Throttle body bypass anyone?

[bowdownmaster]

has anyone done the throttle body bypass on the gen 1 avalons?

[2wickedtoyz]

i've done it on all 3 of my v6's and i haven't a single problem.

[bowdownmaster]

any diy or is it really simple that i cant mess up?

[2wickedtoyz]

exactly

[American Pie]

Bypass the throttle body? Could someone please explain what's involved in this, and why you'd want to do it?

[bowdownmaster]

it means removing the coolant line that goes in and out of the throttle body. what you simply do is take the in and out coolant line going to the TB and connecting them with some sort of tubing. this will stop the flow of coolant into the TB. doing this will make the TB to be cool to the touch rather than hot because originally the coolant would be heating up the TB making the air going into the engine slightly wamer. after doing the bypass the air should be cooler thus resulting in additional HP if this works in theory. i did this today and i can say my throttle response is more better than before. so its worth a try since it is free

[American Pie]

A heated throttle body; now that's interesting. Most modern cars I'm aware of have such high under-hood temperatures that something like this would seemingly be redundant, if heating up the intake charge is somehow considered "desirable".

I recently purchased my '96 Avalon and am still learning its quirks. I'd be willing to try this if it gives more HP, but I wonder why Toyota engineers decided the TB needed to be heated in the first place. Better throttle response/driveability in very cold climates, perhaps? Not that I'd have to worry about it in SoCal, but this mod sounds simple enough that you northern folks could swap it back and forth depending upon the season.

[bowdownmaster]

the reason why toyota and many other manufacturers do this to the TB is because in colder climates like say denver, the weather gets to freezing point and the cold ait being sucked through the TB could make the TB stick so its basically a safety feature.

[The Digital MagE]

ok... the throttle body is a strange "place." it contains, and controls vacuum. ice can and will form at temps as high as 50 degrees because of the pressure differential and the air flow across the pressure boundary, otherwise known as the throttle plate (or butterfly).

the heating provided by the coolant running through the throttle body is there, not only to prevent icing, but to provide a stable temperature range for the intake air. i seriously doubt that the efi has enough range to properly charge ice cold air with fuel. sure, that's done at startup, but it's not done by variation of injector timing and fuel pressure, which is the normal method of matching mixture to conditions. i believe there is a "choke" injector, somewhere in the manifold, that handles extra fuel required for startup and warmup?

i remember seeing this, in its crude and initial form, on my '83 ford 302. it had a thing that redirected the intake air past the exhaust manifold when it was too cold. it was mechanical and operated via a spring in the airstream. even in '83 they were seeking to limit the range of temps in the intake air...

these cars operate on the ragged edge of running too lean, as it is. if you introduce cooler air, it will require more fuel. and yes, cooler air has the capacity to produce more power as it contains more oxygen (because its more dense). however, if the greater amount of fuel is not delivered, the result is an engine that runs really hot, because its too lean.

i won't be doing this, myself. if you do, well, good luck. maybe after you grind your 24 valves or replace your motor you'll have some respect for people that really are engineers, and really do know how to design a fuel system.

[robcam13]

wow digital mag comparing an 83 ford 302 v8 to a 95+ 1mz v6 is not accurate. the computer wont let any damage happen .unless you live in the south pole.

[The Digital MagE]

didn't mean to compare them - just to use the ford as an example of what's going on.

good luck to you.

[robcam13]

sorry digital mag i came off as a dick. didnt mean any dis respect.

[The Digital MagE]

np :]]

[tah]

In 83 I had a 74 Celica that had a coolant line running to the carb, or base plate....... somewhere around there....

I was told it was so the carb would sense the cold water, then the water temperature raising and adjust the choke accordingly. My coolant lines or something that fed them were messed up and I didn't have the money to fix it properly. This would cause carbs to fail.

I bought a NAPA rebuilt carb with a 6 month warranty. As soon as I had carb problems I'd pull into NAPA, remove the carb, exchange it, install the new carb and I was off and running for another 6 months.

These were the good old days before they tracked everything on computer. You wouldn't be able to get by with what I did today.