CVR_Rally

Although I had the injectors reconditioned and tested back to spec back when I got the car I have to wonder if there still is an issue with them.

I was thinking of replacing them but I see different part #'s for the 16v yet from what I could find they all had the same volume output.

Any injector experts able to help?

Chris

JacRyann

What kind of issues are you having that replacing your injectors with identical ones would solve?

CVR_Rally

https://rennlist.com/forums/924-931-...5500-944s.html

CVR_Rally

Found this on Clarkes garage. It's a pressure thing.
http://www.clarks-garage.com/pdf-manual/fuel-12.pdf

Dash01

In the 30+ years since Porsche selected the OEM injectors for the 951, there have been advances in pintle/nozzle design. Among the BMW crowd, Bosch/Mustang injectors with 4 hole pintles are a plug and play option, as the 4 hole nozzeles atomize the fuel into a finer spray, with improved idling and fuel economy. I've used these on several BMWs, with ~10% better cruising mileage and better idle. Flow rate and ohm resistance are similar to the original BMW application. The car's oxygen sensor and computer automatically adjust opening time to deliver the correct fuel mixture, so this is a very simple and inexpensive upgrade. I've bought such injectors at a junkyard for several dollars each, as Ford Mustang, Crown Victoria, and other common cars have the better injectors.

So, I'm wondering if there is a common, more modern alternative to the Bosch 0 280 150 803 injectors used in the Porsche 944 Turbo. Perhaps a turbo VW Passat or supercharged Ford Thunderbird SC, etc., may have suitable injectors.

Thoughts or suggestions?

Dougs951S

Unfortunately 951's have an odd resistance for our injectors. Factory spec is 4.5 ohms which is pretty much unique as it is neither low impedance nor high impedance. They are rated 36.6#/hr @ 3 BAR. For a factory car, low impedance injectors of ~ 2-2.5 ohms and ~36#/hr flow with inline resistors added would probably work, provided such an OEM injector existed that fit our rails. FWIW I switched to modern siemens deka IV injectors which give excellent idle and economy. They are nominal 12 ohms and 80#/hr flow. Of course, this is on a megasquirted car.

I would think finding replacement injectors for an NA would be easier. Factory spec is 2.4 ohms; which is low impedance, and 21.8#/hr.

Our car's use a very common injector electrical plug type called EV1, so there are tons of units that will be plug and play on our harness. Just need to make sure they are the right length. In the end if you were serious about having better injectors on the stock ECU, splicing in different injector harness plugs is super easy anyway if it ended up being required.

19# Ford injectors would probably work for an NA if the resistance was right; when you adjust for the NA's 2.5 BAR fuel pressure the ford injector only flows ~5% less than the factory Porsche injector which is well within acceptable margin @ max power/fuel flow needs.

Edit: Problem is, the ford injectors are high impedance ~12 ohms so wont work.

Jfrahm

I am using a Volvo-spec 4-hole injector in one of my 968s and Ford 4-hole 19 lb/hr injectors in a 928S4. I like 'em, no problems. While I do not know if there are any significant performance or economy benefits I do not recommend refurbishing the older style injectors when there are options to upgrade them.

OP I think had problems with power delivery at lower RPM, not sure how that might be injector related but who knows.

Corresponding EV6 injectors to the stock 28-ish lb/hr injector might be 0-280-155-931 (Chevy/Caddy); 0-280-155-968 (Volvo, SHO, etc., a smidge bigger.) There are probably a few others and you should double check part numbers, flow rates, etc.

One source is Stan Weiss's table:
http://users.erols.com/srweiss/tableifc.htm

Turbo injectors are not as simple to upgrade as the 16v 944, I think you need ballast resistors.

-Joel.

Arominus

Which volvo injectors are you using on your 968? I'd like to get my hands on a set.

Jfrahm

Bosch 0280155831, 0-280-155-831, listed as 32 lb/hr at the standard measurement.

V2Rocket

New style injectors are much quieter than the original jack-hammers, and the spray pattern is nicer.

With no change other than swapping stock injectors for new-style Delphi I got +3whp on my NA...

odonnell

This is my go-to for injector lookup:
http://www.polog40.co.uk/article_injector_table.php
You can see what's reasonably close in flow rate (your O2 sensor will trim slightly so a little difference is ok). You can use high impedance injectors, Im pretty sure kits from Rogue/LR use them with the stock injector drivers. If anything, less stress on the drivers (less current through them).

SloMo228

Heck, I'd be happy with just the quieter injectors, let alone a power or MPG improvement. The injector clatter is louder than my exhaust!

V2Rocket

The other day I finished up a head gasket job on an S2...
I thought the lifters were just noisy from not having oil in 2 months.
But the lifters quieted down after a minute and the injectors were SO LOUD still

CVR_Rally

Can you tell me what part# you used?

V2Rocket

I can sell you my injectors...