Does a by-pass help?????
Thread Starter
Drifting
Joined: Nov 2003
Posts: 1,556
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From: Auburn Washington
St. Jude Donor '03-'05-'06
Does a by-pass help?????
Does "by-passing" the Throttlebody help? Why does the coolant run through it? Please explain to the slow learner, like me. :jester
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Re: Does a by-pass help????? (midlifecrisis91)
The thought was that the throttle body should be warm so it doesn't collect ice from the throttle plate. Later years, GM stopped warming the throttle body with no ill effects. Bypassing is supposed to allow the TB to run cooler, and the fuel/air passing through it will also be cooler and therefore higher density which will produce more horsepower. The throttle body is in good thermal contact with the engine, so the bypass isn't going to do much for a cooler TB. Also, several CFers have admitted that they did not notice any performance improvement after the bypass.
Intermediate
Joined: Feb 2004
Posts: 35
Likes: 0
From: Rancho Cucamonga CA
Re: Does a by-pass help????? (midlifecrisis91)
There is this Write-Up on the topic in the "Tech Tips", "C4" section (from the Pull-Down Menu at the top of this web page.)
https://www.corvetteforum.com/techti...=176&TopicID=2
The reson the Factory designed it that way, was to prevent Throttle-Body iceing (due to High-Humidity/Low Pressure conditions).
[Modified by D_C71, 5:40 AM 2/7/2004]
https://www.corvetteforum.com/techti...=176&TopicID=2
The reson the Factory designed it that way, was to prevent Throttle-Body iceing (due to High-Humidity/Low Pressure conditions).
[Modified by D_C71, 5:40 AM 2/7/2004]
Team Owner
Joined: Sep 2001
Posts: 62,066
Likes: 1,722
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: Does a by-pass help????? (midlifecrisis91)
It runs thru the TB to keep the butterflys from freezing in cold weather, but they would only freeze in EXTREME cold.
It helps, but not by any measure you can feel.
It helps, but not by any measure you can feel.
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: Does a by-pass help????? (jfb)
several CFers have admitted that they did not notice any performance improvement after the bypass.
I bypassed mine (I live in generally HOT Australia) but also cannot say I noticed any difference (TB is still DAMNED hot to touch after a run!!)
Maybe a separate pump running cold water thru it might be the go...hey...room for a new subject there! :smash:
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: Does a by-pass help????? (USAsOnlyWay)
Sorta like the bag of ice on the intake trick eh? :smash:
Drifting
Joined: Jan 2002
Posts: 1,606
Likes: 1
From: Las Cruces NM
Re: Does a by-pass help????? (midlifecrisis91)
My manifold intake temp(measured by the sensor screwed in underneath the upper plenum) dropped by about 25 degrees in the summer and with the weather in the 40's now, it doesn't go above 70*. It doesn't get cold enough even here in colorado to freeze the t/b blades, and it definately doesnt get cold enough in alabama to freeze it.
Chris
Chris
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Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
Re: Does a by-pass help????? (midlifecrisis91)
This modification on my car improved the clutter in a very tight area of the engine. With the hoses gone from the TB, it is much easier to work in that area of the engine. I would do it again for this reason. Did it help performance...only in the mind!
Team Owner
Joined: Jan 2003
Posts: 20,253
Likes: 220
From: Summerland B.C. Canada
Re: Does a by-pass help????? (Sam Lam)
This modification on my car improved the clutter in a very tight area of the engine. With the hoses gone from the TB, it is much easier to work in that area of the engine. I would do it again for this reason. Did it help performance...only in the mind!
I bypassed mine and noticed it was still realy hot after running for a while.
Then I had IAC problems and the bypass hose was in the way, so I returned it to stock.
Now that I have removed air pump and the valve by the ac compressor, I will have more room to reroute hose for bypass.
Only for the reason of making TB removal easier. :smash:
:cheers:
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
Re: Does a by-pass help????? (AGENT 86)
Agent 86: I did not route the new hose under the TB. Instead, I spliced the heater hose just behind the right front wheel and routed the hose forward and looped it to the connection at the front of the engine. I have a picture, but do not know how to post pictures....too much tech stuff for an ole Alabama boy!
Le Mans Master
Joined: Oct 2002
Posts: 7,178
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From: Bahston Mass.
Re: Does a by-pass help????? (midlifecrisis91)
I did mine, but only because it was a completely free mod, and I KNEW I'd never be out in sub-freezing temps... I haven't driven it since, though..
Team Owner
Joined: Jan 2003
Posts: 20,253
Likes: 220
From: Summerland B.C. Canada
Re: Does a by-pass help????? (Sam Lam)
Agent 86: I did not route the new hose under the TB. Instead, I spliced the heater hose just behind the right front wheel and routed the hose forward and looped it to the connection at the front of the engine. I have a picture, but do not know how to post pictures....too much tech stuff for an ole Alabama boy!
It's never too late to teach an old dog new tricks :jester
Melting Slicks
Joined: Jan 2000
Posts: 3,418
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From: NW Chicago Suburbs
Re: Does a by-pass help????? (midlifecrisis91)
I drive both of my 96's with the TB bypass, year round in Chicago. I'm not surprised GM finally dropped this, IMO, it's a relic from carbs. No gas evaporating, no ice build-up.
Eric
Eric
Drifting
Joined: Jan 2002
Posts: 1,606
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From: Las Cruces NM
Re: Does a by-pass help????? (AGENT 86)
I don't know if this only helped in my mind. I certainly didn't feel a difference, but at the track, that along with a couple other free and close to free mods(t/b bypass, bumped up the fuel pressure a couple psi, adjusted tps voltage to .62V from .54V) yielded 3 tenths and 2.8 mph consistently with nearly the same weather conditions.
I guess what I'm saying is that all that free stuff does add up. And yes, it does make it much less of a pita to remove the t/b, which in itself was completely worth it. I did the bypass on my '86 when I first got it and never realized what a pain it is to have to crack open and refill the coolant system every time you mess with the intake till I got the '88.
Chris
Chris
[Modified by okinawa86vette, 8:58 PM 2/9/2004]
I guess what I'm saying is that all that free stuff does add up. And yes, it does make it much less of a pita to remove the t/b, which in itself was completely worth it. I did the bypass on my '86 when I first got it and never realized what a pain it is to have to crack open and refill the coolant system every time you mess with the intake till I got the '88.
Chris
Chris
[Modified by okinawa86vette, 8:58 PM 2/9/2004]
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
adjusting TPS voltage
adjusted tps voltage to .62V from .54V) yielded 3 tenths and 2.8 mph consistently with nearly the same weather conditions.
I'm guessing replacing a resistor etc?
Pro
Joined: Aug 2002
Posts: 715
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From: Warner Robins GA
Re: adjusting TPS voltage (smacko)
OK, this has me intrigued; How DO you adjust TPS voltage?
I'm guessing replacing a resistor etc?
The TPS is held on by I think two torx screws. Measure the voltage between the top two wires going into the TPS. Loosen the screws and rotate the TPS. There's a little lip on the TPS and by rotating the unit, the lip is moved. This is how the voltage is changed. When you get to the desired voltage, simply tighten the torx screws.
Drifting
Joined: Jan 2002
Posts: 1,606
Likes: 1
From: Las Cruces NM
Re: adjusting TPS voltage (Tourney3p0)
:iagree:
The only thing I'll add is that you want to torque the screws a little at a time going back and forth between the two. This'll help it to keep the setting you just adjusted as you tighten everything down. And double check your voltage after you tighten everything down. It's very sensitive.
Some of the later years aren't adjustable, but you'll be fine with an '85.
Chris
The only thing I'll add is that you want to torque the screws a little at a time going back and forth between the two. This'll help it to keep the setting you just adjusted as you tighten everything down. And double check your voltage after you tighten everything down. It's very sensitive.
Some of the later years aren't adjustable, but you'll be fine with an '85.
Chris
Burning Brakes
Joined: Jul 2003
Posts: 922
Likes: 1
From: Brisbane Queensland, Australia
Re: adjusting TPS voltage (Tourney3p0)
AWSOME GUYS!
I'm assuming you test the voltage at ignition on, engine off?
Any ill effects from this mod? Decrease in fuel economy etc?
I'm assuming you test the voltage at ignition on, engine off?
Any ill effects from this mod? Decrease in fuel economy etc?