popping through the exhaust at 4500 rpm or so.. HELP!

[Zedyone_kenobi]

Well just ordered my 40mm DCOE's from MSA. Got the holley regulator, but still need to find a good quiet low pressure pump.

Looking at several right now. Mr. Gasket, Mallory, Aeromotive, etc.

I also plan to use the return line back to the tank as well. Does anybody sell a custom three carb fuel line for Datsuns.

[steve91tt]

I'm a big fan of the OEM RX7 electric fuel pump. I run it on my L30 track car and on my bone stock L24 and never had an issue with fuel supply. It is very quiet inexpensive solution. I can't hear the pump when the car is running.

[Zedyone_kenobi]

I found a carter pump I liked with bushings for vibration and sound insulation. It looks very much like the OEM electric pumps in the 260 or 280 Zs. It puts out 4-7 psi.

[Mike W]

I also run triple Webers (40DCOE's), but had to fabricate the fuel line that I wanted from individual components. I could not find anything that was off the shelf that met the design goals that I had, including the use of all stainless steel braided lines. I have the whole design documented as well as a bill of material if you are interested. This includes not just the fuel lines, but also the pump setup and regulator that I used.

I am not familiar with the Holley regulatr that you selected, but I do know that when I was researching my system there were distinct differences between regulators that required a return line and those that did not. If you plan to use a return you might need to check on the capability of the regulator that you selected to ensure that it supports a return line. I've attached a few pictures of my setup for your reference.

I also agree on the sidedraft central forum. I've only posted there a few times but the folks were very responsive and ultimately solved one the problems I was struggling with. Some very informed folks over there.

Mike.

[Travel'n Man]

Be sure to review the thread below - you can find a single non-return/deadhead fuel line with three fuel inlets and heat shield in Japan with ease of ordering and shipping (contact info included in link with pics). I have had absolutely no issues without having a return line no matter what RPM. I was very concerned with this when I was doing my install but now......not a second thought about it. I have not had to drill any holes in my Mikuni's (per the above message about the Webers) - they have been dead on fantastic since day 1.

Be sure to think about a primary fuel filter back at your tank, it's even more important to make sure there is no trash going into your needle valves since you will soon to have 3 of them at one time. My install is well documented in "my garage" if needed for reference.

http://www.classiczcars.com/forums/showthread.php?42045-Wolf-Creek-Racing-Mikuni-40-s

[Zedyone_kenobi]

Mike W

What are your choke cables going to? It looks like you fabricated some sort of improvised choke. Can you enlighten me on that.

[Mike W]

The Webers do not have a choke circuit per se, but they do have an enrichment circuit that will help during cold starts. The choke cables are the original OEM cables that I cut so that I could use them to engage the enrichment circuit on a dead cold start. That is what you are seeing.

I will say however that for the most part, I never really have to use them especially given the weather here in Texas. I find that typically on a cold start, all I have to do is pump the carbs a few times and the accel pumps provide sufficient fuel to start the engine and so the effect of the chokes is not really necessary Since I have taken this picture, I have actually removed those cables and cleaned up the engine compartment a bit. I also replaced my center console recently and wanted to avoid the console cracking issue where the choke assembly attaches to the console so at least for the time being I have taken them off.

When you do go to the Webers I would strongly recommend removing the stock throttle linkage and replace with a throttle cable. This is probably the single biggest improvement that I have made to the Weber setup as it makes the drivability of the car so much better. I used a cable setup from Lokar and would be happy to provide more details on what I did if you decide to go that route.

Hope that helps.

Mike.

[Zedyone_kenobi]

I was hoping to keep the stock throttle rods in use. But I have noticed many go with the cables. Can you provide some information on what makes the stock linkage so hard to drive?

Thanks again Mike.

I am planning out my fuel system. This is almost as much fun as carb tuning. I really love building custom stuff!

[LeonV]

Mike, I really like the way you set up your throttle return springs, I may have to copy that! I've been considering a throttle cable as well so I wouldn't mind seeing some more details. Nice job!

[Zedyone_kenobi]

UPDATE:

I have been ordering things feverishly. MSA is out of stock on the Webers, it will take 2-5 days for them to get them. Oh well.

IN the mean time, I may have found something that may shed some light into the weaker spark theory. I will hold off my thoughts until I test it when I get home tonight though. But if I fixed it last night, this could be the biggest waste of 18 pages in the history of Z car club.

[madkaw]

Oh great-leave us hanging

[Zedyone_kenobi]

It is so dumb, that I would be ashamed to admit it unless it is the actual problem.

Yes, suspense thrillers keep the audience enthralled