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found some 22.9 lbs/h injectors that will work on a bosch spider... any mid to later 70's to early 80 3.0/3.2 bmw 6 cly car has these injectors bosch no.280-150-151... from what i remember here,, the injectors on usr spiders are way to undersized for our cars.. at a injectore site.. marren injection.. our cars need at least 18.75 lbs/h for a stock car.. and for a mildly uped car lets say 145 hp you need 22.66 lbs/ h, and if you go to 170 hp.. where i am going for you need 26 lbs injectors.. still looking for those , but a 22 lbs injector should work well on a bosch spider. and , yes... you car will not run rich.. the o2 feedback won't alow it... just some more injection at higher rpm's where our injectors go way to lean.
 

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I find a lot of value in building on what others have researched and gotten to work well with our cars... Have a look at this web page. Greg is a contributor to this BB, and very knowledgeable.

Best regards,
 

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The Bosch 151 injectors will fit the L-Jet Spider, and yes they flow about 25% more. There are a few problems, first, they have been out of production for about 15 years so any that are still around have been sitting a while. They are a very high quality injector and can usually be overhauled with success.

On a stock engine, they are a waste. The engine will run rich at full throttle when the O2 sensor is locked out by the throttle position switch. On a modified engine they can help.

I do have 27 pound per hour units in stock, they are new.

Thanks Enrique!
Greg,
Silicone Hose Kits
 

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stock injectors pump 16.95 lbs/h.. this works out to be 16.95 lbs/h..bfsc .5 x no. injectors.. = fuel injceton max hp= 108 hp... a bit lean for our cars.. check out the marren fuel injection site.. you can play with the numbers and find what your injector runs.. alfa injector 280-150-121 alfa spider injector..
 

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First of all, Bosch never published flow numbers for the injectors in the Alfa Spider, GTV6, or Milano. I am not sure where you got 16.95, but it seems a little low to me. More on this later. Second, where did you get a BSFC of .5 for the Nord engine? There is no way that's right, I have seen better on a supercharged Alfa engine. Third, that calculator assumes an 80% max duty cycle. Of hand, I don't know what it is on the Spider, but it could be a little more.

These little variables add up. A stock L-Jet Spider doesn't run lean, and if it does it's because something is wrong with it. You can verify this with the O2 sensor.

Regarding flow numbers, because Bosch doesn't publish them, the various sources on the internet that post them vary a bit. Some are just guessing or repeating what they have heard. The numbers from those that have actually tested them vary due to different testing machines and test conditions. The fuel pressure setting is a big variable. Even the atmospheric pressure on a give day will have an effect, so it's normal for the numbers to vary. The 16.95 number seems reasonable to me considering these variables, but I think it's about a pound low.

Run the calculation at 17.95 and a .45 BSFC and even at an 80% duty cycle, they are enough.

If the stock L-Jet Spider ran lean, I would be trying really hard to let everyone know that so they would buy my Stage 1 injectors!
Greg Gordon,
OKINJECTORS.COM
 

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Discussion Starter #6
first of all , all you need are the bosch numbers on the side of the injectors,, second,, you need to be a old audi tech, with a big data base to look thru.. and these rate at 43.5 psi..and for na motors the rate is 0.5 bsfc.. and the cal. i got at 0.5 120 hp at80% was 18.75 lbs/h.
 

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Discussion Starter #9
....correction...i am not old:):) my mistake:)
 

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If the stock L-Jet Spider ran lean, I would be trying really hard to let everyone know that so they would buy my Stage 1 injectors!
Greg Gordon,
OKINJECTORS.COM
Greg,

My 84 Spider seems to be running rich with the stock injectors. The exhaust is sooty and the fuel mileage has dropped from around 29 mpg in 2008 when I bought it to around 23 mpg. I installed a heated O2 sensor in a free-flowing older style exhaust, new cap, rotor, wires, and NGK Iridium plugs. Based on what i've done and what I describe, do you think your injector service would be a good next step and worth the effort? THe car has 58k miles and runs very well in general (except the poor mileage and sooty exhaust) if that makes a difference. Any comment or advice on what to check would be much appreciated.

THanks,
 

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Before condemning the fuel injectors I'd suggest a thorough check of all the L-jet systems (see link below to the Spider L-jet page).

Sooty exhaust could be from a stuck open T-stat (engine never fully warms up and the computer remains in its default 'warm up' mode) or faulty coolant temp sensor (computer thinks the engine hasn't warmed up). A leaky CSI (Cold Start Injector) could make a rich running mixture. A faulty fuel pressure regulator could allow the injectors to squirt too much fuel.
 

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Phil,
I had the same symptoms ...3 injectors had "poor" spray pattern, 4th had "Fail". You should get an as found flow report.
Ultrasonic/solvent cleaning and blueprinting improved performance.
Also the OVS is a contributor to the normal "sooty" exhaust.
PM me if you want a copy of an article I wrote for our Alfa newsletter on how I did it.
TTFN Elio
 

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Before condemning the fuel injectors I'd suggest a thorough check of all the L-jet systems (see link below to the Spider L-jet page).

Sooty exhaust could be from a stuck open T-stat (engine never fully warms up and the computer remains in its default 'warm up' mode) or faulty coolant temp sensor (computer thinks the engine hasn't warmed up). A leaky CSI (Cold Start Injector) could make a rich running mixture. A faulty fuel pressure regulator could allow the injectors to squirt too much fuel.
Thanks Eric,

Good suggestions. I haven't looked at your diagnostics page lately, I will do that and check things out over all. Engine temp does seem to stay low topping out at around 140. New thermostat may be in order.
 

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Phil,
I had the same symptoms ...3 injectors had "poor" spray pattern, 4th had "Fail". You should get an as found flow report.
Ultrasonic/solvent cleaning and blueprinting improved performance.
Also the OVS is a contributor to the normal "sooty" exhaust.
PM me if you want a copy of an article I wrote for our Alfa newsletter on how I did it.
TTFN Elio
Thanks Elio,

PM sent. I think I will go ahead and do this as well after checking some other things out.
 

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Greg,

My 84 Spider seems to be running rich with the stock injectors. The exhaust is sooty and the fuel mileage has dropped from around 29 mpg in 2008 when I bought it to around 23 mpg. I installed a heated O2 sensor in a free-flowing older style exhaust, new cap, rotor, wires, and NGK Iridium plugs. Based on what i've done and what I describe, do you think your injector service would be a good next step and worth the effort? THe car has 58k miles and runs very well in general (except the poor mileage and sooty exhaust) if that makes a difference. Any comment or advice on what to check would be much appreciated.

THanks,
Hi Phil,

Because of the age of these cars, the fuel injectors are almost always at least partially clogged, usually one or more have a poor spray pattern. So, yes, it's generally worth getting them overhauled. However it's not normally where I start looking for a problem. I normally do start looking for air leaks, bad grounds, and checking the temp sensor, cold starting stuff etc.

Greg,
Silicone Hose Kits
OKINJECTORS.COM
 

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Because of the age of these cars, the fuel injectors are almost always at least partially clogged, usually one or more have a poor spray pattern.
Thanks for the input, sounds like a good project to get done before spring.
 

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Discussion Starter #18
on youtube,, they have a section on how to clean your injectors... looks cool. but i would try it on a injector from a wrecker first.. but it looks like a workable project.
 

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I have seen various youtube videos on this subject. The problem is that you need to pulse the injectors over 10,000 times while they are in the ultrasonic bath, and that's tough to do without the correct machine. They also have to be pulsed really fast or the fluid won't backflow through the injector. Even if you do clean them successfully, how will you know? Without the right machine, you can't tell if it's spraying the right amount at idle, at part throttle 2500rpm, full power at redline etc.

I really do think this is one area, where doing it yourself isn't the best way.

Greg
 

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Discussion Starter #20
just saw it on you tube guy at work told me about it..
 
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