How many people know a VSR 7875 is a turbo? Not me until I looked it up. So yeah, that just might have been missed.
The part about the 600-700 WHP goal was a good tell though...

 

Your setup is pretty much my original build. Basically the same fuel system. If your going with E you will need bigger everything on the fuel system. Once you start pricing it all out, you'll have more in the fuel system than the motor.

Pound for pound, Ethanol requires roughly 30% more than that of gasoline in a NA motor. Add turbo, and you're ramping it up from there. The fuel pump will need to handle volume and pressure. Then you're into amps drawn on the electrical system from the new pump. Wiring, alternator, relays, fuses, etc...

Here's my fuel system:
Aeromotive 5.0gpm variable speed pump
stainless filters
FIC 1650s
More fittings than you would think would be needed.
Flex Fuel sensor. Motion Raceworks makes a nice piece for the ethanol sensor.
-10 Feed to a Y Block to 2 -8 lines running to the back of the fuel rails then to the regulator. And -10 return from reg to the fuel cell.

Fuel line material is something to think about also. From what I've concluded is, even if you have the best fuel line, (say stainless) ethanol will still turn to crap over time unless used. It attracts moisture. Use a good fuel line thats easy to work with and doesn't cost a fortune. Use Ethanol in times when it will provide you with the most benefits. When you don't need it, get it out of the tank and put gas in to help lubricate the fuel system.

 

Uhhh, yes, I did. Sorry about that. I missed the turbo part. Sorry. I'll shut up now.

 

Almost everyone

 

.....who's into snails and hairdryers...

 

Isn't everybody???

 

the deka 80's can get you to your RWHP goal but i wouldn't try it without adding a boost referenced FPR to counter positive manifold pressure and allow you to adjust base fuel pressure to make them work.

boost, or positive manifold pressure, will push against your injectors reducing flow. a boost referenced FPR compensates for this reduction of fuel pressure 1:1.

lower base fuel pressure stretches capabilities of your pump. higher pressure stretches capabilities of your injector. lower pressure requires more of your injectors. higher pressure requires more of your fuel pumps.

RPMs also tax injectors. the higher the RPM, the less time the injector has to inject fuel.

your pump may or may not get you there but you could try it if you log/watch it closely.

at the end of the day, you can see what others have done as they post here, but every setup is different. once again, if you're on the edge of your system's capabilities, log, adjust, rinse, repeat.

FWIW: when i switched to e65, i had 2x walbro 255lph (GS340) pumps and deka 80's @ 4bar of fuel pressure and i was approaching 100% IDC at around 14psi. i wanted to up the boost, so i added a third 255lph walbro and upped the base pressure to 70psi (cheaper than new injectors lol). i hit 100% IDC at 20psi with the deka 80's on e65 but AFRs are in check.

 

210's
Magafuel Boost FPR
-10 feed
-8 return
twin 450 in tank pumps (maxed out on 900whp through a 4l80e and 9" on E98.

upgrading to a triple 525 setup.

 

Bumping my old thread as it's time to revisit fueling.

I made some pulls on the street to collect data and figure out next steps. I'm on 8psi, 55% ethanol and bored already. Since I'm still learning to tune turbo LS's as well as work the Holley software in general, here's the play by play:

What is max boost?
154kpa, 7.9psi

What's the boost curve look like at WOT?
3000 rpm - 1.7psi
3200 rpm - 3.4psi
3400 rpm - 5.6psi
3600 rpm - 7.5psi
3800 rpm - 7.9psi (max boost for now)

So, boost builds quickly and holds steady at 8 lbs from 3800 to redline.

What is AFR throughout a pull?
12.8 @ 100kpa, 10.7-11.0 @ 155kpa. Gas scale

What is Timing throughout a pull?
27 degrees at 100kpa, 20-21 degrees @ 155kpa

What is IAT throughout a pull?
100F-120F cruising, 187F Max

What is max Injector Duty Cycle during a pull?
46-61% depending on length of pull (fuel pressure dropping but stabilizes)

Fuel Pressure during a pull?
Cruising 62psi, end of longest pull 43psi. From 5000-6500rpm only dropped from 46 to 43psi.

Flex composition?
55% ethanol

Current fuel setup is a -6AN feed to a stock LS1 rail and 80# Deka injectors. C5 filter/regulator and a single external AEM 50-1005 (rated 400lph but at 40psi though).

So, my thoughts: I should turn the boost up to 10-12 lbs, but in order to keep fueling in check I should upgrade to a boost referenced FPR. The C5 FPR probably isn't doing my fuel pressure any favors under boost. Any suggestions? Maybe run the adjustable FPR at 43psi to stretch the pump a bit too? Also, my flex sensor is in-line with the feed right at the stock LS1 rails, is that a restriction?

Are IAT's an issue yet? Wondering how hot they'll get with more boost, maybe figure out some meth (I mean -20F windshield wiper fluid injection system) based on a Hobbs switch or a Holley output trigger.

https://drive.google.com/file/d/17YW...usp=share_link

 

Since you are seemingly attentive to monitoring and logging your setup, you could always move up on boost gradually and monitor what happens but you are likely reaching the point where you'll either be buying parts or you'll be adjusting fuel pressure (also buying a part) for pumps and/or injectors to compensate. Me in your shoes I would get a boost referenced FPR and get the ethanol sensor off of the feed and put it on the return side of the fueling. Also I would run a T off of the main fueling line to bleed off to the return line. I've read some have had issues with a FPR inline being a bottleneck. Running a T would eliminate that possibility. Jacked this idea from another ls1tech member, maybe @stevieturbo IIRC. From there I'd run fuel pressure @ factory 4bar, monitor the setup and balance out fuel pressure accordingly until it's clear you need to spend money on another pump, new injectors, or both.

visual of FPR "T"

 

Revised the fuel system slightly. Headed in the right direction I think. I removed the C5 FPR and cut it open to see what was going on inside and if there was a restriction.









The smallest orifice is the supply hole in the end cap. My calipers measured it at about .200", and a 3/16" drill bit fits freely. So the all the fuel was being shoved through a hole smaller than 1/4"...combine that with no boost reference it's no wonder my fuel pressure was dropping before.

Anyhow, the new adjustable FPR was easy to install, I didn't even have to modify the lines. Everything is still a -6AN throughout. The regulator is mounted inline with the feed in the trunk, and there is still the flex sensor mounted inline with the feed right by the fuel rail, so there is technically still room for improvement in removing restrictions. 58psi with engine running and no vacuum applied. Gauge pressure matches rail pressure.

Given how cheap these adjustable regulators are they really need to become the golden standard for the LS swap. I'll never use another C5 FPR again...they might have their place on stock motor swaps but for anything with any semblance of performance would benefit from one of these.





Took the car out and made some pulls rolling into it, slowly increasing the boost to make sure fuel pressure and AFR was in check. It was safe at 8, 10.5, and 12.5 psi, so I turned it up some more. During a sustained 30-70mph pull in 2nd the boost peaked at 14.7psi and settled at 14.5psi. I only revved it out to a hair under 5000 so once I throw some new plugs in it I plan on making some longer pulls and reading plugs #5 and #7.

30-70 Roll



Interestingly enough I stabbed it hard from a dig on the way home and it boils the tires easily, this is the result I have been dreaming of - even with the 2.88 gears! Within 1 second of 100% TPS applied the rear wheels are doing 26mph and 2 seconds later they're at 120mph in 3rd gear (with a little pedaling in the middle). Real vehicle speed probably never exceeded 35mph - cheap thrills for sure.



What an absolute riot of a car.

 

Glad to hear you're headed in the right direction, however I'm questioning the placement of your FPR. in a perfect world, you have the FPR after the fuel rails. i have mine right before the fuel rail because i'm using the stock rails. By having your FPR on the tank in the back of the car, you may not be regulating the actual rail pressure. Where's your fuel pressure sensor located? Hopefully someone that knows more than me can chime in.

 

Yeah, as I mentioned it in the post, it's still not a perfect setup as I still have the FPR and the flex sensor in line with the feed. The fuel pressure sensor is right on the rail so it's reading rail pressure real time. In a perfect world I could throw a giant Magnafuel 4303 and a -10 feed at it but until I show significant issues or restrictions with this setup, I don't really see the need to spend a bunch of money on aftermarket rails, additional plumbing, etc. My bigger concern right now is managing IAT's with the non intercooled setup as I was upwards of 200F on some runs. Appreciate all the help and insight.

 

good deal. as long as you have the sensor up there and it's working i'd leave it alone too. I get it 100% i don't like spending money or creating extra work when i don't need to!