Racetronix -10 feed, -8 return???

J

jdpolzin

Well-Known Member
Joined
Dec 5, 2004
I have tried to get on your Racetronix forum muliple times now like you requested but it wont let me sign in so I'll make a post here. I just bought your 160's and the purple pump double pumper with the -8, -6 fittings. I would like to run a -10, -8 set of lines on my car. I do plan to go with an external pump and Champion rails with a dual feed to the front but for now I would be happy just feeding the stock rail with a -10 and returning off the stock location regulator with a -8. This will allow my Stage car for future growth where he -8,-6 combo wont. Do you or do you plan to make a kit mimicing the kit you already sell but with the larger lines? ----Jeremy
 
There are no plans to pre-make -10/-8 line kits. There is nothing to be gained by going to -10 using our 680LPH DP system. The -8 Teflon line is capable of supporting 1,400HP which is enough for a 3,600LB car going deep into the 8s.
We fail to see why people are so hung up on using oversized lines. In the old days when carb pressures of around 7-15PSI were common -10 or larger rubber lines were required but this is no longer required with FI.

This being said, we are more than happy to custom make any line kit you want with the parts we stock in our web store. Regular store prices will apply. Please allow for 3-5 business days for any custom hose assembly assuming our web store shows stock on all the items required.

If you want to up-convert the fitting sizes on our DP you can use these:
http://www.racetronix.biz/itemdesc.asp?ic=392-497308BL&eq=&Tp=
http://www.racetronix.biz/itemdesc.asp?ic=392-497310BL&eq=&Tp=

A custom -10>16x1.5 Metric adapter fitting would have to be machined to adapt the -10 line to the fuel rail.
The stock-style Accufab regulator's return will not accept anything larger than the current -6 fitting we offer now so adapting it to -8 would have to be done downstream / away from the intake runner.
 
In my case i will probably be running a Twin LSX build in the GN and it will be able to produce those big HP #'s just not all the time on the street! Correct me if i'm wrong but going from a -8 into a -10 all the way to the engine though a -10 filter will that not provide more volume? I want to keep with intank pumps due to the noise factor externals are way to loud but i still need a fuel system that will handle 1400hp flywheel!
 
I would also like to get a measurement of the inside of the hose fittings once installed with the -8,-6. Are they crimped? We tried a set of Fragola -8 crimped fittings and they were smaller inside diameter than the stock feed line was. They were sent back in favor of a -10,-8 set up
 
6togo said:
In my case i will probably be running a Twin LSX build in the GN and it will be able to produce those big HP #'s just not all the time on the street! Correct me if i'm wrong but going from a -8 into a -10 all the way to the engine though a -10 filter will that not provide more volume? I want to keep with intank pumps due to the noise factor externals are way to loud but i still need a fuel system that will handle 1400hp flywheel!
Click to expand...


As stated before, there is nothing to be gained using a -10/-8 combo with our DP 680LPH setup. The flow capability of the -8 Teflon line is more than adequate for this system.
 
jdpolzin said:
I would also like to get a measurement of the inside of the hose fittings once installed with the -8,-6. Are they crimped? We tried a set of Fragola -8 crimped fittings and they were smaller inside diameter than the stock feed line was. They were sent back in favor of a -10,-8 set up
Click to expand...


Perhaps they were over-crimped? Until recently, Fragola did not have a proper crimp collar for the coated hose.
Unlike most swaging machines where the operator has to eyeball the crimp, ours is digital with a positional sensor so the crimps are very consistent.

The reusable True Street -8 fitting has an internal ID of 0.35" and an OD of 0.43". The ID of the coated/conductive hose is 0.405".
The slight reduction in fitting diameter is NOT the proverbial cork in the bottle. You must learn to understand coefficients of friction. You must take an overall look at the plumbing system to determine its flow capability / pressure drop.
The same confusion comes into play with ohms law. Customers ask us all the time about short lengths of thin wire attached to longer lengths of thick wire. It is the overall resistance to flow which has to be determined NOT at one specific point.

Bottom line is that the -8/-6 system we offer is quite capable of supporting everything our DP 680LPH system has to offer.
 
I just find it hard to believe that there are no flow or volume gains with the larger line i would have to see some flow data to verify that. I guess at that point your pumps could be the limiting factor and cant push more than -8 line will take.
 
6togo said:
I guess at that point your pumps could be the limiting factor and cant push more than -8 line will take.
Click to expand...
A simplified explanation is this... the low restrictive nature of the -8 Teflon line is such that there is very little loss in flow so going to a -10 line will net VERY little gain in flow.
In addition to keeping flow volume up we also want to keep the velocity up in the fuel system which will be lower with a -10 based system.
Higher costs, added weight and reduced fuel system responsiveness are some tradeoffs when considering larger fuel lines.
If you want to gain a better understanding of how this all works you must study fluid dynamics and Bernoulli's principle.
 
6togo said:
Or use a better flowing pump/s that will keep the velocity up in the bigger line.
Click to expand...


You can use higher flowing pumps but then you introduce more heat into the fuel system and put excessive load on your electrical system.
There is a BALANCE to everything and our kit provides just that.
 
-10 is overkill for anything less than 1500 hp. I've used -8 and -6 return to run 4.90's at 3350#. My big block has -10 but will make 2500 hp.




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Rafs-T-Type said:
Yet my 120's are maxed at no where near that power level :confused::mad:
Click to expand...

These Racetronix double pumpers are no joke. I was hesitant at first until we flowed my Weldon 2025A against this system at Racetronix. After that, data logs from the track said it all. You might want to try loosening your gas cap and see if that changes your injector duty cycle on your injectors. If it improves you need to vent your fuel system properly.

 
I actually switched to a vented cap, but I don't think it helped. I was going to ditch my cap and see if that made a difference, but the fuel pump guys @ Magnafuel said it wouldn't. Any time I question their pump their answer has consistenly been it needs a bigger vent line. I have a new 30 gallon stock location cell with a bigger vent, plus a volt booster ready to go on in the spring, so I'm hopping they will help cure my issue.

Did you modify the pickup for a bigger vent?...or what did you do?
 
Do we have any good proven numbers with the Racetronix double pumpers, -8/-6 lines, stock rail, on E85 yet?
 
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