02TransAm/Batmobile

iTrader: (32)

Since winter is approaching and Chicago weather could get below zero, should i reconnect the Throttle Body Coolant lines??
thanx

TORCHD 02 TA

iTrader: (39)

store the car that is what i did

02TransAm/Batmobile

iTrader: (32)

if you own one car and have to go to work and school?? i wish i could

02TransAm/Batmobile

iTrader: (32)

oh yea, and great h-pipe set up!

Shallow Bay

iTrader: (3)

https://ls1tech.com/forums/showthrea...ight=tb+bypass

02TransAm/Batmobile

iTrader: (32)

hmmm, . . now im wondering if the TB bypass is worth anything at all cuz of what 300bhp says, which makes sense, . . . . . .

300bhp/ton

Yep I totally believe the TB coolant exists purley for cruise mpg and emissions. It will have ZERO affect on the TB freezing.

There are plenty of cars which have TB's and don't have coolant running thru them. Alternativly there are many CARB setups which have coolant running thru the intake manifold? Is this to stop the intake manifold freezing????? Even though it has no moving parts NO!!! It's there for cruise economy and emissions purposes.

Think about it, if it's so cold that a METAL TB freezes completly shut, then the valves and pistons will also have frozen solid and most likely the coolant as well.

Even if it did freeze shut, the coolant in the eninge will be very cold, well below 0 degrees C, so it would not help in unfreezing the TB. In fact until the engine had warmed up (5 mins +) it would actually help to keep the TB frozen in much the same way as a freezer/refridgerater does when you are trying to keep you beer cold.

Look at the physics behind what it does. Failing that just try logic and common sense.

Internet folk lore is for the TB coolant utter bollocks!

JohnnyC

There seems to be alot of confusion over this, so I will try to clear up a few things:

The air traveling through the throttle body has significant volume and speed, and the heat transfer surface area between the air and the throttle body is small. The bottom line: the coolant flowing through the throttle body has NO effect on the temperature of the air that goes into your engine. The coolant does, however, have an effect on the temperature of the throttle body itself. The purpose of the coolant is to heat up the throttle body. This prevents the formation of ice (unlikely) on the throttle body from EGR and/or PCV water vapor. More importantly, the heated throttle body helps to minimize the formation of carbon on the throttle body. The carbon comes from the EGR and/or PCV systems, and is less likely to stick to heated materials (adhesion properties). The swiping action of the throttle body self-cleans some of the carbon that builds up, but not all of it. Overtime, GM thought that carbon can build up on an un-heated throttle body and cause TB sticking issues. I think that the key word here is overtime. I doubt that all of the guys that have done the TB bypass mod will have to worry about carbon build-up causing the throttle to stick open, so please don’t think that I am turning this into another “is the TB bypass worth it” post. Keep in mind that GM has to design these cars for the common everyday idiots that will drive their cars for 200K miles, never change the oil or clean the fuel system, never change the PCV valve, or filter of any kind, and wonder why their car has a dirty engine. Just wanted to explain the logic behind GM’s madness...

TORCHD 02 TA

iTrader: (39)

thanks for the compliment

5_02ls1

iTrader: (20)

lol hey jonny c you forgot about the high speed floormats as far as the coolant bypass you shouldnt have any freesing problems the underhood temp should keep anything from freesing up this was just an egr thing gm done ford has done this for years and most people just do away with it i have on many vehicles and i live in sw va and it drops below freesing here quiet often never had a problm id find a cheap beater for a winter ride and store the fbody just my 2 cents

98TA a4 3.73 pp3 ported tb and maf slp lid k&n flowmaster cat back crane wires

joecar

Not to prevent freezing, but to prevent icing due pressure/temperature drop that occurs when air speeds up when flowing past a constriction (ventrui effect); even tho the TB has no venturi, the effect is the same due to the throttle blade.

NHRAMAN

iTrader: (1)

we are very happy for you.... ..not everyone can do that. also that is NOT what he asked. me, living on the left coast, we don't have to worry about snow, except on the Mountains. [BTW...Bypass is a waste of time,unless you are removing it occasionally]

notatruews6

iTrader: (3)

Ive heard that the TB Coolant System helps warm the intake charge in colder climates? I dont know, im not going to worry about it here in SW Missouri, it dont get cold enough. if its that damn cold out side im not gonna go out into it...

joecar

The airmass flows past the TB too quick to be heated by it.

02TransAm/Batmobile

iTrader: (32)

hmm, somebody gots to do some dyno runs and track times on this!

300bhp/ton

Interesting take, but logically and in the laws or physics I would disagree.

At WOT I would agree, however at cruise and low throttle conditoins the air moving thru the TB will have time to be affected by it. How different do you think a regualr car heater works when on maximum fan speed?

Think about it, a 2.73 geared auto will turn 2000rpm @ 80mph with next to no throttle input, in this instance the TB blade is almost fully closed and the air flow thru it is very slow (by comparison). This means the IAT's will be a little high and will promote better cruise fuel economy.

Alternatively at idle, the TB blade is closed so the air flow is very very slow by comparison. This allows the heated TB to have a greater affect. This is where it will help with emissions, as most emissions test must be measured when the engine is up to full operating temperture.

If it's unlikely why does it exist?

Also if the engine is HOT and running then it wouldn't freeze regardless. And on cold engine NOT running the coolant would be cold and NOT flowing. = No help at all to prevent freezing.

EGR = Exhaust Gas Recirculation. This is an inert HOT gas taken from the exhaust manifold. This will not freeze on any component under the bonnet, unless it's sold cold out that the engine itself is frozen.

PCV - again is a hot gas.

ummm, maybe. But there are plenty of other cars which don't have a heated TB but also don't suffer carbon build up.

Plus if this is to prevent, then it means it would occur. There are plenty of people (1000's) who have done the TB by-pass mod and run for 50l, 80, 100k miles with no carbon build up.

And what about carbs, older carbs may have PCV/EGR and they still have throttle blades, they don't suffer carbon build up and nore do they freeze either.

So it would be very evident to see carbon build up on a TB then. Care to post a pic of a LS1 TB with carbon build up? If its such a MAJOR issue that GM designed a heated TB to aviod it then there should be pplenty of evidence to back up the suspicion.

Nice, but the Ls1 has been about for 10 years with many having done over 200,000 miles. Not too mention it's predeceesor. So this goes back to being able to prove the carbon build up issue.

WRONG!!!!

They designed them to meet the legal requirements for emissions and fuel standards.

300bhp/ton

They would be far too inconsistant and insignificant.

The variance in HP would only be minimal. BMR have some results on their website (N.B. They sell a TB by-pass kit ). And claim it makes 'x' rwhp.

However their results are flawed because they make the most HP with the highest IAT's which totallt goes against what they are trying to prove.

Measureing the IAT's from within the intake manifold under various conditions will give an indication of how much affect TB coolant or the lack of (by-pass) has. From this you can discern expected HP variance and affect on performance. But I personally beleive under fair conditions you will be talking about hundreds of a second difference maybe even less. In terms of 1/4 mile performance.

JohnnyC

Woah! You seem very intense on this subject, but try to forget your preconceived notions and listen to what I am saying. I am a design engineer and have worked for GM, so I know a little about a little. Your comparison of engine air passing through a throttle body to your heater is a bit off. The heater core has a huge heat transfer surface area compared to the throttle body, and I can post some equations for you if you would like. The amount of air your engine uses even at highway cruise speeds is still significant and is still not really affected by passing by the heated throttle body. The freezing of the throttle body does not happen when the car is parked on a cold night. It happens when cold air feeding a running engine flows through the throttle body (venturi effect) and cools any water vapor left by the PCV or other source. This can cause ice to build up in the TB under some conditions. Yes, there have been throttle bodies over the years that did not have engine coolant running to them, but some of them were problematic; Did you know that many cars had to have throttlebody heaters installed later because of TB freezing issues? There are many factors as to why some TB freeze and some do not, such as under-hood engine temps, length and location of the air intake ductwork, TB geometry, ect. The carbon build-up is also a real issue, and has nothing to do with government emissions regulations. It is an attempt by GM to address throttle sticking concerns that have been brought up by their customers. Simply saying that many cars run for years without carbon or ice problems is not enough to write off the design intent affecting thousands of cars in multiple climates.Once again, I am not arguing for or against doing the TB bypass mod, I am simply trying to explain why the TB is heated in the first place.

2000LS1TA

iTrader: (26)

Buy A Beater!

JohnnyC

I was tired of hearing everyone talk about the "laws of physics", so I decided to actually post some of them.

Here is a simplified (believe it or not) calc showing the effect of a 200 degree throttle body on intake air temperature:

Assumptions:

1) Outside air temp (Tin) = 70°F (21°C, 294°K)

2) Throttle Body is maintained at a temperature of 200°F (93°C, 366.5°K), which maintains the average TB to air temperature difference (Tave) at 72.24K, (conservative).

3) The throttle body flows 100 CFM of air at idle.

4) Heat Transfer Coefficient (h) of 6.81 W/ M^2-K is used for air cooling steel.

The following equation describes internal flow heat transfer through a thin-walled tube with a constant surface temperature:

h = (mfr) (Cp) (Tout – Tin)
( 3.14 ) (Dia) (Length) (Tave)

Where:
h = Heat Transfer Coefficient (6.81 W/ M^2-K is used for air cooling steel).

mfr = mass flow rate of air, calculated using an air density of 1.16 kg / m^3

Cp = specific heat of air at 21°C and atmospheric pressure = 1007 J / Kg-K

Dia = throttle body diameter

Length = throttle body length

Tave = average temperature difference between the TB and the air

mfr = (air volumetric flow rate) x (air density)

mfr = 100 CFM = 100 ft^3 / min = 2.83m^3 / min

mfr = [2.83m^3 / min] x [1.16 kg / m^3] x [1 min / 60 seconds] = 0.055 kg air / sec

By rearranging the equation above we can solve for Tout and finally determine just how much the hot throttle body heats up the air going to the engine:

Tout = Tin +

(h) ( 3.14 ) (Dia) (Length) (Tave)
(mfr) (Cp)

Tout = 294.3°K +

(6.81 W/ m^2-K) ( 3.14) (0.076 m) (0.102 m) (72.24°K)
(0.055 kg air / sec) (1007 J / Kg-K )


Tout = 295 °K = 70.5°F

To recap; that’s an increase of just 0.5 degrees at the worst-case, low-flow idle condition.

At a higher airflow of 500 CFM the temperature only rises 0.14 degrees to 70.14°F!

Hopefully this will help people see how little of an effect that heating the throttle body has on the intake air temperature.