Smaay's Fuel Rail - Phase 1 - LotusTalk

Dave · 08-09-2007, 03:47 PM

I had posted a bit about this in another thread, but have been getting several questions. This is Smaay's fuel rail system, and it's a replacement for the stock fuel rail. It's a high quality piece, and for $220 delivered, IMO a great value. (No, I'm not getting commissions on this!).

Benefits of his fuel rail:

- This rail is fed from the center (vs end), which allows better fuel distribution/pressure to all four injectors. This is especially important in cars with higher fuel demands, in particular, forced injection.

- Each end of the rail has a tap to facilitate the addition of a fuel gauge, return system, nitrous feed, test port, etc. (see the blue caps)

- You can easily add an additional fuel filter. Edit: OE filter is tucked away inside the fuel tank. Note this is not included with his kit. In the last picture, you'll see where I've added. I bought the full-flow filter and coupler from Summit Racing, PNs: EAR-915106ERL and SUM-230100.

- It's simple to install, maybe about an hour or so, and it's built like a tank.

More...This fuel rail is also a stage 1, if you will, of his full return system, which I plan to install as a winter project. Ronin was the first to try/test the return system on an Elise, and is very happy. Smaay has sold these kits to lots of owners on NewCelica too.

So, why a return system? Here is a good explanation from Griffin off of MM:

It enables the use of a 1:1 fuel pressure regulator. The factory system is spring regulater in tank to about 45-47 PSI. The problem is the higher you boost the lower the pressure differential gets between your intake manifodl pressure and your fuel pressure. For example:

In a NA application as long as the fuel system had 45 PSI the car always has 45 PSI effective pressure as the pressure in the intake never significantly exceeds 0 PSI

In a turbo application with static fuel pressure the effective fuel pressure is constantly reduced as the intake manifold pressure goes up. At 5 PSI your 45 PSI of fuel pressure has an effective PSI of 40. AT 15 PSI intake pressure your effective PSI is only 30 PSI. AT 20 PSI of boost your intake pressure goes down to only 25 PSI effective. If you dont do anything about that you wind up with a set of HUGE injectors that don't work well at idle and are still close to maxed out at relatively low power levels.

Switchign to a system with a 1:1 regulator and return system is a much more effective way to deal with a boosted car. The 1:1 regulator ncreases fuel pressure by 1 PSI for every PSI increase in manifold pressure resulting in a constant pressure differential between intake and fuel system. For example:

At idle (0 PSI) system is at 45 PSI fuel pressure 45 psi effective pressure (or whatever you set it to)'
at 10 PSI intake pressure fuel system goes to 55 PSI fuel pressure which is 45 PSI effective pressure
at 20 PSI system goes to 65 PSI fuel pressure which is 45 PSI effective pressure

uglyduck · 08-09-2007, 04:01 PM

Very nice Dave
Is there a tap off the intake to the regulator

Smaay · 08-09-2007, 04:06 PM

actually there is a fuel filter in the tank. not just the sock that you see sticking out of the bottom of fuel pump.

in this picture you can see the sock on the bottom of the fuel pump. the filter is actually enclosed in the pump assembly.

Dave just took an extra step by adding another filter in line which is totally ok.

®ob · 08-09-2007, 04:17 PM

What you are referring to as a 1:1 regulator is a rising rate regulator. In my last supercharged audi, this was actually detrimental to performance and tune. Having a fixed rate FPR worked out much better.

Chris Mackey · 08-09-2007, 04:45 PM

Sometimes I learn from this site. Thanks!

P90Puma · 08-09-2007, 05:15 PM

Quote:

Originally Posted by ®ob

What you are referring to as a 1:1 regulator is a rising rate regulator. In my last supercharged audi, this was actually detrimental to performance and tune. Having a fixed rate FPR worked out much better.

Also known as an AFPR (Adjustable fuel pressure regulator.)

Bleu Omdurman · 08-09-2007, 05:28 PM

Dave, i wonder how many times you have painted your engine trim?

BTW, i like the current one the most!

uglyduck · 08-09-2007, 06:58 PM

Dave, where is the regulator and return line. I have used regulators that tapped into the intake and adjusted the pressure based on manifold pressure.

Dave · 08-09-2007, 07:10 PM

Quote:

Originally Posted by uglyduck

Dave, where is the regulator and return line. I have used regulators that tapped into the intake and adjusted the pressure based on manifold pressure.

This is just the first 'phase'. The return system is my winter project. Some more info here: http://www.newcelica.org/forums/show...ay+fuel+return

Quote:

Originally Posted by Bleu Omdurman

Dave, i wonder how many times you have painted your engine trim?
BTW, i like the current one the most!

If you mean the letters on the cover, my daughter just painted it for the first time last week. Welcome back to the states!

®ob · 08-09-2007, 07:18 PM

Quote:

Originally Posted by P90Puma

Also known as an AFPR (Adjustable fuel pressure regulator.)

Actually, not all the time. AFPR can be fixed pressures.

smokin orange · 08-09-2007, 07:28 PM

very cool, made one for my supercharged 02, and never thaught of it for my FI package in the Elise. It does exactly what Dave says, whereby providing a ample consistant fuel delivery accross all injectors.

ZAMMY1 · 08-10-2007, 04:09 AM

i would expect that, in a system such as the ECU we have, the nonlinearities can be/are dialed out in the calibration so the add-ons may not be needed.

with the small pressures involved with carburetors, a rising rate regulator sure does insure that fuel starvation doesn't occur.
i had a lot of fun playing with maserati biturbos.

aztec1382 · 08-10-2007, 10:43 PM

how do you contact smay or go about purchasing the fuel rail

Dave · 08-11-2007, 03:18 AM

Quote:

Originally Posted by aztec1382

how do you contact smay or go about purchasing the fuel rail

Just send him a PM here or on MM (Smaay).

fpitas · 09-13-2007, 07:17 AM

Dave,

I am going to put mine on tomorrow, how did you get that fuel line clip apart down by the windshield washer tank? Does it just kind of pry apart, or is there a trick? I guess the stock clip is not reused, going by your pictures.

Dave · 09-13-2007, 07:38 AM

Quote:

Originally Posted by fpitas

Dave,

I am going to put mine on tomorrow, how did you get that fuel line clip apart down by the windshield washer tank? Does it just kind of pry apart, or is there a trick? I guess the stock clip is not reused, going by your pictures.

The clip will unsnap about halfway, no need to completely remove. Then just separate the two lines...you might have to work them a bit.

fpitas · 09-13-2007, 07:52 AM

Quote:

Originally Posted by Dave

The clip will unsnap about halfway, no need to completely remove. Then just separate the two lines...you might have to work them a bit.

OK, thanks.

Buz · 09-13-2007, 07:53 AM

Dave; Do you expect to have to alter your ecu tune by swapping the fuel rail?

drummerbrent · 09-13-2007, 09:56 AM

Before I comment, an FYI - I've been involved in fuel system design for > 20 years and actually worked with Lotus on their 2.2L turbo and Chevy LT5 programs. A couple of points. 1st, Regulators in recirculating / return systems should ideally be located at the rail. That reduces pressure pulsations induced by the injectors and the amount of time required by the regulator to react. It also helps with hot fuel handling / hot restart because it can more quickly purge the vapor at the top of the rail. 2nd, fuel system design is a lot harder than it looks. If improperly designed, a system can resonate leading to rich or worse, lean cyclinders under certain operating points. Since people are running these pig rich, maybe that doesn't matter (unless the cylinder walls are getting their oil too washed down with fuel).

The fact that the Lotus rail's inlet is on one end is not necessarily bad, and moving it to the middle won't necessarily help anything if it wasn't optimized for the car, injectors, fuel lines, and calibration. I cannot emphasize how much work goes into designing, testing, and calibrting fuel system for cars. It usually takes OEMs 3 or more years with an unbelieveable amount of resources.

Anyway, I'm not saying that any of this bad stuff will necessarily happen with this rail, I would just like to see some system data before buying it. Otherwise, it looks like a nice piece.

2-Y-CHROMOSOMES · 09-13-2007, 10:21 AM

Quote:

Originally Posted by Buz

Dave; Do you expect to have to alter your ecu tune by swapping the fuel rail?

I believe he will. Dave may use charlies new tuneable solution or swapping back out for the xede to tune it.

08-09-2007, 03:47 PM	#1 (permalink)
Dave Mods are good for you Join Date: Apr 2005 Location: Ohio Posts: 2,961	Smaay's Fuel Rail - Phase 1 I had posted a bit about this in another thread, but have been getting several questions. This is Smaay's fuel rail system, and it's a replacement for the stock fuel rail. It's a high quality piece, and for $220 delivered, IMO a great value. (No, I'm not getting commissions on this!). Benefits of his fuel rail: - This rail is fed from the center (vs end), which allows better fuel distribution/pressure to all four injectors. This is especially important in cars with higher fuel demands, in particular, forced injection. - Each end of the rail has a tap to facilitate the addition of a fuel gauge, return system, nitrous feed, test port, etc. (see the blue caps) - You can easily add an additional fuel filter. Edit: OE filter is tucked away inside the fuel tank. Note this is not included with his kit. In the last picture, you'll see where I've added. I bought the full-flow filter and coupler from Summit Racing, PNs: EAR-915106ERL and SUM-230100. - It's simple to install, maybe about an hour or so, and it's built like a tank. More...This fuel rail is also a stage 1, if you will, of his full return system, which I plan to install as a winter project. Ronin was the first to try/test the return system on an Elise, and is very happy. Smaay has sold these kits to lots of owners on NewCelica too. So, why a return system? Here is a good explanation from Griffin off of MM: It enables the use of a 1:1 fuel pressure regulator. The factory system is spring regulater in tank to about 45-47 PSI. The problem is the higher you boost the lower the pressure differential gets between your intake manifodl pressure and your fuel pressure. For example: In a NA application as long as the fuel system had 45 PSI the car always has 45 PSI effective pressure as the pressure in the intake never significantly exceeds 0 PSI In a turbo application with static fuel pressure the effective fuel pressure is constantly reduced as the intake manifold pressure goes up. At 5 PSI your 45 PSI of fuel pressure has an effective PSI of 40. AT 15 PSI intake pressure your effective PSI is only 30 PSI. AT 20 PSI of boost your intake pressure goes down to only 25 PSI effective. If you dont do anything about that you wind up with a set of HUGE injectors that don't work well at idle and are still close to maxed out at relatively low power levels. Switchign to a system with a 1:1 regulator and return system is a much more effective way to deal with a boosted car. The 1:1 regulator ncreases fuel pressure by 1 PSI for every PSI increase in manifold pressure resulting in a constant pressure differential between intake and fuel system. For example: At idle (0 PSI) system is at 45 PSI fuel pressure 45 psi effective pressure (or whatever you set it to)' at 10 PSI intake pressure fuel system goes to 55 PSI fuel pressure which is 45 PSI effective pressure at 20 PSI system goes to 65 PSI fuel pressure which is 45 PSI effective pressure Attached Images __________________ 2008 Solar S240 Exige 2005 Saffron Elise - BOE TVS Supercharger 291WHP w/ EFI Engine Mgmt Last edited by Dave : 08-09-2007 at 05:00 PM.

08-09-2007, 04:06 PM	#3 (permalink)
Smaay Registered User Join Date: Feb 2006 Location: Home of LACR Posts: 38	actually there is a fuel filter in the tank. not just the sock that you see sticking out of the bottom of fuel pump. in this picture you can see the sock on the bottom of the fuel pump. the filter is actually enclosed in the pump assembly. Dave just took an extra step by adding another filter in line which is totally ok. __________________ 2001 Celica GT-S Turbo 1990 Celica All-Trac Turbo 1997 Supra LE TT 6 Speed

08-09-2007, 04:17 PM	#4 (permalink)
®ob What's a registered user? Join Date: Jan 2006 Location: Austin Posts: 1,108	What you are referring to as a 1:1 regulator is a rising rate regulator. In my last supercharged audi, this was actually detrimental to performance and tune. Having a fixed rate FPR worked out much better. Last edited by ®ob : 08-09-2007 at 05:10 PM.

08-09-2007, 04:45 PM	#5 (permalink)
Chris Mackey Registered User Join Date: Jun 2007 Location: Austin, Texas Posts: 2,587	Sometimes I learn from this site. Thanks! __________________ 2006 Elise, Ardent Red, Black Pack, LSS wheels, shocks and springs. ChuforiaGraffix.com SDD Lives On! SweetDaddyDelicious(at)hotmail(dot)com

08-09-2007, 05:28 PM	#7 (permalink)
Bleu Omdurman More track time please. Join Date: Aug 2005 Location: Seattle Posts: 1,692	Dave, i wonder how many times you have painted your engine trim? BTW, i like the current one the most! __________________ Take my track day survey: here You should enjoy it. 10 questions. Now take survey #2 here Mods: TurboXS Intake, Ultra Disc Rotors, Adare Motorsports Racing Pads.

08-09-2007, 04:01 PM	#2 (permalink)
uglyduck Registered User Join Date: Jun 2005 Location: Toronto Posts: 618	Very nice Dave Is there a tap off the intake to the regulator

08-09-2007, 06:58 PM	#8 (permalink)
uglyduck Registered User Join Date: Jun 2005 Location: Toronto Posts: 618	Dave, where is the regulator and return line. I have used regulators that tapped into the intake and adjusted the pressure based on manifold pressure.

08-09-2007, 07:28 PM	#11 (permalink)
smokin orange Registered User Join Date: Dec 2006 Posts: 413	very cool, made one for my supercharged 02, and never thaught of it for my FI package in the Elise. It does exactly what Dave says, whereby providing a ample consistant fuel delivery accross all injectors. __________________ 05 Elise, (sold) 2002 BMW 330ci convertable, M package 1998 Range Rover (stolen) 1972 BMW 2002 supercharged, fuel injected, liquid intercooled, Haltech E6A ECU...and lots of other stuff 1988 BMW 535Is

08-10-2007, 04:09 AM	#12 (permalink)
ZAMMY1 ZAMMY Join Date: Jan 2007 Location: washington, pa, (near PGH.) Posts: 1,557	i would expect that, in a system such as the ECU we have, the nonlinearities can be/are dialed out in the calibration so the add-ons may not be needed. with the small pressures involved with carburetors, a rising rate regulator sure does insure that fuel starvation doesn't occur. i had a lot of fun playing with maserati biturbos.

08-10-2007, 10:43 PM	#13 (permalink)
aztec1382 be afraid be very afraid Join Date: Aug 2005 Location: los angeles Posts: 505 Images: 12	how do you contact smay or go about purchasing the fuel rail __________________ slwkart

09-13-2007, 07:17 AM	#15 (permalink)
fpitas User, Registered Join Date: Sep 2005 Location: Leesburg, VA Posts: 1,827	Dave, I am going to put mine on tomorrow, how did you get that fuel line clip apart down by the windshield washer tank? Does it just kind of pry apart, or is there a trick? I guess the stock clip is not reused, going by your pictures. __________________ Francis 2006 Chrome Orange Elise: LSD/TC, Nitron SAs with 425/650 springs, BWR 7/8" Front Bar, Eliseparts bumpsteer kit, VF Stage 2, 2bular Header + Sport Cat + 8x24 GT3 Muffler, ECU Tune by Jermaine, Smaay's fuel rail, ACT XT clutch, Saikou Michi dual catch can, Moroso pan, Manly's mount inserts & FF Engine Damper 2000 Black Integra Type R: - 213,000 miles...running again!

09-13-2007, 07:53 AM	#18 (permalink)
Buz Registered User Join Date: Nov 2005 Posts: 1,920	Dave; Do you expect to have to alter your ecu tune by swapping the fuel rail?

09-13-2007, 09:56 AM	#19 (permalink)
drummerbrent Think Lean Join Date: Sep 2005 Location: Rochester, New York Posts: 105	Before I comment, an FYI - I've been involved in fuel system design for > 20 years and actually worked with Lotus on their 2.2L turbo and Chevy LT5 programs. A couple of points. 1st, Regulators in recirculating / return systems should ideally be located at the rail. That reduces pressure pulsations induced by the injectors and the amount of time required by the regulator to react. It also helps with hot fuel handling / hot restart because it can more quickly purge the vapor at the top of the rail. 2nd, fuel system design is a lot harder than it looks. If improperly designed, a system can resonate leading to rich or worse, lean cyclinders under certain operating points. Since people are running these pig rich, maybe that doesn't matter (unless the cylinder walls are getting their oil too washed down with fuel). The fact that the Lotus rail's inlet is on one end is not necessarily bad, and moving it to the middle won't necessarily help anything if it wasn't optimized for the car, injectors, fuel lines, and calibration. I cannot emphasize how much work goes into designing, testing, and calibrting fuel system for cars. It usually takes OEMs 3 or more years with an unbelieveable amount of resources. Anyway, I'm not saying that any of this bad stuff will necessarily happen with this rail, I would just like to see some system data before buying it. Otherwise, it looks like a nice piece.

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