injectors on renix...H.O. injectors viable "upgrade"?

[JeepcoMJ]

the '90 elim. had some pretty crappy injectors, and the o-ring for the fuel pressure regulator leaks.

 

I'm wondering how much, if any, of an upgrade it would be to swap H.O. injectors in? any ideas on fuel mileage gain/loss?

 

just a thought I had, as I'll already need injector o-rings and FPR orings anyways, why not do a small upgrade.

[Geonovast]

I thought the injectors had the same rating?

 

Might be worth the cash to pop in the upgraded 24 lb Mustang injectors.

[JeepcoMJ]

they may be...idk. I'm trying to do "free" as that's what I have.

[Geonovast]

I don't think they're an upgrade.. but certainly won't hurt anything.

[HOrnbrod]

24# Mustang injectors would be a complete waste on a stock or mildly built engine. Most of the fuel would be blown out the tail pipe. Injectors are graded by static flow (lbs/hr) and pressure. To correctly size injectors for a particular engine, the best way is use the HP vs. orfice size vs. pressure (an adj. regulator is necessary for this) formulas to get you into the ballpark. Then do dyno runs to obtain the peak HP/torque vs. economy readings. Case in point: the best injectors for my 4.6 stroker turned out to be the stock 96-99 23.2# running @ 46 lbs.

 

The following is a list of the injectors used on the 4.0L since 1987 along with their rated static flow:

 

Model Year, ...Part #, ......Colour, .....Fuel Pressure, ...Static Flow,

'87-'90, ........53003956, ...Black, ........39psi, .................18.6lb/hr

'91-'93, ........33007127, ...Brown, .......39psi, .................21.0lb/hr

'94-'95, ........53030343, ...Tan, ...........39psi, .................21.0lb/hr

'96-'99, ........53030778, ...Grey, .........49psi, .................23.2lb/hr

'00-'01, ........04854181, ...Blue tip, .....49psi, .................22.5lb/hr

 

The injector flow rate varies as the square root of the pressure drop across the injector. The stock '91-'95 4.0 injectors are rated at 22lb/hr @ 43psi fuel pressure, so at 39psi they flow ( sq. rt.(39/43) x 22.0 = 21.0 ).

 

For stock/modified 4.0 engines or stroker build-ups the following injectors can be installed. The flow rates are:

 

Ford Motorsport 19.0lb/hr @ 39psi (Part no. FMS-M9593-C302)

Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)

Ford Motorsport 30.0lb/hr @ 39psi (Part no. FMS-M9593-B302)

Chevy LT1 24.0lb/hr @ 43.5psi (Part no. 1712424

Chevy LT4 28.0lb/hr @ 43.5psi (Part no. 17124251)

'98 Chevy LS1 25.2lb/hr @ 58.0psi (Part no. 12533952)

'99-'00 Chevy LS1 26.2lb/hr @ 58.0psi (Part no. 12456154)

'01-'02 Chevy LS1/LS6 28.6lb/hr @ 58.0psi (Part no. 12482704)

Accel 19.2lb/hr @ 44.1psi (ACC-150119)

Accel 21.1lb/hr @ 44.1psi (ACC-150121)

Accel 24.4lb/hr @ 44.1psi (ACC-150124)

Accel 25.6lb/hr @ 44.1psi (ACC-150126)

Accel 29.4lb/hr @ 44.1psi (ACC-150130)

 

So to answer your question, the 19# Ford injectors would be very close to right for you. :cheers:

[JeepcoMJ]

Thanks Don.

 

I'd like to not spend any more money than an o-ring set, and I have 92 or 96 injectors to choose from

[mjeff87]

with later model or aftermarket units , even at stock PSI, you do get the benefit of the quad orifices in the injector tip (better atomization)

 

Jeff

[HOrnbrod]

with later model or aftermarket units , even at stock PSI, you do get the benefit of the quad orifices in the injector tip (better atomization) Jeff

 

This is true. :cheers:

[mnkyboy]

the 19# are stock in a 1.9L ford escort,but I'm running 35# in my escort

 

 

whats the impedence on the GM injectors you listed? i put a LT1 injector in my XJ and it fried the ECU within a few days. cooked the transistor that pulsed that injector.

 

I'm now running the ford 5.0L/4.6L 24# yellow tops in it.

[HOrnbrod]

Don't know - I've never used the GM injectors. Probably never would either. :D Good question though. For sure they are all Bosch injectors though.........

[dakineJ]

the 19# are stock in a 1.9L ford escort,but I'm running 35# in my escort

 

 

whats the impedence on the GM injectors you listed? i put a LT1 injector in my XJ and it fried the ECU within a few days. cooked the transistor that pulsed that injector.

 

I'm now running the ford 5.0L/4.6L 24# yellow tops in it.

I was thinking about the LT1 injectors as well due to the fact they are a 6 orifice injector, but this impedence issue cocerns me.

[ratrapp]

i replaced all my injectors with the multi orifice mustang 19lb injectors.i didn't get 1 more mile per gallon or any noticable power gain.the only reason i replaced my stock injectors was because 4 of them were seeping(replaced o-rings and still seeped).the only improvement i seen was i didn't smell fuel when i cut it off.i did use new injectors,not used ones.

[mnkyboy]

I didnt notice anything either with 24# ford injectors but i wasnt expecting anything either.

 

I needed injectors and the Ford injectors were cheaper,i also prefer Bosch over the OEM Siemens/Deka injectors. the Bosch ones should be more reliable.

[jimoshel]

Why do the British drink warm beer (ale) and their cars are hard to start?

They use Bosch refrigerators and ignition systems.

[dakineJ]

Here is some info that might be helpful:

http://www.ausjeepoffroad.com/forum/sho ... hp?t=92236

 

and a flow calculator that's in that link:

http://www.witchhunter.com/injectorcalc1.php4

 

and another source:

http://www.fuelinjector.citymaker.com/contact.html

 

although, I think Precision Injectors has better prices. :cheers:

[1987Comanche]

When you purchased the O-ring kit did you get both black & brown O-rings? I'm planning to put in the mustang 19lb injectors I purchased and they have brown O-rings on both the rail and intake side. The OE ones have black on the rail and brown on the intake and the black ones seem to be about 0.040" smaller. The mustang injector OD is about 0.004" smaller where the O ring for the rail goes.