[Sankar]

I did a throttle body coolant bypass mod today morning, all it takes is some 30mins of time with some elbow grease and coolant on your hands. Its a 0 Paisa mod so even if it doesn't produce any gains there is nothing to complain about. But since an engine runs best with colder air there might be some gains however miniscule it might be because of the plastic manifold. In our climate i see no reason why the TB needs to be warmed up as it doesn't help in performance and it doesn't get anywhere close to freezing here.

Hoses disconnected from throttle body


Bypassed and connected back into the main coolant tube

[anandpadhye]

You mean you circulated coolant around throttle body (which wasn't happening before) or the other way round? Any change you see in the Inlet Air Temp?

[Sankar]

Coolant which flows into the TB in a stock configuration is now bypassing the TB. The inlet air temperature reading will not change because the IAT sensor sits before the TB.

[pramodkumar]

good thinking Shanker, the coolant gets heated up and even if you have a CAI, the air will still be getting warmed up and will lean out, mixture runs rich, but in a closed loop system like ours how will this impact? I agree in theory this works, however, i have felt slightly unresponsive engine during cold starts and it is fine when the temp gauge is reading its optimum, am i missing something?

Pramod

[Sankar]

One thing is in our climate its not going to be detrimental to the performance of the engine since an engine makes the most when it gets cold air. The temp may or may not drop a degree with this simple mod, if it does well and good, if it doesn't nothing is lost! On international forums I have read the experiences of other people staying in cooler climes reporting no loss of reliability with this mod.

There is no dyno report anywhere stating that this mod made anyone lose power, but there are some reports which says this mod help them make some power.

Eg: http://www.ws6.com/mod-8.htm

http://www.ls1gto.com/forums/showthread.php?t=3265

So even if my small engine doesn't get me a 6BHP gain (which it won't) i would still be happy with whatever miniscule gains it might provide because its a gain.

PS: I think engines with cast aluminium manifolds will see better results with this mod compared to newer engines running plastic manifolds.

Edit: Engine being unresponsive in cold is due to the whole engine being cold, the fluids are also cold and components are not upto its optimum operating tolerances. When the engine is at its optimum operating temperature it performs the best because thats when the components inside begins to work at its correct tolerances and the fluids flow well. Its got nothing to do with the cold air ingestion, cold denser air has more oxygen so thats a good thing.

[alpha1]

To think of it - why would there be a throttle body heating design by the manufacturers?

[dhawcash]

hello sir,

Which car is it? what engine? This is something new for me. The coolant is circulated in the intake manifold to preheat the air in colder climates- am i right? and seems like its a diesel?

[ecenandu]

Originally Posted by dhawcash

seems like its a diesel?

Hey, Are there throttle bodies on diesel engines?

EDIT: Diesel engines are fuel-led, hence the above question. Looks like modern diesel engines do have throttle bodies with buttery fly slide to control air to meet stricter emission norms

[Sankar]

Its a 2012 Swift 1.2 VVT (Petrol). Yes its done to preheat the air in colder climate and also to prevent the icing of throttle body.

[Sankar]

I have noticed a slight difference in pulling (torque) after this mod, i can feel that the car is pulling slightly better than before - off idle and midrange. Didn't (couldn't) test the top end performance. I noticed this difference yesterday itself, but wanted to wait one more day and confirm before i post it here. So there is no question of going back to stock config now

Some more net digging yielded this..

Originally Posted by Del33t

Here's some findings, please note these were performed on a Subaru Impreza RS (non turbo):

Ok folks, I ran some numbers and here is the comparison of intake air temp before and after the TB bypass mod. The numbers were taken on 2 different days, both within 1 degree of outside air temp, 60 and 61 degrees. I measured the temp while driving to work the same route, about the same style of driving, same conditions. First graphs shows before and the second shows after the mod

Before bypass:

After bypass:


What is important is the trend, not the spikes although their behavior is also interesting. The average difference is about 15 degrees less when running with TB bypassed. The bypassed run hung between 85 and 90 degress F while the run with no bypass ran around 105 and 110 F. This difference can be felt which these numbers confirm.
The spikes in the temp are due to rapid acceleration which produces rapid heat soak in the TB. When the TB is bypassed, the spikes are lesser when compared to the other graph's counterparts, taking into account the same throttle position as which is a good indicator of how hard the engine is working.

These numbers are without the phenolic gasket which will make things even better.

The phenolic gasket that he speaks about is not important in my case since the manifold is nonmetal.

Src:http://www.wrx.com.au/forum/viewtopic.php?t=25718

[dhawcash]

Originally Posted by Sankar

I did a throttle body coolant bypass mod today morning, all it takes is some 30mins of time with some elbow grease and coolant on your hands. Its a 0 Paisa mod so even if it doesn't produce any gains there is nothing to complain about. But since an engine runs best with colder air there might be some gains however miniscule it might be because of the plastic manifold. In our climate i see no reason why the TB needs to be warmed up as it doesn't help in performance and it doesn't get anywhere close to freezing here.

Hello sankar sir.

I am working on a suzuki G16B unit and dis assembled the head for cleaning and further work.

While dismantling, i noticed, for the first time ever in my life (well im dismantling a suzuki head for the first time as well), the coolant pipes running to the throttle body and the first thing that crossed my mind was your thread.

turns out, the coolant circulates only at a corner of the throttle body (image attached- yeah thats why i said it needs cleaning ) but the assembly being aluminium, must be getting heated around the perimeter. also, the ports combine to make a nice digital smilie.





Planning to do the same mod in my esteem's G13B tomorrow morning first thing.

Thanks for the thread!

[Sankar]

Originally Posted by dhawcash

Hello sankar sir.

I am working on a suzuki G16B unit and dis assembled the head for cleaning and further work.

While dismantling, i noticed, for the first time ever in my life (well im dismantling a suzuki head for the first time as well), the coolant pipes running to the throttle body and the first thing that crossed my mind was your thread.

turns out, the coolant circulates only at a corner of the throttle body (image attached- yeah thats why i said it needs cleaning ) but the assembly being aluminium, must be getting heated around the perimeter. also, the ports combine to make a nice digital smilie.

Planning to do the same mod in my esteem's G13B tomorrow morning first thing.

Thanks for the thread!

Go ahead! Try to get a phenolic manifold gasket or try to get one made from an insulating material to insulate the manifold from cylinder head heat. I believe that too will make a difference.

Call me sankar or bro, no need for sir

[Sankar]

This was attempted on my friend's 2007 MPFi Esteem, since we couldn't find the coolant pipes going into the TB (as listed in the diagram in the parts catalog) we took it to a garage and the mech after inspecting the Tbody told us that this car doesn't have it. He went on to say that the previous model MPFI Esteem had this; prolly that is why it was illustrated in the diagram.

So the 2007 Esteem doesn't have this.

[im_srini]

Originally Posted by dhawcash

... the coolant pipes running to the throttle body and the first thing that crossed my mind was your thread. Turns out, the coolant circulates only at a corner of the throttle body

Yes, you're right, the coolant is circulated through a small chamber at the back of the throttle body & basically serves to heat up the throttle body. Will post pics of the Swift's throttle body.

Originally Posted by Sankar

Go ahead ! Try to get a phenolic manifold gasket or try to get one made from an insulating material to insulate the manifold from cylinder head heat. I believe that too will make a difference.

When I was trying to source Black-Phenolic-AA grade sheets a few years ago for the intake gasket, I was told that Phenolic-AA material was not made anymore (instead was directed to G-11/FR-5 Epoxy Sheets).

Originally Posted by Sankar

This was attempted on my friend's 2007 MPFi Esteem, since we couldn't find the coolant pipes going into the TB (as listed in the diagram in the parts catalog) we took it to a garage and the mech after inspecting the Tbody told us that this car doesn't have it. He went on to say that the previous model MPFI Esteem had this; prolly that is why it was illustrated in the diagram. So the 2007 Esteem doesn't have this.

Similar thing here. Surprising that coolant circulation through the throttle-body was present, then removed in later models, & now appears to have been reinstated !?!

[dhawcash]

Did the 2007 esteem comes with a phenolic gasket by any chance?


Ive told my hardware guy to arrange some Bakelite sheets, which according to Wikipedia,has a continuous operating temperature of 121 degree Celsius. (Bakelite comes under the category of phenolics)

have not removed the system in my esteem yet, the G16B is keeping me busy for a while. But ill do it as soon as i have the Bakelite sheet with me. Should take around two hours to fabricate and install a phenolic gasket.