Fuel line query - MVAgusta.net
 3Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 43 (permalink) Old 02-01-2018, 04:37 AM Thread Starter
cus
Senior Member
 
cus's Avatar
 
Join Date: Apr 2011
Location: Tasmania
Posts: 922
Fuel line query

Put new 3/8 fuel lines on my 1078 brutale and am wondering what the point of the 3/8 lines are when the fittings at the fuel rail are 5/16 and the internal size of the tank quick connects are similar to 5/16 ( couldn’t be arsed measuring them). Just thinking 5/16 lines might have been better for ease of routing.
cus is offline  
Sponsored Links
Advertisement
 
post #2 of 43 (permalink) Old 02-01-2018, 07:19 AM
Senior Member
 
airjawed's Avatar
 
Join Date: Apr 2017
Location: Memphis
Posts: 561
New Site Garage
I think flow would be less if the entire line was 5/16. More overall restriction is harder on pump and allows less fuel across.
airjawed is offline  
post #3 of 43 (permalink) Old 02-01-2018, 07:21 AM
Senior Member
 
silentservice703's Avatar
 
Join Date: Feb 2008
Location: Duxbury, MA, USA
Posts: 20,447
Send a message via Skype™ to silentservice703
5/16 is what you should have used, but it can be difficult to insert the barbed end of the connector.

Gapalicious 2019 at
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
from OCTOBER 2-6, 2019

Call (423) 519-2000 or (423) 253-6213 to reserve your Riverfront Cabin. PM me for The Crow's Nest reservation!!!

Email/Paypal:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


My personal Cell Phone: (781) 223-3020


'07 F4 312R, '10 B4 1090RR, '15 B3 800RR
'07 Ducati Monster S4Rs, '07 Ducati Monster 695
2010 Harley Davidson Ultra-Classic Electra-glide CVO FLHTCUSEBLK
'63 Honda C100A Cub
'61 MVA TRA 125
silentservice703 is offline  
Sponsored Links
Advertisement
 
post #4 of 43 (permalink) Old 02-01-2018, 01:43 PM
MVAgusta.net Sponsor
 
mitchy's Avatar
 
Join Date: Feb 2010
Location: Gold Coast, Australia.
Posts: 4,862
New Site Garage
Send a message via Skype™ to mitchy
Mark I used 5/16 on my 1078 and made them 2 inches longer for ease of tank removal next time.The 5/16 hose fits perfect.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Bike- F4 1078.
Work.Email & Paypal.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Work Phone (+61)0755244655
Facebook- Mitch Covington
Mobile-0423041326
mitchy is offline  
post #5 of 43 (permalink) Old 02-01-2018, 06:10 PM
Senior Member
 
theknurl's Avatar
 
Join Date: Jul 2009
Location: Palos Verdes Est, SoCal, USA
Posts: 13,602
Send a message via Skype™ to theknurl
Thumbs up wtf???

Quote:
Originally Posted by airjawed View Post
I think flow would be less if the entire line was 5/16. More overall restriction is harder on pump and allows less fuel across.
Wrong.....
The male John Guest fittings on the fuel rail are 0.185" I'D 35% of 5/16"
The pressure regulator keeps line pressure at 3 bar
Extra fuel pressure is bled off back into the tank


Noel-theknurl

The Forum Curmudgeon
I'm not PC either
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

'08 910R
'05 F4
ph. 310-414-7247 PST, GMT -8
PayPal;
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Skype; theknurl
theknurl is offline  
post #6 of 43 (permalink) Old 02-01-2018, 07:46 PM
Senior Member
 
airjawed's Avatar
 
Join Date: Apr 2017
Location: Memphis
Posts: 561
New Site Garage
I'm not talking about when the flow is lower than what is needed. I'm talking about full throttle.

My car has a fuel pressure regulator and does flow back to tank. So it always circulates past the injectors and back to tank. It also adds pressure as the manifold pressure changes.... turbo charged fueling. FPR after injectors. I run higher than stock boost and have a high flow fuel tank, bigger injectors etc. Not stock...stage 3 build.

My F3 800 has injector at the end of the line. Regulator is at tank. I've never seen a FPR after injector on a bike but doesn't mean 1078 doesn't. I don't know.

My point is that a fuel line with a single narrowing flows better than a line that is narrow the entire way when flowing at high volume.

Quote:
Originally Posted by theknurl View Post
Wrong.....
The male John Guest fittings on the fuel rail are 0.185" I'D 35% of 5/16"
The pressure regulator keeps line pressure at 3 bar
Extra fuel pressure is bled off back into the tank

airjawed is offline  
post #7 of 43 (permalink) Old 02-02-2018, 05:48 AM
Senior Member
 
silentservice703's Avatar
 
Join Date: Feb 2008
Location: Duxbury, MA, USA
Posts: 20,447
Send a message via Skype™ to silentservice703
While there is a pressure drop over length for any hose, and that pressure drop is relative to inside diameter and length of hose, on this system there is excess supply built in by having a return line pressurized to a value higher than necessary for full throttle demands.

You could put a one inch I.D. supply line in and it would not improve flow.

On the single line systems (later bikes >'10) the pressure is maintained at a value that will encompass all demand and have excess supply.

A cautionary tale about making the hoses longer: I did just that on my 312R. I also installed new CPC fittings both male and female. I believe, but I haven't been able to prove it yet, that the hose routing, coupled with the extra length, puts enough pressure on the fittings such that in time they disconnect enough to interrupt fuel flow.

I'll be testing my theory when riding weather returns, but I have been caught out, as has Curtis when he borrowed my 312R at Gapalicious 2017. Disconnecting and reconnecting the lines is all that was needed to restore fuel flow.

Gapalicious 2019 at
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
from OCTOBER 2-6, 2019

Call (423) 519-2000 or (423) 253-6213 to reserve your Riverfront Cabin. PM me for The Crow's Nest reservation!!!

Email/Paypal:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


My personal Cell Phone: (781) 223-3020


'07 F4 312R, '10 B4 1090RR, '15 B3 800RR
'07 Ducati Monster S4Rs, '07 Ducati Monster 695
2010 Harley Davidson Ultra-Classic Electra-glide CVO FLHTCUSEBLK
'63 Honda C100A Cub
'61 MVA TRA 125
silentservice703 is offline  
post #8 of 43 (permalink) Old 02-02-2018, 05:31 PM
Senior Member
 
theknurl's Avatar
 
Join Date: Jul 2009
Location: Palos Verdes Est, SoCal, USA
Posts: 13,602
Send a message via Skype™ to theknurl
Thumbs up ?

Quote:
Originally Posted by airjawed View Post
I'm not talking about when the flow is lower than what is needed. I'm talking about full throttle.

My car has a fuel pressure regulator and does flow back to tank. So it always circulates past the injectors and back to tank. It also adds pressure as the manifold pressure changes.... turbo charged fueling. FPR after injectors. I run higher than stock boost and have a high flow fuel tank, bigger injectors etc. Not stock...stage 3 build.

My F3 800 has injector at the end of the line. Regulator is at tank. I've never seen a FPR after injector on a bike but doesn't mean 1078 doesn't. I don't know.

My point is that a fuel line with a single narrowing flows better than a line that is narrow the entire way when flowing at high volume.
My '03 built Aprilia RSVR's FPR references manifold pressure
All 1st Gen MVs have FPRs on the return line
Haven't dealt with the 2nd Gen POS

How much REAL horsepower is your racecar making?
Here is where you find out what you need

RC Fuel Injection > Technical

From my mentor and friend RC

Noel-theknurl

The Forum Curmudgeon
I'm not PC either
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

'08 910R
'05 F4
ph. 310-414-7247 PST, GMT -8
PayPal;
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Skype; theknurl

Last edited by theknurl; 02-02-2018 at 10:34 PM.
theknurl is offline  
post #9 of 43 (permalink) Old 02-02-2018, 11:12 PM
Senior Member
 
airjawed's Avatar
 
Join Date: Apr 2017
Location: Memphis
Posts: 561
New Site Garage
I have a F3 800 POS like many of us half ass MV owners. Clearly I we don't live up to your standards. Thanks for letting us live in your world.

I think having a return line type is nice because fuel is always moving and no chance of vapor locking or heating up. Didn't think that bikes would do a return line since I haven't seen that on any of the newer bikes. But, I haven't worked on that many to really say. Again, I own POS bikes and cars and so do all my friends.

My car is a pretty common Audi B5 S4 Avant stage 3 build. I have not put my car on a dyno but most examples are are at 400 hp/tq to the wheels minimum. I didn't want to go excessive since I never wanted to do a built bottom end and I decided to keep my transmission as is(auto). Its a nice sleeper build daily driver.... 250,000 miles so I think I've kept it a reasonable and safe build. Many cars make more power. There is always someone faster. I'm no exception. But I loved the process of doing it!

I'm not going to respond any more to your posts. This thread was a simple one and I just gave something to think about.

Quote:
Originally Posted by theknurl View Post
My '03 built Aprilia RSVR's FPR references manifold pressure
All 1st Gen MVs have FPRs on the return line
Haven't dealt with the 2nd Gen POS

How much REAL horsepower is your racecar making?
Here is where you find out what you need

RC Fuel Injection > Technical

From my mentor and friend RC
airjawed is offline  
post #10 of 43 (permalink) Old 02-03-2018, 03:45 AM
MVAgusta.net Sponsor
 
mitchy's Avatar
 
Join Date: Feb 2010
Location: Gold Coast, Australia.
Posts: 4,862
New Site Garage
Send a message via Skype™ to mitchy
Quote:
Originally Posted by silentservice703 View Post
While there is a pressure drop over length for any hose, and that pressure drop is relative to inside diameter and length of hose, on this system there is excess supply built in by having a return line pressurized to a value higher than necessary for full throttle demands.

You could put a one inch I.D. supply line in and it would not improve flow.

On the single line systems (later bikes >'10) the pressure is maintained at a value that will encompass all demand and have excess supply.

A cautionary tale about making the hoses longer: I did just that on my 312R. I also installed new CPC fittings both male and female. I believe, but I haven't been able to prove it yet, that the hose routing, coupled with the extra length, puts enough pressure on the fittings such that in time they disconnect enough to interrupt fuel flow.

I'll be testing my theory when riding weather returns, but I have been caught out, as has Curtis when he borrowed my 312R at Gapalicious 2017. Disconnecting and reconnecting the lines is all that was needed to restore fuel flow.
Hi Chuck,happy new year.Fitting 5/16 fuel line and 2inches longer makes no drop in fuel pressure at all,the motor runs perfect.The fuel pump delivers enough pressure to handle the slight reduction in hose diameter and a measly 2inches in length.We can All do with an extra 2inches.lol.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Bike- F4 1078.
Work.Email & Paypal.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Work Phone (+61)0755244655
Facebook- Mitch Covington
Mobile-0423041326
mitchy is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to use all of the features of the MVAgusta.net site, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome