Ultima Fuel Delivery System Flaw?

Ultima Fuel Delivery System Flaw?

Author
Discussion

crossram

291 posts

123 months

Thursday 19th June 2014
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skidiiii said:
Congrats on the purchase of a new kit. I hope you are as excited as I was to be be building a GTR. Here is my personal opinion about Ultima and I am sorry if I offend anyone. The first major issue for me was what we refer to as the coloring book of build manual. It has not been updated in many years and as things evolve and change with the car it should be amended to reflect. I offered to make a new manual for the factory if I were to build another GTR just for this reason. I have built 2 now and know them inside and out very well. I have also developed templates on my cnc machine to assist in construction greatly saving time. A few major things I would like to see the factory consider as revisions are:

1) Solid brake lines through the side pod from front to back with flexible terminations that are short. Braided is great for ease of installation however this will fail long before a solid line will rupture. You will notice a bubble in the plastic before it fails, if this is hidden in the side pod and it goes unnoticed you may mash on the brakes and find they are no longer there!

2) Solid line for the clutch as well with short flexible terminations, same as above

3) Fuel system delivery system is way to complicated contrary to the factory's comments. There is absolutely no reason not to link the tanks as so many of us now have. The issues I personally have had with the fuel delivery system should have sparked the factory's interest right away. I have yet to get a clear answer.

4) The baffle material used in the tanks is in my opinion is a joke. I feel as the tanks were being manufactured they could have integrated internal real baffles and it would lead to a much better product. No chance of swarf making its way to the Pollak valve.

5) Fuel filters before the LP pump would be a great addition!

6) A note in the manual or make it standard practice to supply heat shield for the fuel tanks and bulkhead/ rear canopy.

7) Integrating a fuel pressure gauge in the cockpit as I have done to monitor fuel pressure. A very easy way to monitor your fuel filters health.

8) Supply mandrel bent aluminum tubing for the cooling system eliminating all of the silicone with the exception of the connections at the engine.

9) Non factory but worth thinking about.. Make up a plug that houses all engine wires from the ECU to be able to disconnect it right at the engine bay. This way you can simply unhook the plug and pull the engine in short order with out having to remove the entire harness from the engine.

Again sorry if I have offended anyone with my opinions on this matter. I understand it is hard to accept somebody's ideas some time as they are not your own however if it is for the greater good then why the hell not? I feel the brake lines would be a top item and will be retrofitting them in my car shortly. FYI I used all the factory supplied parts and tanks to effectively link mine. I had to order new line and fittings that's it.

These are just a few of my gripes and item I would change if I were to build another GTR.
Thanks for your excellent comments, based on these I plan to change over to hard lines since everything is still out in the open. In addition i am going to customer bladder tanks just for safety reasons.


For the life of me I can't understand why a company wouldn't want to update their build manual, in the long run it saves them office time answering questions and it makes the build process so much easier for the builder. Every customer currently building a car that I have been in contact with has similar feelings.

deadscoob

2,263 posts

259 months

Thursday 19th June 2014
quotequote all
I think a European builder had some custom tanks made from a Stateside company - good Motorsport stuff, looked very nicely made, same dimensions as standard Ultima tanks with integrated bosch pumps. If I was building again I'd definitely go that route instead of the standard tanks.
Can't remember the company name, try searching or email Crafty - he bought a pair too.

deadscoob

2,263 posts

259 months

Thursday 19th June 2014
quotequote all
deadscoob said:
I think a European builder had some custom tanks made from a Stateside company - good Motorsport stuff, looked very nicely made, same dimensions as standard Ultima tanks with integrated bosch pumps. If I was building again I'd definitely go that route instead of the standard tanks.
Can't remember the company name, try searching or email Crafty - he bought a pair too.
Edit - didn't take long, thread about them here:

http://www.pistonheads.com/gassing/topic.asp?h=17&...

Ref skiddiis post, agree with all of it, especially the pressure gauge.

I'd still recommend having dry break connectors on the filters still, as mentioned before, it makes cleaning them a 5 min job.

drivin_me_nuts

17,949 posts

210 months

Thursday 19th June 2014
quotequote all
deadscoob said:
Edit - didn't take long, thread about them here:

http://www.pistonheads.com/gassing/topic.asp?h=17&...

Ref skiddiis post, agree with all of it, especially the pressure gauge.

I'd still recommend having dry break connectors on the filters still, as mentioned before, it makes cleaning them a 5 min job.
... I like this idea. The idea of working on a still connected fuel system leaves me feeling very uncomfortable. Pricey for what they are, but methinks, money well spent.

Storer

5,024 posts

214 months

Friday 20th June 2014
quotequote all
Well, after boiling my fuel (60 deg C) sitting for an hour in a traffic queue at the St Saturnin car show on the Friday before Le Mans, I have now modified it to hopefully prevent a repeat.

I have moved the regulator from the bulkhead above the engine (probably the hottest part of the engine bay) down to the p/s side pod next to the swirl pot. I have changed the pipe routing too.
Now it is:
H/p pump to fine filter, then a 'T' .
One side of 'T' goes straight to the fuel rail.
The other side goes to the regulator. From the regulator it returns to the swirl pot.
The fuel rail now has the valve back in it so that the fuel does not 'flow' over the engine.

Still got some wiring to extend to allow my fuel pressure and temperature sensor to function but she seems to run fine.

Paul

skidiiii

Original Poster:

57 posts

148 months

Friday 20th June 2014
quotequote all
deadscoob said:
Edit - didn't take long, thread about them here:

http://www.pistonheads.com/gassing/topic.asp?h=17&...

Ref skiddiis post, agree with all of it, especially the pressure gauge.

I'd still recommend having dry break connectors on the filters still, as mentioned before, it makes cleaning them a 5 min job.
Yes expensive but well worth the money spent. No need to drain the tanks or system if you put them on either side of the filter highly recommend as well. Thanks for the tip deadscoob!

Slow M

2,726 posts

205 months

Saturday 21st June 2014
quotequote all
Steve_D said:
Slow M said:
What is the theory/benefit to having the filters after the pumps?............
Most pumps do not suck very well so placing a restriction like a filter before the pump is not ideal.
This is also the reason pressurising a swirl pot before the HP pump is a good idea as it helps the fuel entering the HP pump.

Steve
I thought I'd get back with you guys, to let you know that I was posting similar questions on another forum, and the reply, from a generous gent, who used to specify fuel systems, is "to utilize a 100-150 micron filter before the pump or pumps, and a 10-25 micron filter after the pump(s). (. . .) The coarse filter protects the pumps without being so restrictive or easily plugged as to cause cavitation. The fine filter protects everything else".

Best,
B.

skidiiii

Original Poster:

57 posts

148 months

Sunday 22nd June 2014
quotequote all
Storer said:
Well, after boiling my fuel (60 deg C) sitting for an hour in a traffic queue at the St Saturnin car show on the Friday before Le Mans, I have now modified it to hopefully prevent a repeat.

I have moved the regulator from the bulkhead above the engine (probably the hottest part of the engine bay) down to the p/s side pod next to the swirl pot. I have changed the pipe routing too.
Now it is:
H/p pump to fine filter, then a 'T' .
One side of 'T' goes straight to the fuel rail.
The other side goes to the regulator. From the regulator it returns to the swirl pot.
The fuel rail now has the valve back in it so that the fuel does not 'flow' over the engine.

Still got some wiring to extend to allow my fuel pressure and temperature sensor to function but she seems to run fine.

Paul
Paul,
You may also consider if you are running EFI and not naturally aspirated this set up with the fuel regulator and rails. My set up utilized a stock GM fuel rail with an -6 fitting welded onto the inlet. With the new set up this restrictive single inlet rail has been removed and the new rails allow for fuel to enter both much larger rails at the same time. My set up has the HP pump off the bottom of the swirl pot into the 100mc filter then right into the fuel rails via Y. The excess fuel exits the rails left and right and feeds either side of the Aeromotive fuel regulator (part #131098). You will notice in the instructions for the reg in figure 1-2 stated optimum performance for V8 engines. The return from the reg is fed back to the swirl pot nest to bottom fitting or #3 from top. Again by moving the pot to the AC side of the side pod as far away from the exhaust as possible is the key. I sat in dead stopped traffic yesterday for over an hour with the ac running and the car did not stall once nor did the water temp go over 100'C. Hope this may help your situation as well.




Storer

5,024 posts

214 months

Sunday 22nd June 2014
quotequote all
Thanks for the reply Roe

The set up you describe would not change the areas that I think I have that are causing my issues.
I am sure my issue is caused by the fuel passing over the hot engine and the regulator being at the top of the rear bulkhead.
The amount of fuel in the rail probably needs to be as little as possible to run the engine at WOT so it spends as little time absorbing heat as possible. The regulator does heat the fuel a little as it releases the pressure, but as the fuel that is bled off is not passing over the engine before it returns to the swirl pot, it should see the swirl pot temperature much lower than before.

The down side is the plumbers nightmare that now resides in my l/h side pod.

I may build a new swirl pot with many of the components integrated to remove a lot of the pipework if I have no issues for the rest of summer.


Paul

macgtech

997 posts

158 months

Monday 23rd June 2014
quotequote all
We found issues previously linked to the filters getting too hot (among other things!) - if you think that they are made of aluminium so will heat up relatively quickly, and that there will be a slight pressure drop across the filter during use, it is an obvious area. Once we gold foiled them and moved them slightly the issue went away.

spatz

1,783 posts

185 months

Monday 23rd June 2014
quotequote all
I have put a fuel temp probe in my second built since it is not registered yet I cannot report on fuel temperatures but eager to see how hot it gets

macgtech

997 posts

158 months

Monday 23rd June 2014
quotequote all
You can get sticky labels with a temperature gauge on them that records the maximum temperature they reach - might be worthwhile so you can see which bits get hot. You can stick them on each component in the system to keep an eye on temps. They are a 'one shot' sticker though.

skidiiii

Original Poster:

57 posts

148 months

Monday 23rd June 2014
quotequote all
Storer said:
Thanks for the reply Roe

The set up you describe would not change the areas that I think I have that are causing my issues.
I am sure my issue is caused by the fuel passing over the hot engine and the regulator being at the top of the rear bulkhead.
The amount of fuel in the rail probably needs to be as little as possible to run the engine at WOT so it spends as little time absorbing heat as possible. The regulator does heat the fuel a little as it releases the pressure, but as the fuel that is bled off is not passing over the engine before it returns to the swirl pot, it should see the swirl pot temperature much lower than before.

The down side is the plumbers nightmare that now resides in my l/h side pod.

I may build a new swirl pot with many of the components integrated to remove a lot of the pipework if I have no issues for the rest of summer.


Paul
Hey Paul,
What symptoms did you have when the fuel boiled? Just curious what happened and how long you ended up waiting for it to cool down. Got me thinking as well.... never a good thing;) What about this for a thought. The factory has the fuel reg centered on the bulkhead in very close proximity to the "Ram air induction" scoop. What if one were to integrate a small slot on the underside of the enclosure (I have the forced induction panel installed) allowing for a small amount of cool air to pass over that area. You could easily add a deflector to direct the air when moving. When stationary this should allow excess heat a more direct path out as well. I am currently adding function vents to the 944 track car and this just dawned on me. It would not be any visible change to the exterior and I cant imagine it would affect aero considering the factory considers this an option and not included. Thoughts anyone??

Storer

5,024 posts

214 months

Tuesday 24th June 2014
quotequote all
skidiiii said:
Storer said:
Thanks for the reply Roe

The set up you describe would not change the areas that I think I have that are causing my issues.
I am sure my issue is caused by the fuel passing over the hot engine and the regulator being at the top of the rear bulkhead.
The amount of fuel in the rail probably needs to be as little as possible to run the engine at WOT so it spends as little time absorbing heat as possible. The regulator does heat the fuel a little as it releases the pressure, but as the fuel that is bled off is not passing over the engine before it returns to the swirl pot, it should see the swirl pot temperature much lower than before.

The down side is the plumbers nightmare that now resides in my l/h side pod.

I may build a new swirl pot with many of the components integrated to remove a lot of the pipework if I have no issues for the rest of summer.


Paul
Hey Paul,
What symptoms did you have when the fuel boiled? Just curious what happened and how long you ended up waiting for it to cool down. Got me thinking as well.... never a good thing;) What about this for a thought. The factory has the fuel reg centered on the bulkhead in very close proximity to the "Ram air induction" scoop. What if one were to integrate a small slot on the underside of the enclosure (I have the forced induction panel installed) allowing for a small amount of cool air to pass over that area. You could easily add a deflector to direct the air when moving. When stationary this should allow excess heat a more direct path out as well. I am currently adding function vents to the 944 track car and this just dawned on me. It would not be any visible change to the exterior and I cant imagine it would affect aero considering the factory considers this an option and not included. Thoughts anyone??
Roe

The symptoms were the temperature of the fuel (I have a temp sensor in the fuel regulator) gradually climbing from about 30 deg C to a final figure of 66 deg C at which point the engine was running very rough and stalled. Wouldn't restart.
We spent a couple of hours walking round the show and when we went back to the car the fuel was back down to 28 deg C. Car started first time and ran fine. No problem since.

BTW. The engine never went above 92 deg C and until the engine stalled the aircon was keeping us comfortable inside. The last 15 deg rise in fuel temp was quite quick.

Not sure of the value of adding vents in the air inlet. There is no problem with fuel temp when on the move. If you are stationary then you still want cool air from outside the car entering the engine so any hot air bleeding into the air inlet is a bad thing.

The clips have vents above the engine to let hot air out. Maybe they need to be bigger as the hp these cars now tend to produce (and therefore the heat) is way more than when the GTR was first designed.

I like Jonny's idea of wrapping the filter with gold film and any other items may be a good idea. I might look at wrapping the swirl pot.

Paul

Steve_D

13,737 posts

257 months

Tuesday 24th June 2014
quotequote all
Storer said:
....I like Jonny's idea of wrapping the filter with gold film and any other items may be a good idea. I might look at wrapping the swirl pot.

Paul
Wrapped my swirl pot the other week whilst populating the bulkhead.

Steve

Storer

5,024 posts

214 months

Tuesday 24th June 2014
quotequote all
Steve_D said:
Storer said:
....I like Jonny's idea of wrapping the filter with gold film and any other items may be a good idea. I might look at wrapping the swirl pot.

Paul
Wrapped my swirl pot the other week whilst populating the bulkhead.

Steve
Please tell me there is sufficient progress on the yellow devil for it to be able to make the Factory open day in August.....


Paul

skidiiii

Original Poster:

57 posts

148 months

Tuesday 24th June 2014
quotequote all
Should I wrap the swirl pot since it has been moved away from the exhaust and into the open area behind the RH pod? I understand wrapping it if you keep it as the factory installation manual a few inches from the exhaust, however moving it outward to a cooler environment thoughts would be not to insulate it but dissipate heat. Respectfully as heat rises and the fuel filter is on the bottom of the bulkhead and away from the headers(in my set up) wrapping it would make a minimal impact. (IMOP) However the regulator may be the culprit as it is near the top of the canopy where all the heat is trapped. Its funny if you look at serious GTR track cars they all have holes riddled in the canopy to allow the heat to dissipate. Not sure what else can be done to allow the heat to escape. Would be cool in dead stopped traffic to hit a button that would allow the canopy to open 3-4 inches and let the heat out;)

Storer

5,024 posts

214 months

Wednesday 25th June 2014
quotequote all
Not sure how you would secure the clip adequately. Do not underestimate the forces exerted on the rear clip by the air at over 100mph (25mph is sufficient to open it, as I found out).

Maybe a couple of fans in the rear clip blowing the hot air out of the top!!!

On my way to Le Mans we hit the traffic around Rouen and my friend following in his 911 said the heat haze out of the rear of my car was quite spectacular!!!


Paul

deadscoob

2,263 posts

259 months

Wednesday 25th June 2014
quotequote all
Adding more vents has got to be the simplest way of helping heat escape, I can certainly feel a lot coming out of mine above the rear wheels.
Paul's mention of a fan is good - all modern 911s have heat extracting fans, so one either side extracting to additional vents would work well.

I've added additional rear vents, enlarged the standard rear ones, nimbus heat shield between the headers and tanks, covered the swirl pot in gold foil and run fireproof sleeve over the fuel lines near a heat source and never had any issues.

anonymous-user

53 months

Wednesday 25th June 2014
quotequote all
What you really need is exhaust header "chimneys" These stainless or pressed alluminium tubes run upwards from the exhaust manifolds, and duct hot air straight out the top of the clip. There were extremely effective at reducing engine bay upheat at low vehicle speeds on the Vanquish S i help develop:





note 4 square chimneys, that mate up to matching grills in the bonnet. Exhaust manifolds are encased, with holes on the underside, so cool air is sucked up and into the system, and ejected at the top, without heating the engine bay nearly so much ;-)

Edited by anonymous-user on Wednesday 25th June 13:29