What Throttle Body?

[JustinOlson]

I'm looking for a throttle body for my street/strip car. I'm looking for a 90mm throttle body that I won't have issues with it leaking under boost. Also, I don't want to have trouble breaking the TB shaft. What brand have you guys had luck with?

Regards,
Justin

[George Klass]

BBK.

[Racecraft Inc.]

Accufab or Wilson is what has worked best for us.

Mark

http://www.racecraft.com

[JustinOlson]

I'm going to be running ~40psi (import motor) and have heard of people having trouble with leakage around the throttle body shaft. Do any of the brands address this issue directly with orings or some other type of sealing method?

Regards,
Justin

[Procrew]

Justin,

Accufab or Wilson. There is no substantial leak in boost in either of those companies throttle bodies. I know of an import car running 68 # through an Accufab with no issues.

[Jeremy Glass]

I'm looking for a throttle body for my street/strip car. I'm looking for a 90mm throttle body that I won't have issues with it leaking under boost. Also, I don't want to have trouble breaking the TB shaft. What brand have you guys had luck with?

Regards,
Justin

I have a brand new accufab 90mm i will sell you for a good price if you are interested.

[n8secstangg]

im a dealer for Wilson Manifolds if interested

chad
813-784-8248

[JustinOlson]

Whats the deal with all the Toyota supra guys claiming the accufab and wilson throttle bodies leaking? Just untrue?

Justin

[63T-Bolt]

Whats the deal with all the Toyota supra guys claiming the accufab and wilson throttle bodies leaking? Just untrue?

Justin

Just another ricer excuse as to why their car isnt running right. Funniest shit I have heard there!!!



another vote for accufab or wilsion. Both build GREAT products!!

[Procrew]

Whats the deal with all the Toyota supra guys claiming the accufab and wilson throttle bodies leaking? Just untrue?

JustinJust tell them to provide PROVEN REALISTIC data and we will all shut up. Again, plenty of fast turbo cars have run great with either tb.

I think they are just giving you a sales pitch.

Here is a sales pitch for you... The fastest Modular Ford in the country is owned by the owner of Accufab. He has run 6.35, if his stuff leaked dont you think he would fix it?

[craig65]

Just tell them to provide PROVEN REALISTIC data and we will all shut up. Again, plenty of fast turbo cars have run great with either tb.

I think they are just giving you a sales pitch.

Here is a sales pitch for you... The fastest Modular Ford in the country is owned by the owner of Accufab. He has run 6.35, if his stuff leaked dont you think he would fix it?
man joe you're pretty good at that selling thing... guess that's why we plan on dontaing a healthy chunk to hyperaktive perfomance solutions!:p

[Louie L]

Ive ran the Accufab in my Buicks with great luck. For the new project I picked the Wilson over the Accufab just to change it up. But found that the Wilson 90mm necks down and requires you to get an odd ball coupler (4in to 3.75in.) Other than that the billet throttle arm is nice. Cant go wrong with either brand.

[JustinOlson]

Here's what I've read over on the Supraforums. Not trying to start shit. Just trying to learn more abou these throttle bodies before I make a purchase.

Regards,
Justin


We regularly run 50+ pounds of boost in the lights on our twin turbo engine, and we measure the boost in front of and behind the TB, and there are NO leaks. We use sealed bearings. I don't know what's the matter with yours. If you are complaining about it, why don't you send it in and have us check it out, this is done at no charge.



The only way I have EVER seen the seals leak is if someone welds on the TB (like for V-band flanges) or the linkage. This is because the heat runs down the shaft and can burn away the seals.


Responses:


Maybe it's early and I'm not thinking correctly (very possible)

But...

At the point where you measure boost before and after the throttle body...it's the same pressure...because, well... the throttle blade is opened. At that point it's like measuring boost at two points on the same charge pipe (except with an open blade in the middle).

You have to pressurize the system and see if anything leaks out, it doesn't involve pressure sensors unless you put a pressurized pipe attached to both ends of the TB *IN* another (sealed) container with a pressure sensor. If the pressure outside of the pipe/tb rises in the container, then you have a leak on your hands.


Correct. A leak will just lower overall system pressure (assuming the leak is bad enough the turbo doesn't simply overcome it by spinning faster). To bad more people do not or are not able to log turbo shaft rpm, I think they would be suprised at what they find.

The only time measuring differential across the throttle body will show a difference is if there is a restriction, and the air is "piling up" on one side.

[mEr]

I would go Accufab.

[Swampdonkey]

Here's what I've read over on the Supraforums. Not trying to start shit. Just trying to learn more abou these throttle bodies before I make a purchase.

Regards,
Justin



Responses:

Well then what do these guys all run if the wilson and accufab leak, and if your set to believe they do leak why are you asking this question?

[Brian Robards]

Well then what do these guys all run if the wilson and accufab leak, and if your set to believe they do leak why are you asking this question?

He has heard that they have a problem with leaking, and is trying to see if there are any other options on the market for throttle bodies that prove to not have leaking issues. Some other TB manufacturers claim to make a 70hp increase on a 1100 hp supra by switching to their TB. He was probably trying to determine if others have had similar results...

I have already stated this, and I know George will blast me for repeating, but the Accufab TB on my car leaks like badly around the shaft when doing a pressure test on my car. How much of a problem is this? Is this leak bad enough to drive my backpressure up? Is this costing me HP? These are questions I dont know the answer to.

[mrtbolt64]

Assuming the throttle body has .002 clearence "max" around the shaft and it does leak a little, I highly doubt it would make the slightest difference in boost.

Slap another sticker on the import and it will make up the difference of boost lost

[George Klass]

I have already stated this, and I know George will blast me for repeating, but the Accufab TB on my car leaks like badly around the shaft when doing a pressure test on my car. How much of a problem is this? Is this leak bad enough to drive my backpressure up? Is this costing me HP? These are questions I dont know the answer to.

I'm not going to blast you Brian, but I will attempt to educate you. Engines don't run on "boost" (measured in PSI), they run on "volume", (measured in CFM). "Boost" in a supercharged or turbocharged car is really a measurment of back pressure, air that is NOT getting past your closed intake valves. To make more horsepower, you have to move more air THROUGH THE ENGINE. If you want to move more air, you need an efficient throttle body, an efficient intake manifold and an efficient set of heads, etc. If you do, the air will move through the engine. If you don't, the pressurized air runs into the restrictions and will "back up" and look for a place to escape.

Let me try to give you an example. On our Cougar (4.6L, 281 cubic inches) we are running twin 78MM turbos and are making about 2300 HP at 9200 RPM on gasoline (8 horse per cubic inch). We have a 90MM throttle body. There is NO leakage anywhere on the TB and we run 52 PSI in the lights (our engine has an 11.0:1 static compression ratio, too). We have sensors in front of and behind the TB to measure this. Now, if we remove our heavily modified heads and install stock Cobra 4.6L heads and a stock cam, guess what happens? The volume of air from the turbos will NOT move through the heads, the "boost" (back pressure) will go up and the TB seals may leak. This is not a throttle body issue, this is an engine efficiency issue. Do you see where I'm coming from here?

[redvictor]

I'm not going to blast you Brian, but I will attempt to educate you. Engines don't run on "boost" (measured in PSI), they run on "volume", (measured in CFM). "Boost" in a supercharged or turbocharged car is really a measurment of back pressure, air that is NOT getting past your closed intake valves. To make more horsepower, you have to move more air THROUGH THE ENGINE. If you want to move more air, you need an efficient throttle body, an efficient intake manifold and an efficient set of heads, etc. If you do, the air will move through the engine. If you don't, the pressurized air runs into the restrictions and will "back up" and look for a place to escape.

Let me try to give you an example. On our Cougar (4.6L, 281 cubic inches) we are running twin 78MM turbos and are making about 2300 HP at 9200 RPM on gasoline (8 horse per cubic inch). We have a 90MM throttle body. There is NO leakage anywhere on the TB and we run 52 PSI in the lights (our engine has an 11.0:1 static compression ratio, too). We have sensors in front of and behind the TB to measure this. Now, if we remove our heavily modified heads and install stock Cobra 4.6L heads and a stock cam, guess what happens? The volume of air from the turbos will NOT move through the heads, the "boost" (back pressure) will go up and the TB seals may leak. This is not a throttle body issue, this is an engine efficiency issue. Do you see where I'm coming from here?
excellent explaination George... i can't build enough boost on mine,i guess it's not restricted enough...lol

[George Klass]

excellent explaination George... i can't build enough boost on mine,i guess it's not restricted enough...lol

Do what Garlits does, add 10, bump 10 and lean 10, and if that doesn't work, spin the blower 10% faster.

[Swampdonkey]

lol

[George Klass]

When we were running our twice motor digger, we ran it straight out of the can (98%). Those Chevy's ran HOT. You couldn't shut them off after a full pass, they were so hot, the plugs acted like glow plugs and the engines ran for 10-minutes after they were shut off. We could always tell if the engines were OK after a run. We looked at the inside of the zoomie headers. If they had that "aluminized look", it was time to crack open some cold ones and retreat for the day.

[Brian Robards]

I'm not going to blast you Brian, but I will attempt to educate you. Engines don't run on "boost" (measured in PSI), they run on "volume", (measured in CFM). "Boost" in a supercharged or turbocharged car is really a measurment of back pressure, air that is NOT getting past your closed intake valves. To make more horsepower, you have to move more air THROUGH THE ENGINE. If you want to move more air, you need an efficient throttle body, an efficient intake manifold and an efficient set of heads, etc. If you do, the air will move through the engine. If you don't, the pressurized air runs into the restrictions and will "back up" and look for a place to escape.

Let me try to give you an example. On our Cougar (4.6L, 281 cubic inches) we are running twin 78MM turbos and are making about 2300 HP at 9200 RPM on gasoline (8 horse per cubic inch). We have a 90MM throttle body. There is NO leakage anywhere on the TB and we run 52 PSI in the lights (our engine has an 11.0:1 static compression ratio, too). We have sensors in front of and behind the TB to measure this. Now, if we remove our heavily modified heads and install stock Cobra 4.6L heads and a stock cam, guess what happens? The volume of air from the turbos will NOT move through the heads, the "boost" (back pressure) will go up and the TB seals may leak. This is not a throttle body issue, this is an engine efficiency issue. Do you see where I'm coming from here?

Well... I guess I will do some educating as well.

A turbocharger is spec'd out based on 2 things: Pressure ratio and volume flow. The flow of a turbocharger is a function of four things: volumetric efficiency, engine displacement, engine RPM and boost pressure, where

Flow (lb/min)=RPM*Displacement (in^3)*VE*Air density (lb/in^3)

and

Air density (lb/in^3)= (ambient pressure + BOOST PRESSURE) (psi)/ R/ intake manifold temp (Kelvin)

The intake manifold temp is then a function of pressure ratio, intercooler efficiency, ambient temperature and compressor efficiency.

It can all get alittle confusing, but a simple excel spreadsheet can simplify things, which I have and used when I worked at Garrett and Holset.

A turbocharger will only flow so much before it reaches choke, and an engine that is more efficient, larger displacement or revs higher will reach that choke region at a lower boost pressure.

...

Now if there is a leak in the throttle body it would cause problems because any fluid will flow to a region of lower pressure (air would rather flow out to the ambient pressure than into a pressurized plenum). This would cause the compressor to flow at a higher pressure ratio to make up for the pressure that is being leaked off from the TB shaft. When there is a boost leak the turbine side of the turbo will need to be spun faster to make the energy needed to keep the boost pressure at the desired level (which will cause higher backpressure and less power), and because the pressure ratio is higher your intake temps will be higher which can affect power as well.

Measuring the pressure before and after the TB will only show a pressure difference if you TB is acting as an orfice, which would mean the entire TB is too small (at WOT).

[George Klass]

I think I see your problem, Brian. You are in "analysis poralysis" with your formulas. That kind of thinking can make fucking complicated.

Let me see if I can simplify this even more for you. You have dual exhausts on your Chevy Camaro. You stick a potato in the end of one of the exhaust pipes. This causes a leak to spring up in the muffler on that side because of the back pressure. Would you consider this to be a muffler problem?

Maybe you should go back to talking to your Toyota buddy.

[Brian Robards]

I think I see your problem, Brian. You are in "analysis poralysis" with your formulas. That kind of thinking can make fucking complicated.

Let me see if I can simplify this even more for you. You have dual exhausts on your Chevy Camaro. You stick a potato in the end of one of the exhaust pipes. This causes a leak to spring up in the muffler on that side because of the back pressure. Would you consider this to be a muffler problem?

Maybe you should go back to talking to your Toyota buddy.

So you just spew some import hate rather than prove me wrong...

Still doesnt help the fact that when I do a pressure test on my car the throttle body sounds like a whistle tip.

[JustinOlson]

The pressure differential is the same between the air entering the throttle body and the atmospheric air pressure regardless of the flow of your cylinder head.

The pressure differential is the driving force for a leaky throttle body.

You don't need to dumb down your analogies George. Brian and I both are mechanical engineerings. We understand fluid flow.

Justin

[njc.corp]

Justin,

Accufab or Wilson. There is no substantial leak in boost in either of those companies throttle bodies. I know of an import car running 68 # through an Accufab with no issues.

gee's

Thanks

Nick--

[Jeremy Glass]

The pressure differential is the same between the air entering the throttle body and the atmospheric air pressure regardless of the flow of your cylinder head.

The pressure differential is the driving force for a leaky throttle body.

You don't need to dumb down your analogies George. Brian and I both are mechanical engineerings. We understand fluid flow.

Justin

How do you become a 'mechanical engineering'?

[George Klass]

You don't need to dumb down your analogies George. Brian and I both are mechanical engineerings. We understand fluid flow.

Justin

So, now I understand yours and Brian's problem, Justin. You think you know what you are talking about.

[Jeremy Glass]

Im a firm believer in sometimes too many people worry way too much about whats happening on paper. All of this worrying prevents them from every racing.

[njc.corp]

it seems people do find not knowing when they have a problem-

Thanks

Nick--

[gasguzzler]

Holy crap! I actually agree with George and Jeremy in the same thread! Trying to compare a static issue (if you can even call it an issue) and comparing it to when the air is moving at crazy fast speeds at high volume is like apples and oranges in my book. Many air to air intercoolers leak too, yet Supra guys always run them.

- Brian

[Brian Robards]

Holy crap! I actually agree with George and Jeremy in the same thread! Trying to compare a static issue (if you can even call it an issue) and comparing it to when the air is moving at crazy fast speeds at high volume is like apples and oranges in my book. Many air to air intercoolers leak too, yet Supra guys always run them.

- Brian

A pressure differential is still a pressure differential. It is like a leak in a fuel line: it will leak when the fuel is static yet pressurized (priming) or when the fuel is dynamic yet pressurized (engine running). Either way there will be a leak. A boost leak is harder to understand because you can't see the fluid leaking.

[davef]

who cares !!!! pick up your purse !

[mEr]

Im a firm believer in sometimes too many people worry way too much about whats happening on paper. All of this worrying prevents them from every racing.


I totally agree, except in my case, its green paper that ever keeps me from racing.......lol

[JustinOlson]

So there's no other guys that have pressure tested there charge pipes and had a leak at the throttle body?


Justin

[George Klass]

I would say that 99% of the racers don't test for this, primarily because it's meaningless. Any forced induction air (volume) that can go through the engine is going through the engine, and any leakage is the result of back pressure, or in other words, air that would not go through the engine anyway and is forced to either escape somewhere or back up into the turbo or supercharger.

[JustinOlson]

For a given engine, isn't the volumetric flow rate determined by the intake air temperature and intake air pressure? n=PV/RT ?

Also, for a given compressor RPM, your volumetric flow rate goes down if you are bleeding pressure somewhere in the system.

Justin

[George Klass]

Justin, I can't help you. You are hung up on formulas that do not take reality (and sometimes logic) into consideration. There are many things that determine flow rates. The intake system, camshaft design, cylinder head design, displacement, even the exhaust system (you can't get the new stuff in unless you get the old stuff out). You are hung up on a so-called pressure loss, caused by an air leak, for air that is not going IN to the engine, but is trying to get OUT of the engine due to back pressure. This is not rocket science. You can hang out with your "compressor maps" all you want to but that is not your problem. You need to "down shift" from your text books and think like a hot rodder.

Many years ago there was a drag racer by the name of "Sneaky" Pete Robinson. Pete was an automotive engineer, and sharp as a tack. He knew that if the name of the game in drag racing was to accelerate a mass a quarter of a mile from a standing start, the less mass that you had to get moving, the quicker it would go. He consentrated on getting as much weight out of his cars as possible. He told me once to throw all the parts up in the air, and if they came down, they were too heavy and needed to have holes drilled in them to make them lighter. He said that after I drilled holes in them, throw them up in the air again, and if they still came down, drill more holes in them. Then after that, throw them up in the air again and if they still came down, not only were they still too heavy but by now, with all the holes, they were probably too weak too, so I might as well throw the part away, I probably didn't need it anyway.

This kind of logic I could understand, because that's the way a hot rodder thinks. I can't understand your logic. You remind me of the engineer that says that the bumblebee, because of it's design, is unable to fly, despite the reality of the bees buzzing around his head.

[JustinOlson]

George I'm trying to present logic and sound scientific knowledge in this thread.

Instead of having a sound conversation, you tell stores that have no value towards the subject at hand.

You may have gone fast with charge pipes that leak like swish cheese. Doesn't mean there isn't a better way!

Justin

[ea1]

I just bought a 105mm tb with the 4.5" wiggins clamp from Accufab and I hope it doesn't leak, it wasn't cheap!

Having said that, If it leaks a little I would bet money it would make NO difference in performance. Even a substantial leak when pressurized with the motor off would not equate to much actual flow. A tire can sound like its leaking like crazy at 30 psi, but it sure can take a while for it to go flat.

The few CFM it may leak will make a mathmatical difference in PR and a mathmatical difference in outlet temps, but nothing that would make a real world difference. You may see an increase of less than .5 degrees at the TB.

I think most people leave WAY more than that on the table with restrictive HOTSIDE components alone.

[davef]

we have been runing wilson 105mm throttle bodies on both of our racecars for 3 years, almost 4 years now, the car has no problems maintaining steady inlet manifold pressure. we also welded v band flanges onto both of them.