325 tb on 320 question

Post Fri Sep 09, 2005 6:07 pm

i have recently done the 325i throttle body mod and installed a chip on my 320i and its a big improvement but can anyone tell me if swapping the air flow meter will make any difference or are they the same

Post Sat Sep 10, 2005 12:14 pm

anyone

Post Sat Sep 10, 2005 1:30 pm

I looked into this on Vauxhall engines years ago. BMW and the late 80s Vauxhalls use the same Bosch parts. Larger engined cars did have larger air flow meters. However, if you just swap them over the fuelling will probably be wrong, so you'd need to experiment with adjusting the air flow meter spring tension etc and I don't know if it'd ever be right. I do know someome who fitted a 2.0 afm to a 1.6 engine and it seemed to run ok.
A useful listing of part numbers is at www.atpelectronics.co.uk

Post Sat Sep 10, 2005 1:38 pm

thanks for the reply the reason i ask is now ive done the mods im planning on having it set up on a rolling road at the end of the month so if theyre different they would adjust the settings

Post Sat Sep 10, 2005 1:49 pm

as long as the 2.0 unit is in GWO then I'd stick with that TBH.

As for the dyno setup, apart from the idle mix there is nothing they can alter on the car, its all controlled by the chip so dont spend much Ãƒ”šÃ‚£Ãƒ”šÃ‚£ there dude, use the dyno as a diagnostic tool, thats what they are really designed for

Make sure and post the results though dude

Post Sat Sep 10, 2005 1:58 pm

tbh the main reason i want to get it on the rollers is to find out how much difference the tb mod has made (i think a few people would like to know) although i dont know exactly what it was before i believe they should be around 129bhp as standard

i'll stick with my afm though as i know you know your stuff cheers

Post Sat Sep 10, 2005 1:59 pm

You could fit an adjustable fuel pressure regulator and see if they can crudely optimise the fuelling. With a fixed map all you can do is turn it up or down everywhere.
Actually, a tuner I used to use (before he moved to France) said that the super chavvy rising rate regulators (like the Power Boast Valve) actually work very well on some cars.
You can adjust the srping tension and this affects the air flow signal versus air flow rate curve. It's all crude stuff though.

I'd just get them to look at it first and see if the fuelling could be adjusted.
There is a chap call ChipWizards who can modifiy the EEPROM program in the std chip and so do proper tuning.