[Diy_efi] Air fuel meters

Wed Apr 13 11:05:07 UTC 2005

i'd recommend a wide band lambda sensor. the normal narrow band sensors dont have a linear response and are designed to read only a very narrow lambda value of 0.02 (they reliably read from 0.98 to 1.02 lambda) which is a very narrow range around the 14.7 a/f used to run kats.

a wide band lambda sensor will read from a/f 9 to 20 so it is really useful, expecially for turbo engines.

consider that a a/f of 14.7 is suitable only for lean cruising, i wouldnt use anything above 12.5 a/f in a turbo engine, and that falls well out of the narrow band sensors capabilities. therefore, you can set your fueling to rich, but you will never know HOW rich

at leas, use a 3 or 4 wire lambda, which has a heater. the unheated sensor wont read much if installed much down stream of the valves and at low power settings

i use a wbo2 system from www.wbo2.com 
it works great and its very cheap

gm

> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]
> Sent: Mittwoch, 13. April 2005 05:23
> To: diy_efi at diy-efi.org
> Subject: Re: [Diy_efi] Air fuel meters
> 
> 
> At 08:41 PM 4/12/05, you wrote:
> >I also did not know this.  My car is a V6 and runs a Garret T25 turbo
> >-- (Smaller than the T3!)  however, the a/r is .83!
> 
> 
> What's odd is the fact that the T25 I installed on my 1500 Fiat motor 
> that's in my Yugo came from a 2.3 liter Saab 9000. The 2.0 
> liter 900's uses 
> a larger T3. I'm not sure what trim sizes the Saabs use in 
> either turbo. 
> I'm not sure why Saab chose to install a smaller turbo on a 
> larger engine. 
> It doesn't really make sense unless they wanted the 9000 to 
> spool up really 
> quick.
> 
> I do know that the T3 that is in Spider uses a .16 trim. I 
> got this from a 
> friend who wanted a T3 with ceramic ball bearings. He had 
> Turbonetics set 
> this turbo up for the smallest trim available.
> 
> This turbo spools up quick and around 2500 rpms. But the T25 
> on the Yugo 
> takes a bit longer to spool up. I believe it's because the 
> trim is just too 
> large for the 1500 engine. I'd hate to think the lag a T3 
> would have from a 
> 900.
> 
> Since I've been sourcing most of these parts from junked 
> cars, beggars 
> can't be choosers when it comes to find the correct turbo. 
> Since I can't 
> think of any cars sold in the US with 1500 motors I could 
> source a turbo 
> from, I was told a T25 would be a good candidate since allot 
> of cars in 
> Europe with 1500 motors use the T25. So I guess that's as 
> good as it's 
> going to get.
> 
> Now concerning the O2 sensor. I pulled it and found it was 
> coked over with 
> soot. I took a propane torch and heated it until it was 
> cherry red and 
> flaked the soot off. I stuck it back in but low and behold 
> it's doing the 
> exact same thing as before. So I don't know what's going on there.
> 
> I did not kick the turbo on. I just let it idle and drove the 
> car around in 
> my driveway. The backup lights don't work and I got limo tint 
> on the rear 
> windows so...
> 
> I'm wondering if I am just sending too much fuel into the 
> engine under 
> boost which caused it to coke up to begin with. I drilled the 
> secondary jet 
> out to prevent detonation and get me by until I could put the 
> car on the 
> dyno to get some numbers. Hoping someone could analyze the 
> graph and tell 
> me what sort of jets I need.
> 
> I tried to pull the "good" sensor from an old Fiat Spider 
> exhaust manifold 
> but it's seized up pretty good. I tried heating it with a 
> torch but it 
> didn't want to budge. I want to let it soak with PB Blaster 
> for a few days 
> and see if I can remove it. Or just get a new O2 sensor.
> 
> 
> 
> 
> 
> James Seabolt
> Tennessee, United States
> Homepage --->>> http://users.chartertn.net/jseabolt/
> 
> 2003 Subaru Baja
> 1980 FIAT 2000 "turbo" Spider
> 1968 Ford Fairlane 500 (Not a Ford Galaxie!!)
> 1987 Yugo GV 1500cc also turbocharged
> 
> 
> 
> 
> 
> 
> 
> 
> 
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