Olli Snellman

Just curious Tony, do you have experience of Alpha-N systems? Want to share some of it to us, at least i know only what i have read about it.
it seems to be quite interesting way to tune up Motronic equipped cars.

Rogue_Ant

Alpha-N system would take some work... The DME does not have a TPS input.


-Rogue

Olli Snellman

Are you sure? Don't understand what you mean.At least my 951's DME gets input from TPS.
For example this product is for E30 M3, which has identical connection to Motronic (DME connector) compared to 951 one.

http://www.maxx-automotive.com/pp.html

ITB's with Alpha-N sounds nice:

http://www.youtube.com/watch?v=Et0WdmFvFl4

Rogue_Ant

Yes I am sure.
Non of the 951s get a TPS volt input, only idle switch and WOT switch. The KLR gets TPS volt input but not the DME. Alpha-N needs a real TPS angle input.




-Rogue

Olli Snellman

So this means DME gets information of the TPS position if idle & wot info is given to it? Or are all other values in between idle & wot given to KLR?
In that case Alpha-N can be easily added only to 944 n/a models.

Rogue_Ant

No the TPS only gets 'idle contact' and 'WOT'. No actual TPS position, or angle. The 944NA is pretty much the same.
In both cases, one would have to figure out how to add an actual TPS position/angle input to the DME...


-Rogue

Olli Snellman

Somehow it's hard to belive the same period BMW Motronic would be that different.

Sorry Mike about hijacking this thread..

savvas944

nice looking CF plenum.4trumpets connected to a single plenum and one air inlet.

regading the fueling or air parameters,perhaps fixing the TPS at the end of one of the trottle shafts
and a MAF at the inlet of the plenum(for N/A) applications, or straight connector in Turbo,it should be ok.

67King

+1........just start a new thread.

TonyG

Yes I do.

It's fine for a track only car.

But the problem is that Alpha-N is nothing more than a simple 2D tuning map where on one axis you have throttle position, and on the other axis you have engine rpm (plus there are some other small correction tables like temps to skew the map one way or the other depending on the ECU).

The problem is that there is no engine load factor taken into consideration (which is why it's a 2D map).

So when you have different engine loads at the same throttle position and engine rpm, and there being no way to measure and factor in the actual engine load, you end up with the wrong a/f ratio (not to mention ignition timing...).

It's a very poor way to tune a engine.

On the track, where you really focus on WOT and fuel enrichment when you stab the throttle, you can get by with Alpha-N. One the street for an everyday car... no way.


TonyG

Olli Snellman

OK, makes sense. Just wonder why so many E30 M3 owner choose it.

Rogue_Ant

Some EMS setups allow a 'blended Alpha-N'. Which is a blend of regular Alpha-N and Speed Density...
Much more appropriate for a turbo or street car.


-Rogue

Duke

Because they're N/A they don't really need a MAP-sensor and can get away with only TPS.

TonyG

In my experience, with respect to tuning a car to drive on the street, Alpha-N sucks on a N/A car. It just sucks worse on a turbo car.

TonyG

TonyG

Who knows.

Probably because they've all tried the little plenum trick and realized that it too presents its own set of issues. That the size of that plenum affects the map response rate, that the size of the vacuum booster and the line to it also affects the map response rate... that the bigger the plenum, the smoother the signal, the slower more delayed the map signal... on and on and on....


In the end... with an ITB setup... if you want to drive it on the street as an everyday driver, you really need a MAF between the plenum and the air filter.

That's by far the easiest way to get it right.

TonyG