XU5m2z - tuning

R

R8RX

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Fellow Frogger
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Jun 16, 2018
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283
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Norway
Hi all! I have a Peugeot 309 with a 1.6 XU5 engine (xu5m2z - bdy). This has the monopoint fuel system. Anyone have a easy way of making a few extra horsepower out of this? Don't really want to do anything internally at this moment so tips regarding exhaust or fuel system will be appreciated.
 
That sounds like our 205Si (BDY engine, monopoint injection). A number of people have looked into it around here and I have a feeling the conclusion is the factory did a pretty good job with that engine as is. Graham might know more.
 
Factory GTi inlet manifold, cam etc.
 
Get a diagnostic tool (there was one made back in the day, maybe a dealership will have one, TAD100, I think) and check that the timing is set correctly. Over here most were retarded so they would run on 91 octane fuel. Also, replace the oxygen sensor and make sure it is connected properly including heater connections. Make sure the exhaust hasn't been reduced in size from original, often happens, and that it has a free flowing muffler.
Maximum power is at 6400 so you can't really say that it doesn't breathe well.
 
Thank you! Have to check with my father about diagnostic tool. He works at the local Peugeot dealership. I've made a new exhaust, stock manifold, emptied the catalyst converter and 2 inch pipe. Tried to get hold of an GTi exhaust manifold, but isn't so easy to get used parts.
 
The inlet is so restrictive on that engine. Moving to a GTi inlet is the only real cheap alternative. I wouldn't even attempt a cam change until you've addressed that. Even then, it's not so easy, as you need to fit four injectors and thus a different ECU.
 
Ok, thank you guys!

Do I need anything else than inlet, injectors and ecu if I change to a GTi inlet? Wiring loom or sensors or something?
 
The only way would be with an aftermarket ecu, so you can retain 60-2 Motronic trigger and current wasted spark ignition. Unless you use a later model ecu and reflash it.
 
Ditching the ECU (if your car has the same Marelli ECU as our Si model) you lose control of the ignition as Peter implied above. Hence you either need to leave the ECU in place to control the ignition or go aftermarket. A number of places offer ignition that accommodate the 60-2 setup but then you also have to create the ignition map and the old Si map might not be enough if you upgrade your intake and go multipoint injection. So in short, no. You can not just simply bolt on some stuff as I suggested above.

I was going to suggest upgrading the suspension or at least the underframe setup, but Graham seems to appreciate the handling of the Si better (at least off road) so why not use the car as is?
 
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Ok, seems to be a lot of cost and effort to get some extra power out of this engine then. So I guess I just leave it like it is. An engine swap is the plan at some point, but that is far down on the list of things to be done around here.
 
This is a 309 don't forget. I've had no experience with a base model 309.
 
i think the standard inlet definately holds the xu5m back. It will spin up much quicker with a better designed or more free flowing inlet setup. i modify a 205 which had a stock standard xu5m bdy motor with 200000kms on the clock. compression tested at 165 psi on all 4.

stage 1 was a 2" straight thru exhaust from cat back
stage 2 gti front subframe with 306 dampers all round
stage 3 38mm kawasaki zx6r bike carbs

each one has made it a bit quicker in the performance department but by far the bike carbs made the biggest difference. it now accelerates alot quicker than it did before and has a little bit more power. i did a 0-100km with std motor and inlet and it took about 16 secs. with just the bike carbs fitted and roughly tuned its now just under 10 secs.

1st gear revs out extremely quick but 2-3 felt a bit lazy but a close ratio box fixes this a bit. the bike carbs are std other than i drill out the mains from 1.5mm to 1.9mm i did this at 0.1mm at a time then test drove each time and it kept getting better. i stopped at 1.9 becuase i dont have any spare jet to mess with but it could want more fuel. it runs a balance bar off the quad runner inlet then one hose into map sensor. i modified the zx6r tps to put out the corecct reading and the xu5m ecu is happy with no error codes.

ive since fitted foam air filters so it needs a re tune and i have also notice that the cold weather has slowed it down a bit as i tuned it in middle of summer with no air filters. next stage would be more compression and camshaft. then a final tune with factory jets rather than drilled out ones. but it does work!

there a few tricks with the bike carbs also. some say you can block off the air correctors and run smaller mains which i havent tried i think the main reason for this is factory jets can only go to 2.0mm. i found the idle circuit to be fine and no need to change and the carbs i have adjustable needles for the mid range so once you have mains right you can tune it in the mid.

you could do the exact same thing but use twin dellortos or webers instead of bike carbs. the induction sound alone puts a smile on your face!
 

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16.5 is way too slow, that's 504 territory, my 205 is much quicker than that. I think that if people just got their cars running as they should there would be no need to modify them.
 
GRAHAM WALLIS said:
16.5 is way too slow, that's 504 territory, my 205 is much quicker than that. I think that if people just got their cars running as they should there would be no need to modify them.
Click to expand...

Well actually it's was more like 15.5 sec but I rounded it up. Not sure were 16.5 came from? Maybe it's just easier to say that stock std 205 si cars are slow in any case what ever state of tune there in. My felt pretty Lively before the induction mod. My point was that std inlet is restrictive you only have to look at it. I've got a tad99 and its timing is set at 2deg and everything works fine.

Without any facts including conditions it was run under and test wasn't back to back etc pants in the seat tells me it would crap all over a stock si. Fact is std manifold is good but very restrictive.
 
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Sorry, typo re 16.5
I still can't see how the manifold is restrictive when max power is at 6400, same as Mi16. There can be a lag in some cars due to faulty O2 sensor. These management systems rely heavily on that sensor, they are only supposed to last 60000km, so every car would need a replacement.
 
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If in doubt, I think some measurements could answer. Not sure how you'd rig something up to measure airflow at a given RPM under load, but it can be done. Sure, you can go on a dyno, but in keeping with a DIY low cost tune, I would try to rig something myself. Isn't there an app for it? There should be. Theoretical calculations can help to establish a baseline as well and go from there. At least one could find if the intake is indeed restrictive.

I remember the Top Gear episode when they tried tuning a Renault with all sorts of add-ons and none worked (power was going down), then James did a proper service (new intake, injectors, plugs, filters, oil, etc) and basically restored it to factory spec power (if I remember correctly, about 50BHp had been lost out of a total of 200). Maybe that would be a good point to start. I guess you could try properly cleaning the intake instead of getting a new one. I cleaned my GTI intake when I rebuilt the engine and couldn't believe how much crap came out before it got to nice clean metal inside. Replaced all the rubber intake bits with new OEM and rebuilt the injectors professionally.
 
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