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Discussion Starter · #1 ·
The way a throttle plate closes indicates to me that either the throttle bore or throttle plate is elliptical. So which is it?
I think it would be the plate as that would be much easier to do during manufacturing.
Have been studying(Google,YouTube) port/polish of throttle bodies so this and a few other questions have come up. Affect on mass airflow sensor/ecu?
 

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2007 ZX5 2.0 | 2007 ZX4ST 2.3
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from what I’ve seen the focus TB plate is circular, as well as the bore and or housing, on the filter side there’s a center indention. From my understand An ellipses on one but not the other wouldn’t make sense as there would be a gap between the plate and housing or vice verse. If you’re interested in better flow I would suggest a different throttle body (I think 65MM is the upgrade size) then consider porting/polishing that, regardless I don’t see it affecting the MAF as the air moving thru would’ve already been metered long before.
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Discussion Starter · #3 ·
Thanks for the reply. My first question after your reply was going to be..then why does the throttle plate remain tilted?

But after looking at an OEM spare tb I have, I see it's the throttle stop screw.

If that screw is adjusted to close the plate further, it might cause the plate to be stuck.

So who sells this 65 mm tb? Mine is a stock 63.4 mm 07 Duratec.
 

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Thanks for the reply. My first question after your reply was going to be..then why does the throttle plate remain tilted?

But after looking at an OEM spare tb I have, I see it's the throttle stop screw.

If that screw is adjusted to close the plate further, it might cause the plate to be stuck.

So who sells this 65 mm tb? Mine is a stock 63.4 mm 07 Duratec.
I thought I remembered seeing people using ranger throttle bodies or an aftermarket one but not seeing anything about that after doing a search. I did see people “porting” the stock TB, basically they get rid of that little intention and make it a complete circle. You’ll need epoxy and will have to reshape it so there aren’t holes/gaps though.
 

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Discussion Starter · #5 ·
After doing a bunch of reading on the subject, I don't think it will be worth the effort at this time. The engine has no mods other than sri. From what I read, it will only ad 3-4 hp. Money and time better spent would be an aftermarket intake.
I see at eBay, those Chinese intakes for just a bit more than OEM. I am a bit gun shy on those though.
 

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After doing a bunch of reading on the subject, I don't think it will be worth the effort at this time. The engine has no mods other than sri. From what I read, it will only ad 3-4 hp. Money and time better spent would be an aftermarket intake.
I see at eBay, those Chinese intakes for just a bit more than OEM. I am a bit gun shy on those though.
Yep unfortunately there’s not much bar major internal work. I’d suggest removing the tumble flaps, de-valving the PCV and blocking off maf though, I just did that and it feels faster/ Better response etc and no more oil filled slushy intake
 

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2013 Focus SE gray 5 spd hatch
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After doing a bunch of reading on the subject, I don't think it will be worth the effort at this time. The engine has no mods other than sri. From what I read, it will only ad 3-4 hp. Money and time better spent would be an aftermarket intake.
I see at eBay, those Chinese intakes for just a bit more than OEM. I am a bit gun shy on those though.
You made a wise decision. You won't get 3-4hp from doing anything with your TB. In order to get a hp gain from a TB replacement or in your case modification you would need to have MAJOR engine upgrades done to it(head, cams, intake manifold, turbo, etc). Otherwise, like most everyone else that's gotten an aftermarket TB you'd just be telling yourself that you did something to make it faster. In reality, it'd do nothing or even possibly make it slower as the PCM would be compensating for the TB modification at it's programming limits.
 

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Discussion Starter · #8 ·
I would also think that more air in would be restricted by the limitations of the exhaust. Would need headers and higher flowing exhaust.
 

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The exhaust will be a factor but the biggest bottleneck to any power gain with bigger TB is your intake manifold, head, and cam profiles.
 

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<<< Affect on mass airflow sensor >>>
All mech/electr engines re base on one principle, HEAT
to achieve max eff you need to get optimal temperature of fuel
next you need optimal air (drop temperature and increase Oxygen content )
finally this is graphed out to possible BTU generation

<<< biggest bottleneck to any power gain with bigger TB is your intake manifold, head, and cam profiles. >>>
The process of capturing these BTUs means energy retention and transfer:
like a boiler contain the heat with wrappings. Then reduce friction in mechanical
transfer to transmission, finally get the correct TIRE/WHEEL package for the surface involved.
Weight must be observed at point of contact for optimal transfer (too much - friction; too little - slippage)
 

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<<< Affect on mass airflow sensor >>>
All mech/electr engines re base on one principle, HEAT
to achieve max eff you need to get optimal temperature of fuel
next you need optimal air (drop temperature and increase Oxygen content )
finally this is graphed out to possible BTU generation

<<< biggest bottleneck to any power gain with bigger TB is your intake manifold, head, and cam profiles. >>>
The process of capturing these BTUs means energy retention and transfer:
like a boiler contain the heat with wrappings. Then reduce friction in mechanical
transfer to transmission, finally get the correct TIRE/WHEEL package for the surface involved.
Weight must be observed at point of contact for optimal transfer (too much - friction; too little - slippage)
This is all very vague, off topic, and somewhat strange. I'm really not sure how any of this is really relevant to this conversation and some of it is not accurate as well.

Electric engines aren't based on the principle of heat.
Fuel temperature is an exceptionally low factor when it comes to achieving high efficiency or power. I mean it makes such an inordinately marginal difference that it's not even worth mentioning. Air intake temperature actually has more of an effect on engine efficiency but even that isn't all that much of a concern unless you have a turbo. Engines will run at pretty consistent power levels at 30°F or 90°F fuel or air intake temperature. Is there a difference? Yes, but not much and there's not a drastic amount that you can really do to change the effect of whatever ambient temperature is outside with your fuel or air anyway. Most factory air intakes already draw in cooler outside air from in front of the engine compartment.
I've heard of air conditioning precooling the air charge in Mopar products but that's an extreme modification that most people won't have the ability to accomplish. Additionally, you have to weigh the power lost in running the a/c on a 4 cylinder engine to the gain in cooler air going into the engine.
 

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Discussion Starter · #12 ·
I disagree with part of your post. My 07 duratec needed a new air filter and instead of changing that, I installed a short ram intake system and there was a very noticeable difference. Not being rich, I created my own and the results were worth the effort
 

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An aftermarket or in your case a homemade "cold air intake" won't make a difference at least not anything truly noticeable. When you do a mod like this it's all in your mind just hoping there'll be a difference and because the sound changes it makes you think there's an actual power change. There wasn't though as this is all just basic human nature. Your expectations color your beliefs. Dyno results consistently prove there's such a marginal difference if any at all(on a 4 cylinder maybe 1hp) that you aren't going to feel anything.
CAI and TB replacements on otherwise stock or near stock cars are persistent old fallacies that won't ever go away because of the internet keeping these myths going. Look up legit before and after videos of CAI replacements with NO other changes including no tune change and see what they show.
 

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Yes to that. Fix the driver first. The added noise of a new intake and they all think it is faster and it might be, up to maybe 5 hp. max, which you really cannot feel by itself. The dynos show the reality of it over and over.

To first post, almost every butterfly (throttle PLATE ) on earth is NOT round, they are elliptical in OD shape.
 
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