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Quote:
Originally posted by dfink
Not me I bought original 150-158 injectors from the porsche dealer.

The motronic system will only adjust in the range where the O2 sensor is functioning. Otherwise it is a straight fuel map to the position of the MAF sensor. With a bigger injector it should be rich at WOT as the pulse will be same just more fuel passing through.
Sorry, was PorscheSki89 that bought these.

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Old 07-20-2007, 09:08 AM
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Quote:
Originally posted by dfink
The motronic system will only adjust in the range where the O2 sensor is functioning. Otherwise it is a straight fuel map to the position of the MAF sensor. With a bigger injector it should be rich at WOT as the pulse will be same just more fuel passing through.
The O2 sensor in our cars only indicates rich or lean.

So the question is does the DME have the control authority to alter the fuel maps lean with the slightly larger injector flow. The only way I could answer that question would be to put a DMM on the O2 sensor of a car with the larger injectors and see if it is operating closed loop.
Old 07-20-2007, 01:09 PM
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Quote:
Originally posted by rick-l
The O2 sensor in our cars only indicates rich or lean.

So the question is does the DME have the control authority to alter the fuel maps lean with the slightly larger injector flow. The only way I could answer that question would be to put a DMM on the O2 sensor of a car with the larger injectors and see if it is operating closed loop.
Here's the issue: I just looked over the DME spec book, at Wide Open Throttle the WOT switch on the throttle plate is activated (closed) when this happens the O2 sensor circuit is ignored, this means the fuel/air ratio is really controlled by the Air Flow Meter (AFM) and the WOT fuel maps in the DME. So I really think the DME will not adjust for larger or smaller injectors at WOT. The real worry is lean mixture at WOT, so I would never undersize the injectors - you could most likely go slightly oversize and be safe.

The 0-208-150-201 injector is slightly larger (not by much) than the stock 0-208-150-158 this is most likely why they work just fine. The ...-150-201 is stock part for a 83-84 Porsche 944 2.5L. Also, this 208 injector seems much more available from suppliers.

If I get new injectors I will most likely buy these 208 ones.
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Last edited by scarceller; 07-20-2007 at 01:19 PM..
Old 07-20-2007, 01:15 PM
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Remember that we can't know for sure whether the 159's actually flow more than the 158's with the data we have available, because Stan's site does not list the pressures at which these flow rates were derived for the 159. If it was tested at a higher press than that listed for the 158, of course the flow rate will be greater.

ianc
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Old 07-20-2007, 01:24 PM
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Quote:
Originally posted by ianc
Remember that we can't know for sure whether the 159's actually flow more than the 158's with the data we have available, because Stan's site does not list the pressures at which these flow rates were derived for the 159. If it was tested at a higher press than that listed for the 158, of course the flow rate will be greater.

ianc
You are correct, this is why I only compared the 158 to the 201 and adjusted for the 2.5bar vs 3bar test pressure. Note that the 158 where tested at 2.5bar while the 201 was at 3bar. But if you convert them to same test pressure the 201 is almost a match to the 158 with the 201 being slightly higher.
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Old 07-20-2007, 01:32 PM
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Just thought I'd throw this out:

We discussed how the 0-208-150-201 injector seems to be a really good replacement for the stock Carrera 0-208-150-198.

The 208 injector happens to be stock injector for 83-84 944 2.5L - so based on this I did little poking around and I found this: goto http://www.********.com and search for injector for 84 944 and you may be very surprised what you find, tons of choices, even includes the 208 OEM one. But it also includes ones from Beck/Arnely at less than $35 each!

Now who dare order? Are they really the same?
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Old 07-20-2007, 01:41 PM
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thats where i ordered the 944 injectors for my carrera a long time ago. i've had them in for over a year and a half no problems

rock is also a very good place to order plugs at cheaper prices and hard to find ones, as in stepping down from the bosch wr7 to a six or a five or a four
Old 07-20-2007, 02:26 PM
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Additionally, RE: the higher flow rates:

If one removes the plastic top of the AFM, there is an adjustment inside which controls the spring tension on the flapper. I suppose one could install the beefier injectors, hook the car up to an EGA and tweak that spring tension until the %CO was correct while running at some off idle speed; by increasing the spring tension slightly, you would decrease the flapper deflection and hence the pulse time.

Idle mixture can be adjusted via the screw on the airbox.

I have thought about doing this, but I don't know what the correct %CO should be for, say, 2500 RPM. Anbody?

ianc
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Old 07-20-2007, 02:35 PM
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"Placing a high ohm injector on a PH system may function but does it function at its best."

- dfink -

It should function properly, i.e. given that the flow rates are the same at the
same system pressures.

"Does anyone have dyno AF information that this situation if effective and what does it do to the stock ECU that is not designed for that type of injector. "

- dfink -

There would be no real issues with the older DME ECM (3.2), as the DME
would never reach the current limit and begin switching on/off to protect
the output driver because of its max curent limitation of 10-12 amps.
Low impedence injectors usually have resistance values of 1-3 ohms
which results in peak currents exceeding the max of the output device.

"There is a reason Porsche used the PH injectors. They are designed for high performance engines."

- dfink -

Not really, at the design time (late '70s) Bosch engineers thought this type
of injector was the best at the time for an EFI system whether L-Jetronic
or Motronic. This injector/ECM design was used on VW/BMW/Porsche until
the late '80s. Starting with the 964, a simple output stage was used in the
DME utilizing high impedence injectors. This was also the case for BMW
('87 635/735).
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Old 07-21-2007, 04:20 AM
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This morning I installed the new set of 159s I bought from FiveO for $259.50. I started the job at 7am and was finished by around 10am. My biggest problem was getting the old injectors out of the intake. I didn't have a tool so I just pulled, wiggled, and twisted until they finally came out. I also found that putting the new injectors in the intake first and then putting on the fuel rail worked better from me than putting them in the rail first and then trying to put the whole assembly in the car (Bentley said to put them in the rail first and then install the whole assembly). I also found that a little bit of grease on o rings on both ends really helped.

When I started the car, the first thing I noticed is that it had a smoother idle when cold. My car always smoothed out pretty quickly and settled into a smooth idle of about 750 rpm. My idle used to be about 850 rpm before I put in a SW chip but I digress. Anyway, the car found the 750 rpm smooth idle much quicker than before.

I then went for a test drive. What I found was better throttle response and stronger pull. The old injectors were original (89 3.2 Cab). I drove about 30 miles altogether and so far the 159 injectors seem to work great and would appear to be a cost effective alternative to the stock 158s.

I also have to recommend FiveO Motorsports. They shipped same day and answered to emails with questions within minutes of them being sent.
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Old 07-21-2007, 09:57 AM
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This morning I installed the new set of 159s I bought from FiveO for $259.50. I started the job at 7am and was finished by around 10am. My biggest problem was getting the old injectors out of the intake. I didn't have a tool so I just pulled, wiggled, and twisted until they finally came out. I also found that putting the new injectors in the intake first and then putting on the fuel rail worked better from me than putting them in the rail first and then trying to put the whole assembly in the car (Bentley said to put them in the rail first and then install the whole assembly). I also found that a little bit of grease on o rings on both ends really helped.

When I started the car, the first thing I noticed is that it had a smoother idle when cold. My car always smoothed out pretty quickly and settled into a smooth idle of about 750 rpm. My idle used to be about 850 rpm before I put in a SW chip but I digress. Anyway, the car found the 750 rpm smooth idle much quicker than before.

I then went for a test drive. What I found was better throttle response and stronger pull. The old injectors were original (89 3.2 Cab). I drove about 30 miles altogether and so far the 159 injectors seem to work great and would appear to be a cost effective alternative to the stock 158s.

I also have to recommend FiveO Motorsports. They shipped same day and answered to emails with questions within minutes of them being sent.
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Old 07-21-2007, 10:06 AM
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Thanks for posting back with your results Porscheski. Sounds like the results are fairly positive subjectively. I'm guessing you don't have access to an EGA to determine whether the mixture might have changed as a result? I'd also be interested to hear whether your fuel economy changes.

ianc
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Old 07-21-2007, 12:12 PM
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someone should try running a AFR guage in the dash to monitor the exhaust which will tell if the mixture is +/- at rpm's.
I would hate to see you guys save a couple of hundred bucks to only have to tear down your engine in 2k miles from WOT lean condition...UNLESS you need an excise to tweak the engine and make it bigger!
I am all for saving any $$ I can, however, my suggestion is to test, somehow, to make sure ok and wont hurt your engine. Maybe I am too conservitive...just my 2cents worth not asked for.
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Old 07-21-2007, 12:18 PM
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Quote:
I would hate to see you guys save a couple of hundred bucks to only have to tear down your engine in 2k miles from WOT lean condition...
A lean condition would only occur if the replacement injectors didn't flow as much fuel as the stock ones. I don't believe that has been suggested about any of the replacements being discussed...

ianc
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Old 07-21-2007, 02:12 PM
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Quote:
Originally posted by PorscheSki89
This morning I installed the new set of 159s I bought from FiveO for $259.50. I started the job at 7am and was finished by around 10am. My biggest problem was getting the old injectors out of the intake. I didn't have a tool so I just pulled, wiggled, and twisted until they finally came out. I also found that putting the new injectors in the intake first and then putting on the fuel rail worked better from me than putting them in the rail first and then trying to put the whole assembly in the car (Bentley said to put them in the rail first and then install the whole assembly). I also found that a little bit of grease on o rings on both ends really helped.

When I started the car, the first thing I noticed is that it had a smoother idle when cold. My car always smoothed out pretty quickly and settled into a smooth idle of about 750 rpm. My idle used to be about 850 rpm before I put in a SW chip but I digress. Anyway, the car found the 750 rpm smooth idle much quicker than before.

I then went for a test drive. What I found was better throttle response and stronger pull. The old injectors were original (89 3.2 Cab). I drove about 30 miles altogether and so far the 159 injectors seem to work great and would appear to be a cost effective alternative to the stock 158s.

I also have to recommend FiveO Motorsports. They shipped same day and answered to emails with questions within minutes of them being sent.
Thanks for the update, since we have not yet found exact flow rate for this 159 injector keep an eye on Wide Open Throttle because it is at WOT that the ECU will not adjust mixture based on O2 sensor.

Stan Weiss's site (http://users.erols.com/srweiss/tableifc.htm) shows a flow rate of 24.35lbs/hr or 255.9cc/min but it does NOT state at what fuel pressure they where tested at. However, if these run very well in your Carrera I would have to take an educated guess and say they where tested at 3bar (43.5psi) and if you adjust this to 2.5bar (36.25psi) fuel pressure it gets converted to 22.2lbs/hr (233.6cc/min) and this certaily lines up nicely with the stock 158 injector numbers of 21.8lbs/hr (229.1cc/min) at 2.5bar fuel pressure. This means the 159 injector flows about 4.5cc/min more (richer) than the stock 158.

What would make me more sure is if someone can find exact flow rate for the 159 injector, we need the flow rate and the fuel pressure tested at. Would be nice to double check.

Thanks for the update on your install of the 159 injectors. Sounds like things really cleaned up in your car with these. I'm sure the spray patterns and flow is much better than what you had.
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Old 07-23-2007, 08:03 AM
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FiveO sells on Ebay as well, this listing is for the Bosch 159 injector, it's for new a set of 6 at $200.00 including shipping

http://ebay.com listing number 330135546938

They have them listed as BMW set but they are the 159 injectors.

I think this is one of the best deals you will find, that comes to $33.33 each shipped!
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Last edited by scarceller; 07-23-2007 at 09:08 AM..
Old 07-23-2007, 09:01 AM
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Alright, for a couple hundred bucks I couldn't resist, so I grabbed a set. I'll report back...

ianc
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Old 07-23-2007, 03:10 PM
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ianc, I may be right behind you on a set of these...

Please keep us posted.
Old 07-23-2007, 03:27 PM
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I'm trying to follow this but I have a question...is the general consensus that if the flow rate can be confirmed to be close to the OEM part this is a safe, inexpensive alternative? If the flow rate it too high (or too low) would that show up in, for example, a smog check or is this a stupid question?
TIA
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Old 07-23-2007, 03:50 PM
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Quote:
Originally Posted by 88911coupe View Post
I'm trying to follow this but I have a question...is the general consensus that if the flow rate can be confirmed to be close to the OEM part this is a safe, inexpensive alternative? If the flow rate it too high (or too low) would that show up in, for example, a smog check or is this a stupid question?
TIA
First, your question is not Stupid.

The 201 injector is confirmed to flow 7.4cc/min more (richer) than the stock OEM 158 injector. At 2.5bar (36.25PSI) fuel pressure the stock flows 229.1cc/min and the 201 flows 236.5cc/min.

The other injector on the table as well is the 159 injector but we are not 100% certain but it is believed to flow 4.5cc/min more (richer) than the OEM stock 158, it's flow rate is believed to be measured at 3.0bar (43.5psi) and comes in at 255.9cc/min but we are not 100% of the fuel input preasure. However, if it is 3.0bar and we then adjust the flow rate for 2.5bar we get a flow rate of 233.6cc/min and based on the fact that several floks have also used these 159 injectors as well I feel very certain that the numbers we saw posted where at 3.0bar and not 2.5bar. What we really need is 100% confirmation of the flow rate and at what fuel pressure.

OK, so what we have are 2 injectors (159 and 201) that flow slightly more than the stock ones (they flow about 2-3% more than stock) a flow increase of 2% is really nothing in our cars. First, the O2 sensor circuit will just adjust for this at idle and mid throttle. But the O2 sensor circuit is disabled after about 3/4 throttle by the Wide Open Throttle switch on the Throttle Body. What this means is the DME will use special fuel maps for WOT and the extra 2% fuel will just cause a slightly richer mixture at WOT. I bet no one driving the car will ever notice. Also richer is much better than leaner at WOT so I think you have no need for concern.

The other reason folks report better response and overall improvement is because you are replacing OLD 158 injectors that most likely have bad spray patters as well as improper flow rates because of wear and age.

So, bottom line is the 201 injector has been confirmed to be slightly larger (about 7cc/min) while the 159 is belived to be slightly larger as well (about 4cc/min). Also both injectors have been installed by various folks on this board with good results.

I would safely say I would use either injector as a drop in replacement in my personal car. I am leaning toward the 201 because it is easy to find cheap. The 201 is OEM part for 83-84 944 2.5L as well as many early 80s BMWs.

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Old 07-24-2007, 07:45 AM
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