Injector sizes? control?
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,638
Likes: 3
Injector sizes? control?
I am currently doing a ZZ4 swap into my 86. I will be using the stock TPI on the engine. I am wondering wether I should change injectors? and if so - to what - I know a bunch of guys here like the Ford 24LBs. I drive this thing daily so I need drivability and I don't want the thing loading up on me at low speeds - but on the other hand I will be running in excess of 160 MPH on races like silver state or out on the Bonneville salt flats - but on the 3rd hand it will be running autoX also.
How much does the computer control fuel pressures and delivery?
Someone help me out please - and soon - this is happening right now.
Thanks
Carl Johansson
How much does the computer control fuel pressures and delivery?
Someone help me out please - and soon - this is happening right now.
Thanks
Carl Johansson
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
The injector needed depends on how much HP you expect to make with the new ZZ4 engine. Our stock injectors are good to around 350chp but may require an AFPR to bump fuel pressure or a custom chip to change the fuel curves.
At part throttle in closed loop mode the ECM uses the O2 sensor feedback to trim A/F by modifying injector pulse width for optimum performance. But at WOT the ECM controls injector pulse width from fuel tables stored in the EPROM in the CalPac.
At part throttle in closed loop mode the ECM uses the O2 sensor feedback to trim A/F by modifying injector pulse width for optimum performance. But at WOT the ECM controls injector pulse width from fuel tables stored in the EPROM in the CalPac.
Pro
Joined: Sep 2001
Posts: 542
Likes: 1
From: Stuck in the 80's
Just from my experieince, the above mentioned injectors put my part throttle BLM's at 108-110 (rich) and I lost throttle response. I bought the chip burning tools and changed the constant to ~26.25 to get my BLM's back to ~128 and got my throttle response back.
Your car may or may not exhibit the same, or to the extent mine did, but I know I'm not the only one to have this problem.
Your car may or may not exhibit the same, or to the extent mine did, but I know I'm not the only one to have this problem.
Thread Starter
Drifting
Joined: Sep 2004
Posts: 1,638
Likes: 3
Thanks - here's my plan
Thanks for the inputs guys. Heres my plan. I will put the stock injectors onto the ZZ4 - then after it's all up and running I will go to the dyno and get a wide O2 band along with the regular stuff. That way - if the wide O2 shows a lean condition at WOT then I'll know to get 24 LBS injectors - sound like a good idea?
Carl Johansson
Carl Johansson
