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L28 NA Fuel Injection Upgrades.... Confusion


MidnightRider

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So I know there are plenty of options for upgrading the fuel injection of an L28, especially L28's with turbos. I've searched around and I can't really find much on upgrading injectors on an NA L28. I have an N42 Head with a Schneider Cam. The car sat for 20 years so I'm thinking the injectors aren't as good as they used to be, everything but the intake manifold has since been rebuilt.

 

What injectors will fit and be appropriate my engine?

 

Are Supra, GM, Audi, and RC injectors ok for an NA car?

 

What number of CC's would I want?

 

Any Suggestions for a specific injector + rail set up?

 

 

 

Also:

I want to go to an aftermarket fuel rail but don't know where to start, I can't seem to find much on it, it mostly seems to be a thing for turbo cars.

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You can ask pallnet for a fuel rail. Is this is a stock motor? I remember seeing a yellow 280Z at Sunrise Z that had a 3.1 stroker in it an 11:1 comp. He was running EDIS and Megasquirt and a Lonewolf intake. Made 270ish to the wheels I think and he was running supra injectors.

 

What exactly have you done to your engine that makes you think you need bigger injectors? we need cam specs.

 

If its the stage 2 that msa sells you can use stock injectors with it.

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The motor:

Stock Pistons, Crank, L28 Block,

6-2 Headers

The cam is the one from MSA, stage II

Specs: Grind: 17033. Lift(In/Ex): .480/.480. Duration(In/Ex): 274/274

 

Basically, it's not slow, but doesn't feel as fast as it should, especially after a rebuild.

Getting the timing right made a big difference but I still feel like my girlfriend's CRV pass me.

I have a feeling it's somewhat weak injectors or pump, so if I'm going to replace them why not upgrade?

 

There's two junkyards less than a half hour from my house. So it's not too hard to get a hold of parts.

They have a 300ZX there, ever heard of those being put on an L28?

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People use the turbo injectors in place of the factory l28et injectors. You can also get mustang svo injectors 370cc They fit but are to big for the stock ecu. Not to sure about the non turbo vg injectors but I know the vg30det injectors work for the L28et. I'm pretty sure there is an injector upgrade thread also.

 

 

http://forums.hybridz.org/index.php/topic/52695-fuel-injector-upgradesswap/

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Get a wideband on that thing and find out what's really going on! Even if you have to pay for dyno time for it.

 

Don't guess when it comes to modifying an EFI system. If your numbers are off less than a point you can probably get away with just some extra rail pressure. If the wideband is being jumpy then you know you're looking for an issue.

 

Also remember that with a different cam you're moving the power band, which would generally require a retune of the ECU to adjust the maps. Unfortunately modding these old systems is a little crude, and more like modifying a "smart" mechanical fuel injection setup, hardly better than a carb in some ways. You can't just go and increase the power 50% without some serious drawbacks/limitations. Odds are you'll be able to get it to run nice on the top under WOT with just a pressure regulator and some time on a dyno if everything is working correctly, but you'll be giving up tune quality in other areas.

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Thanks, great advice and I will definitely go to lonewolf if I do anything to my intake.

 

What CC would be too high to run off the stock ECU on my non-turbo?

 

Turbo injectors would be as much as I'd run. That'd be equivalent to running your NA injectors at around 70-75PSI. That's a lot of extra flow. You might even still want an adjustable regulator so you can drop a few PSI if you can't get it to run right at WOT with AFM adjustments.

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No need for a rising rate, so you aren't running boost. The point of a rising rate is that it leaves your pressure stock at anything bellow atmospheric, but then as boost increases fuel pressure increases giving you the extra fuel required if you're running higher than stock boost levels, thus running lean on the top end. It's a band-aid fix work around if you're in a situation where modifying the ECU isn't really an option. It's not a bad option at all for boosted motors, but it's limits should be understood.

 

As far what to get for your NA application, anything will work, just don't got for a $50 ebay special. Expect to pay $100 at least for a decent unit. Brand doesn't really matter imo, as it's just a simple mechanical device that could be replicated by anyone, even cheap chinese knock of shops in many cases.

 

This is a quality piece, though a little pricey imo. I like it's features, like that it has a dedicated gauge out, but at nearly $150 it's a hard sell.

 

http://www.diyautotune.com/catalog/sx-performance-15402-10-an-fuel-pressure-regulator-p-301.html

 

 

This is about as cheap as I'd go. Yes it's $100, but it's coming with a lot of kit, which honestly makes me wonder how good it really is. If it were me, I'd be willing to give it a shot though.

 

http://www.ebay.com/itm/Adjustable-Fuel-Pressure-Regulator-Kit-Gauge-GTE-2JZGTE-/200634819155?hash=item2eb6c46253&item=200634819155&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr#ht_2941wt_941

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That looks like a surprising load of BS from MSA. Can't believe they have that ad copy on their site. More power from NA with a rising rate FPR, "when conditions call for it". "Reports of 15 - 20 HP gains". $269. You should call them up and see if anyone there actually believes what they're advertising.

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Thats way too overpriced. I bought an aeromotive one from ebay for $100ish

 

It was pretty much this one, but I found it cheaper:

 

http://www.ebay.com/itm/Aeromotive-13109-A1000-6-Injected-Bypass-Fuel-Pressure-Regulator-Adjustable-PSI-/330674402209?pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr&hash=item4cfdbaf3a1#ht_4847wt_1110

 

It was hard for me to go to SS braided lines since it was my first time flaring the stock fuel lines( not fun btw)

 

Price breakdown

bought a liquid filled gauge for $25

bought a -6 fuel filter for $25

had like 4 ft of SS lines make in -8 and -6 $50ish

spent like $100 on a bunch of fittings for the fuel rail and SS lines and FPR

 

Couple of reasons why I went with an aftermarket FPR is:

1. I sold my stock fuel rail to my friend to get his car running

2. I wanted to clean up my bay and use a fuel rail similar to pallnets ( cockerstar made mine)

3. I plan to run boost later and this will only make tuning easier ( after I get a wideband sensor)

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Haha, off topic but you should check out the "performance throttle body" sold by MSA.... Looks almost identical to a 240sx tb.... but costs $349.99

 

It's a TWM Custom Throttle Body and they have sold them for years before there ever was a 240SX... :rolleyes:

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I don't know if this helps, but here's a link to a swap I did a few years back.injector swap I'm still running it and I drive the car everyday. I don't know that you need more fuel to the motor with what you're running. I agree that since your cam could/has altered the factory torque curve the fuel maps could be off. Necessitating a re-tune of the factory injection.

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