More boost with out adding fuel.

[nickmcdonald]

Hi all. I have myself a QD32eti R50 Terrano. I'm looking at adding a few basic parts to warm her up a bit, mainly a turbo back exhaust and winding the boost pressure up a tad. Now I'm looking at maintaining it's fuel economy, so I'm trying to get away with not upping the fuel delivery. Is it possible / advisable / beneficial to increase turbo pressure slightly, say 2-3 psi without needing to add more fuel? Obviously you have to keep the fuel / air ratios in check, but will a little bit more add a few ponies without requiring the fuel pump tweaked? Or am I thinking about it the wrong way? Diesel hot rod experts get at me! Cheers.

[BlakeNZ]

i'm not sure you can turn a screw to adjust the fuel delivery on those "Eti" pumps anyway.
IMHO 2-3 psi wont hurt.
My mistral ETi is running 15 psi with no fiddling.

[BlakeNZ]

BTW , a KZN185 SURF that belonged to one of this forum members gained 6-10% better fuel economy when the stock exhaust was replaced with a 3" down pipe and exhaust. So perhaps there will be gains for you too?

[nickmcdonald]

Yeah I'd imagine a free-er flower exhaust would take a bit of load off the engine, hence a small boost in economy. Exhaust plus a few extra psi should wake the thing up a bit!

[tweake]

Obviously you have to keep the fuel / air ratios in check,.........

no need to to, diesels don't work that way. you basically can't run to lean, its running to rich thats the problem. so you can chuck in as much air as you like but its to much fuel is the issue.
a couple lb boost certainly will not hurt anything.
i would fit a ball and spring boost controller. that will help get boost up earlier and make it better to drive.
but your not going to get real power gains until you increase the fuel.

3litre surfs are known for restrictive dump pipes. i don't know with nissan qd32eti.

[Crash bandicoot]

as above,

3 inch dump, 2.5 inch exhaust, no use cranking the boost as the hot wire AFM will max out anyway once you hit 15 psi and throw up fault codes.

best thing to do is to remove the egr system and service it every 5000kms and it will out last the chassi.

[nickmcdonald]

Ah yes Ive been looking at giving the EGR stuff the flick. Do QD32's gunk up like the ZD30's do? I've seen the pics of ZD30's absolutely rammed full of oil and gunk build up, all through the inlet manifold, intercooler etc. And Crash, 3 inch down pipe, with a 2.5inch exhaust ya reckon? You wouldn't go bigger on the exhaust? Or is there a pretty good reason to keeping it at 2.5 inch? Cheers for the feedback guys, interesting stuff.

[Crash bandicoot]

Cost vs benefit. You cant really do much to increase the power significantly with out spending mega dollars on aftermarket ecu or mechanical pump swap an tune....there for going 3 inch on a engine that is pretty much stock is pointless when the cost of 2.5 is significantly less and no noticable difference in performance. Where you can get better performance and fuel consumption is making it easier for the turbo to do its job sooner. Hense i said 3 inch dump. Vs the cast iron dogleg that is there you will notice the power ban start sooner in the rev range.

[Crash bandicoot]

Egr is there purely to force the engine to digest its own emissions. Now i dont know about you, but craming carbon an hot gas back into the intake isnt my idea of of clean air and fuel burn.

[tweake]

Ah yes Ive been looking at giving the EGR stuff the flick. Do QD32's gunk up like the ZD30's do? I've seen the pics of ZD30's absolutely rammed full of oil and gunk build up, all through the inlet manifold, intercooler etc.

the ZD30 is a bit worse. they where the first of the high flow hot egr engines. tho there should be no gunk in the intercooler. that may have been oil from the turbo or breather.
but generally egr will clog up things up eventually.