i hear about it but i don't know what it is or how to do it? is it diverting the coolant to not go through the throttle body? thanks for the help
Andrew

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Andrew Peery
1987 IROC, 305 TPI, T5
Hooker Competition Ceramic Coated Headers, Flowmaster, Ported Plenum
All smog equipment gone and no cat
before headers
192hp and 265tq
15.20 @ 92.5 mph 2.4 60ft
After Headers
14.480 @ 95.01mph 2.194 60ft

 

Yes.

Check out this link. It's all you need.
https://www.thirdgen.org/newdesign/t...ntbypass.shtml

 

umm ok can someone please list some REAL results proveing that this is a REAL increase in performance and HP...

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1989 pontiac firebird
bright red exterior(just repainted)
grey interior
5 spd
305 TBI (stock)
WS.6 formula wheels
3.73 posi rear end
http://members.aol.com/j007golden/Mikey89.html
http://www.geocities.com/firebird/myfirebird.html
-------------------------
1985 trans am
factory bright yellow
4 wheel disks
16 inch wheels
305 TPI
power antenna and mirrors
t tops

 

Hey,
I just did the TB bypass to my car last week.... The next time you drive somewhere, open the hood and feel how hot the TB is... well if you do the TB bypass it will be cool to the touch..... It really lowered the car temp down....... The colder the air going in the engine, the more horsepower.... Kinda like a cold air intake id say it gained anywhere between 3 - 5 Horse!

 

The vast majority of the knowledgeable car folks who have done this mod will tell you that any power gain is minimal. Why we do it instead is so that you have one less piece of **** hose doing nothing in the way of the engine. The correct way to do a TB bypass for max usefulness is to relocate the heater bypass valve at the same time to over by the strut tower so the end result is mu cheasier access to the oass side of teh engine. Move the AIR junk and it will get even better.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

I agree with the last post.

I did this when i got my car to get some chit out of the way and clean it up under the hood, and i would say it is FAR from "cool to the touch" Its only maybe a few degrees cooler than your coolant temp.

Peace

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1985 IROC-Z, nuff said :P

 

Oh....geez! THANK YOU Ed for finally pointing out that for the sake of HP this is basically a useless mod.

GM made the throttle body heated for a specific design reason...and rightfully so......to cover their butts.

If you have ever flown a small plane and had to use "carb heat" in the middle of July you would understand that forced air flow into a venturi system combined with moisture in the air can cause an "icing" condition even in "less than freezing" conditions.

The last thing they probably wanted was someones TB plates to stick open in the Walmart parking lot.

 

The reason that there is "Carb heat" on aircraft engine is, when you have a lower pressure, caused by the vaccuum of your engine sucking air. The water also condenses out when you have lower pressure. PLUS as the gasoline evaporates it causes more cooling. Add the higher elevation to this and it all gets worse. More moisture, less pressure, etc.

Carb heat is not used usually on aircraft with Fuel injection.

I believe the purpose of the collant going through the throttlebody is more for colder climates. It is much like the "heat riser" on some of the older cars. Like the valve on one side of the exhaust that forces exhaust gasses to go through the intake to warm it up. More recently, starting in the late 60's the automakers started to take the heat from the exhaust manifolds to get the car up to tempreture faster. As the car would get warmer, there would be a valve to redirect the air to a cooler source, IE the front of the car. These were in place to help with drivability, emissions, and better fuel economy.

With our Fuel injection, these things are no longer needed, the computer compensates for the differences in tempretures of the engine, incoming air, etc.

To get back on topic, the throttlebody bypass would probably give you only a little benefit, I noticed NONE, but I did it anyway. If you live in a colder climate, less than 50°F then I would leave it on.

Thats my opinion.

As for knowing about Aircraft, my father & sister are pilots, and My father owns a Cessna 172. I also happen to work in the Aviation industry.

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87 Formula Yellow/Black
Engine & Transmission
.040 over 5.0 converted to TPI, 9.5:1 Compression, SLP Cam Dur 206/212, Lift 480/487, Cent Line 112, SLP headers, SLP cat-back exhaust, K&N Airfilter, Modified Stock cold air intake, Ported & polished Stock TPI intake, Holley Adjustable Fuel Press regulator, AC Rapidfire Spark Plugs.
Gil Younger (no yo-yo) Shift Kit, Aluminum Driveshaft, 3.73 Posi gear
Suspension & Brakes:
Baer 12" brakes 4 wheels, KYB AGX Adjustable Shocks & struts, Hotchkis strut tower brace, South side machine frame connectors, Custom reinforced control arms and pan hard bar.
Interior:
Custom Leather interior, CUSTOM Yellow Gauge Faces, Kenwood Receiver, Pioneer Speakers, Kicker Substations, Kenwood 10 Disk Changer, Pioneer Amp.

87 Formula TPI (5 Speed) Yellow/Gray STOCK

1967 Buick Riviera 430hp Turns high 14's (Not bad for 4300 lbs)

83 Camaro (Parts)
83 T/A (parts)

http://www.3rdgenformula.com

 

The "icing of the throttle blades", while valid does not really occur except in the coldest of climates. I have driven my car (with the TB Bypass) in 0*F with NO PROBLEMS.

The reason GM has coolant going through the TB is to help in calculating whether the engine is fully warmed up. Part of the code in the eprom compares the MAT to the CTS. Also, the EGR is controlled by the MAT temperature. With a TB Bypass, your EGR will cease to function when the temperature gets around 30-40*F...this will cause you to burn a lot of gasoline and put you in "warm up" mode.

Something to think about when you bypass the TB. It can all be corrected in the eprom however.

 

OK Okfoz I will stand corrected on the airplane theory. It's been too many years since my lessons in the 152 and my last 55 landing were in an ultralight which DEFINITELY doesn't deal with carb heat.....LOL.

I do however remember reading the design on the throttle body had to do with icing of the plates but I'll even stand corrected on that until I can substantiate it. All the theories also mentioned sound very feasible.

 

can anyone substantiate what glen is saying,i find it kinda hard to beleive because my throttle body gets really hot after the plenum heats up.so i assume the plenum heat would just warm it up the same as coolant.

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1987 Trans AM GTA
305 5SPD
Hypertech airfoil
gutted maf
kn filter
High Flow Cat,
3"Walker pipe
Dynomax Super turbo Muffler
TB Coolant bypass

 

Get a Scan Tool and read the "hac" for the eprom. All the proof is inside their.

I should point out that MAF cars work slightly differently. First, the MAF compensates for air temp. As far as the ecm goes, it has no bearing whether you have a relocated MAT and/or a bypassed TB; it does not affect how the ecm calculates air flow. On Speed Density, a relocated MAT and/or TB Bypass DOES affect the calculation of the incoming air flow. Unfortunately, it tends to overcompensate and runs on the rich side.

As for the EGR, in both MAF and SD, if the ecm detects an MAT reading of betweeen 30 and 40*F, it turns off the EGR which affects a lot of calculations.

 

feel the radiator hose after your engine has been running for a few minutes.... imagine that boiling hot .... going through your throttle body.....not good

 

Hey Andrew I could help you do it at the next COFBA meeting. its as easy as pie.

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91 Z28 5.7l Camaro
T-56,McLeod Street Clutch, Cross Drilled Brakes, KYB's,AFPR, 3.73 Gears, Borla Adjustable Cat Back, Hypertech Chip, Hooker Headers.
more to come....
My 91 Z28

 

yeah i did it in like 20 min. i'm gonna get a longer hose so i don't have to connect the two hoses together.
thanks though
Andrew