Hi guys, I'm new to ITBs on my Peugeot 106 rallye 1.6 8V from 1998. Is the amateur rally competition car. That topic has inspired me to go for ITB. So now I have a question to all ITB's masters Project was low cost that itb's came from Honda Hornet PC41 - 36mm on diameter, home made manifold. Now the question: Car runs - but runs quite RICH (more than on stock manifold with ori throttle body) ... Is it a common case with ITBs ? 36mm is probably not much - but anyway watching MAP sensor on full throttle it can not go much more so do not think is problem with airflow over the throties. Running stock (not really ) ECU - I have mapped it - works perfect for stock manifold. Now I can not get fueling maps to work - so or don't have proper maps catch or don't know the way how they are working Magneti Marelli 8p.16 ECU. Ignition maps cracked. Please take a look on pic's below and share some thoughts about .... (is not pretty project but it have to work not really look)
Because your ECU needs a manifold pressure reading for the MAP sensor to point to the correct load for a given engine speed for mapped spark and fuel. On an ITB set up, your map sensor will be at atmosphere, which is largely the same as WOT on the plenum manifold. This means your injectors will be opening at large durations at part load, hence the rich running on your current set up. Your spark timing at light loads will also be to retarded or at WOT timing, therefore with a rich mixture and retarding timing, the engine will run like ****e.
Just to clarify - MAP is connected to manifold - ITB has 4 connecting pipes behind the butterfly valves - I have connected all of them together and with MAP and fuel pressure regulator. But - Cheers - it make sense - as the pressure (under-pressure) dropped comparing to stock manifold the ECU enriching to fit .... unfortunately looks like Peugeot engineers didn't thought about that big pressure drop so probably map's on this areas are that bad (theory is that the whole range for MAP sensor should be set) Unfortunately this Magneti Marelli ECU is so difficult to crack the maps ... so playing and still don't have effect i need.
were are you based ? Wayne Schofield (Chipwizards) is the man to re map it if you can get hold of him,I run this ecu om my 16v mk1 golf,Google his name for results
Bit different area of world Poland ... believe we have some ECUmagicWizards around but the fun is do it yourself as ITB mod ... just looking for some hint's from more experienced guys Cheers
That looks like way which will sort all problems with tuning - do I really want easy life ?? Any suggestions about stand-alone's ? Didn't hear about something dedicated to Peugeot 8V ... so which is cheap enough to do not multiply car value ?
And by the way - what the thoughts about this air-box - do it look big enough ? Is the big impact to run this bodies without trumpets ?
Standalones have a look at; DTA S40 Emerald K6 OMEX 600 or even Megasquirt 2. Airbox could be more optimum I suppose. You would need a good calibration on the car to determine if the car is right for you before adding or reworking any hardware.
think some small trumpets are hugely better than none. I have built two ali airboxes for webers over the years, neither was anywhere big enough, so both were wasted effort. Jon
So with advice from Peugeot Rally UK forum looks like the best option will be dome filter over the trumpets - so get rid of any airbox What yours thought about ?
If the airbox is too small I would agree, but a well designed airbox Will run cooler and at positive pressure You can work it out with some simple formula on the interweb, just need capacity and rpm, some of the fancy ones use VE, but since it will not be over 1, and you don't want to under size I wouldn't bother Socks over trumpets totally destroy the air flow att he most important part
Cheers for all advice. Have read some physics articles about calculating length and capacity of boxes based on acoustic wave rules .... so complicated if you really want to do it proper and need to know exact dimensions (bit impossible now at don't want to take engine apart) ... but getting some hints like - the open trumpets are good for really high revs (as capacity and length of air duct is to small for "air wave" on low revs)... So looks like I should make a airbox much bigger - but is so tight in there over the bodies - looks like I will expand the airbox in right side and getting it to the front of the car with filter between battery and engine...
Your packaging will compromise the ideal design, however I would still try to engineer it to the best that can be done.
