Big Bore Throttle Body installed............

[Duke]

I had this BB throttle body from the OH days. I did not install it because it was not black like the rest of the intake and engine. I just got it back from the powder coaters. I reassembled it and slapped it on. It has made a difference, all of my fuel setting under partial throttle and low MAP were running too lean. I had to add fuel across the board to get the A/F ration back into the 14s.

I am currently working thru a fuel delivery issue and can not boost the car. Once the new pump and filter is installed tomorrow, I will then know how it does on boost. I suspect very well.

It was bored 10% larger..............so that should be 21% more air (thanks Shawn) allowed to enter the engine. Hummmmmmmm, I wonder what the air restriction is now?

So I have the B35 TB for sale now. It is in perfect condition and powder coated black. The B35 is nice because it has a idle stop screw and is tapped for the TB cover. I would be happy with $80 for it.

[T_C_D]

I had this BB throttle body from the OH days. I did not install it because it was not black like the rest of the intake and engine. I just got it back from the powder coaters. I reassembled it and slapped it on. It has made a difference, all of my fuel setting under partial throttle and low MAP were running too lean. I had to add fuel across the board to get the A/F ration back into the 14s.

I am currently working thru a fuel delivery issue and can not boost the car. Once the new pump and filter is installed tomorrow, I will then know how it does on boost. I suspect very well.

It was bored 10% larger..............so that should be 10% more air allowed to enter the engine. Hummmmmmmm, I wonder what the air restriction is now?

So I have the B35 TB for sale now. It is in perfect condition and powder coated black. The B35 is nice because it has a idle stop screw and is tapped for the TB cover. I would be happy with $80 for it.

Duke,

I think you are dreaming. The charge pipe from the turbo to the intercooler is 2". No way the TB made a difference.

Todd

[Shawn D.]

It was bored 10% larger..............so that should be 10% more air allowed to enter the engine.

Duke, we went over the math the last time you made the 10% = 10% statement, remember? The area of a circle is pi*r2, so the increase in area is actually 21%, not counting the area subtracted by the throttle shaft.

That having been said, I'm with Todd on this.

[DMNaskale]

Maybe the fuel delivery problem is making it run lean? The air still has to squeeze past the butterfly, the only time that thing could be of any benefit is WOT.

[Andy335Touring]

If i ever get around to fitting it this is my take on a BBTB, 2 x 60mm



Sorry, i might have already posted this up before ?

[m.olennick]

Jesus you are intense!

[Velocewest]

That fits well. Is that the Chevy piece?

[Andy335Touring]

That fits well. Is that the Chevy piece?

Ford V8 of some sort

[Duke]

Duke,

I think you are dreaming. The charge pipe from the turbo to the intercooler is 2". No way the TB made a difference.

Todd

I disagree. The 2" pipe from the turbo to the intercooler not a factor. If it were in front of the turbo it would be. The air is compressed and pushed through that 2" tube and then it expands inside the inter cooler and travels through the 3" pipe through the TB and into the intake manifold. The intake is a even bigger chamber. An opening to that intake manifold that is bigger, i.e. a 21% larger throttle body, will offer less resistance (in necking down the flow) and thus allow more flow of the compressed and expanding air from the turbo. The perfect TB opening would be 3" to match the 3" feed tube.

You will also notice from the picture that the TB shaft has been machined down along with the screws. This will also increase flow/ limit turbulence. Take a look at a stock TB and you will see how thick the center rod is and it will have the head and the shaft of the screws exposed. I used to modify SU carbs this way and two SU carbs that were set up right would yield more powder than a two barrel weber.

If the size of a TB does not matter on a turbo engine, put a TB from a 1.8L M10 on your engine and see what happens.

Todd likes to poo poo my ideas - Hummm, lets take a look at this closer.

Todd poo pooed my TEC3 stand alone. He felt the Motronic was fine for FI. Todd now offers a MS stand alone in his s3 package.

Todd poo pooed my Hartge H5s cylinder head with bigger vales and porting. Todd now recommends the B35 head which has bigger intake valves and different porting (still is not as good as my H5s though .

Todd is poo pooing my water injection system. I bet the future holds a TCD WI system.

Todd is poo pooing a BB TB. Hummmm.....time will tell on this too.

Love ya Todd......................I have no problem being the TCD "shadow" R&D guy

[Matt]

why not measure the pressure on either side of the TB at various throttle angles to see if it matters at all? is that the wrong measurement to make? if so, what's the right measurement?

[Duke]

why not measure the pressure on either side of the TB at various throttle angles to see if it matters at all? is that the wrong measurement to make? if so, what's the right measurement?

Dyno numbers with and without. Problem is, the tuning must be changed for the larger TB. Not worth the time or money to get the numbers.

[M635CSi]

Duke,

I think you are dreaming. The charge pipe from the turbo to the intercooler is 2". No way the TB made a difference.

Todd

I disagree. The 2" pipe from the turbo to the intercooler not a factor. If it were in front of the turbo it would be. The air is compressed and pushed through that 2" tube and then it expands inside the inter cooler and travels through the 3" pipe through the TB and into the intake manifold.

Isn't it true the purpose of the intercooler is to make more dense the charge air within it's core by negotiating the heat of compression for a decrease in charge air temperature?

The intake is a even bigger chamber.

The purpose of that "even bigger chamber" is as a plenum to provide a specific volume for proper cylinder filling. This plenum is a specific fixed volume which is now incorrect in size as it was originally based on calculations for an engine of natural aspiration.

An opening to that intake manifold that is bigger, i.e. a 21% larger throttle body, will offer less resistance (in necking down the flow) and thus allow more flow of the compressed and expanding air from the turbo. The perfect TB opening would be 3" to match the 3" feed tube.

Don’t confuse reducing air restriction with increasing volumetric efficiency or increasing charge air velocity. It may seem intuitively they always go together, they do not.

You will also notice from the picture that the TB shaft has been machined down along with the screws. This will also increase flow/ limit turbulence. Take a look at a stock TB and you will see how thick the center rod is and it will have the head and the shaft of the screws exposed. I used to modify SU carbs this way and two SU carbs that were set up right would yield more powder than a two barrel weber.

Carburetors work on different principles to fuel injection. I believe the SU carburetors you refer to are of the constant velocity type which self regulates intake charge velocity. The intake tract on the M30 engine has no such facility. It should be further noted that limiting charge air turbulence can also reduce power and torque.

If the size of a TB does not matter on a turbo engine, put a TB from a 1.8L M10 on your engine and see what happens.

Oh it matters, I suspect putting a TB from a 1.8L M10 on an M30 would reduce the RPM at which maximum volumetric efficiency was reached.

Todd likes to poo poo my ideas - Hummm, lets take a look at this closer.

Todd poo pooed my TEC3 stand alone. He felt the Motronic was fine for FI. Todd now offers a MS stand alone in his s3 package.

Todd poo pooed my Hartge H5s cylinder head with bigger vales and porting. Todd now recommends the B35 head which has bigger intake valves and different porting (still is not as good as my H5s though .

Todd is poo pooing my water injection system. I bet the future holds a TCD WI system.

Todd is poo pooing a BB TB. Hummmm.....time will tell on this too.

Love ya Todd......................I have no problem being the TCD "shadow" R&D guy [/quote
Duke, I think I speak for the group when I say we are grateful for you going first on these projects and allowing us to see and enjoy the results.

Duke, I think I speak for the group when I say we are grateful for you going first on these projects and reporting back with the results.

[Duke]

Hey Todd, where did your message go ? Well anyway, you are welcome.

Isn't it true the purpose of the intercooler is to make more dense the charge air within it's core by negotiating the heat of compression for a decrease in charge air temperature?

Yes...........what is your point in reference to the 2" tube?

The purpose of that "even bigger chamber" is as a plenum to provide a specific volume for proper cylinder filling. This plenum is a specific fixed volume which is now incorrect in size as it was originally based on calculations for an engine of natural aspiration.

Its not a NA engine anymore. I can also fully adjust the VE tables in the TEC3.

It should be further noted that limiting charge air turbulence can also reduce power and torque.

This is true, that is why you do not polish the intake ports or the manifold. I even made specific modification when porting the manifold to maintain turbulence by the injector ports. Turbulence is not needed at the TB.

Duke, I think I speak for the group when I say we are grateful for you going first on these projects and reporting back with the results.

Thank you. At least one person is willing to admit it without a smart ass tongue in cheek reply. Don't get me wrong, I enjoy doing it. It just takes A LOT of time and some money.

[T_C_D]

Duke,

Don;t forget to take credit for introducing me to my wife, fathering my children, establishing TCD and whatever elese you need to keep your rather large ego inflated.



I hate to break it to you but you have not done any R&D for us.

[Duke]

Nice Todd............you are still welcome good buddy.

"rather large ego inflated"...... , now ain't that the pot calling the kettle black. Oh, brother

[T_C_D]

Nice Todd............you are still welcome good buddy.

"rather large ego inflated"...... , now ain't that the pot calling the kettle black. Oh, brother

Shawn D reminded me that you did invent/found/establish 5erFest and I do thank you for that.

[Duke]

Nice Todd............you are still welcome good buddy.

"rather large ego inflated"...... , now ain't that the pot calling the kettle black. Oh, brother

Shawn D reminded me that you did invent/found/establish 5erFest and I do thank you for that.

And I thank you for the establishment/R&D and great customer service of TCD. I have wanted to turbo since 2001, you made it reality.

XXOOXX Duke

[j9fd3s]

[quote="Duke M535ti"]
Its not a NA engine anymore. I can also fully adjust the VE tables in the TEC3.

[quote]

the engine will still respond to the same tuning principals as an na engine, in fact the pioneers (or at least the well published examples) are the bmw F1 engines.

i think you'll like the water injection too, on the rotaries its almost magic stuff. 20+ psi, 500+ hp on a stock unopened engine....