Good day Sir or Madam,
Here's the deal:
Out with the old, non-E85-approved single-stream EV1 injectors (bottom) and in with the new, E85-proof, quieter quad-stream EV6 injectors (top) as a drop-in replacement for a bit better MPG, a bit more torque and eventual E85-compatibility if you wish to have that. Read on to know why or just skip to the part numbers if you need new injectors.
Originally Posted by Bosch
Effects of Fuel Pressure on Pintle Type Fuel Injectors.
Fuel velocity through a pintle type fuel injector (type code EV 1) can dramatically affect its ability to atomise fuel. The profile of the pintle used in a fuel injector has a direct relationship to the operating pressure it is designed to operate under. Whilst Bosch produce various fuel injectors that may flow the same amount of fuel at a given specification, the system operating pressure will influence the pintle profile. Correct pressure will result in a well atomised spray, while insufficient pressure will result in a “hosing” effect. Excessive pressure will result in either “hosing” or a spray angle that is too large for the targeted area dependent on the pintle profile.
The consequence of excessive fuel pressure on a pintle type injector may well be that as the pressure is increased the mixture values of the engine may appear to get leaner. This is of course not the case, but the fuel being injected is no longer atomised and is entering the cylinder as a liquid mass. This will typically cause the Hydrocarbon [HC] values to rise due to the raw fuel exiting the cylinder, and the Carbon Monoxide [CO] to drop due to insufficient combustion.
Later design fuel injectors [type code EV 6] use “director plate” multi-orifice technology to better atomise fuel across various operating pressures. These injectors allow more flexibility in relation to operating pressures without compromising spray efficiency or fuel atomisation.
So, they improve fuel atomization, which leads to a bit more torque thus more power and a bit higher MPG. They're also quieter, those EV1s are pretty noisy.
(Pintle vs. "director plate multi-orifice")
Originally Posted by Bosch
EV 6 injection valves are designed to inject the fuel as efficiently as possible into the intake manifold runner to achieve a homogeneous distribution of fuel in air flow.
"As efficiently as possible" sounds good to me.
Here's the current valving:
• USA MY94/95 (what you call 164S?), 3.0 24V, 4-cyl 2.0 Turbo (164, 155 Q4): 5969614 aka Bosch 0 280 150 701, sand-colored top, flow rate 21.5lb/h, 225ccm.
• USA MY91/93, 3.0 12V, 2.0 V6 TB, 2.0 TwinSpark, Boxer 16V, Fiat Uno Turbo: 7626715 aka Bosch 0 280 150 702, yellow-colored top, flow rate 18.0lb/h, 190ccm.
(For my own pleasure, Alfa 155 2.5 V6, 1.7L TwinSpark, 1.7L 8V Boxer: 60537527 aka Bosch 0 280 150 703, teal-colored top, flow-rate 14.2lb/h, 150ccm)
Those are all single-stream EV1. There are specific long-style EV6 quad-stream injectors that have identical notches for the clip-nut, length, connectors and 14mm o-rings, so they're are a drop-in replacement for the injectors currently installed in the Alfas. If the injectors happen to be faulty, why install old ones when new ones fit perfectly as well.
New EV6 valves
164 24-Valve: 0 280 150 701 -> 0 280 156 038 from the later 3.2 24V, same 225ccm, available in the US from a dealer in Michigan in the US (who's apparently on AlfaBB, as the international shipping costs are $100 now). (or 0 280 155 828 (VW) resp. 0 280 155 832 (Volvo S80 2.9, Light wine red, a bit larger: 235ccm))
164 12-Valve: 0 280 150 702 -> 0 280 155 823 (BMW V8 part, gray) or 0 280 155 820 (Ford; Beige) (alternatively 200ccm: 0 280 155 746 (Orange, Volvo), 0 280 155 702 (Black, Volvo 850/960) or 0 280 155 712 (Blue, GM/Holden/Opel/Saab 9-5))
155 12-Valve: 0 280 150 703 -> 0 280 155 821 (Ford V8 and some Mercedes, black)
This modification is nothing new and has been around for a while, but people buy the wrong injectors with different electrical connectors, so you have to replace those as well. These are EV6L injectors, with the old EV1 connector ("Version 92" as they call it, not "USCAR" with the wrong connector). No wire cutting, adapters or other modifications required. Loosen two nuts and the fuel line, pull up the fuel rail, remove the clip-nuts, pull the old injectors out, put the new ones in and reverse. Takes about 15 minutes for both rails. Please use reconditioned injectors to prevent any oddities during the operation.
But, while we're at it, we might as well increase the valving by 33%. This proofs the injection system for the use of up to E85, which requires exactly 33% more fuel than regular gas. Your car will run fine on the larger valves with whatever kind of gas you're using right now, the ECU adapts to them. The Brazilian Alfa models are already Ethanol compatible and use mostly the same parts. Also, the old EV1 valves are only safe up to E22, keep that in mind when and if E85 keeps popping up around you. You have the data to change the injectors for that occasion right here.
Today, you can skip this, but one day this information might be useful.
E85 also cleans the complete injection system plus intake valves and keeps it that way (you can even use it as an injection cleaner on non-converted cars by adding a gallon or two of E85 before going on a freeway), and it burns cleaner as well, so the catalytic converter also stays clean. It's good for the environment.
If you're revalving the car anyways and have a gas station with E85 nearby, it might make sense for you to do this modification. If you revalve a TwinSpark 8V or 16V, you have the perfect E85 car, because the two spark plugs ignite even slightly lean mixtures securely and the engine doesn't "lean shake" (If the mixture gets too lean, it will burn too hot and your engine will eventually take damage, though).
Also all the hoses etc., even on the 164, are identical with those installed in the Brazilian market where the Alfas come out of the factory Ethanol-ready, so they are E85-proof and you haven't got a problem there.
, here are the 33% larger valves. As a comparison, the Brazilian injectors for the 156 2.0 TwinSpark 16V are 220ccm, as opposed to the European 175ccm - or 26% larger (the newer EU Alfas are E10-ready, and 33% is a figure for pure gasoline). I stayed between +26% and +33% (and tried to hit the latter spot-on as a bit bigger won't hurt) while maintaining part availability both for the US and Europe.
164 24-Valve: Was 225ccm, target 300ccm -> 0 280 155 752 (GM LS6 as in the Corvette Z06 etc.) or 0 280 155 759 (Red, Volvo Turbo, easier to find, less expensive and nice color).
164 12-Valve: Was 190ccm, target 240-255ccm. 0 280 155 832 (Volvo)
(155 12-Valve: Was 150ccm, target 200ccm. -> 0 280 155 746 (Orange, Volvo), 0 280 155 702 (Black, Volvo 850/960) or 0 280 155 712 (Blue, GM/Holden/Opel/Saab 9-5). All of them widely available in the US as well as Europe and they can also be used as the stock replacement for 164 12-Valve.
147, 156 1.8 and 2.0 TwinSpark: Replace with 0 280 156 038 from the 3.2 24 V6. The Brazilian model uses 0 280 155 822, 21lb/h, 220ccm, but those are hard to come by.)
Alfa 147 1.6L (non-Eco) TwinSpark is the only model (outside of Brazil) that doesn't has to be revalved at all, as they're equipped with the 2.0 injectors. Unfortunately, that makes them too small for E85 on the 2.0.
1) Yes, you need about 33% more E85 than pure gasoline - even if you install the larger injectors, calc out whether that makes economical sense for your situation.
2) If you're running larger injectors and your lambda probe fails, your engine will go into the emergency mode, which will be gasoline + 33%, or E85-only. That's why it's often suggested that you also replace the probe when you do the conversion, luckily the 164, 155 and 1st-series newer models only have one of them. Chances are that it's 20 years old and not that accurate anymore anyways (technically, there's a periodical replacement scheduled every 75.000mi). It brings fuel consumption to normal, so rather be safe than driving on gasoline while it fails completely or waste fuel.
3) When installing, fill your gas tank with E85 then drive home under 3500RPM with the old injectors to flush any dirt from the system, afterwards install the new ones. Also, please replace your fuel filter 1000 miles after you started driving on E85, as it will clear all debris from the fuel tank and pump.
Hope it helps - or even makes sense at all.