]

I saw the update where you removed the sound deadening. You replacing it with any heat reflective material?

[Nev]

Im going to do a trial lowering of the engine into the void soon, will take some measurements to see what might get roasted. I will be fabricating heat shields from alu sheet I have already bought and possibly wrapping various bits as I see fit. I may also buy or make a turbo jacket.

[Vespa]

Loving the bling!!!

[Nev]

Man dat is wel wikd innit - i iz der top dawg in dis est8

[Vespa]

Loving the bling!!!

[VXT Tim]

Delayed double post?

[siztenboots]

something which would be a good test is, check MAF peak readings with standard TB 57mm and your 63mm on a simple back to back road test.

[Nev]

Thats a good idea Steve, do you know which contacts I need to put a volt meter accross? I dont want to short circuit it as they cost £150+ At the moment I think I am going to run the engine in with the Astra VXR MAF (which the ECU is already calibrated to). Then I'll get it mapped and if we think the MAF is causeing a resistance, I may either buy the 92mm Audi S4 one or build my own 80mm I/D MAF from a piece of pipe and the sensor unit out of a standard OEM 70mm MAF.

[siztenboots]

Thats a good idea Steve, do you know which contacts I need to put a volt meter accross? I dont want to short circuit it as they cost £150+

At the moment I think I am going to run the engine in with the Astra VXR MAF (which the ECU is already calibrated to). Then I'll get it mapped and if we think the MAF is causeing a resistance, I may either buy the 92mm Audi S4 one or build my own 80mm I/D MAF from a piece of pipe and the sensor unit out of a standard OEM 70mm MAF.

i can read all that info on my scanguage as its not a linear thing, the ecu has a correction table which you get with a remap for the 80mm MAF upgrade. It would be a 5 minute TB swap to compare on mine if the 63mm benefits flow. For a custom MAF tube, you need to know the cross-section area to get the fuelling correct.

[Nev]

Just so I can get an idea of the voltage, can you tell me what your max power is your car and then what the max voltage the MAF outputs at this power level (and for which MAF). From that I can extrapolate at what power level my MAF will max out at approximately.

[cs_]

You can read the MAF value with any OBD interface. It comes as a 16-bit value with PID $10. The value translates as grams per second multiplied with 100. So a value of 300 decimal means 3 grams per second mass air flow. Usually you do not have to cope with the translation as the software of the OBD interface will do the translation for you, giving lbs/hrs or g/s.


(the interface depicted here translated lb/min in a wrong way, picture is just for illustrating the OBD reader)

Measuring the voltage will not be the best way to compare the TBs. And just in case you happen to have some 300HP and still the 70mm MAF sensor built in you will simply read some 4.7V with full throttle because it clips. That's why every Z20 engine with a power of 280+ should have the 80mm MAF. Gives much better throttle response because of the sensor not clipping at all.

Edited by cs_, 16 February 2011 - 01:45 PM.

[vxr36]

i can read all that info on my scanguage as its not a linear thing, the ecu has a correction table which you get with a remap for the 80mm MAF upgrade. It would be a 5 minute TB swap to compare on mine if the 63mm benefits flow. For a custom MAF tube, you need to know the cross-section area to get the fuelling correct.

I can't read the MAF on mine. Is there a manual code?

[Nev]

CS_ thanks for telling me about the ODB PID. The problem I face is: While running the car/engine in I cannot push it hard for obvious reasons. So when I arrive at the mappers, it will be too late to just 'nip out and buy a larger' MAF that is compatable. This is why I am concerend about my MAF being able to accurately cope with measuring my air flow. BTW, I am not trying to compare TBs. Just trying to estimate whether my Astra VXR MAF will clip due to too much air being sucked through it. CS_ , can you kindly provide us with all the registry (PIDs) and what they all mean, this would be very usefull info for .Org

Edited by Nev, 16 February 2011 - 01:51 PM.

[cs_]

The clipping is a very interesting point actually. I drove around with the 70mm MAF for four years, from stock 200HP to 290HP. Any tuning stage from 250HP to 290HP I drove showed the same weird behaviour: the first half way down the throttle acted normal, the more you press it down, the more power you get. The second half was different: there was a point, at which an avalanche of boost broke free. I had to decide there to accelerate very hard or to release the pedal a bit again to stop the avalanche.
For four years I considered that as a normal thing, not an issue. Until I swapped to 80mm MAF last spring and remapped the lookup table in the engine ECU. After the upgrade to 80mm my throttle acted completely different, giving a linear 0-100% response, more down, more power, the whole way. The engine now acts more like a big N/A and less aggressive. The car is not slower, develops the same power, but less nervous. The engines is much more controllable now. Almost a brand new car, much more driving pleasure.
Discussing this topic with some mates in the german forum one came with actual measurements of the MAF voltage. And see, the 70mm MAF clipped at overboost. The 80mm doesn't. The opinion of the tuners seem to differ, the one which made my engine neglects that the 70mm MAF may clip, Klasen I heard says you need 80mm for 280HP or more. So I decided to rely on my own results. They tell me clipping is real with 70mm MAF. And is now gone for me.

The OBD PIDs are to be found in the web. For instance on Wikipedia. These are standard data words. Not Vauxhall specific.