Quad 4 injector upgrade

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1990BerettaGTZ2.3L
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Quad 4 injector upgrade

Postby 1990BerettaGTZ2.3L » Mon May 13, 2013 7:57 pm

So I read on a post about this the quad 4s stock flow rate is 32lb/hr, I want to upgrade to I think 34Lbs cause its in between the typical swap which are brown top ford injectors with 36/lb hr I'm just looking for a little extra umph out of her with the 226 cams so I need to know what injector design/car I would need these out of any help would be appricated thanks


1990 Beretta GTZ Quad,226 cams, 3.94 W-41 trans
1990 Beretta GTZ Quad 4, 3.61 muncie 5 speed (project)
1968 Chevelle 300 deluxe 327ci 4 speed M-21, 12 bolt 4.10 posi
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Re: Quad 4 injector upgrade

Postby 3X00-Modified » Tue May 14, 2013 6:09 am

32lb to 34lb won't make much of a difference especially if you aren't logging and seeing it reach max duty cycle. Only if your in a 100% duty cycle or higher a larger injector will help out. Otherwise you won't notice a thing.



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DanteGTZ
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Re: Quad 4 injector upgrade

Postby DanteGTZ » Thu Jun 13, 2013 7:51 pm

First, the stockers are 26-28# injectors - Second, they are low impedance injectors - Many of the Bosch injectors are high impedance and the Quads are low impedance. I am currently in the same boat, but in my case, I'm just looking for some good stockers.


1993 Quasar Quad4 GTZ - Project WTF
1993 Garnet Quad4 GTZ - GTZed-Eh? - SOLD
1993 Aqua GT - 3.1 / 5 speed - 82k original miles - SOLD

Previous Berettas: 1990 GT and 1993 Quasar GTZ

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Rettax3
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Re: Quad 4 injector upgrade

Postby Rettax3 » Sat Jul 13, 2013 12:04 am

DanteGTZ wrote:First, the stockers are 26-28# injectors - Second, they are low impedance injectors - Many of the Bosch injectors are high impedance and the Quads are low impedance. I am currently in the same boat, but in my case, I'm just looking for some good stockers.

Ummm, okay, I am not a Quad guy, but I had a SOHC Quad '92 Grand Am and two 2.4 Twin Cam Z-24s, and a 2001 Grad Am. I'm still not an expert here, but to my knowledge, the low-impedance injectors did not appear on the Quad family until about 2000 or 2001 on the 2.4 Twin Cams. They are drastically different-looking from the older Multec-style injectors I've seen on the older Quads. My Z-24 has a '01 2.4 engine, and I had to swap-out the low-impedance injectors for the original '97 injectors when I swapped the engine in. I also swapped the engine on the '01 GA, with one from a '98, and the injectors were again totally different and had to be swapped back over. Now, I have no idea what flow-rate any of these are, and I am not 100% certain regarding the impedance of the Vin-A H.O. Quads in the Berettas, but again I don't think they were low impedance in this era...


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 Five-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 Five-Speed Indy GTi (Rebuild Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 3400 Top-End Auto OD Z-26

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Re: Quad 4 injector upgrade

Postby RobertISaar » Sat Jul 13, 2013 10:11 am

according to some spec sheets i've pulled through alldata, all Q4(meaning DOHC, no idea on the SOHC) used low impedance until quite late in production.

because of this, they're operated in a peak/hold method, so you'll either need to upgrade them with more low impedance units or change the ECM wiring slightly to allow for saturated operation with high impedance units.



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Re: Quad 4 injector upgrade

Postby Rettax3 » Sat Jul 13, 2013 12:53 pm

RobertISaar wrote:according to some spec sheets i've pulled through alldata, all Q4(meaning DOHC, no idea on the SOHC) used low impedance until quite late in production.
because of this, they're operated in a peak/hold method, so you'll either need to upgrade them with more low impedance units or change the ECM wiring slightly to allow for saturated operation with high impedance units.

SOHC SHOULD be the same, I can't see that anything except the PROM would be different between Vin A (H.O.), D (L.O.), and 3 (SOHC) ECMs. Okay, like I said I'm not an expert, but the low impedance injectors used on the newer 3400s look exactly like the later Twin Cam injectors (I doubt flow-rate is the same, but the body of the injector is). That means very little, of course. Use a multi-meter on the injector terminals, if you read ~12 Ohms, it is a high impedance, 2.5-3 Ohms is a low impedance... I'll try to measure the ones I have some time, and see what I've got for sure. As I understand it, the high impedance injectors are much more common because of the lower operating temperature and therefore greater reliability. Low impedance injectors seem to be fairly common on imports and higher-performance engines that require greater fuel-flow and faster-responding injectors. Anyone who has absolute knowledge on what is correct want to chime-in and put the rest of us (particularly me) in line? :wink:


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 Five-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 Five-Speed Indy GTi (Rebuild Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 3400 Top-End Auto OD Z-26

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Re: Quad 4 injector upgrade

Postby RobertISaar » Sat Jul 13, 2013 1:04 pm

no MPFI/SFI 60V6 used low impedance injectors.



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Re: Quad 4 injector upgrade

Postby Cliff8928 » Sat Jul 13, 2013 1:58 pm

Maybe Impedance is being confused with amperage...

The Quad has low-impedance, high amperage "peak and hold" injectors

The V6 has high-impedance, low amperage "saturated" injectors


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Rettax3
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Re: Quad 4 injector upgrade

Postby Rettax3 » Sat Jul 13, 2013 2:57 pm

Again, the shape of the injector has little to do with how it functions, but it does imply similar construction and functionality.

I did an engine-swap for a friend with an '03 3400 Impala several years ago, the replacement engine came from a similar-year Alero. The salvage-yard that sold him the new engine told him emphatically that his new engine used low-impedance injectors that would fry his ECU if the engine was going in an older car, so I was basing my knowledge in part on that statement (I've also read on the ultra trust-worthy internet that the newer 3400s used low-impedance injectors) -but maybe there is a reason why that particular person was working in a salvage-yard instead of a mechanic's shop. :wink:

Here are some pics of various injectors applicable to this discussion:

F-I pics1a.png
Pictures courtesy of Rock Auto


Of course, none of this is proof of high vs low impedance -a multi-meter will prove that to me one way or another.*
It also does nothing to inform regarding flow-rates, sorry.

*Edit: The general concensus does seem to be that the Quads are low-impedance (high amperage/high current) injectors -and there are a lot of people here who know a lot more about that than I do, so sorry if my oar is rowing backwards here, I was just trying to clear something up that seemed wrong to me. Thanks for the input guys.
Last edited by Rettax3 on Sun Jul 14, 2013 4:15 am, edited 1 time in total.


1989 Super Charged 3800 Series II (First)Six-Speed Conversion GTU
1990 Turbo 3.4 Five-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 Five-Speed Indy GTi (Rebuild Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 3400 Top-End Auto OD Z-26

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Re: Quad 4 injector upgrade

Postby Cliff8928 » Sun Jul 14, 2013 1:15 am

The Multec 2 injector is high impedance. Nothing would happen and nothing is different between a 99 and 2000 PCM. The Multec 2 injectors do generally run at higher pressures however.


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