TXCASE801 Posted October 29, 2009 Share Posted October 29, 2009 1. I have a 78z and i am wondering do you need to replace the stock fuel lines when going to a CARBED V-8? i have looked all over and cant find the answer. 2. will the factory electric fuel pump work or would it be better to go to a mechanical pump? thanks jj Quote Link to comment Share on other sites More sharing options...
Trevor Posted October 29, 2009 Share Posted October 29, 2009 The answer is in the JTR manual. You need a replacement electric pump, and most likely a fuel pressure regulator to provide 4-6 psi fuel pressure. THe stock 280Z fuel pump won't work, and the stock V8 mechnical pump is in the way of the set-back plates for the motor mounts. Quote Link to comment Share on other sites More sharing options...
CJBrian Posted October 29, 2009 Share Posted October 29, 2009 Also Ive read that 3/8 fuel line is recommended. Quote Link to comment Share on other sites More sharing options...
TXCASE801 Posted October 30, 2009 Author Share Posted October 30, 2009 i have the manual, it doesnt say use 3/8" lines. over looked the part about the z fuel pump. thanks for your help Quote Link to comment Share on other sites More sharing options...
CJBrian Posted October 30, 2009 Share Posted October 30, 2009 i have the manual, it doesnt say use 3/8" lines. over looked the part about the z fuel pump. thanks for your help I read it somewhere here. I believe Grumpyvette recommend it. Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted November 1, 2009 Share Posted November 1, 2009 (edited) 1. I have a 78z and i am wondering do you need to replace the stock fuel lines when going to a CARBED V-8? i have looked all over and cant find the answer. http://forum.grumpysperformance.com/viewtopic.php?f=55&t=211&p=247#p247 http://forum.grumpysperformance.com/viewtopic.php?f=55&t=1030 AN4 or 5/16 id line will support up to about 420hp, AN6 or 3/8 ID fuel line will support about 550-600hp if its correctly set up, youll want to jump to AN8 or 1/2" id line if your in the 550-800hp power zone 2. will the factory electric fuel pump work or would it be better to go to a mechanical pump? the factory efi fuel pump won,t generally work, as its producing too much pressure for a carb but if the fuel lines are of sufficient size and you use the correct series of two fuel pressure regulators, it can be rigged to function, but the best results will be thru the use of a pump designed to produce about 7-8 psi and about 130-160gph and a return style fuel pressure regulator that maintains about 5 psi at the carb. READ THE LINKED INFO AND SUB LINKS Edited November 1, 2009 by grumpyvette Quote Link to comment Share on other sites More sharing options...
HICKL Posted November 2, 2009 Share Posted November 2, 2009 To support Grumpy's numbers, I am running a holley red pump and still using the stock Z lines with no current issues. About to change to set up for nos though. See signature for car specs Quote Link to comment Share on other sites More sharing options...
sstallings Posted November 3, 2009 Share Posted November 3, 2009 I don't mean to hijack this thread, but I have a related question. I read somewhere on this forum that I can use the stock '77 280Z EFI pump for my '90 TPI 5.7L, but that the 5/16" line might cause WOT fuel starvation problems. I've just re-plumbed my chassis from the pump to the fuel rails with 3/8" line & AN-6 fittings using a 5/16" to 3/8" adapter at the pump's outlet flex line. I plan to leave the 5/16" return in place since that is what GM used. The fuel pressure will be controlled by the stock GM regulator. Since I've got the engine back out temporarily to secure all the new plumbing, is there anything else I should do while I'm at this? Combo: '77 280Z, '90 TPI 5.7L, WC T-5 AC has been upgraded to Vintage Air; wiring is finally done; suspension mods and brake upgrades are still on the to-do list. Thanks, Steve Quote Link to comment Share on other sites More sharing options...
wonder53 Posted January 2, 2010 Share Posted January 2, 2010 I think this is a great idea..I have a 400 horse 383 that has never run very strong since I put it in my 73. The stock fuel line coming out of my tank is tiny. I think this might be the problem with fuel starvation..I may take the tank out and replace this line and all the stock fuel lines..certainly can't hurt. Quote Link to comment Share on other sites More sharing options...
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