Throttle body mod
Thread Starter
Joined: Nov 2005
Posts: 484
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From: Marysville, Wa
Throttle body mod
I searched the forums because I remember seeing it once, can't find it now. But isn't there a mod you can do to your throttle body like removing the secondaries or something? I think it was an S4 NA thing...
What does it do exactly and why would you do it?
Problem with top end??
Anyone do this?
What does it do exactly and why would you do it?
Problem with top end??
Anyone do this?
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
6 of one and a half a dozen of the other.
you may get one good result but you lose other Factors.
I would just search: "Throtte body mod" and read for yourself the Pros and cons of doing this.
It's not everyone's cup of tea.
I removed the throttle plates and the delay valve but left the thermowax intact/functional.
Starts fine with no problem- even in the winter, never touch the gas.
Fuel consumption did not change, no apparent loss or gain in power.
Occasional bark during decel, but no other changes to exhaust sound.
Kind of a "meh" mod, IMO.
Starts fine with no problem- even in the winter, never touch the gas.
Fuel consumption did not change, no apparent loss or gain in power.
Occasional bark during decel, but no other changes to exhaust sound.
Kind of a "meh" mod, IMO.
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Vintage sportcars
Joined: Jun 2010
Posts: 348
Likes: 1
From: Germany
Waste of time.
There are other restrictions on the air flow which are bigger than the TB.
Take a look around here, for serious facts:
https://www.rx7club.com/showthread.p...d+airflow+data
And here for the howto:
http://fc3spro.com/TECH/HOWTO/TBM/tbm.html
AFAIK it does remove the second set of the upper TB butterflies, located just behind the first ones (seen from air flow direction) which do block the passage until coolant temp reaches a specified temp.
Doing so they are a restriction of air flow even when they are fully opened.
Feel free to correct me as I am not entirly sure about this TB thing, I read a lot about it but I am not 100 % sure.
Make sure to visits the NA performance section of the forum
https://www.rx7club.com/naturally-aspirated-performance-forum-220/
Some really good stuff there...
Joined: Sep 2005
Posts: 25,581
Likes: 136
From: Smiths Falls.(near Ottawa!.Mapquest IT!)
http://fc3spro.com/TECH/HOWTO/TBM/tb10.jpg.
that is basically what all the Hub-Bub is about.
that is basically what all the Hub-Bub is about.
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Uh, on an S4 NA, the throttle body mod is totally pointless.
Why? Because after the car is warmed up the tertiary throttle plates are held open anyway by a spring. They are only closed during warmup because the thermo valve allows vacuum to the actuator. This is to keep people from going WOT when the car is cold.
Prove me wrong. I'll PayPal $100 to anyone who can show on a dyno sheet any gain (outside the dyno's margin of error) to performing the "throttle body mod" on an NA car.
On a TII it is a little different because those tertiary plates are vacuum controlled. You gain more crisp throttle response if you remove them. But still, no power gain as long as they are working properly.
Now, the other parts that people often include on the throttle body mod are removing the cold start cam and removing the dashpot. Both those things are stupid to do. No gains, only losses in drivability.
Why? Because after the car is warmed up the tertiary throttle plates are held open anyway by a spring. They are only closed during warmup because the thermo valve allows vacuum to the actuator. This is to keep people from going WOT when the car is cold.
Prove me wrong. I'll PayPal $100 to anyone who can show on a dyno sheet any gain (outside the dyno's margin of error) to performing the "throttle body mod" on an NA car.
On a TII it is a little different because those tertiary plates are vacuum controlled. You gain more crisp throttle response if you remove them. But still, no power gain as long as they are working properly.
Now, the other parts that people often include on the throttle body mod are removing the cold start cam and removing the dashpot. Both those things are stupid to do. No gains, only losses in drivability.
Rotary Freak
Joined: Jul 2008
Posts: 1,660
Likes: 2
From: FORT WORTH TEXAS
Marshall13B. Fully warm your engine up. Now remove the duct that covers up the thorttle plates. Look at the outter (number 2 secondary) throttle plates. They are fully open. As in all the way open. Now think for a moment. How does removal of those two OUTTER plates going to give you squat?
I also refer you to the post above this one.
I also refer you to the post above this one.
I removed the throttle plates and the delay valve but left the thermowax intact/functional.
Starts fine with no problem- even in the winter, never touch the gas.
Fuel consumption did not change, no apparent loss or gain in power.
Occasional bark during decel, but no other changes to exhaust sound.
Kind of a "meh" mod, IMO.
Starts fine with no problem- even in the winter, never touch the gas.
Fuel consumption did not change, no apparent loss or gain in power.
Occasional bark during decel, but no other changes to exhaust sound.
Kind of a "meh" mod, IMO.
I have it done as well and it wasn't really worth the effort. I can't really feel the difference. Maybe you'd notice it more on an n/a but not so much on my turbo s4
Uh, on an S4 NA, the throttle body mod is totally pointless.
Why? Because after the car is warmed up the tertiary throttle plates are held open anyway by a spring. They are only closed during warmup because the thermo valve allows vacuum to the actuator. This is to keep people from going WOT when the car is cold.
Prove me wrong. I'll PayPal $100 to anyone who can show on a dyno sheet any gain (outside the dyno's margin of error) to performing the "throttle body mod" on an NA car.
On a TII it is a little different because those tertiary plates are vacuum controlled. You gain more crisp throttle response if you remove them. But still, no power gain as long as they are working properly.
Now, the other parts that people often include on the throttle body mod are removing the cold start cam and removing the dashpot. Both those things are stupid to do. No gains, only losses in drivability.
Why? Because after the car is warmed up the tertiary throttle plates are held open anyway by a spring. They are only closed during warmup because the thermo valve allows vacuum to the actuator. This is to keep people from going WOT when the car is cold.
Prove me wrong. I'll PayPal $100 to anyone who can show on a dyno sheet any gain (outside the dyno's margin of error) to performing the "throttle body mod" on an NA car.
On a TII it is a little different because those tertiary plates are vacuum controlled. You gain more crisp throttle response if you remove them. But still, no power gain as long as they are working properly.
Now, the other parts that people often include on the throttle body mod are removing the cold start cam and removing the dashpot. Both those things are stupid to do. No gains, only losses in drivability.
Thread Starter
Joined: Nov 2005
Posts: 484
Likes: 0
From: Marysville, Wa
It wouldn't. That's what he is saying. With the positive pressure created by a turbocharger, the t2's benefit from this mod because of improved airflow.... potentially. The n/a's however, in particular the s4's get absolutely nothing from the mod except a crisper throttle response and a lightswitch throttle.
I don't know about "crisper" throttle response. Although I don't have a NA engine, I know for sure on my TII after completing this throttle body mod I had to add more acceleration enrichment (I run a Megasquirt ecu). It would lean out and nearly die with WORSE throttle response. If the ECU expects less air than it's getting, it's just going to lean it out. With the standalone ECU, all that can be taken care of and compensated for, but with the stock one, it's not something that you'll like very much.
By the way, once you remove the secondary butterflies and install the pipe plugs, there's no going back. You can't just re-install the shaft and butterflies, the journals and seals get damaged in doing so.
Bottom line, this is a stupid mod.
By the way, once you remove the secondary butterflies and install the pipe plugs, there's no going back. You can't just re-install the shaft and butterflies, the journals and seals get damaged in doing so.
Bottom line, this is a stupid mod.
This.
I did it on the TII. Under light throttle(which is pretty much all you use for driving around town) driveability sucks. I have another throttle body I took apart for this, and some day I'm going to put the throttle body back to the original way it was.
I did it on the TII. Under light throttle(which is pretty much all you use for driving around town) driveability sucks. I have another throttle body I took apart for this, and some day I'm going to put the throttle body back to the original way it was.
It's funny how this was an "in" mod 5-10 years ago. Now the tide seems to have turned. I've never done it to my RX-7s as I never really saw the point. Of course, I also have full emissions, so what do I know?
Nothing to see here.
Joined: May 2001
Posts: 1,255
Likes: 1
From: Jacksonville, FL
I've done it to a spare tb that I had. If there were any gains, I never saw them and they never outweighed the stock functionality. Then again, I also retained my a/c, power steering, ABS so I like the creature comforts and factory functionality.
Even with my standalone, I can't tune the slight hesitation out, but maybe I need to try a little harder. I went crazy looking in the classifieds for stock TB's. I must have bought 4 or 5 just trying to collect all the parts, but not luck. Something was always broken or missing. I still don't have the fully functioning secondaries, but I got a working thermowax, dashpot and BAC back in my car. Tuning the car for starting was so much easier with these in place.
+1 for me as another who says "LEAVE THE STOCK COMPONENTS ON!"
+1 for me as another who says "LEAVE THE STOCK COMPONENTS ON!"