Throttle body bypass - more power plus...

[alchemist]

Does anyone do a TB bypass on these cars. It's a pretty easy thing and commonly done w/GM b-bodies, plus, it helps them make a little more power (i.e. less heat in the TB, more cool air induction). It would eliminate those two pesky coolant hoses (that go to the pits of hell) too, that you have to contend with when doing anything to the intake (upper). I honestly can't see where they end up, but looks like you could put plugs in the intake?

[1990LTD]

Yep.

[86VickyLX]

Yes. Many people do it.

[1990LTD]

Some have said that it is their to prevent the throttle body icing up in colder climates. Others have said other things. Nobody really knows why it's there.



I don't know if it does anything negative to the performance of our cars...Chebbies might be designed differently, I don't know anything about them.


I just ran a small hose between the in/out on the EGR spacer itself and a hose between the in/out ports behind it

[gadget73]

I did some testing a while back with my car, and I'd really love for someone else to try it to back up my findings. I took a drive with the coolant hoses hooked up, went like 15 miles on the highway and checked the voltage at the IAT sensor to find out how hot the air was in the lower intake. I then unhooked the lines and drove back and re-checked my readings. I found the air was about 20 degrees cooler with the lines unhooked. Never did any more in-depth testing and I never bothered to try it again to see if it was repeatable but it would be interesting.

One end of the line goes to a fitting screwed into the lower intake. The other end goes to a port on the metal pipe under the upper intake. Can't really plug that one easily unless you cut the tit off and braze it shut.

[sly]

I bypassed it on my car. warmer climate here... not worried about icing... even in the winter. I didn't do any tests like Gadget... but... it didn't make any real difference other than the peace of mind that comes with knowing that coolant can NOT get into the engine that way any more. I didn't seal the tits... I just ran the hose from the heater pipe to the spacer down to the tit on the upper intake.

[alchemist]

looks like you could even pull that whole heater tube piece out of the intake manifold and plug holes? I live in eastern NC and we don't get a lot of cold weather (i.e. sub 20 degrees F). Thinking seriously about it. But if you pull that tube, I think the EEC-IV coolant temp sensor might be associated with it, maybe on the tube itself?

[86VickyLX]

looks like you could even pull that whole heater tube piece out of the intake manifold and plug holes? I live in eastern NC and we don't get a lot of cold weather (i.e. sub 20 degrees F). Thinking seriously about it. But if you pull that tube, I think the EEC-IV coolant temp sensor might be associated with it, maybe on the tube itself?

Run the hose from the pipe, to the fitting on the other side of the manifold.

[1990LTD]

I did some testing a while back with my car, and I'd really love for someone else to try it to back up my findings. I took a drive with the coolant hoses hooked up, went like 15 miles on the highway and checked the voltage at the IAT sensor to find out how hot the air was in the lower intake. I then unhooked the lines and drove back and re-checked my readings. I found the air was about 20 degrees cooler with the lines unhooked. Never did any more in-depth testing and I never bothered to try it again to see if it was repeatable but it would be interesting.

One end of the line goes to a fitting screwed into the lower intake. The other end goes to a port on the metal pipe under the upper intake. Can't really plug that one easily unless you cut the tit off and braze it shut.

I'd like to see the results but have no real way of testing on-the-move. Hope someone else does it too

[Neal 97 250]

I went to a machine shop and had them take a thick piece of aluminum and machine out the holes to replace it. I have seen no difference in anything. And it runs just fine in the winter sub freezing.

See here:

http://s480.photobucket.com/albums/rr166/Neal97250/Lincoln%20Stuff/?action=view&current=DSCF1094.jpg

[86VickyLX]

Holy crap, how much did that cost? And did you use your throttle bracket from your Towny?

[Neal 97 250]

Yup I used the stock throttle bracket. I had to align it and make the marks once I got it on the car. Drilled and tapped the two holes to mount the bracket. I had to shim the bracket out a tad with some washers to get the correct amount of movement in the cables. But it is a fine piece. Would look good polished huh?
Simple and it just bolted right on.
It cost less than $100 all total. He had the piece of aluminum layin around scrap. Just had to do the big hole and 4 bolt holes, then I did the bracket holes. I gave him a new gasket from a 2001 5.0 Explorer to use as a template.

I couldn't figure out how to post the pic on here since I have it on a photobucket acct and not on my computer so I had to post a link. Sorry.

[merc91]

i bypassed it because i bored out my spacer to 67mm for the tb. didn't notice a power difference, it gets to -25 C here and no icing up. theres plenty of heat under the hood to keep it warm. nice to get some more hoses out of the way. then i went on to delete the egr for my dyno tune and that felt like a few more horsies... maybe 5 and ran a little smoother. all had no effect on gas consumption and i picked up 15hp after the dyno tune and these mods.

[gadget73]

I'd like to see the results but have no real way of testing on-the-move. Hope someone else does it too

I pulled over and stuck a voltmeter on the sensor leads. Not really anything fancy. I have no equipment to do on the move testing, though I guess I could get fancy and run long leads from the sensor into the car with the voltmeter hooked up. I really didn't care enough to go to the trouble though.


When I first did the HO swap, I hooked those coolant lines up. It was pissing coolant into the throttle body, and at first I thought I had a blown head gasket. First run of the motor and all I see is steam and I was smelling coolant out of the exhaust. Shut the motor off and I saw it spraying around the throttle body. it got unhooked and stayed that way for years. I only hooked it up briefly to see what would happen at the IAT. Its been unhooked since. Car runs just fine winter and summer, and I do have working EGR. I've been told the coolant is required to keep the EGR spacer from melting. Mine seems to be just fine. I've had it off several times over the years and have yet to see any indications of damage.