Gus

I want to upgrade to 35 lb injectors and am having trouble finding a good source in my area.
Anyone know of a good supplier for 35 lb fuel injectors for the 964 -

biggles

Just bought 4 on ebay about a week ago - Check the 944T forum

Biggles

Marc Shaw

Try John @ Vitesse Racing (a RL sponsor).

Marc

Geoffrey

The 944T injectors are peak and hold and not compatible with the 964 ECU. They are also very, very old injector technology.

biggles

Geoffrey
Does the 964 use high impedance/saturated injectors? Assuming that the ECU is programmed for such? Does the size of the injector make a difference? Would assume that a smaller injector would not be a problem?

Thanks

biggles

Geoffrey

Yes, the 964 stock injectors are 16ohm injectors (24lb/hr I believe). The ECU's injector driver is designed to supply a saturated injector signal, not a peak and hold injector signal. I don't know if the injector driver inside the ECU can handle the low current injector or if it can supply the peak and hold signal. A question Loren can probably answer. I know the injector drivers MoTeC uses are designed to handle either, and the software can be configured for either injector signal.

Does the size of the injector matter for what? Obviously the injector sizing needs to be appropriate for the engine.

fast951

Low impedance injectors should not be used with the 964 DME.
As I recall the stock 964 injectors are rated at 20-21# @3bar fuel pressure (or around 23# @ 3.8bar fuel pressure). Can anyone verify or correct?

biggles

Gus – My apology – Thread hijack

Geoffrey,

Thanks for the knowledge.

Geoffrey

John, your data matches mine, 24lb/hr at 3.8bar psi.

biggles

How necessary are bigger injectors if changing out the exhaust, including headers? Having read feedback here on the forum about the lost in HP with changes in headers, I was wondering if this had to do with a lack of fuel, so wanted to go with bigger FI. Assumed that I could pay for a chip remapping from SW after getting a base reading for the A/F ratio. Would increasing fuel pressure with an AFPR while using OEM FI increase the fuel delivery and resolve any lean conditions?

biggles

Geoffrey

The stock injectors will support approximately 305hp. Installing headers and an air filter will not cause the engine to require more fuel than the stock injectors can flow. Adjusting the fuel pressure will increase the effective flow rate of the injector. I would not run the EV4 injectors past 5bar of fuel pressure.