Thread: HQ 396 Coupe - High Country Targa 2012

Thanks guys, all good stuff to think about. I have ordered the 1/2" solid pipe and it should be here tomorrow. The wiring has been tidied up and moved to the other side of the driveshaft and I'm just making up a bracket, a mirror of the other side. It will need a heat shield on the exhaust side but will all fit in there ok.

I stripped the pump and cleaned a bit of fluff out of the internal filter, no other filter at this stage. Pump has only done about 1000k and was as new.

The fuel line from the tank will still need to go up and over the diff but will be about 200mm shorter. I may even be able to make this out of hard fuel line depending on its bendability. This should reduce any flow resistance in the rubber. I will also go through everything and disassemble, test and reassemble as I go. There are no pressure leaks but I will have a good look at the vacuum side even though it's all new.

Another reason I like the Holley is that the pump end is at the bottom and the motor at the top. So much easier to get the pump below the tank.

I will rubber mount the pump this time to try and keep the noise down, could hardly hear the Carter on its rubber mounts.

I have some heat shielding but to be honest everything has been routed well away from the exhaust anyway.

If all goes well it should be running tomorrow without the hard line and with the hard line in the weekend.

Does anyone else run a full length rubber 1/2" hose?

My original intention was to run hard line from the tank to the bay, but it was a bugger to bend up and I could not easily get past the cross members under the car; so now I have braided/rubber from tank to bay and return (runs in the frame c channel) - I have not experiened any issue with this.

Thanks EH179, that's exactly what I have with a small variation. One side of the regulator has the gauge and the other has a 3/8 outlet then a T to each bowl.

Hi Bill, I don't know how successful fitting the hard line will be but I should be able to reduce the rubber line by 1.5 - 2M.

Thanks ffsuc, I did think of running two pumps in parallel but increasing the pressure may work. Are springs or adjustments available and is there any down side?

My wife had a good suggestion ... she said that it sounds like the 'system' is not working and it was a combination of the components that introduces a problem even though each of the components test ok.

I'm kind of working on that theory as a 'B' option, if I keep changing things sooner or later it will work.

ffsuc, may look at switching that around, ez to do.

hq2door, the tank has two breathers (I had Borwn Davis fit a second one) and both are clear.

I have just picked up the 1/2" hard line from GMP and it looks good. Can be bent at quite a tight radius so I will be able to run it over the diff on the vacuum side if I have enough left over. Comes in a 3m length.

So everything is in now bar the hard line. In summary:
• Holley Blue has replaced the Carter Black
• The pump now runs on a relay directly from the battery
• Tank has two breathers both working
• Tank has ½” pickup
• Line from tank to pump is new ½” rubber line with SpeedFlow fitting on tank and brass on pump
• On the pressure side there is a brass fitting in the pump, to a ½” rubber fuel line to the Holley regulator
• The regulator has the gauge on one side and a 3/8” fitting on the other splitting into two 3/8” lines one for each bowl
• The pump has now been relocated to the RH side of the diff and all lines are well away from the exhaust
• The wiring has been replaced an now only services the one pump
• The tank to pump line has been shortened about 200mm
• The pump to regulator line has been shortened about 400mm and a Speedflow joiner removed
• Only using the internal Holley Blue filter atm

So what did we find when we tested it?

Firstly the Holley started with a roar and self-primed in a few seconds. Pressure at the gauge was 9 ½ lbs, a huge improvement on the Carter. I adjusted it back to 7 1/2lbs and checked the float levels and backed off the idle. Everything was looking good so time for a road test …

The car ran well with no overheating due to lean condition and power was GREAT! So headed back to the garage to check the pressure. Lifted the bonnet to find it had dropped to 5 ½ lbs!!! Why Why Why???

I adjusted the regulator back to just over 7 lbs (couldn’t do this with the Carter) and locked it off at that. This will mean that it will have about 9 lbs on cold start up, not the end of the world but still frustrating. I remember back now that the car has always had a tendency to fowl plugs on cold start up and on two occasions I have had to replace plugs due to this problem. My guess is that the pressure has been set at 7 ½ lbs at operating temperature and has always been 9 – 10 lbs on cold start up causing the difficult starts.

I checked all of the components and nothing was hot.

Next is of course the hard line pump to Reg to reduce the resistance of the rubber. I could change the brass fittings on the pump to Speedflow? Then there is the idea of reducing the internal bypass of the Holley with adjustment or a heavier spring. Or I could go to a Holley Black and a return line. Or just plumb a return line and some sort of Reg with the blue. Or get a regulator that actually regulates to a pre-determined pressure as opposed to the Holley reg that seems to be just a pressure reducer.

Agreed and I hope that is the case with the pressure line. That means it will be fixed when I fit the hard line.