VRFPR with 16197427 Strategy

Looking at using this for idle purposes using the 80lb BBC injectors.

Was planning on going stock L31 but thinking for $500 more this is a good deal and should really only require a bit more fueling which I have the over head for. https://www.summitracing.com/parts/mll-bp3503ct1

Using the VRFPR I was hoping to keep the fuel pressure at around 17PSI at idle and then up at 22-23 at WOT. Looking at the Holley 12-880 to do this.

With the 16197427 it doesn't use the BPW but instead just has the injector flow constant scalar. Obviously this would change dependent on the pressure so does anyone have a strategy for running a variable regulator with this PCM.

I think one option for successful TBI VRFPR is Dynamic EFI https://www.dynamicefi.com/TBI_Fueling.php

The 16197427 is NOT a good candidate for TBI VRFPR, unless you write code and create a table that can calculate injector flow vs. vacuum.

dave w

Unfortunately that's kind of what I thought. I really don't want to swap out the 16197427 though as I really like the idea of being able to return the truck to stock should I ever need to.

I realize that it all depends on the individual setup, but do you anticipate idle issues running at the required 23-24 PSI with a stock 350 throttle body and the BBC injectors? If its rich at idle I can live with that knowing the hard parts aren't going to melt at the top end, but would prefer it not to be so rich that it stumbles and idles poorly. It seems to some end that the computer should be able to compensate adequately if it has the injector flow scalar, is that true?

I run a L31 with a sbc bored out TBI and BBC 454 80lb injectors. After months of trying to tune around the large injectors at idle I gave up and bought a aeromotive VRFPR. I just could't control the larger injectors at a high pressure at idle to get an idle that wasn't super rich. It would idle between 10-11 AFR from what i remember and just ran like crap. The VRFPR fixed that problem. I have the pressure set to the mid 20s i think but it actually idles around 6-8 psi. I also run the EBL flash piggy backed with my old 7427 that still controls my 4l60e. Like mentioned above the EBL flash has tables you can utilize with a VRFPR. It was super easy to add the regulator and right away i noticed a difference. This is my first tuning project and I went from going in circles to making progress after the upgrade.

Hey whatif3387. how did you solve the return line problem , a retrun on the tbi and on the VRFPR. this may help solve my problem of not enough fp at wot above 4k

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Originally Posted by Loyd

Hey whatif3387. how did you solve the return line problem , a retrun on the tbi and on the VRFPR. this may help solve my problem of not enough fp at wot above 4k

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I can take a good look when I get home as I havn't been wrenching on or driving the truck in well over a year since moving but from what I remember my VRFPR is in line before the the TBI unit and has it's return plugged. The tbi regulator is modded with a block off plate and the return is from the TBI return like it was from the factory. So fuel flows from sending unit to the aftermarket VRFPR to the tbi injector pod then out the factory return back to the tank. I also upgraded to AN line and fittings when I did this.

I wonder how this guy was able to use a VRFPR with a stock style ECM. He lists 8746 as the ECM he was using. Looks like it's similar to the 747 I think...

http://z28boy.cz28.com/throttlebody.htm

Also found this thread pertaining to this. GM used a VRFPR it seems.

http://www.gearhead-efi.com/Fuel-Inj...sure-Regulator


Dave, did you find after playing around with this that the 7427 just simply will not accomodate a VRFPR whatsoever without significant changes like you mentioned?

Food for thought...I was poking around an '8062 and found a BPW EGR ON table so provided EGR is physically disabled, commanding EGR on all the time, possible to have VFPR follow the fueling strategy based on this table modified as it applies.

I'm pretty sure Fast355 has used a VAFPR on the 7427. This would be going back 8-10 years when he use to run TBI on his van. He posts here and I remember him posting lots on thirdgen.org. The more I think I believe it was with the MAF code that dimented24x7 wrote. I lost interest in my TBI project a long time ago so my memory is fuzzy.