nickz32

It's deffinatly something I'm considering. My supply and return lines have extra insulation where they come up the from the underside of the car and past the down pipe and turbo. The routing of the lines has been the biggest challenge with the new setup, aswell as deciding on the location of the FPR. I could relocate the battery to the boot and use that space for the FPR, but frankly I couldn't be arsed with the ball ache!

Yeah I went through all those changes aswell as a part of the diagnostics sessions I had on the dyno. Changed the wiring to the pump to thicker gauge (hence that extra connection on my tank lid in one of the pics) and bypassed the FP controller, changed where we took the vac feed from, different sized vac lines, different pumps, different fprs Trust me when I say I've spent much much much more money trying to diagnose the issue than I have on replacing the fuel lines!

Yeah spoke to Greg and Mitch at EPRacing, both agree that what I'm saying is entirely feasible. There do seem to be some exceptions to which I've found, which I can't explain. However I would say that it's not an issue that's directly linked to power levels, it's more around pressure requirement. Obviously a larger turbo will make more power at a set psi compared to a smaller turbo. It's also worth pointing out that in the vast majority of cases with in tank pumps, as pressure requirement goes up actual fuel flow reduces from the pump.

Because our fuel tanks are designed to pressurise and the pump is submerged it's highly highly unlikely. I suppose you could say that if it was occurring on track with rapid changes of direction that it could be fuel starve from the fuel sloshing around in the tank, but all my testing and data is from dyno time where the car is effectively motionless. I feel it makes more sense with the data that's available that the fuel is vapourising as its drawn into the pump itself, causing the cavitation and loss of delivery

Cheaper, no. Larger hard pipe may be cheaper to buy but requires a more expensive type of fitting. Easier: deffinatly not! Routing the braided lines was a simple task that took very little time. Having helped my motorsport friend fit 12mm hard pipe fuel lines to one of his race cars, it's a ROYAL pita, very time consuming and you make one wrong bend it potentially ruins the whole section of pipe.

Wide open throttle. Now while it could be suggested that I simply don't boot it with less than a third of a tank of fuel, that simply just isnt acceptable to me. if I'm driving down a country road and want to overtake a car, I don't feel that having to glance at the fuel gauge first before making the manoeuvre is something that I even contemplate having to consider in such s situation. It wouldn't be acceptable to a company that releases a 500hp car, so it isn't acceptable to me.

I ordered 3 meters of AN6 and 9 meters of AN8. I've probably got half a meter of AN6 left and maybe 1.5 meters of AN8 left over. It was the fittings that were the most expensive part, about double what the piping costs.

Ive not finalised the underside yet. The pipes run along the carbon cannister pipes (I still use mine as I was getting noticeable fumes after hard runs) but it's all nicely protected like the stock lines

Unless your planning on running 35+psi of boost, you shouldn't need such a pump. I still have an AEM pump in my car and I'm confident it's capable of delivering the amount of fuel I need. The main point that I'm trying to make with this thread is this. While there are plenty of example of high (500rwhp plus) cars running stock fuel lines, it isn't with undesirable side effect and potentially serious consequences. At best they suffer pressure drop at low fuel levels, at worst they eventually run lean and blow an engine.... Like me. In the grand scheme, when those of us are spending thousand of pounds on speccing high horsepower engines, to the not consider auxillery parts like fuel systems may prove naive. Another £400 quid on a £6000 bill is nothing. I'm guilty of it, and it cost me a forged engine. I'm hoping that those of you that potentially high hp builds, or are considering them in the future, will consider this advice and take a moment to consider their entire setup not just the physical engine. The above is why I went to a Haltech. If something goes wrong, I now have the right sensors in the right places to identify these problems and an Ecu that is capable of saving the engine should I encounter issues. Those of us who ran a mapped stock Ecu wouldn't know about these problems without a fuel pressure sensor and a capability of data logging. Fuel pressure gauges just don't cut it, as evidenced by this article http://www.adaptronic.com.au/fuel-pressure-regs-is-there-much-of-a-difference/

I decided to uprate the whole fuel line setup with braided hoses and AN fittings. This cost me a total of around £400, which to be honest is a drop in the ocean compared to the rest of the engine build! Having conducted many hours researching chose to run AN8 fuel lines main feed from the tank, split into AN6 lines to feed the fuel rail in parallel, back into an8 to the fuel pressure reg and an8 back to the tank. Being braided, they're more insulated than stock lines. Further more, as they have a large cross section, less heat can be absorbed by the fuel. It was best described to me as this. If you pass X amount of fluid through a thin walled small diameter pipe over a heat source, the temp of the fluid will be higher to that of the same volume of fluid passed through a larger walled pipe with a larger cross section. Over the same distance using the above sized piping, I will only get a 0.7psi pressure drop across my system. This option will kill two birds with one stone. Less heat soak from outside heat sources, less pressure drop meaning the pump doesn't hawork as hard to create the volume and pressure I require ve to The first part I modified was the fuel tank lid. I had an AN8 boss welded on to the existing exit pipe on the tank lid. I also drilled out the return pipe and fitted an 90 degree an8 bulkhead fitting. I then fed an8 lines down the underside of the car, fitting a slimline 30micron fuel filter inline under the car. For the fuel rail, I cut the ends and OE feeds off the OE fuel rails (my car is a 1995) and had an6 bosses welded on the end of each rail. The reason I chose to do this vs aftermarket rails was after speaking to some of the big guys in the states (ep racing, specialty z) there is very little if any flow benefit with aftermarket side feed rails. The main reason people fit then is to end able the fitment of later style injectors. Being a late car, I don't have this issue, so modifying the stock rail for significantly less £££ made more sense to me. This is the system all complete (return was plumbed in after this pic was taken) I've got a few more things to sort on the car before it goes back on the dyno, so I will be able to report back with the final results, but I'm confident in my theory, which should result in a consistent fuel pressure, lower fuel temps and I can use more of the fuel in my tank without fear of sudden pressure drops

So as some of you know, for the last year or so I've been rebuilding my Z after having an engine failure at Vmax back in 2012. The aim of this rebuild has been to make the setup more efficient and rectifying what I believed contributed to the engine failure. The physical engine rebuild was completed late last year and it's been on and off the dyno (over 1000 dyno miles and 280 litres of fuel) since the beginning of the year. The main source of my issues has been around fuel delivery and maintaining fuel pressure. After going through a couple of fuel pumps and fuel pressure regulators (all of reputable brands like AEM, Tomei and SARD) and testing my Nismo 740's to find no issues there, I decided to further investigate other aspects of the fuel delivery system. At peak boost I required a fuel pressure of 66.5 psi (43.5psi base plus 23psi boost) at a minimum of 240lph The main symptoms I was suffering with were: Sudden fuel pressure drop (down to 1 bar at times) when fuel level was below 1/4 tank Fuel pressure differential not holding a consistent 3bar Fuel temp hitting 50c higher VE numbers than expected on the VE map The OE fuel lines on the Z of a 8mm bore with a lot of 90 and 45 degree bends in the system an is near as dam it 4.5 meters from the exit pipe of the tank lid to the FPR. I spoke to a friend of mine who works in the motorsport industry who did a fuel calculations for me around the delivery capability of the OE fuel lines. The maths showed that at 67psi and attempting to flow 240lph through an 8mm bore pipe along a LEVEL AND STRAIGHT (important point) there would be a 15.2 psi pressure drop from end to end of that section of pipe. That pressure drop is then increased for every bend that is put into the pipe and any changes of elevation in that pipe. Realistically there is potential of a 20psi pressure drop along stock fuel lines at the fuelling requirements I needed. This means that for the FPR to maintain 66.5psi at full boost, the fuel pump has to generate a minimum of 81psi of pressure and still deliver a minimum of 240lph (which if you look at the AEM 320lph pump, it can't deliver that much fuel at that pressure!) But the problems don't stop there. Heat is the next issue. None of the stock fuel lines are insulated, so heat soak can become an issue. But that's not the only source of heat. At that pressure, the friction of the fuel being forced down a skinny pipe heats up the fuel. On top of that you then have a fuel pump that is working absolutely flat out, so the fuel heat soaks as it passes through the pump. This is where a viscous cycle becomes apparent. As your fuel is heated up as its pushed through the pump, down the fuel lines and into the engine bay, only a small amount of it is used in all but WOT situations. What fuel isn't used is returned to the tank via the FPR. No while this isn't a huge issue when you have a near full tank, as the volume of fuel in the tank is able to absorb that heat with very little increase in temp to the rest of the fuel in the tank. However, when fuel levels get lower, there is less volume to soak up the heat of the fuel, causing the remaining fuel to slowly get warmer and warmer and warmer. Based on the data I have collected from my data logs there is a direct correlation between fuel pressure and fuel temps, in that when the fuel gets above 40c fuel pressure becomes more and more unstable. Once into the 50c area is where sudden pressure drops appear. This ONLY happens at fuel levels below 1/3 tank. My theory is that at those fuel temps, the fuel pump begins to cavitate, which is what causes the sudden drop in fuel delivery and pressure. There appears to only be two viable options to solve this problem: 1. fit a fuel cooler 2. Increase the size of the fuel lines. Which leads me to my chosen solution for the problem.....

I actually find drying puts more swirls in than washing to be honest mate. From those pics, they look like really fine swirls, so you I would guess you won't need a cutting compound to get rid of those at all. A straight polishing compound should clear those up no problems. Just take your time and make sure your properly prime your polishing pads

I'll be there Nick/Nickz32

I am going to write a thread in the future about what I have found about the stock z fuel system, but I need to complete my new setup to make sure my theory to resolve the flaw is actually sound. Once I can prove my theory I'll post up

Clearly out of practice with this forum malarkey, was meant to be quoting Birds post about him being a little worried

As long as you don't run under a 1/4 of a tank at WOT, you should be ok

1995 LWB TT Manual - - - Updated - - - JDM of course

I spoke to him today. He's in finer spirits today and has had all the ops he needs for the foreseeable future. Luckily his knee joint escaped unscathed and the rest is skeletal damage that been pinned and plated with a couple of skin grafts to boot. He's hoping to out of hospital fairly soon once he's got a bit of mobility back

Lee, keep it simple mate. First of all I WOULDNT lock out your hicas just that. The car is a ROAD car not a track weapon or drifter (where the argument around hicas delete is made). The HICAS (when properly working) gives you low-mid speed agility and high speed stability. If you want to be able to get the correct geometry settings you need the following FRONT Adjustable upper control arms - camber FRONT adjustable tension rods - caster Rear adjustable control arms - camber That's effectively all you need for a road car. There are then NUMEROUS modifications to change various aspects of how the car feels/responds/behaves which can be done at a later time. - - - Updated - - - *hicas just yet. (Poxy auto correct)

Going with my two besties, one in a Gen 1 Legacy turbo with a 2.5 forged engine I built and the other in his 83 Porsche 944 that I'm helping him refurb. There will deffo be pic and hopefully a bit of drone footage of us on some of the passes. Si told me all about your trip, pics were superb

It's only a quick 5 day jaunt. Spending 3 days in Brig in Switzerland to spend time exploring as many passes as possible (Grimsel, Furka, Gotthard, Susten and a couple of others) then up to the Ring for a couple of days. I've put off a trip to the Alps and the Ring for too long, decided while it's not the big 2 week 3000 mile road trip I've had planned for the last 6 years, it's better than nothing!

Varrstoen MK2 (CZP are a varrstoen dealer)

Personally can't stand Pirelli's, regardless of how good they are in the dry (pilot sports are better imho) the last set of p-zeros I had on the z were frankly dangerous in the wet. Never ever will I have a car shod with Pirelli! Potenza S02 is still the best tyre I've ever had on a Z, but ultra rare now. I'd love to run Pilot Sport 2's, but I don't have a spare grand that I'd need for my tyre sizes. Running Falkens at the moment. As mentioned, a good mid range tyre. Don't have the most outright grip, but the manner they behave when they lose grip is progressive and predictable in my experience.

I get back from my euro trip a few days before, so as long as the car makes it back unscathed, I'll be there

Feature wise, it doesn't seem to bring anything new to the table