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1997 940 Turbo 300hp setup HELP!

Do you have an AFR gauge in there? I can't tell. If not you definitely need one. Nothing wrong with white plugs, that's a good clean burn. But running lean in boost is pretty much guaranteed going to melt something.

edit: holy crap, okoye was right, those are stock green tops. You need more injector to go along with that bigger AMM! IIRC they need to be ~30% larger than what you would run with a stock AMM.
 
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Invest in a decent wide band O2 sensor and display. Tuning in the sense you are doing it NEEDS an accurate and reliable wide band in order to know what the fuelling is doing. When or if you go for a proper aftermarket mappable ECU you can then run it in closed loop off the wide band sensor. Reading plugs that are run in an engine that is on unleaded fuel is pretty unreliable and meaningless, it was the lead in the old fuels that gave meaningful colouration. You NEED that wide band!!
 
VB242 said:
Googling 558 injectors indicates they are 440cc's, those aren't stock green tops. I still think his MAF is just dirty.
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Even a 440cc is a bit small for 20psi..

With a 3bar FPR and 80% duty cycle you're looking at almost 500cc for 300hp on a 4cyl.

440's are going to be running ~90% D/C for 300hp. Which I guess that's fine and all but if it were me I'd have some 550s in there.

Also yes, clean that nasty ass AMM :-P

edit: but on LH 2.4, with chips and a bigger-than-stock AMM, isn't it recommended to increase injector size proportionally with AMM cross-section diameter to keep the maps playing nicely together?

Edit #2: Okay, math says 440 is just barely under 30% so as long as it isn't running lean injector size seems acceptable for 300hp.
 
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I've found the math isn't exact/linear. There are a lot of assumptions made with the variables.

I'm running 660's at over 20psi on E85, and I'm not leaning out. He'll be fine on 440's (42 lbs) at 20psi on pump gas.
 
It sounds like you have a deadly fuell pump ! Mine was likely the same problems on higher rpm with white spark plugs after i have tested E85 the intank pump dies very quickly... so check the fuell pressure even at higher rpms!
 
turbotankshane said:
The math can't be linear if your variable is a pressure ratio...

Oh wait, turbobricks. Sorry, I forgot.
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Voluumetric efficiency, adiabatic efficiency, brake specific fuel consumption, duty cycles, etc...we're taking shots in the dark and guesstimating when it comes to calculating fuel. None of these are laser accurate or the same for all of us. That's all I mean.
 
440cc @ 3 bar or 4.5 bar

A 440ccm @ 3 bar injector will flow 540cc at 4.5 bar (43,5psi + 20psi).

DMFWallace said:
Even a 440cc is a bit small for 20psi..

With a 3bar FPR and 80% duty cycle you're looking at almost 500cc for 300hp on a 4cyl.

440's are going to be running ~90% D/C for 300hp. Which I guess that's fine and all but if it were me I'd have some 550s in there.

Also yes, clean that nasty ass AMM :-P

edit: but on LH 2.4, with chips and a bigger-than-stock AMM, isn't it recommended to increase injector size proportionally with AMM cross-section diameter to keep the maps playing nicely together?

Edit #2: Okay, math says 440 is just barely under 30% so as long as it isn't running lean injector size seems acceptable for 300hp.
Click to expand...
 
Yea it is the 558 bosch ones, not china copy, Im running a T camshaft and thats also very deadly for my engine im not running it hard at all, all granny style for now :p

Iv installed a new bosch fuel filter and a 044 pump, no difference....... I really think my fuel regulator is ****ed, iv got a steady idle runs perfect, no holding back or anything anymore, my problems with the idle and stuttering went away when i moved the AMM infront of the turbo.

Im waiting on a gauge to measure my fuel flow, now its just down to the regulator or the chips.

The original injectors are turquoise
 
Check your radio suppression relay my car was bogging out on me then wouldn't start and that ended up being my problem. That and a clogged cat
 
Car is now fixed :) I think my main problem was the wastegate lever had come off the turbo so it was doing nothing with my boost preasure, i also replaced the rotor and cap, and the car runs soo good that its pulling loose in 3d gear :p
 
Sounds ready to go hunt and kill some trolls!!!

I always suggest boost leak tests. Pressurize and soapy water. Or smoke machine.
 
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