So with my aftermarket TPI and BBK reg....with the MAP line and the Holley pressure transducer, there is NO room to adjust fuel pressure. I've read about other guys modding the fuel rails and obviously there are many many ways to set up an EFI fuel system, but I just wanted to make sure my thinking was correct. I drew a quick diagram comparing stock to my idea. -for the record I'm sure someone has done this so not trying to blaze new paths....just making sure I'm not missing something in my thinking.

Any reason NOT to do this??? -I may or may not use angled or straight fittings....run line across the firewall or back through the rails and out the front. Haven't got that far. Just trying to make sure using TWO front crossover tubes and one inlet fitting and one outlet fitting passes muster.

Thoughts?

 

Look at aftermarket rails they are similar to your design but I think many have the input and return on the same end of the rail with the cross overs... but from a fluid dynamics I can't think of a reason why yours wouldn't work as long as your fuel pump could always keep your flow and pressure above the regulator threshold under a starvation situation you would probably go more lean on one side of the engine than the other but that would be true on the factory design also.

 

I've done a bit of research and my Racetronix 255 is more than capable of power my 400hp engine, using the stock fuel rails. My goal is to basically remove the regulator and make it more accessible. I realize this may sound like overkill since you ideally shouldn't be messing with pressure, but over the years that frustration adds up, and now with the Holley HP, I have been tuning and tweaking a bit more. It's kinda like the principal of it all now.

If this set up performed as well as factory, that would be enough. I thought about a two in two out set up, but that seemed excessive.

 

So here's another question I literally JUST though of: Can you leave all the currently plumbing in place and just completely remove all "regulation" from the reg? So fuel would pass at max pressure? -Unregulated? ....then of course just run a remote reg???

 

Remove the internals and diaphram maybe lol if so it would work then put reg down by factory hardlines on body

 

You can use another front crossover line in the rear.
hawks has a company or it’s on eBay that does the 85-88 fuel rail rear entry fittings.
if you need a rail I have one I’d sell. I can also make the crossover tubes. The inlet on a stock rail is a press fit. You can remove them by applying heat to the rail and pull out the restrictor fitting/line.
https://www.thirdgen.org/forums/engi...crossover.html
its been awhile since I have modified the front inlet but I think with the fitting removed you can tap 3/4 npt.

 

https://www.ebay.com/itm/Chevy-TPI-S...gAAOxyThVTZA-G

 

Interesting. ...so I do have an entire extra fuel rail/line. Just texted a buddy that I thought had one, sure enough, he said to buy him Mexican for lunch and it's mine. ....so that'll gives me an extra front crossover, plus a set to play with and not ruin mine if I botch this.

Tuned, your saying the front fuel line will pull out of the rail with a little heat? That's good to know.

As for fitting the -6 fitting....you're saying use that Hawk's 9th injector fitting? Tapped for 3/4 NPT? ...what about the REAR fitting? Can I just drill that out, then tap? ...honestly I was just gonna pay a buddy (same buddy, lol) to TIG some AN fittings to the rail, but this may be an easier option if I'm understanding correctly.

 

I used a small hand held torch and heated up the rail by the pressed in fitting. I think you will see a o-ring on the piece once you remove it.
the hawks I think is a metric size. I cant recall what it is in the rear of the rail. for a 89-92 rail you can drill and tap the plug.

 

OK cool.....well thanks for the help. Definitely gives me some direction to get started.

 

Attachment 351538
Attachment 351539
you can still use your tpi fpr lol, one I modified for a buddy’s hsr.

 

Ha! That's awesome! I may do that!
Thanks again for all the first hand info. ...I was confused last night when you were talking about the 9th injector. Not having one I wasn't overly familiar with the fuel rails, and kept remembering how it was in between the runner. Then it occurred to me that it had to come off the rail somewhere. IN THE BACK! Yes...obvious now.....I just wasn't seeing it when you said it.

Thanks!

 

Tuned performance is on the right track.

I had my factory rails like that for up to 800 RWHP and it was still OK. The front was tapped there and the rear was as well. Then, the return was welded shut, but your idea of two front ones seems easier. (going off of memory here)

 

GM High Tech / Project Snow ball did something similar as well I think. Basically welded the crossovers shut and ran two lines in, two lines out. Felt that was probably overkill for my needs.

 

Tap the front and send it. You will have no issues!

 

For anyone wanting to pull the restrictor, what I ended up having to do is drill and tap the restrictor.
use a socket and bolt/washer . Impacted the bolt and the restrictor went into the socket. All while applying heat.
Its really a tight press fit. All this after trying to use vice grips to twist the restrictor. And breaking a bolt off inside the restrictor while trying to push the fitting side to side and twist it to extract it.
lesson learned on how to remove it lol.

 

What he said! Thanks Brian!!!!

 

TPIS will weld on AN fittings on your fuel rails for $115. They modded my miniram fuel rails with 4 -6AN fittings.