LS7 fuel system.

LS7 fuel system.

Author
Discussion

JBC

Original Poster:

41 posts

70 months

Monday 7th May
quotequote all
Firstly, nice to meet a few of you at Stoneleigh today.

After having a chat re fuel systems, I'd love to hear peoples thoughts and recommendations.

I'm currently building an LS7 ( stock ) GTR. The tanks are still accessable and can be removed.
I would like to give myself the option of upgrading the engine if I see fit at a later date.

Given all of this, what fuel system would you recommend I go with?

Thanks in advance for any help / info given..

deadscoob

1,947 posts

192 months

Monday 7th May
quotequote all
Get the tanks modified so you can use in tank pumps, or do it yourself with the aeromotive phantom kit. Getting them modified would be better at the stage you’re at, the aeromotive is very good to retrofit.
Quiet and simple, just make sure the pick up
is positioned correctly so under acceleration or cornering when low it can get a feed.
1 in each tank or to keep it single, 2 in one tank so you have a fail safe, just link the tanks together.
No packaging or cavitation worries if you do this.

Or, sell your tanks and buy a pair of fuel safe cells for ultimas with built in pumps, but that’s obviously pricey smile

Go for decent pumps, Bosch would be my choice, not bling but bullet proof.



JBC

Original Poster:

41 posts

70 months

Tuesday 8th May
quotequote all
Thanks for that. I'm going to contact aeromotive today. Do you think a 40mm tank connecting tube is too large / small?

deadscoob

1,947 posts

192 months

Tuesday 8th May
quotequote all
I’d go with Bosch over aeromotive every day.
2nd choice would be walbro.

Ask yourself:
How many oems use aeromotive?
How many endurance race teams use aeromotive fuel pumps?

Answer us probably around none and not many. Aeromotive tend to be used for drag racing so flow is there for sure, but usage is different.

I’m not saying aeromotive are cr4p, but Bosch and walbro are better for our installations imo.


GTRS

287 posts

155 months

Tuesday 8th May
quotequote all
I’ve just purchased the aeromotive fuel system components and xrp fittings from Murray’s speed shop in florida. I dealt with a chap called Marc Whithall. I can send you his contact details if you like. He was excellent in offering advise and helping me to configure my system.
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ROWDYRENAULT

1,189 posts

146 months

Tuesday 8th May
quotequote all
as said above, in tank systems have lots of advantages. As far as aeromotive systems go that's what I installed on my GTR in 2007 and it's still there with the new owner. With the Motec system on the car, we always look at the data to monitor fuel pressure and in all these years it's never varied over a pound or two. lee

mt308

415 posts

75 months

Wednesday 9th May
quotequote all
On the subject of LS7 fuel systems has anyone else experienced problems with restarting the car when warm/hot. I have a recurring but intermittent issue where the pumps don't seem to prime when I have stopped for a few mins (e.g. getting fuel) then the engine won't start. Generally after a couple of minutes I hear the pumps prime then she starts every time. My hunch is it is something electrical but have not managed to sort it yet.

Mark

Storer

4,736 posts

147 months

Wednesday 9th May
quotequote all
mt308 said:
On the subject of LS7 fuel systems has anyone else experienced problems with restarting the car when warm/hot. I have a recurring but intermittent issue where the pumps don't seem to prime when I have stopped for a few mins (e.g. getting fuel) then the engine won't start. Generally after a couple of minutes I hear the pumps prime then she starts every time. My hunch is it is something electrical but have not managed to sort it yet.

Mark
Mark
I think your hunch may be correct. My pumps fire up as soon as I disarm my immobiliser.
What ECU are you using? If GM, have you posted a question on the US LS forum?

Paul

xrtim

121 posts

39 months

Wednesday 9th May
quotequote all
After a lot of research I went with Fuelab cant comment on the system performance as motor is not running yet. pump is good enough for 1500hp and is variable speed, controlled by fuel pressure regulator. I was going to use both tanks to feed the single pump but after asking the question on here I received a reply where a racer tried the same thing and couldn't get the tanks to balance even with the largest pipe they could fit, so 2 separate tanks some one way valves and switchable return feeds to send the excess fuel to the tank it came from. Holley make a mat that fits in the bottom of a tank and will supply fuel to the last drop in the tank so surge no problem (not fitted them but thinking about it). Fuelab filters are used also, the final filter is a one way version non return that maintains fuel rail pressure on shut down so should make restarts easier

Tim

BogBeast

892 posts

195 months

Wednesday 9th May
quotequote all
Hi Jon,

Nice to meet you on Sunday.

My tanks were firmly installed when I did my carb > EFI conversion, so I ended leaving the standard pumps in place to be used low pressure 'lift' pumps into a combined pump, regulator & swirlpot from Radium:

http://www.radiumauto.com/FST-R-Fuel-Surge-Tank-wi...

I have a return from the swirl pot to a T piece that feeds both tanks; it has an alloy bung in the leg from the swirl pot that has a 1mm hole drilled through to allow air and a small amount of fuel to circulate out of the pot.

The pump in the swirl pot then feeds both my fuel rails at injection pressure and is returnless - the fuel regulator in the swirl pot mages the fuel pressure. I also put in one of the radium pulse dampers in the fuel lines as a belt and braces..-

It works very well as an adaption of the old Ultima carb fuel system but if I was doing it all again and had the tanks out, I would also go for an in-tank solution

From Aeromotive,

https://www.aeromotiveinc.com/product/phantom-340-...

or Holley have an option as well

https://www.holley.com/products/fuel_systems/fuel_...

I would probably go Holley as I have their FI and so far everything I have had from them has worked flawlessly.. I would probably go returnless as well...

My twopenneth wink



John1949

41 posts

127 months

Thursday 10th May
quotequote all
If i was to build a new Ultima and money was not a problem. The fuel system i would install is twin Fuel Safe tanks with internal pick ups and pumps, They do make a nice system for the car. I would make sure there is a cross over to the two tanks with a valve to close off if you wanted to run different types of fuel to the engine. This would be more important if you were running a supercharged of turbocharged engine. The most likely way you would die in this car is from fire. Also, if i was going to track this car i would install a fire extinguisher system.

JBC

Original Poster:

41 posts

70 months

Thursday 10th May
quotequote all
More great advice, thanks everyone. I'm favouring keeping the existing tanks, but balancing them, and I'll give holley a call, like the sound of the mat pick up. Will keep everyone posted here on in..

xrtim

121 posts

39 months

Thursday 10th May
quotequote all
I think the Holley product is called Hydramat, I think you need to cut access into the tank and secure the mat inside and connect to the outlet. I would increase the size of the outlet pipe, AN fitting and hose for increased fuel supply potential if you opt for different fuels per tank. I’ve gone for a large swirl pot and if needed both tanks and pumps can operate together to keep the swirl pot topped up, I’m going to sort the fuel quality under boost with methanol injection with a separate tank beside the gearbox for the methanol

BogBeast

892 posts

195 months

Saturday 12th May
quotequote all
JBC said:
More great advice, thanks everyone. I'm favouring keeping the existing tanks, but balancing them, and I'll give holley a call, like the sound of the mat pick up. Will keep everyone posted here on in..
A single pump in one tank with a socking big feed to the other tank?

(BTW that Holley intank pump comes with hydramat..)

humble

75 posts

40 months

Monday 14th May
quotequote all
For my fuel system, I upgraded the tanks to Fuel Safe fuel cells, each with Holley Hydramat pickups. Both tanks have a -10 balance tube, -8 fuel feed, and -6 fuel return AN fittings. The -10 balance pipe links the tanks, the -8 feed lines tee into a low pressure filter then feed the Bosch 044 lift pump, which goes to a high pressure fuel filter. From the high pressure filter there's a -6 feed to the 1.5L sump tank which holds the submerged Bosch 044 high pressure pump that feeds the AEM fuel pressure regulator, then engine, all in -6 line. Return fuel from the regulator (-6), and overflow (-6) from the sump tank tee together into a -8 line, then split into 2 -6 lines returning to both tanks. It seems a little complicated at first glance, but everything is very serviceable, the tanks stay balanced, and I've been able to suck the tanks completely dry on several occasions.

Will