righto, i'm gonna get serious about the fuel system for the Z18ET.

as far as fuel regulators go, given that i'm aiming for a max of 250 engine hp, will the malpassi 1:1 rising rate regulator be ok, or should i go 1.7:1? and are malpassi good regulators?

what high volume fuel pump are people using? at the moment i'm using a pissy little electric fuel pump that feeds a vl turbo high pressure pump. should i go a carter high volume pump?

i'm really hoping the pinging is due to leaning out and not too high a compression ratio....

_________________
1971 Datsun 1600 - Z18ET
1996 Suzuki RGV250 VJ22
1996 Suzuki RGV250 SP VJ23

If you get a rising rate that is more than 1:1 then you are increasing the fuel pressure dynamically as you get boost. That is, your fuel pressure will increase beyond the backpressure by the air pressure meaning that the pressure differential across the injector increases with boost meaning that you are more likely to bugger the spray pattern.

You should have a surge tank already I hope.

I have a carter 110gph pump. No complaints except its damn noisy. Like twice as noisy as the 044.

Whats your timing like? What engine/head? What boost? What CR?



Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

what if he was to use larger injectors than needed for his appilcation. that would not destroy the spray pattern. what the benefits would be has got me f*ked

I hear that, those carters are louder than a lot of exhausts, especially if mounted badly. On the plus side they flow a lot of fuel, are reliable, and rebuildable.

Like thehelix said, rising rate regulators dont seem to be such a great idea if you are really getting serious about a fuel system. Better to select injectors that will flow your required hp plus a bit in reserve so you arent getting up near 100% duty cycle and have the correct pressure across them at all times.

i have got a surge tank, but i got a boiler-maker mate to make it for me out of stainless steel. it leaks and it's only got a 'live' volume of about 500mL so i'll either get him to fix it or buy an off-the-shelf item

i'm running the standard Z18ET. i had the block bored, the head welded up and ported, bought new pistons, rings, bearings etc then i put it all together myself.

the boost pressure according to vaughan's boost gauge is 5psi

i have no idea what the C/R is and believe me i'm kicking myself that i didn't calculate it before i assembled the engine - i just assumed it would be ok. can you tell whether a static C/R is too high from pressure gauge readings? i'll take some measurements tonight.

i believe the timing is set on 11deg, but to cut a long-story short, a workshop set it for me.

there is a diaphragm on the side of the dizzy which i have no idea what it does, but it's not connected. could it be an ignition-retard diaphragm for when the engine comes on boost?

_________________
1971 Datsun 1600 - Z18ET
1996 Suzuki RGV250 VJ22
1996 Suzuki RGV250 SP VJ23