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blade7
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Re: Modern fuel injectors 2021/05/08 15:14:31 (permalink)
I used to have to lean the idle mixture of my Cosworth to the point it stumbled, to get it through an MOT years ago.
post edited by blade7 - 2021/05/08 15:17:59
PSH
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Re: Modern fuel injectors 2021/05/08 17:46:16 (permalink)
Funny, as I have never had a rough idle due to AFR, it can be lean of rich within reason and the idle remains solid
 My AFR reading has never been rock solid, it bounches around by 2 or 3, my son did tell me why but I can't remember, it might have been due to where my O2 sensor is positioned. I do have the ability to data log the AFR but have never had a reason to do so.
 
Pete

944 Turbo......was 368BHP/382Torque.... now more...
blade7
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Re: Modern fuel injectors 2021/05/08 23:11:59 (permalink)
Where is the 02 sensor positioned?
PSH
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Re: Modern fuel injectors 2021/05/08 23:19:58 (permalink)
blade7
Where is the 02 sensor positioned?


The front end of the tailpipe, on top of the bend that goes over the torsion bar. Wiring goes up through a bung into the boot 

944 Turbo......was 368BHP/382Torque.... now more...
blade7
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Re: Modern fuel injectors 2021/05/09 00:11:28 (permalink)
Every guide I've ever seen is for the sensor to be between the bottom of the downpipe and the first silencer. That's where I put mine.
PSH
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Re: Modern fuel injectors 2021/05/09 00:38:32 (permalink)
Guides seem to vary... Bosch states no closer than 8 inches to Turbo and 24 inches from tailpipe which mine fits into nicely. It doesn't really matter where on a pre cat car, needs to fit in as stated above.  Needs to have the wires upright, between something like 10 - 2, must be the top of the pipe to avoid condensation and any joints between need to be fully sealed. I use a heated o2 sensor so no need to be closer to the engine. 

944 Turbo......was 368BHP/382Torque.... now more...
blade7
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Re: Modern fuel injectors 2021/05/09 00:50:41 (permalink)
A  WB sensor 8 inches from the turbo probably wouldn't last long.  And AFAIK WB sensors are all heated. I don't think any UK 944 turbo has to have a cat fitted either.
James0
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Re: Modern fuel injectors 2021/05/09 01:35:45 (permalink)
Mines near the starter motor, the boss was already welded into the exhaust. 
I'd be disappointed if I ended up with a worse, richer idle with over 30 year newer injector technology.
 
Needs some tinkering.
James0
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Re: Modern fuel injectors 2021/05/09 15:05:07 (permalink)
Interestingly, it idles fine today. However I have small fuel leaks at the rail, the O rings are definitely too small.
So I pulled the fuel pump fuse and let the engine burn off the fuel in the rail.
 
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Re: Modern fuel injectors 2021/05/09 18:44:24 (permalink)
blade7
A  WB sensor 8 inches from the turbo probably wouldn't last long.  And AFAIK WB sensors are all heated. I don't think any UK 944 turbo has to have a cat fitted either.




I could be wrong but pretty sure that later turbo's had a CAT, I seem to recall a friend with an 89 complaining about the cost of one from Porsche.  There certaimly seems to be plenty of suppliers out there selling CAT's for the turbo?
I've never really paid it much attention having none fitted to the 86 so stand to be corrected  if wrong. Perhaps others can say if they have one and for which year might answer the quedtion?
 
Pete

944 Turbo......was 368BHP/382Torque.... now more...
James0
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Re: Modern fuel injectors 2021/05/09 18:57:11 (permalink)
Some had them but they don't have to have them for the MOT. I can't remember what year they would be mandatory 93?
Mines got a hollowed out cat (not by me, I'd imagine that was a dirty job), obvs off a later car. The S2 exhaust in my garage (from when my engine was 16v N/A) has a cat. 
 
blade7
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Re: Modern fuel injectors 2021/05/09 19:28:49 (permalink)
I'm fairly sure the cat was optional on a turbo Coupe. May be different for a cab. 
Eldavo
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Re: Modern fuel injectors 2021/05/10 13:10:21 (permalink)
A good friend and exceptional tuner (he maps BTCC cars, etc) pointed out that the low flow at idle and the position of the WB bung on my car meant it wouldn’t be massively accurate. He also said not to worry about it jumping about a bit at idle either, as long as it’s right when it’s under boost and higher flow. 


My wideband bung is in this generally accepted position:
 
https://www.lindseyracing.com/LR/Parts/WBO2LOCATION.html
 

Current:
1988 944 Turbo S (not exactly standard)
Past:
2002 996 3.6 C2
2006 987 Boxster 2.7
1988 944 2.7
Caucus Marine Ti
PSH
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Re: Modern fuel injectors 2021/05/10 13:14:39 (permalink)
Eldavo
A good friend and exceptional tuner (he maps BTCC cars, etc) pointed out that the low flow at idle and the position of the WB bung on my car meant it wouldn’t be massively accurate. He also said not to worry about it jumping about a bit at idle either, as long as it’s right when it’s under boost and higher flow. 


My wideband bung is in this generally accepted position:
 
https://www.lindseyracing.com/LR/Parts/WBO2LOCATION.html
 


 from those in the known that I have spoken to over the years, the factory location is a very bad place..

944 Turbo......was 368BHP/382Torque.... now more...
James0
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Re: Modern fuel injectors 2021/05/10 14:27:30 (permalink)
I'm a little concerned that being an injector for a 16 valve car, the spray pattern doesn't fire directly onto the inlet valve, but to either side.
A quick mock up with a 30 degree paper template suggests a lot of the fuel wil hit the walls just before the valve .
It's batch fire so there will be fuel on the back of the valve.
Just not sure how critical firing straight at valve is. I'm annoyed I didn't think about it
blade7
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Re: Modern fuel injectors 2021/05/10 14:34:34 (permalink)
PSH
Eldavo
A good friend and exceptional tuner (he maps BTCC cars, etc) pointed out that the low flow at idle and the position of the WB bung on my car meant it wouldn’t be massively accurate. He also said not to worry about it jumping about a bit at idle either, as long as it’s right when it’s under boost and higher flow. 


My wideband bung is in this generally accepted position:
 
https://www.lindseyracing.com/LR/Parts/WBO2LOCATION.html
 


from those in the known that I have spoken to over the years, the factory location is a very bad place..


The factory location in the downpipe, is for a narrow band 02 sensor.  You should be careful who you speak to. Plus if you were using a engine management system that can use info from an 02 sensor, having it mounted near the tailpipe probably isn't the most effective place.
post edited by blade7 - 2021/05/10 14:42:12
PSH
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Re: Modern fuel injectors 2021/05/10 14:39:39 (permalink)
I've never really studied these things James but do know that if a head is polished too much it will affect the way that the fuel atomizes and thus lose power. If it's that susceptible to how the fuel burns then perhaps having the correct pattern is also very important. Hopefully, someone with more knowledge/experience of such things will be along soon to give a more informed answer. 
 
Pete

944 Turbo......was 368BHP/382Torque.... now more...
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