remapping

[Roger 04 RT]

I'm sure you've thought of it, but some guys sell the PC V and use the proceeds to buy the AF-XIEDs. But in any case, take your time and be sure of what you want to do. In the end it's about the fun of riding.

 

[Bendy toy]

I'm sure you've thought of it, but some guys sell the PC V and use the proceeds to buy the AF-XIEDs. But in any case, take your time and be sure of what you want to do. In the end it's about the fun of riding.

Brand new Power commanders like mine look to be about £200 to £250 then they have the autotune add on (which I don't have) for another wedge. Used I guess 50% of that.

Its eBay so who knows if this is the add on only or a PCV with add on. http://www.ebay.co.uk/itm/DYNOJET-A...750907?hash=item23647cb97b:g:vdwAAOSwoudW4JsH

I will be keeping it simple and certainly don't want yet another add on box.

 

[Mistacat]

I purchased the PCV and Autotune second hand and played with them for a while.
The sale of the units recouped the majority of my outlay which I spent on the AF-XIED`s (They had not been out long so no second hand units around).
Having said that I cant see anything on the horizon that will be as reliable, simple to install and use, so one happy bunny.

 

[backstreet hero]

Ah, I think I may be starting to understand why the O2 sensors and closed loop are so important on our bikes (but tell me if I'm barking up the wrong tree). If they don't use manifold pressure sensors, am I right in thinking that they use some very complex calculations to determine engine load using a variety of sensors instead (tps, crankshaft, camshaft, temperature, O2, altitude) and the long term fuel trim tables to a greater extent? Presumably the sensor data is all the more important to substitute for MAP sensors, which I guess aren't used because a parallel twin has two entirely separate inlet tracts as if it's two single cylinder engines and this would be a nightmare for the ECU to manage simultaneously?

In which case I can see why open loop mapping and Powercommanders are less than ideal, because the ECU needs the feedback loop from the O2 sensors. And this explains why the AF-XiED are such an effective way to improve the fuelling? As well as being able to add fuel to closed loop, am I right in thinking that the AF-XiEDs are also better than the OEM O2 sensors in terms of the data accumulated in the long term fuel trim tables (which then provide adaptability for the open loop range of engine operation)? Or do the AF-XiEDs only take care of closed loop in which case an open loop remap or PCV in addition would be advisable for decat headers and open exhausts?

 

[comberjohn]

That sounds very like the conclusions that Roger came to. Including the alterations in the long term fuel trims.
I'm sure Roger can confirm this.
You should read the very long thread on how the AF XiED units were developed, if you haven't already done so.
Sounds like you might get more from it than most of us.
It's http://http://advrider.com/index.php?threads/2004-r1150rt-wideband-o2-sensor-project-and-af-xied-for-bmw.749080/
Enjoy!

 

[backstreet hero]

Many thanks, I'll have a look through that. And I meant to write horizontally opposed twin and not parallel twin in my last post (doh, that's the other half's Versys!).

 

[Bendy toy]

Just had a quick look at that thread. It needs more than a quick look. !!!

All this complication to get a throttle body on to each cylinder. The properly set up 1200 makes about 100bhp. About 83 maybe 85 per litre. A chunk less in OEM form.

The 1747cc Fiat Alfa twin spark makes 144bhp out of the box - about 83 bhp per litre.

The Alfa TS also has to produce the torque and flexibility to drive a car but has just the one throttle body with MAF sensor and the usual stuff. So why did BMW bike department feel so welded to bike engine orthodoxy that they could not use proven tech from the car industry. The old excuse about lack of space doesn't apply because that air box is huge and TBH the bike makes poor use of space under the petrol tank.

It looks like an interesting project for a tuning expert to chuck the twin throttles and made a single throttle body version with air box and all the normal control systems. If the Alfa 1.8TS is anything to go by, it may well make more power than a tuned 1200.

 

[Martyn H]

Just had a quick look at that thread. It needs more than a quick look. !!!

All this complication to get a throttle body on to each cylinder. The properly set up 1200 makes about 100bhp. About 83 maybe 85 per litre. A chunk less in OEM form.

The 1747cc Fiat Alfa twin spark makes 144bhp out of the box - about 83 bhp per litre.
The Alfa TS also has to produce the torque and flexibility to drive a car but has just the one throttle body with MAF sensor and the usual stuff. So why did BMW bike department feel so welded to bike engine orthodoxy that they could not use proven tech from the car industry. The old excuse about lack of space doesn't apply because that air box is huge and TBH the bike makes poor use of space under the petrol tank.
It looks like an interesting project for a tuning expert to chuck the twin throttles and made a single throttle body version with air box and all the normal control systems. If the Alfa 1.8TS is anything to go by, it may well make more power than a tuned 1200.

I think I'm right in saying (read that as "can't be arsed to Google it") that the latest generation Moto-Guzzi's make do with one central throttle body. Does away with a lot of faffing about, as it did in the 1960's for those who were perfectly happy with a single carbed Triumph or BSA, as opposed to the twin carbed models.

 

[Bendy toy]

The Guzzi 750 certainly has a single TB but at 48bhp its not especially powerful. It tends to continue the myth that power must have separate throttles.

I suspect that a parallel twin would struggle with air box space to get the most from just one throttle body. But The Guzzi and BMW have cylinders well out of the way leaving space for whatever it is that air boxes and plenum chambers actually need.