Intake and T/B Installed

[MysteryMachine]

not sure if that was towards me but a TFS is a 75mm opening

 

[94MustangGT5.0]

my only ? why put a 75mm throttle body on a intake with only 65mm? opening? if you anything about flow you would understand why this is bad, it may not hurt power output that much but a 65 would make the same power .its called an sudden contraction and it hurts air flow ...

I agree completely, the in flowing air is going to deflect off of the smaller diameter intake inlet and cause unwanted resistance. When I posted before, I meant to say that as well. I just meant that if you have the 70mm opening, you should/could run a 70mm TB.

 

[a50sn95]

Right.






Interesting, I swore a diesel had an intake tube track?




Well you better hope that engine can withstand to be revving to 6,250 bouncing off the limiter. It would not run fine.



A bigger straw has a more dispersed area of incoming (blowing) air. A smaller straw (throttle body) has a more concentrated hit of air. Make sense? Sure it controls it but not as concentrated.





You will lose velocity (concentration) and that is key for overall driveability. A 75mm TB will give you a goosy feeling (especially in the lower gears). Some like it, some don't. I'm sure your AFW makes up for that off idle...

A 75mm TB does have an effect on incoming air. Many more cc's of air come thru

273's wont' effect driveability. It is a set gear ratio that doesn't vary. Your AFW, tune, TB could very well be those effects.

My only issue is to make sure to rev it high enough to get the car rolling. If I don't, it'll stall. That's due to the gears and flywheel.


What's an AFW? You mean flywheel?

A diesel will have a tube from an air cleaner to the throttle opening, but there is no throttle body. Engine speed is controlled by fuel. It'll run the same with out the tube. (Think OLD John Deere Johnny Popper, not a Modern electronic diesel.)

As long as you can TUNE for the additional AIR, it makes NO difference, in my opinion.
That's why there are settings for TB Airflow, Neutral Idle Airflow, and so in in your EEC. Change anything in the intake tract, and those numbers need to be changed.
You'll noticed that I've already mentioned that when I said what I said...

 

[MysteryMachine]

As long as you can TUNE for the additional AIR, it makes NO difference, in my opinion.
That's why there are settings for TB Airflow, Neutral Idle Airflow, and so in in your EEC. Change anything in the intake tract, and those numbers need to be changed.
You'll noticed that I've already mentioned that when I said what I said...

I didn't Tune anything i just bolted it on. Only thing we messed with the the screw on the tb to get the idle normal. But as far as tuning the PCM you don't have too

 

[5spd GT]

Mystery Machine - I have a couple friends with "bigger TB's" than needed and get the same results. I have been thru a couple myself. No need to go bigger than needs be for some peak numbers.

YeahLOH95 - You can dremel out the intake opening a bit but it still can only breathe as good as the upper intake initial trac.

My only issue is to make sure to rev it high enough to get the car rolling. If I don't, it'll stall. That's due to the gears and flywheel.

That is due to your flywheel, not your stock gears than came from the factory. It didn't have the problem before. Don't blame it on the gears.

What's an AFW? You mean flywheel?

Aluminum Flywheel

A diesel will have a tube from an air cleaner to the throttle opening, but there is no throttle body. Engine speed is controlled by fuel. It'll run the same with out the tube. (Think OLD John Deere Johnny Popper, not a Modern electronic diesel.)

So your talking "old school" when we are talking the new age It's like comparing TB's too carbs

As long as you can TUNE for the additional AIR, it makes NO difference, in my opinion.
That's why there are settings for TB Airflow, Neutral Idle Airflow, and so in in your EEC. Change anything in the intake tract, and those numbers need to be changed.
You'll noticed that I've already mentioned that when I said what I said...

Your engine can only support so much air, so their is a limit on both sides of the fence that you can tune for.

Not everyone has the funds or availability to tune everytime they do a mod.

 

[MysteryMachine]

well theres a couple reasons i went with the 75mm. 1. it was a gift I was asked what i wanted and what size so i picked the biggest lol 2. when i get the h/c and bigger inj it will need more air 3. if i ever decide to go the turbo route I have the stuff big and ready for it. I'm all about thinking about the long run on things so i go big and get it over with so I only gotta get things once

 

[a50sn95]

You can dremel out the intake opening a bit but it still can only breathe as good as the upper intake initial trac.

EXACTLY! By putting the 75mm on there, now it's NOT the restriction anymore, something else is. The heads or the intake or the MAF or the intake tube or the air filter, etc.... So on a stock engine you MAY get more air, but it really depends. So, then, how can it really matter if the TB is 5 or 15 mm bigger? The engine is STILL drawing through a straw.
I'm just saying, why put a 65 on there if you are going to keep adding mods? You'll be replacing it again, and my OPINION is that they'll work the same.

That is due to your flywheel, not your stock gears than came from the factory. It didn't have the problem before. Don't blame it on the gears.

It's not really a blame thing. I don't view this as a BIG issue. It just needs a few extra hundred RPM...
So you don't think a set of 3.73's would make it a little easier to pull away from a stoplight.....?

So your talking "old school" when we are talking the new age It's like comparing TB's too carbs

Hmm TB's and carbs don't compare, and I didn't SAY they do. I was comparing a fuel injected engine to a fuel injected engine. Diesels don't use TB's to control rpm. Gasoline engines do.
Ayway the ORIGINAL point was that a gas eninge could or could not run without a TB. I say it would (assuming you could get it started). It would be no different the HAVING a TB at WOT.

Your engine can only support so much air, so their is a limit on both sides of the fence that you can tune for.

I don't know what you mean here. Say your engine needs 43 kg/hr of air to run at 2500 rom (making up these numbers). So with a 60 mm tb you have to crack open the TB, say 20 percent to get this. So now you put a 75mm TB on it. All I see is that you now only have to open it 15 percent.
So like I said, the ONLY time it matters is WOT, and the transition to WOT, which I say can be adjusted in the tune.

Not everyone has the funds or availability to tune everytime they do a mod.

I use a Tweecer R/T. Only costs me a little time to change my tune. AND I can DATALOG the results to make sure I understand what I just did.

 

[5spd GT]

EXACTLY! By putting the 75mm on there, now it's NOT the restriction anymore, something else is. The heads or the intake or the MAF or the intake tube or the air filter, etc.... So on a stock engine you MAY get more air, but it really depends. So, then, how can it really matter if the TB is 5 or 15 mm bigger? The engine is STILL drawing through a straw.
I'm just saying, why put a 65 on there if you are going to keep adding mods? You'll be replacing it again, and my OPINION is that they'll work the same.

Well if you have a big insert of air from a throttle body. The merging of air will have to come from more of an extreme angle. More turbulence and uncontrolled/unconcentrated flow. That is my opinion.

It's not really a blame thing. I don't view this as a BIG issue. It just needs a few extra hundred RPM...
So you don't think a set of 3.73's would make it a little easier to pull away from a stoplight.....?

You were saying (and I can quote) that your takeoff problems were due to your flywheel and gears.

Yes, the gears will help. When did I say it wouldn't. Obviously the problem is the AFW because the gears worked fine from the factory and before the AFW. Easy figuring...

Hmm TB's and carbs don't compare, and I didn't SAY they do. I was comparing a fuel injected engine to a fuel injected engine. Diesels don't use TB's to control rpm. Gasoline engines do.
Ayway the ORIGINAL point was that a gas eninge could or could not run without a TB. I say it would (assuming you could get it started). It would be no different the HAVING a TB at WOT.

You said: Think OLD John Deere Johnny Popper, not a Modern electronic diesel.

You were talking about "old" and then saying don't talk about the "modern". So why are you using an "old john deere johnny popper" when we are talking about "modern" EFI throttle bodies. What's your point? Engines act differently and have different internals and uses/needs. Why compare?

I don't know what you mean here. Say your engine needs 43 kg/hr of air to run at 2500 rom (making up these numbers). So with a 60 mm tb you have to crack open the TB, say 20 percent to get this. So now you put a 75mm TB on it. All I see is that you now only have to open it 15 percent.
So like I said, the ONLY time it matters is WOT, and the transition to WOT, which I say can be adjusted in the tune.

Not everyone has the money, funds, avalability, time, to tune their car.

Yep, and the less crack you have to give the more goosy the engine can get in the lower rpms. Since the tps factors into the ECC the tuning factor needs to be addressed if applicable.

I use a Tweecer R/T. Only costs me a little time to change my tune. AND I can DATALOG the results to make sure I understand what I just did.

If your computer literate and have extra money running around. You could save that $800 bucks and by something that is more needed than using it on a simple h/c/i car for example. House payment maybe

 

[Black95GTS]

If your computer literate and have extra money running around. You could save that $800 bucks and by something that is more needed than using it on a simple h/c/i car for example. House payment maybe

Tweecer R/T is 550. Custom burnt chip isn't that much less, if less at all. You don't have to be computer literate, you have to be Car literate. But going through tables of values isn't as fun as bolting on a S/C, so people ignore that aspect of customization and leave it to "pros" who basically read the same literature but also own a dyno. Bolting on a bunch of mods is crap without paying attention to the computer that controls them all.

on topic: My TB sizing method is thus:
1 - How big is your intake opening.
2 - How much air can your engine flow at its most restrictive point.
3 - Find a TB with the correct size that flows a little more then your engine can handle. Don't worry about that velocity crap, thats old carb thinking. Your velocity comes from the intake stroke.
4 - How much money do you want to spend

I say get one that flows a little bit more because there will be losses along the way... like the air filter for example or various stages where the flow is compressed / expanded. YEAHLOH95 is totally correct in his statement, I've taken both fluid dynamics and compressible flow in college and this is the same realization that I've come to.

Adam

 

[Swarzkopf]

The opening on a Cobra manifold is 70mm...I went with a 70mm TB because I figured that it'd be good to have matching sizes.

 

[a50sn95]

Well if you have a big insert of air from a throttle body. The merging of air will have to come from more of an extreme angle. More turbulence and uncontrolled/unconcentrated flow. That is my opinion.

Ok, you can have your opinion.

You were saying (and I can quote) that your takeoff problems were due to your flywheel and gears.

Yes, the gears will help. When did I say it wouldn't. Obviously the problem is the AFW because the gears worked fine from the factory and before the AFW. Easy figuring...

Yes, my takeoff problems are due to the combination of a light flywheel and 2.73 gears. I don't know why we are arguing over this.

You said: Think OLD John Deere Johnny Popper, not a Modern electronic diesel.

You were talking about "old" and then saying don't talk about the "modern". So why are you using an "old john deere johnny popper" when we are talking about "modern" EFI throttle bodies. What's your point? Engines act differently and have different internals and uses/needs. Why compare?

Again, the point was that an injected engine would run without a TB.

Not everyone has the money, funds, avalability, time, to tune their car.

Yep, and the less crack you have to give the more goosy the engine can get in the lower rpms. Since the tps factors into the ECC the tuning factor needs to be addressed if applicable.

Oh well, if you WANT to play with these engines, sooner or later you're gonna need a tune.

If your computer literate and have extra money running around. You could save that $800 bucks and by something that is more needed than using it on a simple h/c/i car for example. House payment maybe

Again, it's your opinion. 800.00 would even come close to my house payment.

Anyway, this is getting tiresome. I don't think you are right. Others have said they've done it, and it didn't seem to bother their cars. You don't think I'm right. I'm getting tired of "discussing" it.
It's far from the original post, anyway...
You can make the last post so :Teh-Win:

 

[YEAHLOH95]

my post wasn't dirrected towards anyone just wantedf to make a point . i'm just not on the bigger is better band wagon . i'm only running a 70 mm on my car til i switch to a fox set up then i'm not sure on the size i'll use maybe a 65mm???.

 

[final5-0]

my post wasn't dirrected towards anyone just wantedf to make a point . i'm just not on the bigger is better band wagon . i'm only running a 70 mm on my car til i switch to a fox set up then i'm not sure on the size i'll use maybe a 65mm???.

Would you please confirm my understanding of what you were saying above

I think you were trying to get across the smallest part in the air path is gonna determine airflow
OR
That smallest part is where the greatest restriction is gonna be.

Sooooooooo

Say you got a
80mm maf
75mm tb
70mm elbow
75mm intake opening

The larger tb & intake opening is doing you no good due to the smaller elbow.

Do I have a correct understanding here

Grady

 

[MysteryMachine]

Would you please confirm my understanding of what you were saying above

I think you were trying to get across the smallest part in the air path is gonna determine airflow
OR
That smallest part is where the greatest restriction is gonna be.

Sooooooooo

Say you got a
80mm maf
75mm tb
70mm elbow
75mm intake opening

The larger tb & intake opening is doing you no good due to the smaller elbow.

Do I have a correct understanding here

Grady

Yup thats it. I know I have restriction problems with my MAF and everything else being 75mm but after talking to you a long time ago about how good a stock MAF is i decided not to change it. I do look from time to time for one if i could get one at a good price i'd change it. Then comes the issue with what do i get. I have been told 80mm maf but i figure at least a 75 and what do i get it calibrated for 19's or 24's I don't want to have to spend the money on new inj's just cause i'm upgrading my MAF but I also don't want to spend the money on getting it recaled when i put 24's in it. i have thought about just getting one for 24's and not putting it in till i do the h/c and inj but I'll have it ready to just throw on

 

[Guero]

dam it got into a big ass argument. it was only meant for me to say i successfully installed the intake. lol

 

[Stang95fyvo]

Someone mentioned above that if you increase the opening size then you are getting into a more turbulent flow and that the air will be less concentrated.

Actually it is quite the opposite. If you increase the velocity, the flow becomes turbulent, and this is due to the density, velocity, diameter of the pipe and the viscosity of the air. I am a Mechanical Engineering student and was actually just in a course regarding fluidic flow.

So in order to keep the flow laminar and more concentrated, one would want to increase the throttle body size and slow down the air movement. However the part about a sudden contraction IS correct. A sudden contraction will cause less flow. So I would agree that if you have a 70mm opening, get a 70mm TB. And the same for a 75 mm opening and TB.

 

[5spd GT]

Ok, you can have your opinion.

Right.

Yes, my takeoff problems are due to the combination of a light flywheel and 2.73 gears. I don't know why we are arguing over this.

Because you put:

have no issues with drivability that I blame on the TB. (Maybe the aluminum flywheel and the 2.73's...)

Just letting you know it wasn't the gears.

Again, the point was that an injected engine would run without a TB.

Not an efi like were talking about...not correctly or practically at all obviously.

Oh well, if you WANT to play with these engines, sooner or later you're gonna need a tune.

A throttle body change (if it wasn't to big) shouldn't effect tune where you "need a tune" in your words. I have messed with mine and I have no tune except my two hands.

Again, it's your opinion. 800.00 would even come close to my house payment.

I deal with loans for "a" company...800.00 can be put towards a payment. Way to brag...lol...not impressed.

Anyway, this is getting tiresome. I don't think you are right. Others have said they've done it, and it didn't seem to bother their cars. You don't think I'm right. I'm getting tired of "discussing" it.
It's far from the original post, anyway...
You can make the last post so :Teh-Win:

I'm wide awake...

 

[5spd GT]

Someone mentioned above that if you increase the opening size then you are getting into a more turbulent flow and that the air will be less concentrated.

Actually it is quite the opposite. If you increase the velocity, the flow becomes turbulent, and this is due to the density, velocity, diameter of the pipe and the viscosity of the air. I am a Mechanical Engineering student and was actually just in a course regarding fluidic flow.

So in order to keep the flow laminar and more concentrated, one would want to increase the throttle body size and slow down the air movement. However the part about a sudden contraction IS correct. A sudden contraction will cause less flow. So I would agree that if you have a 70mm opening, get a 70mm TB. And the same for a 75 mm opening and TB.

So if we want to get less concentration (more turbulence) let's port the lower intake "long and wide" and the intake side of the heads and install some bigger valves. Let's see if we lose any driving characteristics (showing a bit more extreme case to example how concentration/velocity is important).

If you enter to much dispersed air you lose velocity/concentration and under WOT (until the engine catches up with the incoming air) your going to lose a torque response, more so in the lower rpm powerband IMO.

 

[YEAHLOH95]

Would you please confirm my understanding of what you were saying above

I think you were trying to get across the smallest part in the air path is gonna determine airflow
OR
That smallest part is where the greatest restriction is gonna be.

Sooooooooo

Say you got a
80mm maf
75mm tb
70mm elbow
75mm intake opening

The larger tb & intake opening is doing you no good due to the smaller elbow.

Do I have a correct understanding here

Grady

yes the smaller elbow will hurt in 2 ways on the front side and the exit it will cause turbulence and hurt flow 2 fold sudden contactions and sudden enlargments are both bad you want gradual if at all possible hence gasket matching .....

 

[Stang95fyvo]

So if we want to get less concentration (more turbulence) let's port the lower intake "long and wide" and the intake side of the heads and install some bigger valves. Let's see if we lose any driving characteristics (showing a bit more extreme case to example how concentration/velocity is important).

If you enter to much dispersed air you lose velocity/concentration and under WOT (until the engine catches up with the incoming air) your going to lose a torque response, more so in the lower rpm powerband IMO.

FWIW...the low end torque loss is correct. But if all you want is hp, then more air means more power.