What can go?

[Guest Steven]

I’ve been up and down thread through thread and I haven’t really found a clear and definite answer to my question "what’s necessary and what’s not in the l28 setup?" I bought a shaved manifold and I’m going to be tearing into my engine...again and Id really like to eliminate as much "un-necessary" parts (hoses, vacuum lines, regulators, etc...) but I’m still a little fuzzy on just what is required to maintain proper performance (ie running). A little help, even if its calling my dumb for mot searching hard enough and linking me to this already covered topic, or just some info on what has to stay and what doesn’t. I’d appreciate the help.

[BRAAP]

This thread linked below, post #15! (Post numbers are in the upper right hand corner of each post in a thread.)

 

http://forums.hybridz.org/showthread.php?t=146552

 

...

Here is an intake swap with a 60mm TB conversion I just completed a couple weeks ago for a local customer. Some of the details may be of help in your project. Local customer located a non-EGR N-42 intake, 60mm TB, Pallnet fuel rail and TB spacer kit then dropped the car off and wanted it installed and tidied up including rerouting the EFI harness along the firewall and under the fuel rail instead of over the middle of the plenum. Car runs great, just as it did when it came in, other than the deleted air flow regulator as described below, other than that, no differnet!

 

This is a bone stock L-28 EFI.

 

Items deleted;

1) EGR, (This is a ’75 car registered outside of CA)

2) Air Flow Regulator (for a cold idle speed that the engine will idle on its own without holding the gas pedal, a "warm" idle speed has to be approx 1000-1200 RPM on a properly tuned L-28. If a warm idle speed of 650-800 is desired, then you’ll have to hold the gas pedal to keep the car running when cold till the car warms up, or reinstall the Air Flow Regulator.)

3) Coolant by pass that ran under the Air Flow Regulator.

4) Cold start injector and Thermo time switch. Tapped the cold start injector hole for 1/8" NPT, brass pipe plug installed. (left the Thermo-time switch in the thermostat housing, just deleted the wiring.)

5) A/C equipment in the engine bay.

 

Items rearranged; but still functioning as OE!

1) Carbon Canister vacuum line has new port drilled and tapped into the back of the plenum and vacuum line rerouted along passenger frame rail and across the lower firewall.

2) Fuel Pressure regulator relocated to the firewall, fuel rail plumbed in a pseudo dead head style arrangement, (before anyone jumps on the “dead end EFI fuel systems cant be done” bandwagon, SEARCH! It can, has, and is still being successfully done, by the OE and tuners such as myself with NO ill effects NO vapor lock etc). Vacuum port of the FPR also has its own new dedicated vacuum port added to the back of the plenum next to the canister port.

3) PCV is now drawing fresh air, K&N filter on valve cover. (This caused the engine to ingest "false air" as the air being drawn in through the PCV system is no longer being measured by the AFM, yet the engine is breathing that air, i.e. “false air”), as such I will be fine tuning the part throttle tune with a combination of the water temp resistance and AFM adjustments, todays project. For those new to the stock EFI or EFI in general, just leave the valve cover breather plumbed to any port between the Throttle body-butterfly and the AFM and you’ll be just fine!

4) Removed the EFI harness and removed the outer sheathing from the harness that resides in the engine bay. Deleted the Thermo-time switching wiring back to the splice, also deleted the cold start injector wiring. (Just leave the wires cut, but protected from grounding/shorting. The computer doesn’t know the difference nor does the engine.) Separated the injector wires and the water temp sensor wires of the AFM and TPS wires into two separate runs. Retaped those as 2 runs. Reinstalled harness, routed the injector and water temp wires along firewall and then under the fuel rail, (can’t even really see them in this photo below, but they are there) and routed the AFM and TPS wires back in the stock location.

 

Customer wasn’t ready to for a shaved intake, so this one was just painted and installed. Original fuel pressure regulator port plugged as well as a couple other deleted vacuum ports.

 

Here is the picture, below that is a diagram of the dead-head fuel rail system.

 

Boot between TB and AFM is not secured in picture, it needs to be secured!

 

 

 

 

Hope this helps,

Paul

Edited April 27, 2009 by BRAAP