4 Cylinder Turbo = How to wire Staged Injectors?

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4 Cylinder Turbo = How to wire Staged Injectors?

Postby KDW » Tue Dec 26, 2017 3:50 am

I have a 4 cylinder engine...planning to go 700 plus HP...so I need my fueling ready. This is for my friend and has no large budget for his project.

Staged injection is new to me so I hope many can help :?
Primary Injectors are 4x 550cc(high impedance) and currently on alternating 2 squirts on MS1( MS2 upgrade is also an option since i have the MS2 processor in stock)....when we swapped in our brandnew Bosch 1680cc with part number 0280150842 light blue tops with resistor pack,...as in the hopes for just using these set of injectors and no staging at all...... we cant tune it right, the engine runs really bad even with maintaining 11.5 AFR(jumping). So we reverted to all 4 550cc's and the engine runs good again

So now im planning to use staged injection...using the 550'c as primary and using the 1680cc's as secondary(will mount the 1680's under the intake manifold

My question is:
=Is there a hope of using only 4x1680cc's(no staged injection)? But Ive read they are bad injectors at idle for a 1800cc engine
=If going staged, how do i wire the 4x 550cc high impedance injectors? all four in parallel connection only to Bank1? and then select simultaneous injection, 1 squirt? will it not overload the transistor driver in megasquirt V2.2? Then the secondary 4 x 1680cc injectors with resistor pack also in parallel connection to bank 2 of megasquirt V2.2? will it also not overload the injector driver transistors in megasquirt V2.2?

Note: Im using a Miata CAS in wasted spark mode(no crank triggers)

Thanks in advance for your inputs :)
KDW
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby prof315 » Tue Dec 26, 2017 6:11 am

:roll: Seriously? For starters upgrade to an MS2 V3.0 at an absolute minimum. That way you'll have PWM current limiting available for the Low-Zs. Better still use an MS3/3X and use the 3X drivers for primaries and the mainboard drivers for secondaries.
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby KDW » Tue Dec 26, 2017 6:18 am

prof315 wrote::roll: Seriously? For starters upgrade to an MS2 V3.0 at an absolute minimum. That way you'll have PWM current limiting available for the Low-Zs. Better still use an MS3/3X and use the 3X drivers for primaries and the mainboard drivers for secondaries.


MS2 is an option, but MS3..he has no budget for that. Also V3 board ...I also have a on hand stock...so I can also have my friend use it. So if using a MS2 with V3 board...how do i wire the injectors? For the Low z injectors..I already have the resistor pack

Thanks for the input ...
KDW
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby jsmcortina » Tue Dec 26, 2017 6:25 am

Section 4.10.3in the Hardware Manual covers this.

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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby KDW » Tue Dec 26, 2017 6:45 am

jsmcortina wrote:Section 4.10.3in the Hardware Manual covers this.

James

I think I have read that already yesterday, I will double check...as i know some of my questions are not answered there...
I will check again

Thanks...
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby KDW » Tue Dec 26, 2017 7:22 am

KDW wrote:
jsmcortina wrote:Section 4.10.3in the Hardware Manual covers this.

James

I think I have read that already yesterday, I will double check...as i know some of my questions are not answered there...
I will check again

Thanks...


Ive read that...I just want to confirm these questions: because.....

Q1 = If 4x injectors in a single bank(Bank 1 for all 4x primary high impedance injectors) is installed the resultant total impedance is 3.8 Ohms. Ordinary install is where one injector bank handles only 2x High impedance injectors which results only to 7.2 ohms. So the question is...can a single Injector bank handle a 3.8 ohms load(total impedance of 4pcs high impedance injectors measuring 14 ohms in one injector) Can the injector driver handle this 3.8 Ohms load with out the transistor failing?

Q2 = I need to select "Injector staging" from alternating to simultaneous right? how many squirts?

Many Thanks...
KDW
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby racingmini_mtl » Tue Dec 26, 2017 10:58 am

Yes and yes. And 1 squirt simultaneous is equivalent to 2 squirts alternating.

Jean
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Re: 4 Cylinder Turbo = How to wire Staged Injectors?

Postby KDW » Tue Dec 26, 2017 11:10 am

racingmini_mtl wrote:Yes and yes. And 1 squirt simultaneous is equivalent to 2 squirts alternating.

Jean


Many Thanks :) :D
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