hey guys just a quick ? opened up the hood just to look around and do checks,on the throttle body to the right of it the hose thats supposed to connect there is blocked off,i heard of something before called "tb hose delete" if im correct. Now what is that delete supposed to do? And the egr is deleted too and i heard people doing that too,and why does that get deleted for thank u guys

 

The Tb delete is supposed to make your air intake cooler. The egr is for emissions. Exhaust gas recirculation is what it stands for if I remember right. People delete these for slight HP gains.

94 Z28 A4- ported heads/intake long tube headers. Egr/smog delete.

 

Deleting EGR has no real effect on HP. EGR helps to regulate elevated combustion temperatures which can lead to detonation and performance loss from timing retard. So, leaving it on a stock engine can actually be more beneficial than deleting it.

 

Not clear which hose on the throttle body you are asking about. There are 4 hoses connected to the throttle body.

There is a coolant supply and a coolant return connected to the bottom plate on the throttle body. Those connections can be deleted by simply unplugging the hoses and connecting them together (93/94 only) with a 3/8" hose barb, and a couple clamps. This reduces the temp of the throttle body and intake air. Good for about 6HP at the rear wheels:

Modifications #8

No problems without the cooling connections at the throttle body. GM put it there to prevent throttle body "icing". Those of us who have deleted the coolant and driven our cars in 0*F weather have not experienced any problems. When disconnecting the hoses, coolant will flow out - MAKE SURE IT DOES NOT DRIP ON THE OPTISPARK DISTRIBUTOR.

Then there are two hose connections on the passenger side of the throttle body. The upper connection is for a large diameter hose that runs to the passenger valve cover. That is the clean air supply for the PCV (crankcase ventilation) system. Some people take that hose off and put a "breather" in the valve cover. No benefits in doing this, unless you have excessive ring blowby, and are blowing oil into the hose, then into the throttle body.

Smaller hose connection is for the EVAP system. That's the system that collect fuel tank hydrocarbon vapor in a carbon canister in the driver's side fender, and the vacuum at the throttle body pulls the vapor out of the canister when the PCM opens the EVAP purge solenoid on the bracket on the passenger side of the intake manifold. Again, nothing to be gained by deleting it, and if you do delete it, you are going to notice an increased smell of fuel vapor at the back of the car.

Shoebox has photos of the two connections on the side of the TB:

http://shbox.com/1/map.jpg

http://shbox.com/1/evap_sol.jpg

 

I ended up tapping the holes in my Holley and installing plugs. Easily to remove and add screw in fittings if I need them. Fresh air was fed to the valve cover via a line from the air filter before the supercharger and pulled out with a PCV enabled catch can.



Looks better this way. Sorry for the blurry pic, my camera wasn't diggin the shiny.

 

The whole idea of the water hose going through the TB was to avoid icing during cold weather high humidity driving. Most of us don't drive in these conditions and a cooler intake air flow is beneficial to power gains. That's why most of us by-pass the TB. Remember, when they design these cars, many compromises control the out come of cars. For those of you that fly, it's like carb heat.

 

thank you buddy for that. its the hose connection thats underneath the accelerator cable thats the side im talking about.