paulb
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- Joined
- Jul 14, 2006
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I would like to keep this thread on tuning large injectors, and in particular the BBI stage 4's. I use a Smarty SSR with UDC for tuning, but the "concepts" should pertain to EFI Live as well. Please keep this to a technical discussion. It seems like these threads often end up in vendor bashing/vendor cheer leading, and I would like to avoid that.
I own two sets of BBI injectors a set of stage 1's that I bought for my 06, and a set of stage 4's for my 05. I installed the stage 1's in my 05 first, and took it to Sacramento Raceway, on 12/31/2012. For tuning it was pretty much set it for high duration and high timing, with modest rail pressure. No dyno time, or much street time either, because of the snow at my house. The truck ran high 11's low 12's. The best being an 11.95 @ 113mph. The truck weighs ~7200 lbs with me in it. That puts the hp right at 700hp. This was with mud and snow tires, and no time playing with the tuning. Rail pressure was at 24,000, so there was an easy 15-20hp left there. The purpose of this testing was just to see out of the box,what the stage 1's would do in a truck with all the supporting mods. The turbos are overly large for 700hp, so that hurt the E.T. but they probably didn't hurt the mph much.
The stage 4's supply a lot of fuel. That was very apparent even on my first road test. The spec on them I believe is 144/l/h @ a pressure of 100bar (~1450 psi). This is how stock injectors are rated. A flow rate at 100bar. None of us run our injectors at 100 bar. My truck idles at ~480bar. What the rating does do, is let us know how the injectors compare to stock. Each set of BBI's come with flow certificates showing the flow at 250bar (3625psi), 1000bar (14,500psi) and 1600bar(23200psi). The certificate shows the flows at those pressures from 160us, to 2000us. At the top end of the charts the flows are pretty linear, so you can extrapolate from there. My stage 4's flow ~380mm3/stroke, at 1600bar, and 2000us. My personal "safe" tuning limit is 2800us, and 26,000psi. With the stage 4's this works out to ~530mm3/stroke. Way more fuel than I have air to use. Drop this down to 1700us, at 26,000psi and it's 366mm3/stroke. That's more in line with what I can handle. For comparison with the stage 1's making ~700hp, they were flowing 258mm3 with the settings I was using (2800us, 24,000psi). As another comparison using my max "safe" settings, stage 3's flow ~426mm3/stroke. With my old injectors, I made 1040hp, with a fuel flow of about 385mm3/stroke. So I could have gone with stage 3's and made more hp then I was making before, and it would have been easier to tune for the street. Where is the fun in that!?!
So now the question is, how do we take an injector that flows that much fuel, and tune it for the street? The stage 4 was designed and marketed for extreme competition, but I drive my truck on the street as well as at the track. Keep in mind too, that the stage 4's fuel flow doesn't fall off as much with rpm as a stock injector does.
More to follow...
I own two sets of BBI injectors a set of stage 1's that I bought for my 06, and a set of stage 4's for my 05. I installed the stage 1's in my 05 first, and took it to Sacramento Raceway, on 12/31/2012. For tuning it was pretty much set it for high duration and high timing, with modest rail pressure. No dyno time, or much street time either, because of the snow at my house. The truck ran high 11's low 12's. The best being an 11.95 @ 113mph. The truck weighs ~7200 lbs with me in it. That puts the hp right at 700hp. This was with mud and snow tires, and no time playing with the tuning. Rail pressure was at 24,000, so there was an easy 15-20hp left there. The purpose of this testing was just to see out of the box,what the stage 1's would do in a truck with all the supporting mods. The turbos are overly large for 700hp, so that hurt the E.T. but they probably didn't hurt the mph much.
The stage 4's supply a lot of fuel. That was very apparent even on my first road test. The spec on them I believe is 144/l/h @ a pressure of 100bar (~1450 psi). This is how stock injectors are rated. A flow rate at 100bar. None of us run our injectors at 100 bar. My truck idles at ~480bar. What the rating does do, is let us know how the injectors compare to stock. Each set of BBI's come with flow certificates showing the flow at 250bar (3625psi), 1000bar (14,500psi) and 1600bar(23200psi). The certificate shows the flows at those pressures from 160us, to 2000us. At the top end of the charts the flows are pretty linear, so you can extrapolate from there. My stage 4's flow ~380mm3/stroke, at 1600bar, and 2000us. My personal "safe" tuning limit is 2800us, and 26,000psi. With the stage 4's this works out to ~530mm3/stroke. Way more fuel than I have air to use. Drop this down to 1700us, at 26,000psi and it's 366mm3/stroke. That's more in line with what I can handle. For comparison with the stage 1's making ~700hp, they were flowing 258mm3 with the settings I was using (2800us, 24,000psi). As another comparison using my max "safe" settings, stage 3's flow ~426mm3/stroke. With my old injectors, I made 1040hp, with a fuel flow of about 385mm3/stroke. So I could have gone with stage 3's and made more hp then I was making before, and it would have been easier to tune for the street. Where is the fun in that!?!
So now the question is, how do we take an injector that flows that much fuel, and tune it for the street? The stage 4 was designed and marketed for extreme competition, but I drive my truck on the street as well as at the track. Keep in mind too, that the stage 4's fuel flow doesn't fall off as much with rpm as a stock injector does.
More to follow...
