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| joshwilson3 | Running lean with Bosch III | ||
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Has anyone ran any scans before and after installing Bosch III injectors? I've read of a few people finding they run lean with the Bosch III on the Corvette boards. One guy ran lean with the Bosch III according to his scans, put his Lucas injectors back in and was at 128 BLM.
The PO installed some 24# Accel injectors in my 89. It ran rich according to my scans, and when I replaced the spark plugs. They were carbon fouled. So, I replaced the injectors with some Bosch III's from FIC. And when I ran my scans, my BLM's were high. Sometimes going to 150+. Also noticed the INT sometimes going to 160 when hitting the throttle. I installed an adjustable fuel pressure regulator. Bumped the pressure to 47 with the FPR disconnected. And ran a scan later on at start up, and the BLM was at 144. So still lean. I raised the fuel pressure to 55 with the FPR disconnected. Reset the computer. And ran a scan which shows an INT and BLM count of 130. I still need to drive around to see what the counts do. I pulled some plugs and noticed the ground strap were light gray/white looking. As was the O2 sensor I pulled. Which I've read means it is running lean:  The one the left is the sensor I pulled while it had Accel's and looked carboned. The one on the right is the O2 sensor I pulled after the Bosch III were installed:  |
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Posted on: 2010/11/29 5:19
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| Steve40th | Re: Running lean with Bosch III | ||
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Josh, I will pull a plug tomorrow and see how mine running. I retuned mine for the flow rate/constant Jon gave me when I ordered the injectors. My BLMs are fine, and didnt run lean with 43.5 psi at regulator with vacuum line off.
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Posted on: 2010/11/29 6:16
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| joshwilson3 | Re: Running lean with Bosch III | ||
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Did you check your BLM's before or after you did your tune? I saw on the other sets of injectors for sell that you are supposed to get the flow rates for the actual set of injectors you get when they run tests on them. But I didn't get any data on my injectors. I'm gonna see what my BLM's do with the pressure at 55 with the FPR disconnected. Which puts it at a running pressure of 47. What exactly is that 43.5 psi rating for on the injector? Is that a running pressure or the pressure with the FPR disconnected? Stock, my 89 had a running pressure of 34, and it was 41 with the FPR disconnected. |
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Posted on: 2010/11/29 8:31
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| Steve40th | Re: Running lean with Bosch III | ||
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Yes, I checked my BLMS, the only issue I have really had was a standard split BLM issue with the LT1 and a big cam. I have hundreds of datalogs, and my car was tuned by a pcmforless and LT1tuning, for example. The 43.5 psi with engine running an vacuum line disconnected is LT1. I cant remember the L98 pressure off hand. My injectors were Ford Red Tops at 30#'s, then I went to Bosch III 42#'s. The Fords have a constant of about 31 in your tune, and the Bosch are 42, because that is what they flow at 43.5 psi. And, Jon did/does give you flow data sheets on the injectors so you can change the constant accordingly for your injectors. If your engine runs that lean, you just need to retune the chip. |
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Posted on: 2010/11/29 16:03
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| joshwilson3 | Re: Running lean with Bosch III | ||
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I'm hoping raising the fuel pressure fixes it. As I had only planned on replacing the injectors to replace the 24# injectors the PO installed. Then had to buy an expensive adjustable top and tear back into it to put that on the FPR so I could raise the fuel pressure. If that doesn't work. Then I'll look to see if FIC can do Bosch III at 23# since the ones I have are 22#. If not then maybe I could swap them for Bosch II's and see what those do as they spray more of a stream instead of a mist like the Bosch III's. Or just return them and put the 24# Accel back in. I think getting a chip burned costs the same as a set of injectors. These Bosch III are advertised as stock replacements with no mods needed. But for some reason, some people find they run lean with the Bosch III on the stock Vettes. Kinda strange a running pressure of 34 with 24# calculate the same flow as running a pressure of 41 with the 22#. Yet I ran rich with the Accel 24# at that pressure of 34. And at the pressure of 41 with the Bosch III 22#, I was running lean with an idle BLM of 144. |
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Posted on: 2010/11/29 16:26
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| Steve40th | Re: Running lean with Bosch III | ||
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Remember Josh, injectors are rated at zero vacuum, always. Your 24#'s were rated at that flow rate at zero vacuum, not at 34psi which is running pressure. It is way lower than 24#'s at 34 psi.
Jon will also tell you the flow rate/#'s based of off fuel pressure. But it is always with the vacuum line disconnected. Running pressure fluctuates with driving. The only way to tell what your injectors run is on a test rig, like Jon and many other injector companies have, and to see how much they put out at specific pressures. |
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Posted on: 2010/11/29 16:33
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| mseven | Re: Running lean with Bosch III | ||
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Once in upper 140's and soaring is too lean, using a wide band I have seen 145 + start to go over 15:1+.
The problem you encountered is simple the ev6 (design III) delivers fuel mass differently (fuel mass v.s.injection time in m.s.). When comparing the ev1 (older style)to an ev6 of the same lb. rating, the fuel mass below 6 m.s. is quite a bit different...and not linear. Once above that they start to look similar (or somewhat linear). Unfortunately 0-6 ms. represents typical street driving. When vendors speak of flowing an injector, it only refers to what might simulate WOT, and not how much fuel mass is being delivered at lower m.s. or predicted pulse width....not to mention other various effects of slope gain, injection time to deliver the same amount of fuel, etc.etc. They can be made to work well but requires extra work in the tune to compensate. Your old accels were an ev1 style, and the tables set-up in tune favor that style injector. I am not a fan of tuning through increasing or decreasing the f.p. Most injectors we use are designed to operate at 43.5 or 39.15 delta. That combined with the proper offsets (all available data for almost every injector has been supplied by ford racing) for a particular inj. is were I start and then I begin actually tuning....however if you raise the fp. to "fix" idle/off idle, once in higher/rpm load there's a very good chance that may not be right. Bosch IMO has always made a great product, but remember that the ev6 style is designed for the newer motors. Aside from psi. used in newer motore, valve angle, injector distance from the valve etc.etc. also plays a role in the "whys" of how this inj. delivers fuel mass. Many seem to think think that look of "fuel frothing/misting" in a tube means better atomization, performance or a better injector..it does not. The "spray patterns" were developed due to the type of engine design. Unfortunately ev1's are discontinued. Therefor, if one still wants to use a Bosch injector the option is to work with the ev6/new body design (this means giving the ecm more info than just the offsets and linear flow rate), or perhaps find some new ev1's (old style). IMO, since you don't want to retune the best approach would be to get an injector that works better with all the stock inputs in the tune (i.e. larger # rated inj.) Either way data logging is the right thing to do.. |
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Posted on: 2010/11/29 16:54
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| Steve40th | Re: Running lean with Bosch III | ||
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I know when I received my Bosch III's, I received and offset table to for battery voltages. And they were different than the Factory injectors/tune.
I did change the tables. Also, I can run a higher psi with these injectors, as Bosch III's were designed with a higher pressure in mind. But, the injector constant would definitely be changed to the new rating and datalogging would have to be done. |
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Posted on: 2010/11/29 16:59
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| mseven | Re: Running lean with Bosch III | ||
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Hey Steve, actually it's a little more involved than just the battery offset (as I described in my above post).
here is a typical cal. chart for the 30lb ev6: M-9593-BB302 Calibration Summary Target Injection Pressure = 39.15 psid (delta) (all injector flow rates are quoted at a delta pressure of 39.15 psi. To convert to a delta pressure of 43.5 psi, multiply flow rate by 1.054) FNPW_LSCOMP FNPW_BKCOMP Pressure Multiplier Pressure Multiplier ALOSL (lb/s) 0.010023 (psid) (psid) AHISL (lb/s) 0.008542 20.01 0.7149 20.01 0.7149 FUEL_BKPT (lb) 0.0000132400 30.02 0.9381 30.02 0.7704 MINPW (ms) 0.776 39.15 1.0000 39.15 1.0000 50.03 1.1890 50.03 1.0242 54.96 1.2331 54.96 1.0627 60.03 1.3339 60.03 1.0899 FNPW_OFFSET FNPW_HSCOMP FNPW_OFFCOMP VBAT Voltage Offset Pressure Multiplier Pressure Multiplier (volts) (ms) (psid) (psid) 6 3.366 20.01 0.7149 20.01 0.7149 8 2.044 30.02 0.8717 30.02 1.0056 10 1.440 39.15 1.0000 39.15 1.0000 11 1.240 50.03 1.1384 44.95 1.0689 12 1.083 54.96 1.1971 50.03 1.0926 13 0.950 60.03 1.2537 54.96 1.1035 14 0.824 60.03 1.1639 15 0.741 ALOSL "low" injector slope AHISL "high" injector slope FUEL_BKPT Fuel mass at which to switch from low to high injector slope MINPW Minimum repeatable fuel pulsewidth at 39.15 psid FNPW_LSCOMP Multiplier to low slope as a function of injection pressure in psid FNPW_HSCOMP Multiplier to high slope as a function of injection pressure in psid FNPW_BKCOMP Multiplier to FUEL_BKPT as a function of injection pressure in psid FNPW_OFFSET Injector voltage offset as a function of battery voltage FNPW_OFFCOMP Multiplier on FNPW_OFFSET as a function of injection pressure in psid GM and Ford use different ways of describing the same physics/nonlinear flow characteristic of the same injector. The injector offset can be described as the intercept of the high slope with zero fuel mass or, as the point at which the injector really opens (where the low slope intercepts zero fuel mass). GM uses a short pulse adjustment to make up for the lack of a second injector slope at low masses. Translating from Ford to GM units and tables is not easy, but itÂ’s necessary if you want to get idle airflow estimates right when tuning/calibrating. Increasing pressure can be made to work, however, an increase in pressure also effects the both the opening delay and the nonlinear flow region of injection. For it to be done right, you have to adjust both the linear flow rate (high slope), and nonlinear characteristics (low slope, breakpoint, and offset) to compensate for these changes. The way to create a comparison for the two types of inj.(and better understand) using the same flow rate, is to take the call. charts/offsets provided from ford racing, and using the data provided (by the OEM test lab), for both inj. It is then easy to plot the fuel mass delivered (basic geometry)v.s. injection time for each injector. I personally don't know of any better data available than what the ford test lab has provided....if there is I am interested. There are some very real publications on all these tests and actually tuning for different injectors. sorry for the long post. |
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Posted on: 2010/11/29 17:19
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| jonszr1 | Re: Running lean with Bosch III | ||
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i dont mean to hijack but are the multec injectors that are used in the zr1.ie spray pattern compatable with the bosch type 3s
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Posted on: 2010/11/29 19:08
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i have a blast playing with my 4 babies 2 zr1s and 2 mustangs 68 coupe with a jon bennit 408 art car fully rollered c4 with a gearvendors over drive .88 mustang built by my kids with a ported lt5 and a bill boudreau blue printed zf 6 spd. with these 4 ... |
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| Steve40th | Re: Running lean with Bosch III | ||
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You can tune my car anytime. I know its very involved, especially when I see all the tables that can be changed. Lots of work involved.
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Posted on: 2010/11/29 19:09
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| Josh | Re: Running lean with Bosch III | ||
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FIC had a large supply of the older injectors a year or so ago. When I talked to him on the phone he said, "I have an entire pallet of the older ones." He might still have some kicking around.
That, IMO, would be the way to go. New injectors of the older design. |
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Posted on: 2010/11/29 23:58
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| joshwilson3 | Re: Running lean with Bosch III | ||
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What is the name for the "older" injectors? What do you guys think about the Bosch II? |
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Posted on: 2010/11/30 0:42
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| screamin_conure | Re: Running lean with Bosch III | ||
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That guy was me. Back in September or October, Jon had sent me a set of black Bosch III injectors that flow 23# in exchange for the yellow 22# units that I had installed way back in March. He told me he thought they would work better on an LT1 car, and these did help my BLM situation somewhat. She still seems to want more fuel than she's getting (BLMs are now 135-145 instead of 150-160), and is still giving me a bit of a low/rough idle, especially when cold, but the black Bosch IIIs were a HUGE improvement in smoothness and power over the Lucas injectors. So, I'm sort of in the same boat as Joshwilson3. I know the car should idle at least SOMEWHAT smoother than it does, and I still think my BLMs should be corrected closer to 128, so I'm thinking that my options are to install an adjustable FPR, or somehow, someway, get my ECM retuned. I have a basic OBD1 scan tool, but I don't have the necessary equipment to tune my ECM. Even if I did, I'd be hesitant to do it simply because of my lack of in depth knowledge, which is why I'm leaning toward the adjustable FPR. I did experiment a bit with disconnecting the vacuum line to my stock FPR and plugging the ports on both the manifold and FPR. My fuel pressure set up like this was a constant 49 PSI. (I taped my FP gauge to my windshield and drove around a bit). My BLMs actually showed a bit rich now, running in the low 120's. The idle still wasn't perfect, but was noticeably improved and very liveable. It seems like running the FPR at full pressure is obviously too much, but a very small bump in FP over stock would get me where I want to be. I've seen more people recommend to do the ECM re-tune instead of bumping fuel pressure, but I don't know. I know there are places like http://www.lt1pcmtuning.com/ who seem to be pretty good, but I'm still a bit intimidated by the whole thing. Any suggestions? I'm learning that fitting older cars/ECMs with newer injectors isn't exactly a plug-and-play deal. By the way, the pics of that plug and 02 sensor really have me concerned. Ron |
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Posted on: 2010/12/10 19:49
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| Steve40th | Re: Running lean with Bosch III | ||
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Well, you could get a racetronix fuel pump, because it is a very good pump, and run the injectors are their designed pressure within the LSx engines, 58 psi I believe. Then retune your chip to recongize the new constant. See how she runs?
There are some experts on this forum that hopefully will chime in. I just got told by a tuner to throw my DELTEQ into the trash because he refuses to tune a car with it. I just cant afford to go back to Opti stand alone as I was breaking them, so I cant work with that tuner. I have Bosch III's, and was looking at another tuner as my last one wasnt very comfortable with my set up, and it ran really hot too (oil and water even though fans were set to mid 190's) Regardless, Bosch III's are different, maybe they need to be treated differently within the tune and fuel pressure. |
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Posted on: 2010/12/10 19:56
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| joshwilson3 | Re: Running lean with Bosch III | ||
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I raised the FP to 55 with the FPR disconnected. And ran some scans. My BLM's were still high. But I believe it to be mostly in the safe range. According to my FSM, you are running lean if your BLM's go over 138. My BLM's now are staying mostly in the 130's. I noticed it hit 141 and 144 a few times in certain cells.
When it warms up outside, I may try the Bosch III at 23# and see what that does. But with the adjustable FPR, I should be able to get the BLM's closer to 128 with the 23# injectors. The only thing I really care about is not burning the engine up. The Bosch III should be easy to swap since there are no clips. So all you have to do is lift the rail up and pop them out. |
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Posted on: 2010/12/13 13:35
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| screamin_conure | Re: Running lean with Bosch III | ||
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Hey Josh, you're still running a stock tune in your ECM, right? |
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Posted on: 2010/12/14 22:56
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| joshwilson3 | Re: Running lean with Bosch III | ||
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It should be. I haven't messed with the ECM. And I doubt the PO did as well since it ran rich with 24# injectors that he had installed. He liked to buy crap out of the magazines. |
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Posted on: 2010/12/15 5:19
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