Throttle Bodies

[Big Jim M]

Howdy James

I guess i just can't wrap my head around the fact that a comparable sized motor ( duratec 2.5's in contours, 3.0 duratec's in taurus's, the 3.3 in a dodge intrepid) all have such noticeably bigger throttle bodies and such if the cylinder is only a given size. I understand the principle of what you're saying, but i think that the throttle is a fair bit smaller than it ought to be. Of course I haven't cracked mine off to see how thick the casting for the upper is, but im sure a TB could be a bit bigger before its pointless.

Best illustration I can find is this link:

http://www.cardomain.com/ride/333436/1995-ford-ranger-regular-cab-tacoma-wa-us?p=4

The tricky part is that rangers have the IAC on the TB instead of the intake, and many sites that extoll the virtues of such a swap walk thru how to do it with a composite intake, which has the IAC on the upper intake. So either I'm sorta venturing into unknow territiry (I have the stock 1999 intake) or I'd have to swap to a composite which I've heard pros and cons about as well, so I'm sorta reaching out to see what others have done. The more I think about it, the more I think a 3.8 might work even though the throttle linkage and TPS are flipped but the pull is the same direction....

What you ned to get grip on is this>>> With the bigger throttle body the engine will be able to suck in enough air to go beyond the 5500/6000 rpm it now has enough air to accomplish.
HOWEVER the engine cannot get up there as it is built without grenading! So in order to USE a bigger TB you must first BUILD the engine to run at 8,000 and above. WITHOUT such a build the bigger TB will only be a henderance when used at lower rpm.
AS BUILT the TB supplies all the air the engine can injest. With the bigger one on there the engine will FALL ON IT"S FACE off the line!
The intake system DEPENDS on a certain VELOCITY of the intake air. This velocity is what helps FILL the cylinders. Without that velocity the engine won't preform at lower rpm.
Don't think for one minute the engineers at Ford didn't take EVERYTHING into consideration when designing the TB on your engine.
Big JIm

 

[stmitch]

So you guys have personally tried a larger throttle body on a stock 3.0 and you found little to no power increase?

No I have not. And if you read my post, I don't claim that there is no benfit, only that the benfit would not be as great as doing the box intake. I definitley support modding the 3.0, I just figure if you're going to invest time and money on a mod, it should net the largest gains possible.

Don't think for one minute the engineers at Ford didn't take EVERYTHING into consideration when designing the TB on your engine.
Big JIm

Ford's engineers have designed everything to work together as a system, but the OP has already modified parts of that system by increasing the volume that his exhaust can flow. Wouldn't it then be able to injest more air? I agree that a slighly larger throttle body on an otherwise stock engine would see little to no gain, but what about when the engine is no longer in stock form? It's true that the engine can only flow a certain amount of air, but the engineers would likely put "bottlenecks" in the system to keep the engine components from running@ or near their flow limits. By removing some of those "bottlenecks", the engine should be able to inch closer to it's full potential.

 

[Big Jim M]

Ford's engineers have designed everything to work together as a system, but the OP has already modified parts of that system by increasing the volume that his exhaust can flow. Wouldn't it then be able to injest more air? I agree that a slighly larger throttle body on an otherwise stock engine would see little to no gain, but what about when the engine is no longer in stock form? It's true that the engine can only flow a certain amount of air, but the engineers would likely put "bottlenecks" in the system to keep the engine components from running@ or near their flow limits. By removing some of those "bottlenecks", the engine should be able to inch closer to it's full potential.

Well in short...NO! You are assuming there is a "bottleneck".. Yet you don't seem to know where it may be.
If there IS a bottleneck in the system it would be in the camshaft.. That is the device that tells the engine how much fuel/air mixture to injest. The engine does zackly what the camshaft allows it to do. Without modifing the camshaft the engine will continnue to do what it did before adding Tb and exhaust.
As built the cylinders FILL TO CAPACITY on each stroke. Only adding a device that will PUSH more mixture into the cylinders will add more power to the engine. There is NO bottleneck in the engine when advertised rpm are used.
So, in short, if the engine is intended to be streeted, as most are, little if anything can be done to the TB to improve it. HOWEVER if the tack is to be the place where the engine is going.. Then a complete rebuild is in order.. not just a new TB and headers!
We have what we have! Our engines do zackly what they are intended to do.
No matter how many radical IDEAS we get, they have already been got by the engineers at Ford. Then they were discarded and the proper devices were designed and built.
Big JIm

 

[disciplerocks]

Don't think for one minute the engineers at Ford didn't take EVERYTHING into consideration when designing the TB on your engine.
Big JIm

I completely agree.....except the on the stock jack. What were they thinking there?

 

[DeepSouthRanger]

So, If you have a cold air intake, Larger MAS, roller rockers,upgraded ignition, High flow exhaust, and new tunes. Would it then be ok to put a larger TB on it???? Whether Escape, Mustang, ect...

 

[James86]

My take on auto engineering is there are three prerequisites to balance:

1.) How cheap can we build it?
2.) Will it meet emissions?
3.) Will it last 100,000 miles?

Not everything is optimal or there would be no need for aftermarket parts. If engineering did everything right the first, or even second time, the 3.0 wouldn't have nearly a half dozen cranks, four head designs, and multiple intake configurations across the board. I'm not knocking Ford, but maybe thers a corner thats been cut.

The thinking sounds simplistic but then again, why do you think the US auto industry needed a bailout? Just sayin...

I value your guys's opinions, or else I wouldn't have posted the questions in the first place. I'm trying to ask the questions before I make any serious error.

 

[Beanmachine7000]

So, If you have a cold air intake, Larger MAS, roller rockers,upgraded ignition, High flow exhaust, and new tunes. Would it then be ok to put a larger TB on it???? Whether Escape, Mustang, ect...

None of that stuff does jack crap... Now, if you had a stroker crank, higher lift cam, ported heads, etc... Then yes... All this stuff you guys think will give you more power came from the sports car world... I see all the time throttle bodies restricting air into engines (of course this is on 400+ c.i. LS engines)... So, yes, a throttle body made to work correctly on a stock LQ4 (6.0L LS1 basically) will, of course be choking out a stroked 408 c.i. with much more aggressive cam... Now, on a stock 3.0L? Of course not... If you really want power open it up and make it suck in more air... Then a new TB might be useful

 

[disciplerocks]

My supercharger on my Focus was designed to be used with the stock TB and airbox. Guess what I never bothered changing.....

 

[McCormack]

No I have not. And if you read my post, I don't claim that there is no benfit, only that the benfit would not be as great as doing the box intake. I definitley support modding the 3.0, I just figure if you're going to invest time and money on a mod, it should net the largest gains possible.

So if you yourself haven't run a larger TB on a stock 3.0 engine, then how can you state as fact that it will only give a small increase in power? Aren't you just guessing?

 

[McCormack]

My take on auto engineering is there are three prerequisites to balance:

1.) How cheap can we build it?
2.) Will it meet emissions?
3.) Will it last 100,000 miles?

Not everything is optimal or there would be no need for aftermarket parts. If engineering did everything right the first, or even second time, the 3.0 wouldn't have nearly a half dozen cranks, four head designs, and multiple intake configurations across the board. I'm not knocking Ford, but maybe thers a corner thats been cut.

I'm with ya. When discussing modifications to Rangers I always laugh at those that claim that Ford's way is the best way and we should leave things alone. Nonsense... engineers design most things to be just good enough to work, and many times there is ample room to improve on a design.

 

[Big Jim M]

Great questions!!!

So, If you have a cold air intake, Larger MAS, roller rockers,upgraded ignition, High flow exhaust, and new tunes. Would it then be ok to put a larger TB on it???? Whether Escape, Mustang, ect...

The CAI is JUNK.. all it does is allow more dirt into your engine.
If the roller rockers open the valves wider, You may see a gain above 6,000 rpm.
Upgraded ignition is fun to install but the ignition that came on your ride was lighting up the plugs when you took it off.. so no gain!! Now if you are using the engine above 6,000 and it is chugging up there then "upgrading" the ignition will fire the plugs. I could dissertate on ignition...but I won't here.
High-flow exhaust? Was the exhaust not exiting thru the stock exhaust?
If you really want a race engine then pull the engine and BUILD a race engine!! Adding this and that won't do one damn thing for you as long as you KEEP the stock heads and camshaft.
You have to understand the LIFE of the engine is the heads and the camshaft.
As long as you keep them stock they can only do what they were designed to do. You could put the TB from a 460 and run open exhausts and the gain would be minimal at best... Not to mention it wouldn't hardly go get groceries.
Big Jim

 

[McCormack]

Some better responsiveness would be nice, then i might not have to creep up on the car ahead of me with O/D off just to pass someone in a reasonable hurry...lol

I did a couple of things to my '00 3.0 that gave me a small but very worthwhile increase in power, especially in the low end:

MAF mod as described on the Rogue Ranger site; removed the snorkel from my airbox; drilled some holes in my airbox; 180* T-stat; intake manifold hot water bypass; electric radiator fan. And for the adventuresome, disconnect the EGR valve.

I really like the added low-end power - it's nice that I don't have to rev the tar out of it to get anywhere, the OD isn't constantly kicking in and out when out on the freeway, and my gas mileage went up too.

 

[James86]

So far all I've dont is get a flowmaster 40, and make it 2.5" all the way from the cats back, since it was 2.5" goin into the cats in the first place. I just did the MAF mod as well and noticed a HUGE difference in response, as well as make the hole in front of the airbox bigger. Also, it wasn't explained why a 2.5 duratec would have a TB big enough for a 3.0 vulcan to fit inside of it... only that a 3.0 will use what it uses based on cylinder size, which is odd because the 3.0 duratec is neither turbo nor supercharched yet has about 220 HP... I doubt the redline is 8,000rpm or anything, at least the duratec in my wifes contour wasnt...

 

[James86]

The CAI is JUNK.. all it does is allow more dirt into your engine.

I'm likely to agree; oiling filters and then cleaing the oil off your MAF sensor and stuff gets old realy quick...

If the roller rockers open the valves wider, You may see a gain above 6,000 rpm.

This is something I am interested in doing, but haven't found much of a walkthru or really heard how difficult this is. I'm going to chalk this one up as one of those "If it needs to be explained, don't attept" sort of things...

Upgraded ignition is fun to install but the ignition that came on your ride was lighting up the plugs when you took it off.. so no gain!! Now if you are using the engine above 6,000 and it is chugging up there then "upgrading" the ignition will fire the plugs. I could dissertate on ignition...but I won't here.

I'm somewhat skeptical of the "stronger spark" train of thought myself...

High-flow exhaust? Was the exhaust not exiting thru the stock exhaust?

Everyone who has headers seems to like them, and there are instances of cars leaving the factory with them, so they must serve a purpose, especially when one glances at the manifolds some vehicles have...

If you really want a race engine then pull the engine and BUILD a race engine!! Adding this and that won't do one damn thing for you as long as you KEEP the stock heads and camshaft.
You have to understand the LIFE of the engine is the heads and the camshaft.
As long as you keep them stock they can only do what they were designed to do. You could put the TB from a 460 and run open exhausts and the gain would be minimal at best... Not to mention it wouldn't hardly go get groceries.
Big Jim

I don't WANT a race engine, nor have I ever SAID I wanted a race engine. I merely want to make something a little better. This thread was about what TB's can be interchanged, not about how much you Cologne fanboys love to talk trash about Vulcans and people who decide to stick their money into their vehicles in pursuit of a few more ponies.

 

[disciplerocks]

I'll tell you what headers ARE good for on your truck, dissipating heat away from the head.