setzep

You are right the 37 deg JIC fitting is awsome lol. If you have a look down a tube with a JIC flare on it it's almost seamless compared to your typical barb fitting.

I always wondered why they had a internal relief on those carb pumps. Why not have the regulator or relief right up on the carb or at least next to it where the pressure should be regulated?? What I did for a buddys camaro is "T" in a 7psi relief valve in the engine bay to regulate the pressure the carb sees. This way he was able to run the stock high pressure fuel pump that was already mounted in the tank. That pump is going to last forever at that pressure

5GPH?? I think you mean 5GPM

fatboy7

Yea.... 5 GPM.....

Carlos Iglesias

iTrader: (6)

I love ALL of this plumbing thread... can you tell!

As to why parallel has advantages over serial plumbing, I offer the following.
- Pulsation/pressure (MAJOR): There is ALWAYS a pulsation effect AND lower pressure on the downstream injectors. If you plumb the larger injectors upstream to get the max flow to them, the smaller downstream injectors get the larger pulsation. If the other way around, then the downstream/larger injectors get less pulse, but also less avail pressure/volume. Parallel doe not have this effect (discounting the effect between two like injectors.) Large "Sewer Pipe" can help ameliorate the condition as describe before.
- Pressure Resevoir (MINOR): The extra pressurized plumbing involved in parallel configuration creates an addition inhibitor to plusation.
- Complexity/cost (MINOR): An admitted disadvantage to the parallel route. I guess you could therefore throw in weight as well.

That said, back to the original discussion. If you will allow my arguement for parallel plumbing, and you look at the total ID cross sections of a dual/parrallel -8 rails (looks aweful familiar), then the math is pretty easy.

For the total rail cross section:
(ð[1/4]*2) x two rails = 0.39 sqr inches

For the feed hose (an-10)
(ð[5/16]*2) = 0.31 sqr inches

So you can see that even my MEGA fuel system is not ideally designed. If you'll do the math you'll see that a -12 line is above (at .44 sqr inches) the requirement for the dual -8 rails.

Oh yeah, and I don't know about anybody elses pumps, but my secondary Aeromitive A1000 pump has -10 inlets AND outlet. So add that in to my arguement.

As for the dissusions about checking the system limit by detecting pressure drop at max flow, I don't know about you guys, but the last thing that I want is TO EVER HAVE pressure drop at max flow (even under testing conditions.) Though I've only been into rotaries for 10 years, I do know one thing: this arguement must give Murphy (of the famous Law) a hard-on the size of a Sequoia. I don't know about anyone else, but each and every ping is a ping too many in my book (see my previous posted Rotary Narcissism about my engine legacy).

Ok, not I'm ranting again, so I'll stop...

Carlos Iglesias

iTrader: (6)

Oops, I guess the "pi" symbol wasn't compatible in the equation above. For that matter, it's always painful to reread my own posts because of my lackadasical spelling (e.g. "Aeromitive", et). Now back to our regular programming...

setzep

Testing the pressure drop at max flow is going to be your worse case scenario. This will give you an idea if your lines are indeed too small. Of course you always have to keep in the back of your mind that with time the fuel filter will collect contamination and therefore the pressure drop will rise even more so get the biggest fuel filter you can fit in the location. Big filters hold a lot of dirt.

RageRace

Thanks for the feedback bros, i see that a couple of you seem to like the JIC fittings a lot, does anybody have any problems with them? where can i check them out online? also i believe that everytime i see funny car engines, top fuel, or any of the really big dogs(i could definetly be wrong on this) from the looks of it those guys only use -8 max. adding to that(another could be wrong) i know the Pettit drag car(9.9? et)uses -6, also i believe that Ari uses -6. If they are why are those guys not running -12 line or similar. Thanks for everyones help your feedback is greatly appreciated!

Carl Byck

O'k, I have resurected this thread. I read it twice, and I do not see a clear answer to the question. My proposed set-up is to support ~500rwhp in a road race car. Output will be a little less(for now) but I want plenty of head room.The setup will consist of the following in order of flow;
Bosch in tank(from a porsche turbo, I think it is one step down from an 044) -8 to surge tank-8 back to fuel cell. -10 from surge tank to mid size -10 filter,-10 big SX filter, Aeromotive A1000( supposed to flow 65GPH@80PSI, -10 to front, Y block to two -8an parallel rails, -8 to SX fpr return to surge tank-8.
My concerns are;
1- should I run a -10 to the front, or a -8? I am tending toward a -10 as it is the outlet size on the pump, and seems better matched to either two -8, or two -6 lines to the rails. my only concern is pushing that fuel column to the front of the car when accelerating a ~450rwhp 2400lb car on 13" slicks.

2- should I use two -8 lines to the rails, or -6, I am tending towards -8.

3- .5"ID, or .8" ID rail? I am tending toward .5

4- IF I use a Marren FPD, where should it be plumbed? I will probably diagram the system, and ask Marren, but if someone has already done this, speak up.

5- Injectors are 1680 bosch secondaries, and 850 primaries(proposed) I currently have GSL-SE 680s, but planned on upgrading.

6- the Bosch injectors I have look like they were modded(plastic shortened) to fit the stock rail, would I use these in the fabricated rail, or buy new? Also they are utilizing three stacked O rings(which I gather is standard practice).

7- when using "kieths rails" for example(we are making our own) do you modify the injector as I described? I'll post a link to some pictures of the injectors.


I am looking for folks who really know their stuff, and are supporting the power levels described. I do not need an "I think this will work" thread.(with all due respect ) Thanks, Carl Byck

Carl Byck

Here is a link to the existing injector pics. https://www.rx7club.com/rotary-car-performance-77/help-me-identify-these-injectors-pics-368684/ Thanks, Carl

BTW I have posted a link to this thread in the Rotary Performance Section.

paul_3rdgen

iTrader: (6)

I am using a similar setup except, gas tank sumped with Aeromotive Eliminator pump http://216.242.145.16/products/product.phtml?p=2, and 12302 fuel filter. I run it pump to filter to distribution block, spliting to two -6 lines one to primary rail and one to secondary all ending at the regulator. -8 return, I am making 425rwhp and don't have any problems. I know the setup is overkill but why build it twice. Oh injectors 1600's and 850's.

GQMRacerX7

I was looking to do a surge tank setup too. I spent a lot of time with spatial issues but to make a long story short several emails to Aeromotive gave me enough doubt for me to go away from it.

Here's a sample of one of the responses about the surge tank: "This is a recipe for hot fuel handling problems, as the big Aeromotive pump is basically only recycling through the engine compartment the small volume of fuel held in the surge (you're returning the A1000 to the surge tank). In addition, the in-tank pump is insufficient to supply the surge on demand and negative pressure will build, if only during high load, risking low pressure at the A1000 inlet and causing cavitation (liquid fuel changing to vapor thanks to high temperature and low pressure)."

I don't necessarily agree with everything (like the ability of the in-tank pump to keep up with the A1000 inline) but overall I figured they have more experience than I do (understatement) and a lot of what they told me did not seem to be a sales job.

I'm going to try improving the baffling of the stock tank (similar to Gene Felber's) and use a 100 micron filter and A1000 pump to replace the stock sock and pump. Bulkhead out of the tank (-8) to a 10 micron filter, -8 to engine compartment, split to (2) -6 lines to a parallel rail setup, (2) -6 back to the regulator, -6 back to the tank. The Aeromotive tech thought this was the best route outside of adding a custom tank made up like (http://www.rickshotrodshop.com/StealthSeries.htm) or fuel cell.

They said by going to a parallel rail setup a FPD is really not needed.

If nothing else, I'd contact Aeromotive (or Weldon or whichever fuel component vendor you trust) and see what they suggest.

Good luck,
Grant

GQMRacerX7

Oh ya. KG Parts rail (Keith Rails) do not require modifications to the injectors. I used DNewbern's bushings to help with the injector o-ring sealing and I also used resistors, but no mods to the injector.

Carl Byck

FWIW, the person that thinks you're pumping heated fuel does not understand that the in tank pump is working against zero pressure, and therfore is cycling the entire contents of the main tank through the surge at ~300 LPH, inother words the fuel is completely changed out roughly once a minute. Now, if you are low on fuel, then heating can be an issue. I have a provision in my system to measure fuel temperature, if it is too high on low fuel, I will add a cooler. The largest pumps available will not pump 255LPH @ 80psi, this is what a pump would need to be capable of to outflow the bosch in tank pump working against no pressure. Thanks, Carl

GQMRacerX7

I agree. <Devil's advocate> But you're also bringing back hot fuel from the engine to the surge... For a race car I'm not sure if that would be as much of an issue as a sometime street-driven car... I just don't know.

Like I mentioned the Aeromotive techs were just so strongly against it, I didn't feel comfortable with it.

How long until you think you'll have your system running?

Carl Byck

It is really no different than returning it to the fuel cell, same volume of hot fuel being mixed withe the same volume of cool fuel. The only difference is you are actively circulating it with a surge tank.

GQMRacerX7

How big is your surge tank? Mine was planned to be small enough to fit where the charcoal canister is and last for ~15 seconds of fuel (54 gal/hr max with a tank at 3.25"ID and 6"L) Anyway, I hope this doesn't come across as disputing your information, I'm just trying to learn.

I hope you take lots of pics of your setup I saw someone else's surge tank setup and it was what started me looking at it. But he seems to work on his cars more than drive... LOL Shannon, you reading this?

Good luck,
Grant