Performance Chips for P7 "box"

roger851

I've got 851 with the 888 motor in it. I'm using the 851 intakes with the single green injectors and the chip in the P7 box at present says "+10 percent" on it. I don't know where it's from. The bike runs quite well although it usually stalls once or twice before it will idle (just using the start button and not touching the throttle). The airbox is stock and I have carbon Fast by Ferracci mufflers.
Here's my question : The motor came with 2 other chips; one marked "888 SPO USA 038U" and the other marked " Fast By Ferracci F00107S " Will either of these chips work with a single injector setup? and Can I just swap one chip in the P7 for another, hit the starter button and go? Ideas?

brad black

p8 eproms won't work in a p7 ecu - i think the 038U would be p8. anything for a '92 851 should work ok - the 888 is only 4.5% bigger.

loony888

arrow used to supply eproms that were the std map plus 10%, it may be one of those. the F00107S is,according to my ferracci catalogue to suit a 888SPO stage 1 so it's probably for a P8 also.

paul.

roger851

Are there benefits to changing from a P7 To P8 box, and if so, are good P8 box's difficult to find?

Mr.R

Hi Roger,
The P8 ECU is better if you're going to tune the motor, it has the ability to run offset maps between the cylinders and it can run a electronic rev counter.
My mildly tuned 851/916 has a P8 with a FIM UM chip, it runs +5% on one cylinder and -17% on the other.
The P8's do turn up every now and again on sites like here or e-bay, but they're quite sought after, get snapped up quickly and command a higher price than the P7's.
I was lucky and found a brand new old stock one for £400, then sold my P7 to offset the outlay to a guy on here.

They were also fitted to the 916 Strada, 916/996SPS's, Corsa models from the 888-996, some Guzzi's and performance cars like the Ford Cosworth, some Lancia's etc, the tend to be cheaper if you can get one from a car source and if broken can be rebuilt here in the UK for no where near as much as a new one (If you could find one), IIRC the cost to rebuild one with a warrenty is around £200.
The guy who repairs/rebuilds them is a Rally car specialist, in my experience prices charged in the car tuning World are WAY cheaper than bike prices (around 75% cheaper!) and well worth checking out.
I think when they were last available new from Ducati they cost around £1,000 here in the UK.

Steve R

marvin

I have a new old stock P8 if anyone is looking for one. It won't be cheap though! 😉

griff851

Steve just on a note about the +5% and the -17%, what were the corresponding cylinder total volumes? In another thread Marvin mentioned his head volumes were slightly different, i was wondering if yours are as well, hence the different fuel figures. Or are they different because of the exhaust manifold/header?

Griff

loony888

the rear cylinder runs quite a bit hotter than the front cylinder, that and the difference in exhaust header length before the collector would be the main reasons for the benefits of using offset mapping.

paul.

greenmonster

it runs +5% on one cylinder and -17% on the other.

I`ve only seen a few % more on rear.
Should we read this as the rear get 22% more fuel than front?😳

Mr.R

griff851 wroteSteve just on a note about the +5% and the -17%, what were the corresponding cylinder total volumes? In another thread Marvin mentioned his head volumes were slightly different, i was wondering if yours are as well, hence the different fuel figures. Or are they different because of the exhaust manifold/header? Griff

Griff,
I cc'd the combustion chambers and they are spot on after some adustment, (They both pump up on the comp' tester the same as near as 'Damn It' is to swearing) the cams are spot on, the squish is also 1mm on both pots, (Maybe 0.9 but I can't remember) both headers on the exhaust system are the same length being a Spaghetti system, of course the front header is in the airflow and the rear sits behind the motor...
It's known that the rear cylinder runs at a different temp' to the front on the Desmoquatro motors.
The other difference is that when using the standard 851 airbox, with V Two modified 54mm bodies with the huge bellmouths that they come with (as they're ment for a 916 airbox) the front inlet/injector body is shrouded and the rear touches the air filter even after shortening the bellmouths/ Velocity stacks, which I had to do to get them into the airbox, the rear stack still causes the ITG foam airfilter to bulge upwards.
This problem will be sorted when I fit the 3 piece Carbon airbox and runners.
Both plugs show the same colour and seem to wear at the same rate and the motor pulls like a train to the redline.

The dyno sheet gives this info'...
FIM chip refuelling-
FIM UM 061 916 Strada chip Map 15... Now map 20 +7.0 and map 21 -15.

If you look in Falloon's Desmoquatro Performance Handbook you'll see the big difference's in the mapping between the cylinders.

Steve R

Mr.R

griff851 wroteSteve just on a note about the +5% and the -17%, what were the corresponding cylinder total volumes? In another thread Marvin mentioned his head volumes were slightly different, i was wondering if yours are as well, hence the different fuel figures. Or are they different because of the exhaust manifold/header? Griff

Griff,
I cc'd the combustion chambers and they are spot on after some adustment, (They both pump up on the comp' tester the same as near as 'Damn It' is to swearing) the cams are spot on, the squish is also 1mm on both pots, (Maybe 0.9 but I can't remember) both headers on the exhaust system are the same length being a Spaghetti system, of course the front header is in the airflow and the rear sits behind the motor...
It's known that the rear cylinder runs at a different temp' to the front on the Desmoquatro motors.
The other difference is that when using the standard 851 airbox, with V Two modified 54mm bodies with the huge bellmouths that they come with (as they're ment for a 916 airbox) the front inlet/injector body is shrouded and the rear touches the air filter even after shortening the bellmouths/ Velocity stacks, which I had to do to get them into the airbox, the rear stack still causes the ITG foam airfilter to bulge upwards.
This problem will be sorted when I fit the 3 piece Carbon airbox and runners.
Both plugs show the same colour and seem to wear at the same rate and the motor pulls like a train to the redline.

The dyno sheet gives this info'...
FIM chip refuelling-
FIM UM 061 916 Strada chip Map 15... Now map 20 +7.0 and map 21 -15.
All this is hand written maybe he slipped with the pen??

If you look in Falloon's Desmoquatro Performance Handbook you'll see the big difference's in the mapping between the cylinders.

Steve R

griff851

Hi Steve, thanks. I don't disbelieve those figures for a moment. I just have to now read the hand book(At the shop) to learn how to do it. Preferably with out the dyno. Sounds tricky.