Modena's progress update

[LoBelly]

w00t

(I think you're being stalked by a Daytona)


LB

[Aussie Mike]

Congratulations Ben. Two huge milestones in one weekend! First start and first drive!

Cheers

[stephen low]

Well done Ben, that's a huge step forward.

How did the string lined alignment feel?

I'll catch up with you so I can understand how that is done for my car.

Bet you are still grinning too!!

Ciao

Steve

[Gav]

Nice work Ben, my pressure pump was very loud until I rubber mounted it.

[guye]

Originally Posted by stephen low

Well done Ben, that's a huge step forward.

How did the string lined alignment feel?

I'll catch up with you so I can understand how that is done for my car.

Bet you are still grinning too!!

Ciao

Steve

Agreed. Sounds like a excellent activity one summer club meeting night!

[Modena]

The post-start tinkering has begun. Tonight fixed the brake fail light (just needed a bit more fluid in each master), made a rad hose support (still to do one more) as the silicon rad hoses are a little droopy when hot.

Earthed the oil temp sender body as it was not getting earth in the anodised aluminium AN fitting that it sits in.

Slowy the alignment is fine, she drives straight and true (around the block anyway!)

[Modena]

Have fixed some more things. I did not have sufficient earth tie-in points in the electrical system. This manifested as a water temp gauge that read about 10 degrees higher than the ECU was reporting, and when the thermo fan or headlights switched on the extra current sent the water gauge instantly over 130C. I added two more 6mm earth tie-in points to the chassis, near the thermo fan and one at the fuel pumps, and now gauge readings match the ECU and give zero distortion even under full electrical load with everything switched on, it still has 14.1volts even with everything switched on and music/amp going as well.

thanks sideshow for your help.

the fuel pump seems a bit quieter now, maybe it had some air in it, the car has had 4x15min idles now since last weekend. It's still loud and will rubber mount it this weekend also.

the list on the whiteboard is getting smaller and smaller. Next drive on Sunday.

[Gav]

You can't have too many earths.
I have just used 'bobbin' style mounts that have an M6 stud either end to mount mine.

[gjkrv8]

Originally Posted by Modena

Next drive on Sunday.

Sat weather is looking good too Ben :-)

[boxhead]

Update please....

[Modena]

I mounted the high pressure pump to rubber on both sides off the boot wall and it is heaps quieter now. Went driving, out to an industrial estate about 5 kms from home, give it a bootful through second to get some speed up and test the brakes a few times. They work good

These KU36 are really sticky, you have to be seriously on it to even look like locking up. Got a couple of chirps out of the right front, will leave the balance bar where it is for now. This thing stops on a dime. That's the good news.

I drove for about 15 minutes then headed home, but nearing home the pump started to sound funny and fuel pressure started to drop.....it went down to under 30 before I pulled over as it nearly died. The low pressure pump was cold. The high pressure pump was just slightly warm to touch. I waited 30 minutes, then it fired again with 54psi and I got half way home before it happened again - when I switched it off I could hear gurgling like the surge tank emptying or some sort of vacuum going on or something.

Fuelab have been helping me via email with the noise and they told me my HP inlet from surge tank to pump was too small (-6) so I upgraded that to -8 after having the pressure problem, but still the pressure drop after driving remains. When it happens I can hear the high pressure pump starting to cavitate like the surge tank is out of fuel. I can only reason that this is whats happening, the car will idle forever will no problem, but after driving a few mins it seems the surge tank is emptying.

I have the test data sheets on the pumps, the HP pump is 70gph at 55psi, the low pressure pump is 120gph and there is no regulator on the LP pump. Both pump are running low speed mode (these stats are for low speed mode).

The line from tank to low pressure pump is also -6, and it has a strain filter on it, next step is to upgrade that to -8 and maybe a -10 strain filter.

Fuelab also tell me the overflow line from surge tank to main tank is too small (-6) and could cause a vacuum lock. I can't upgrade this without major work as the fitting on the tank is welded -6.

[Tenrocca]

I reckon the -6 return should be fine. Are you 100% sure the low pressure pump is running all the time? Maybe there is a tank breather issue does the tank suck in air when you release the cap - and most obviously have you got plenty of gas in there?

[Modena]

opened the gas cap yesterday as soon as the issue occurred, no pressure pop. This was when I could hear gurgling but stuck my ear at the open gas cap and could not hear anything so it must be the surge tank gurgling, and it did sound like it was coming from that area.

There is now about 15L in the tank, I don't think this is a problem because when the drop happens if I let it sit for a while then it will be fine again.

both pumps run off the same relay and the same 6mm wire and 6mm earth.

[Aussie Mike]

I've got a #6 inline fitting for a gauge port lying around. It might be worth putting it in line with a pressure gauge attached and seeing what sort of pressure you have in your swirl pot. I'd been told it's good to have about 2 PSI pressure in the swirl pot and this can be achieved by putting a restrictor in the return line from the swirl pot to the main tank.

With the swirl pot partly pressurized you will always have positive feed to the pump.

Cheers

[stephen low]

Ben

Until I changed to an in-tank system I had a similar issue and though never really confirmed believed my in-line filter may have been too small and essentially throttling fuel supply at high demand.

For me the engine would die at any modest speed but on restart after a crank or two would fire straight up.

Sounds possibly similar.

Just a thought!

[gjkrv8]

Ben, I just had a look at my Surge Tank diagram. I have the following:

-8 from Tank to -8 to 1/4 NPT barb to Carter LP Pump
From Carter LP Pump to 0.6L Surge Tank is 1/4 NPT to -6 barb and 8mm hose

From Surge Tank to HP Bosch 044 is 12.5mm hose then EFI filter and then -6 to Tee/Reg

Pretty well all -6/8mm hose etc everywhere else.

Been on the track Wakefield and Winton ok. And road ok.

I'll attach a diagram or email to you.

cheers

Gregg
p.s. I have spare Carter LP and Bosch 044 if you need em. (I just bought the spares as one of the pumps sounds a little "different" lately - just being cautious)

[Gav]

I have used 8mm hose everywhere apart from the feed from the swirl pot to my HP pump which is 12mm.
I have no restriction back to the main tank, perhaps I should though.
I have only had gurgling sounds from the fuel system once after a drive on a 45 degC day, I put it down to the fuel boiling!
Mine doesn't do many k's but it hasn't skipped a beat when it has been on a decent run in the current configuration.

[Towmaster]

I just use -8 fittings & hose everywhere in my fuel system. Carter lift pump & 044 but mine (Ford) only uses 42 psi max.
The Supercar runs twin Holley red lift pumps (one from each side of the tank) all -8 into the 5 liter surge tank then through an 044 (two actually, one main & one reserve , only one runs at a time) then through the -10 lines to the engine then splits to two x -8 feed to the fuel rails...
I'm guessing -6 should supply enough fuel really for what you want.

[gjkrv8]

Hey Ben, does your Fuel Pressure Reg "pressure bleed offload etc" go back to your Surge Tank or Fuel Tank?

It goes back to the surge tank on mine.

I was thinking your EFI was draining the Surge tank and not bleeding back to it (Surge Tank), but bleeding back to the Fuel Tank etc??? Maybe the LP pump isn't able to fill it quick enough with the HP pump draining it??

Just a dumb suggestion

cheers

Gregg

[Modena]

everything goes back to the surge tank, surge tank overflows back to main tank. Am going to upgrade low pressure pump inlet to -8, and will also check voltage at both pumps.