Xu7 lfx Engine build

[Fox4130 0]

Hi folks, firstly I have a terrible Admission to make, I don’t own a 205 ! I am however building a Peugeot Citroen hybrid using the Xu7 Jfx engine and you 205 guys seem to be the ones tuning them. So here’s the question if I wanted to retain the stock ecu what are my best options to get good power from this engine and what could I expect ? The engine will be being rebuilt so over boring isn’t out of the question. I’d love to hear about your set up’s and if there’s any one you’d recommend to build an engine of this type. I’d also be interested to hear about going the hole hog and the aftermarket ecu route. Thanks guys

Edited May 25, 2021 by Fox4130

[opticaltrigger 52]

Hi Martin,

Basically there's a couple of routes for you. You can keep the stock ecu and engage in the cam's, exhausts, compression, etc, etc, route. You could to a point, keep the OEM ecu or you could change it for a modern standalone here. This could yield quite an impressive boost in performance for you.

Or the other option is forced induction using a turbo / supercharger, which requires quite a lot more engineering work and a modern standalone ecu. The cost of standalone's has plummeted in recent years, so there not to painful anymore but the required engineering for turbos etc is quite extensive.

Depending on what your looking for. If you just want the odd traffic light Grand Prix and don't want to bigger project, there's always the nitrous oxide route. Relatively cheap in BHP / £s terms, very reliable (if you don't go mad with it), and comparatively not to much work either. Although a standalone is desirable for a proper job, and you do have to re-fill the bottle. (quite often !!!.....)

Or you can really run with it and go for everything.

That's my take on it anyway. Hope it helps a little...

There's a few guys on here who build great engines professionally for people, and have done for years, so if it's not for you, I'm sure one of the guy's will happily deal with it for you.

 

All the best,

O.T.

[calvinhorse 870]

The xu7 head had the inlet ports deliberately narrowed when casting so that the engine didn’t make as much (or more) power as the 2.0 16v xu10j4r

 

you can however use the xu10 head on your bottom end which is very similar to an Mi16 head so releases a lot of power!

 

im actually selling one of these heads on this very forum..  

[Fox4130 0]

Thanks soo much, that’s really helpful info. Hopefully I’ll be able to give some useful feedback when I start building the engine.

 

[Type-R 3]

AFAIK the standard ECU is not reprogrammable, try a GTI-6 ECU instead.

[Gianni205 1]

I have the XU7JP4 in my 205, easiest way to gain 10-15 hp on the standard ecu:

- XU10J4RS in & exhaust manifold (plug and play, also sensor wise),

- adustable fuelpressure reg. with the XU7 injectors ( i have tried the XU10J4RS injectors, but it ran way to rich AFR that way).

 

Otherwise the XU7 head is it's main restriction, not only the ports, but also the cam is very lazy, en de valvesprings can't handle more than 7000 rpm (standard ecu rev limit is 6500 anyway).

So have found out in my reasearch (mainly old posts on here & other forums etc..) that swapping a complete XU10J4RS Head + manifolds on to the XU7 block with mappable ECU, should result in a very rev happy 160+ hp engine.

[Fox4130 0]

That’s great info again guys thanks so much,just what I needed to know. So the gti6 ecu could work ? Would I need to change locks etc with the ecu ?

[Type-R 3]

What ECU do you have fitted? If you have a Sagem you need to swap it out for something mappable.

[Gianni205 1]

On 6/11/2021 at 10:46 AM, Fox4130 said:

That’s great info again guys thanks so much,just what I needed to know. So the gti6 ecu could work ? Would I need to change locks etc with the ecu ?

The GTI6 ecu will only work with a GTI6 head & wiringloom. This i because the GTI6 ECU needs the Camshaft Positioning Sensor for the sequential COP ignition & sequential injection. The LFY head doesn't have this sensor as it runs a single big Wasted Spark ignition coil pack & paired injection.

 

So in simpler terms:

GTI6 ecu gives 4 ignition & injector signals due to the extra timing info via the cam & crank sensor

Sagem LFY ecu only gives 2 ingnition & injector signals, as it run only on crank sensor.

 

So even though the GTI6 & LFY ecu have the same JPT 55 pin "Bosch motronic type" connector, and the pinouts are very simillar (as you can see in the attached PDF's), they are NOT interchangeble without the correct wiring loom & (cam) sensors.

 

 

Sagem SL96 ECU pinout.pdf

Magnetti Marelli 1AP.10 (GTI6) ECU pinout.pdf

[Gianni205 1]

On 6/11/2021 at 10:46 AM, Fox4130 said:

Would I need to change locks etc with the ecu ?

You can keep the lock as it is if the GTI6 ecu is correctly "Unlocked", just make sure the car you put the engine in has the Immobilizer module & transponder removed before putting the ecu in the car.