Subject: Re: Running lean with Bosch III by joshwilson3 on 2010/11/29 16:26:33
Quote:
Steve40th wrote: Quote:
joshwilson3 wrote: Quote:
Steve40th wrote: 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.
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.
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.
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.
