Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: EFI Conversion fuel flow
r1_pete

posted on 29/5/14 at 05:24 PM Reply With Quote
EFI Conversion fuel flow

Now my E Type is back on the road I want to get on with prepping for EFI next winter.

I really don't want to run a return line, and modify the fuel tank etc. etc. so I've come up with the idea below:

Fuel flow
Fuel flow


The stock SU pump feeds a swirl pot in the engine bay, with a float arrangement to cut the fuel when the pot is full.

I've an in tank pump to fit into the pot, feed the injectors, then return to the pot via the pressure regulator.

Does this look like a workable solution?

Cheers.

Pete.

[Edited on 29/5/14 by r1_pete]

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
coyoteboy

posted on 29/5/14 at 06:44 PM Reply With Quote
Yep, but only if your LP pump can out-flow the HP pump at almost all times and you will almost undoubtedly see quite high temp increases at low EFI flow rates - this is normally negated by the large tank volume and long pipe flows- consider passing the fuel through a cooler on the return.

My biggest concern is venting and how you're going to achieve it without A) starving the pot and b) risking spillage.






View User's Profile E-Mail User View All Posts By User U2U Member
r1_pete

posted on 29/5/14 at 07:25 PM Reply With Quote
Thanks, I hadn't thought about heat, thats probably enough to justify an extra line and a more conventional setup....
View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
matt_gsxr

posted on 29/5/14 at 08:13 PM Reply With Quote
Adding a return line is a good idea really.

In the design you show there are a couple of problems
1) return line from fuel pressure regulator is pressurised so you won't get stable fuel pressure
2) if you run out of fuel then I don't know how you will get the air from the swirl pot
3) fuel temp (but you already knew that)

I wish I was building an e-type. Very jealous.


If you do want to minimise plumbing then I don't see why you can't run a dead-head systems (i.e. fuel pressure regulator next to swirl pot near tank, and just one line to the injectors with no return line). People worry about dead head, but several BMW run dead head as do suzuki motorcycles. Just a thought.





http://jpsc.org.uk/forum/

View User's Profile Visit User's Homepage View All Posts By User U2U Member
mark chandler

posted on 29/5/14 at 08:47 PM Reply With Quote
I tried that, it failed to work

The EFI circuit became a closed circuit, pump cavitation means that over a period of time the swirl pot empties itself and you stop.

View User's Profile View All Posts By User U2U Member
matt_claydon

posted on 29/5/14 at 09:30 PM Reply With Quote
quote:
Originally posted by matt_gsxr
If you do want to minimise plumbing then I don't see why you can't run a dead-head systems (i.e. fuel pressure regulator next to swirl pot near tank, and just one line to the injectors with no return line). People worry about dead head, but several BMW run dead head as do suzuki motorcycles. Just a thought.


Yep, like this:

Feed only injection fuel sys
Feed only injection fuel sys


The tank, pump and reg can all be at the rear of the vehicle. It works, but I assume there are downsides as otherwise OEMs wouldn't bother with the 2-line systems fitted on pretty much every production car.

The obvious problems are:

*Difficult to vacuum-reference the regulator
*Pressure drop along the feed line means the pressure at the injectors is not exactly what the reg is set at. The difference will vary with flow rate.

Both of these should be able to be compensated for in the mapping though. OEMs have a lot more to worry about in terms of getting perfect fueling for emissions and fuel consumption reasons than you do.

View User's Profile Visit User's Homepage View All Posts By User U2U Member
r1_pete

posted on 29/5/14 at 10:04 PM Reply With Quote
The Dead Head system could be quite neat, the fuel tank has a small sump in the bottom, so if I use the subaru pump in the tank, the reg in the boot, I wouldn't need a swirl pot, and 10mm pipe would minimize pressure loss, and as its regulated have less pressure in the rear to front pipe.

Thanks guys, that could really work out nicely, and be less fussy under the bonnet.

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member
Uphill Racer

posted on 29/5/14 at 11:18 PM Reply With Quote
Why not tee the return in before the low pressure pump?
View User's Profile View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.