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Saab 9-7X
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Discussion Starter #1
Anybody know what the difference is between the 05-07 fuel pump assemblies and the 08-09 fuel pump assembles? I will be running an 09 OS in my 07, and as part of the build am swapping the fuel pump for a second time. If there is some benefit to it, I would certainly consider running a later pump assembly (with Walbro 450 and bypassed FPR...).

Tim
 

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07 TrailblazerSS AWD
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If you're going to do a 450 pump and bypass the in tank regulator it wont matter what year the pump assembly is from because it will be a completely custom fuel pump assembly when youre done adding the aftermarket pump and ditching the reg.
 

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TT AWD SS Pwrd Jeep
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Brandon said it well, Id just like to add (Im sure u know it, but...) you will still need an external regulator and a new return line. Another option is to use the evap line as the return and disable evap in the tune. That also cleans up the intake area a bunch.
 

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If you run an aftermarket feed line you can also use the stock feed line as your return.
 

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Discussion Starter #5 (Edited)
I guess that I was thinking more in terms of the fuel tank pressure sensor and fuel level sensor. I am planning to use an 09 OS (using an 08 in my 07 right now) so that I can use ID850s without scaling and a LS9 MAP sensor with real values. If there is an electronic difference, I would rather use the right one to start with, rather than hoping that EFI Live and HPTuners have the ability to edit the correct parameters.

Thoughts so far have been:
Walbro 450 (purchased - Aeromotive 340 currently installed)
-8 feed
stock return (roughly -6)
Radium MPR or Fore F2i/F4i FPR
Fuel pressure gauge in rail

Step 1 - factory L92 intake with ID 850 injectors dead headed (already have all of these parts) Start here to break in the engine and tune the transmission.
Step 2 - Whipple fuel rails with ID 850 injectors either dead-head rails or return after rails to tank. Whipple fuel rails use a -6 ORB connection. Still debating dead-head vs. return after the the rails.

For fuel line, I have considered lightweight fuel line from Improved Racing, Mocal, or Aeromotive Startlite. I already have Mocal AN hose and fittings for my oil cooler, so matching fuel and replacement transmission cooler lines (for the PCMofNC fender well cooler) would be nice. I thought about Earls Ultraflex 650 or Startlite with crimped ends, the challenge is how to crimp the ends and to make sure that every dimension is exactly correct.

Tim
 

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Few things, instead of buying a whole new fuel sending unit to hack up, just buy the correct level sensor and evap sensor if needed(which probably wont be needed). I am running the Fore f2i pressure regulator (no need for the f4i) which you can get an optional pressure gauge with the regulator so no need for additional fittings and whatever else to mount a guage on the rail. Another thing, if you change the fuel feed line out I do believe that if you want to race it at a drag strip technically you're supposed to have stainless braided line passing by the bellhousing per NHRA rules. Hope that helps. I would convert to a return style system. Fuel dead headed at the rails will actually boil inside the rails and hot fuel does not atomize as well as cool fuel.

Oh and if you use the 09 OS you might have to swap out the entire engine/trans harness. The 09's use something different with the transmissions so you might have to swap the trans as well? Would be much, much easier to leave what you have alone and scale the tune. I can promise you that whatever you're trying to do has more than likely been done before. You wont be the first to do whatever you're doing on your current OS.
 

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Discussion Starter #7 (Edited)
I'll definitely have to look into the NHRA rules about fuel lines passing a bell housing. That could be a problem. I am not building a track truck/car, but I would like to be able to run it once its done. Thanks for the heads up.

In a few months, when everything is done, I will post a build thread that should make some of this more clear. Some of what I am doing has never been done before. In the meantime, a brief overview is below. The car is in its 4th or 5th round of mods and has been down for over a year. Right now, it is probably 50% done depending on how many things I decide to address while I am in there... The fuel system is one of those things that popped up in the last month, that I had not even considered a year ago because I put an Aeromotive 340 in ~2 years ago and have a set of LS9 and ID850 cc injectors. The 340 lph + 850s should be enough, but better to upgrade now when the car is on jack stands than in 6 months or 1 year when I find out that the current system isn't enough.

I was thinking about the Radium FPR or Fore F4i just to avoid a Y feeding the rails. Both are very high quality, but they're coming at the market from different segments. The F2i may work and I would prefer it for certain setups, but it depends on the final routing. I am leaning toward the Radium MPR due to its port combinations and the desire to build a setup that works both NA (GM factory rails) or boosted (Whipple rails).
https://www.radiumauto.com/Multi-Pump-Regulator-P383.aspx

I have heard about dead headed rails creating hot starting problems due to fuel vaporization, but the factory rails are dead headed and I have never had that problem. If the regulator is after the rails, the possibility of vapor lock from the fuel in the tank heating up exists, and premature fuel pump wear from overheating is also possible. I like road trips, so keeping the fuel in the tank cool is a good thing. For my goals, it seems that putting the regulator before or after the rails question is more a matter of preference than performance. I may not know exactly which I will do until I start assembling the hoses and this is likely still months away.

The Whipple fuel rail has a fitting built in for a fuel pressure gauge - no adapters needed. Where I would mount a FPR depends on what is easiest to see and access. If I use a F2i, I would most likely put it on the regulator.

I have a spare PCM and BCM, and will be using a 6L80E and the TBSS transfer case. The 6L80E is the only reason why the Whipple won't be completely installed when I finish putting the car back together (but all of the supporting mods for it including the aftercooler and pump will be installed). I want to make sure the engine and transmission tune are spot on and the engine is broken in before adding boost. This should also make the tuning process much easier.

I may use an 09 tune with real injector data, or an 08 tune with scaled injector data. Scaling a tune with a 6L80E is not trivial. I will do it if I have to, but would strongly prefer to run a OS that I don't have to trick into running my injectors or seeing boost (I converted my S2000 from AEM series 1 to KPro 3 to KPro 4. Before that, I had a Split Second FTC1 on my Monte Carlo to run 42 lb/hr injectors when 22 lb/hr was stock. Both drove me nuts because they relied on fake data and were somewhat unpredictable as a result.). I plan to have one set of PCM/BCM running a known good program/OS/year and the other used to test changes (similar to what I do now).

Tim
 
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