No, i'm suggesting doing it yourself with a 2p resistor.... It all depends on how much time and effort you want to put in getting your car right....I've built a frig box, that allows me, from the dash, to: 1. Adjust the value of the resistor that i add. 2. Add another variable Resistor at 0 to 100% throttle. 3. Bring in the WOT switch early, also selectable batween 0 and 100% throttle.
My injectors suposedly came from a 2.0XE, the Saab ones look close to what I have, even the shape of the tips is similar. The specs I have for the Saab injector part number are 213.9cc/min, pretty close
tell ya what, heres a list of all the injectors I have (ones that I know what car they are from, combined with bosch part numbers) VW MK3 2e = 173.9cc/min, Bosch 0 280 155 600, VW 073 906 031 Alfa 1.7-3.0, Fiat, Ford 2.0, Nissan - 189.2cc/min, Bosch 0 280 150 702 VW MK2 digifant = 191.8cc/min, Bosch 0 280 150 757, VW 037 906 031A VW MK2 digifant = 197cc/min, Bosch 0 280 150 903 Saab white = 213.9cc/min, Bosch 0 280 150 712 Vauxhall 20XE cream = 214cc/min, Bosch 0 280 150 744 VW MK3 ABF = 215.5cc/min, Bosch 0 280 155 606, VW 037 906 031 G Audi 2.0 ABK or VW MK2 Digifant = 197.1 or 218.1cc/min??, Bosch 0 280 150 902, VW 037 906 031C Vauxhall C20XE blue = 241cc/min, Bosch 0 280 150 427 VW MK2 G60 = 245cc/min, 49hp, Bosch 0 280 150 905 Vauxhall C20LET yellow = 304cc/min, Bosch 0 280 150 420 "Red Top" Mustang injectors = 315cc/min Audi S2 = 345.8cc/min, Bosch 0 280 150 951, VW 034 906 031b Saab reds = 359cc/min, Bosch 0 280 150 431 There are loads of different injectors fitted to the MK2 digi, the ones in the table are just 3 I know the bosch part numbers of. As you can see they are 192 - 197cc/min depending which ones they are. Edit: The 037 906 031C 2.0 ABK or MK2 Digifant one is a grey area, I was told it was a MK2 digi injector, ETKA tells me it was replaced with 037 906 031P which comes back to the 2.0 Audi ABK, and the MK2 Digifant PB. It was then replaced with 037 906 031R, but ETKA can't tell me what it was fitted to?? Also my injector table has two entries for Bosch 0 280 150 902, either 197 which is closer to mk2 digi, or 218 which is a bit too much for a 1.8 and more suited to the Audi. Anyone have more info?
It changes the spark advance and enrichens the fuel mixture depending on rpm and AFM load signal. WOT and Idle are on the same wire.
I think the best thing to do is to add a AFPR, the FSE ones are quiet good fro richening the mixture a tad higher up the rev range. Obviously its not a solution, but its a step in the right direction because as you well know, running lean is less than ideal for power and the engine internals in general.
Not entirly true as I have DI engines that run lambdas of 1 at full load steady state and produce best torque on the proviso that your spark is at an optimum for the conditions. But in the context of this thread and older VW PFI engines where the user is looking for a cheap bolt on solution to suit his unknown drivability targets or dyno improvments using hp as the yardstick, you can put an adjustable fuel regualtor to increase injector flow throughout your the rev range. But to optmise this increase you would have to prove that the engine requires increased fuel flow to match the aircharge then optimise the igntion timing to give the optimium torque for the leanest fuel mixture and and or minimum spark advance. As I have shown in the printouts lean mixtures do not always mean less torque in the same way that rich mixtures do not ensure best torque. Engine calibration is interseting isnt it. LOL
Except I never said what you are implying! WOT and Idle contacts share the same common path to the ecu on a 8v digifant 2. WOT/idle optimum fuelling is determined by AFM position and engine speed. Enrichment happens in both states.
What i mean is: you've just reminded me that WOT too early can be dangerous.... acting as over-run cutt-off.
right then i have a few questions i'd like answering. 1) those saab injectors i gave the link to- would they actually be compatible with the digi system? I can see they are bosch, and they flow around the same rate as the vauxhall ones we mentioned, so would they be any good? At the end of the day, could i just get any bosch injectors that flow a tad more and stick them in providing they look right? 2) Is it worth me getting an Adjustable fuel pressure regulator? As just mentioned, a richer mixture doesn't always mean more torque, and it will increase fuel a uniform amount over the rev range, but at least i can optimise what i have now and prevent it running lean at the top. 3) (not really a question) In light of the larger TB, I moved the WOT switch as far forward as it would go. Obviously now it is going to be flowing as much air as it did at full throttle at somewhere around 75-85% of full throttle now, so i do need it to cut in a bit earlier. Did seem a tiny bit perkier, but can't be totally sure. Is this a wise move? whats the easiest way to optimise the position of the WOT switch? cheers
1) They are correct for the MK2 digi system I can't really recommend saab/vaux injectors one way or another, I'm not really a qualified engine tuner. I got them becasue they were only a few k old and cheap! I con't say I noticed any difference after I put them in once I tuned the idle & CO, which suggested to me my old injectors were just fine. What I really needed to do was get a wideband in there and test before & after! I can say that after over a year, my car has not exploded 2) Perhaps, but before you do that I'd have a look at what your engine is actually doing with a wideband before you spend your money, unless you can get one cheap! Other issue is getting one that fits, as the location is quite awkward on the MK2 digi fuel rail. What we really need is something that can just give a bit extra fuel on WOT, since the digis always seem to lean out up there. 3) This depends how the ECU decides if the engine is at idle or WOT, and what exactly the ECU does when it detects a switch input. I'd suspect if the rpm is lower than say 2k, then the ECU goes into idle mode. But if it also messes about with the ignition map, it may not be ideal to have it cutting in early as the ignition map wont quite match up to the current engine condition. But then it never is once you start modifiying
the adjustable fuel regs are 30 brand new on the 'bay! But as you say, the mixture only really needs richening at the top end of the revs. My injectors definitely could do with replacing, so if i decide to invest in some, i'll have a look at getting some bosch 214cc ones, either the saab ones, or the vauxhall ones you have, to give a touch extra. I can check to see if it is leaning out, but i suspect if the digi ECU normally runs lean top end anyway, then with the modifications i have carried out it must be a certainty. I guess the only answer is a fuelling re-map, and i'm hoping you get good results when you and Toyotec test the 'blitzchip' against a normal ECU, as this will be a cheaper alternative! keep me updated! I also have a question about the VAG setting up procedure, seeing as you are the man to talk to about this, and i have your attention! Tried setting up my car the correct way, to get my CO down to 2%, followed the correct procedure, letting it warm up, plugging air hose, removing blue temp sender, revving over 3k 3 times, exactly as you decribe it, however, before i went through the procedure, with just the probe up the tailpipe (while the car was warming up) the CO was about 2.8%. once i had gone through the process, the CO was at 0.5%, and it didn't matter which way i turned the allan key or how much i turned it, the CO stayed at 0.5%. Tried reconnecting the blue temp sender plug, and that didn't change anything, so in the end i just trimmed it back with the blue plug back on and the hose reconnected. whats gone wrong there then?
Not so bad then, got a link? the factory spec is 1.0 +- 0.5 according to the haynes so its not far wrong. did you block off the other pipe? Only other things I can think of are an air leak or perhaps the throttle body is just pulling thru too much air to be adjusted? I assume the idle switch was clicking as it should and the wiring is ok?
yeah i know the factory would like it to be between 0.5 and 1%, but taking 1.8% as a 'best' setting for standard, i thought around 2% would suit a mild cam. Probably an airleak somewhere, although i have changed the vacuum hoses, the rubber bung on the rocker is totally knackered at the moment! You would think that it would still alter on adjustment though, but it wouldn't budge no matter how much i turned the allan key. I only blocked off the pipe that goes from the UFO-shaped thing to the inlet, i presume thats right?? I do have my crank breather (from 2litre block) plumbed into that hose though, so i don't know if that affects it. Don't have a link for the AFPR, but i just searched under 'fuel pressure'
well the breather bung leak wouldnt affect the co adjustment, becasue you've got that open to air anyway You just block the hole on the inlet side off, and leave the PCV side open to air.
