Polished Throttle Body and TB Coolant Bypass MODS

[ToolGuy]

Over the weekend I got adventurous and thought what would happen if I polished the throttle body and by passed the throttle body coolant lines? First off polishing the TB is simply polishing the rough casting or smoothing the TB walls. Maybe you have heard the term Polished and Ported Throttle Body? This is a poor mans version...This was the first time I have even done this so I am not even sure you could port the Vibes TB, did not know what to port so I just polished it. The TB coolant lines are there to heat the air going into TB so the engine warms up faster. The down side to this is the air going into the engine is extremely heated; over 200 degrees. Obviously in the winter you would want the lines connected to heat the TB and I will have to reconnect the lines come winter... With another vehicle of mine some guys swear by the TB coolant by pass, others say it is a waste of time. The car mentioned currently does not have this mod. Its engine likes a certain heat range and I left it that way, it does have a CAI set up though. However with the Vibe I said it cannot hurt and only took minutes to do. Here is a TB before polishing pic...

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[ToolGuy]

Here is a TB after pic...Bottom of TB, not too much to polish here...

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[ToolGuy]

TB after polish top side...You should be able to tell a difference looking at the TB walls.

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[ToolGuy]

TB coolant By Pass lines. You must take these off to get the TB off anyway.Had to make a union and a faucet pipe donor worked fine, two new clamps too.

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[ToolGuy]

So the results you ask...Honestly we only drove the car twice over the weekend very short trips and with the air on. The car sounds the same BTW, no change there. I do not have a CAI kit on this car, could put one on but my wife drives it and she does not want one, either do I. I feel at the very least throttle response may be better. Once she drives it on the highway and with the air off, she may notice a bigger difference.IMO, if a CAI kit were added you may see and feel it better.Both mods took me about an hour, cost nothing and the TB coolant line clamps were the bear! Threw those right out once I had them off! I ended up using a screwdriver against the clamp and pushed them off the nipples! They sucked...Do these mods with a cold engine, you will lose less coolant and not get burned. You will drop a tad but work fast and keep the hoses tilted upwards.

[drunkenmaxx]

huh huh, you said nipple.

[Mr. Poopypants]

Quote, originally posted by drunkenvibe »huh huh, you said nipple.You beat me to it!!

[ToolGuy]

Quote, originally posted by Mr. Poopypants »You beat me!!

[Mr. Poopypants]

What did you use to polish the TB?

[drunkenmaxx]

Quote, originally posted by MiVibe-ToolGuy »i want to put one of these on drunkenvibe's nipple

[ToolGuy]

Quote, originally posted by Mr. Poopypants »What did you use to polish the TB?I used 1000 Grit sandpaper, followed by a Scotch Bright pad. Cleaned throughly afterwards.

[Mr. Poopypants]

See, now I'm curious, I may try that out. How tough is it to get the TB off? It doesn't look all that bad, I will have at least take the CAI off a little bit. Are the TB bolts torqued?

[ToolGuy]

Quote, originally posted by Mr. Poopypants »See, now I'm curious, I may try that out. How tough is it to get the TB off? It doesn't look all that bad, I will have at least take the CAI off a little bit. Are the TB bolts torqued?Yeah, probably move it out of the way at least. It really was not that bad... In fact I left the cam cover on while doing it. Again those TB coolant lines were pain but have to come off. Once off, four TB fasteners, 2 bolts & 2 nuts hold it in place. One of the bolts goes through a bracket and the bracket nut needs to be loosened. That bolt is on the front of the engine, still easy to get to and same size as the TB fasteners. The PCV hose was bonded to its pipe a bit, strong twist broke it free and after disconnecting the IAC and Throttle Position sensor connectors, and throttle cable, it was off. All the TB fasteners are tightened to 16 Lbs. Ft. per the GM serv manual. Composite intake have to be careful! I covered the TB plate with duct tape from the sand grit and the Idle Air Control port just to be safe. The PCV port is a straight exit so I did not cover it up.

[rlfreese]

let us know if it makes any power Mr. Poopypants, i am getting my CAI and will do this before i install it if it is worth the hassle

[Mr. Poopypants]

Quote, originally posted by rlfreese »let us know if it makes any power Mr. Poopypants, i am getting my CAI and will do this before i install it if it is worth the hassleThis may be a "down the road a bit" project. I have not had much time to work on the car with the new house and a wedding in less than 2 monts. I will let you know if I do it though.

[rlfreese]

that is cool. if i get it done first i will let you know. kinda debating on using my accident settlement money on turbo or body kit, i have an 05 with DBW and waiting tor the ATR turbo to hury up.

[BlueCrush]

I also did hte TB coolant by-pass mod this weekend and also noticed a small increase in acceleration when the engine is at operating temp. Just because now the air is not getting heated up after passing thru the TB. I will have to hook it back up for the winters though. It was only a 15 minute procedure for me so that 's not too bad.

[Ponyota]

There should be a little better response and a little better gas mileage. Great mod you guys!

[THE VIBERATOR]

Hmmm...i was thinking about doing this mod to my vibe...which lines are the coolant lines on the throttle body, and do you have to take the TB off to get the coupler on?

[carbonwidow]

OK so don't polish the TB! its a waste of time and isnt going to do any good. the whole purpose behind porting is used on the intake ports and polishing is used on the exhaust ports of the head. by polishing the exhaust side of the head you make the side of ports larger, smoother, and shiny. which movies the exhaust gases out faster allowing more to exit the piston cylinder. and porting is only making the intake ports larger so MORE air can go through them. so in the case of the TB you really cant make it any bigger by polishing it. and the rough surface helps create a small cyclone affect which helps the air and fuel mix better in the cylinder. look at the TB spacer they are grooved to increase the cyclone affect and give yo more hp. so polishing might hurt your hp but im pretty sure that it wont give you any gain. now you cant get a bored over TB from http://www.maxbore.com but that really the only way.now the coolant bypass does work and is a cheap HP gain.

[northvibe]

I had a TB that was bored at maxbore. mixed with a throttle rotor it was a very good mod.

[djb383]

The automotive experts I've talked to, and read in their published articles, state that the purpose of flowing coolant around the TB is to prevent ice from forming on/sticking to the backside of the butterfly, which would disturb the airflow, especially at idle. It has nothing to do with heating the intake air. Virtually all modern cars have factory cold air intakes, so what's the purpose of taking in cool air from outside of the hot engine compartment and heating it????

[Silversn95]

Quote, originally posted by djb383 »The automotive experts I've talked to, and read in their published articles, state that the purpose of flowing coolant around the TB is to prevent ice from forming on/sticking to the backside of the butterfly, which would disturb the airflow, especially at idle. It has nothing to do with heating the intake air. Virtually all modern cars have factory cold air intakes, so what's the purpose of taking in cool air from outside of the hot engine compartment and heating it???? And we have a winner!! You are correct, the heated throttle body is not there to get the engine up to temperature faster or to heat the incoming air. It is there to prevent the icing of the throttle body under certain cold weather operating conditions. Neither mod is really going to gain you anything but an iced-up throttle body will definitely affect your cold weather driveability.

[djb383]

.......and if certain conditions are ripe (humidity, air speed across the butterfly, location of the TB, etc.), ice can form on the backside of the butterfly even though ambient temps may be well above freezing.

[Wokyerdog]

ok, so on one hand we have ice on the butterfly valve, possibly preventing a bit of airflow and creating a leaner mix. Power loss - increased engine wear.On the other hand, we know that the intake air is superheated to 200 deg (proven?). From my limited experience, the cooler the intake air, the smoother the engine runs. Power gainI guess my question is this. How common would the icing be on the TB if we bypassed the coolant lines? I would suspect that if icing does occur, it wouldn't happen right away. Maybe this mod needs something additional like a open/close valve for the bypass lines. This way you can bypass it when you are at the track or setting up for a quick race.Just a thought..-wok

[BlueCrush]

I've had mine bypassed for 3 winters now and had zero problems. It's been down to -20F actual temp and it has not frozen up yet.My cruise cables did freeze up once though after a car wash in winter.