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3RZ 2.7L throttle body cleaning questions...

Old 09-03-2008, 03:31 PM
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3RZ 2.7L throttle body cleaning questions...

Hey All,

Picked up a 2000 4runner a couple of weeks ago to replace my venerable 1988 runner with the 22RE. The new rig has the 3RZ 4 cylinder engine.

Cleaning the throttle body regularly really helped my 22RE, so I went to do this on the new rig. But I'm having problems accessing the throttle body because the crossover tube assembly fits against throttle body in a very rigid fashion, even with the hose clamps undone. It looks like the part of the crossover tube that has a rectangular box attaches to upper part of the motor with some bolts that are out of sight. Not sure if removing these bolts would allow me to pull the cross over tube off, even if I could get them off.

Could really use some tips on how to accomplish throttle body cleaning on this motor, from someone more experienced with the 3RZ engine than I am.

Along these same lines, has anyone tried doing the Seafoam treatment on this motor? If so, where do you spray it into the intake?
Old 09-03-2008, 03:58 PM
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The rectangle box bolts to the head. Take an extension and a socket, and undo them, and it will slide off allowing you access to the throttle body.
Old 09-03-2008, 04:16 PM
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Thanks DC!
Old 09-03-2008, 07:09 PM
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Yeah...the intake should completely just slide off with no issue. Make sure all the vacuum lines are disconnected before you start pulling too hard though. Its very simple though, you shouldn't have too much trouble.
Old 09-06-2008, 12:05 PM
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Originally Posted by DeathCougar
The rectangle box bolts to the head....
Is this rectangular box by any chance the intake silencer that I might want to remove? If so, any tips on doing that specifically on the 3RZ?
Old 09-06-2008, 12:56 PM
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Are you having a hard time taking off the intake tube?

The 2 bolts under the Intake Silencer come of with a 10MM(if i remember correctly) socket and one the ISR is loose it makes the whole intake way easier to take apart, its not as rigid as you think when those bolts are undone
Old 09-06-2008, 03:16 PM
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Originally Posted by NwRunner
Are you having a hard time taking off the intake tube?

The 2 bolts under the Intake Silencer come of with a 10MM(if i remember correctly) socket and one the ISR is loose it makes the whole intake way easier to take apart, its not as rigid as you think when those bolts are undone
NWrunner, sorry wasn't clear in my post. I have not had time to work on this yet, but I don't think I will have any problems once I do (tomorrow), it seems pretty clear and easy, based on yours and the prior responses to my original query.

I was asking if the "rectangular box" is indeed the intake silencer, I wasn't sure about that. I am considering removing it- I know this is a common mod on the V6's. You have confirmed that's what the box is. I will learn more about what all might be involved with taking it out of the intake apparatus when I detach it all tomorrow to clean the intake.

Thanks for your post!
Old 09-07-2008, 12:33 PM
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I think the metal box is the intake silencer, but there really isn't any reason to remove it. You wont gain any power from doing it.
Old 09-07-2008, 01:11 PM
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more direct airflow couldnt hurt, im not sure why its there in the first place.
Old 09-07-2008, 01:29 PM
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The airflow is already direct. The silencer is there to do exactly what its name is...silence the intake so its not loud and obnoxious. Since you are eliminating an air chamber instead of creating a direct flow, its not giving you any power gain what so ever. Its just for show.
Old 09-07-2008, 02:24 PM
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I appreciate quiet, and certainly won't bother with any mod that simply increases noise. But many people with the V6 engines seem to think removing the silencer does make a difference in throttle response/power by providing a more direct airflow. Not sure if this would also be true with the 3RZ. I am not very happy with the throttle response so far...suspect a dirty intake, and also possibly a slightly sticky gas pedal. This rig is new to me and the PO didn't have any maintenance records so I will probably also replace the plugs and plug wires and perhaps do a Seafoam treatment.

Having a h*ll of a time getting the bolts off, will try again but I don't want to round them off...

EDIT: Got the bolts off, destroyed one of them in the process, bought a replacement and successfully completed the task. Seems to have helped some, definitely worth doing.

Last edited by riverrat; 09-07-2008 at 04:58 PM.
Old 09-07-2008, 09:10 PM
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Originally Posted by DeathCougar
The airflow is already direct. The silencer is there to do exactly what its name is...silence the intake so its not loud and obnoxious. Since you are eliminating an air chamber instead of creating a direct flow, its not giving you any power gain what so ever. Its just for show.
Intakes arent loud by any means, you can hear some draw at an open ended filter with a straight tube, but when the hoods down there will be no difference.

And as far as no power benefeit, wrong. Your taking the air that was brought through the tube and sending some of it down into a little box before it enters the throttle body. As more air goes down into the ISR it starts to get pushed back out, creating friction and slowing airflow. Once the cycle of air gets going it is no problem. But snappy acceleration is decreased when you have to cylce it through the ISR, rather than bypass it and send all the air straight to the TB.

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I used the only photoshop i can afford... A.K.A. paint.

Last edited by NwRunner; 09-07-2008 at 09:25 PM.
Old 09-07-2008, 09:34 PM
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The intake silencer does just that....silences the SOUND of the intake. It has little or nothing to do with the airflow. Removing the intake silencer will NOT gain you any horsepower, and even if it did, it would be negligable at best. The air flows OVER the hole/tube, not down and in through it.

Direct flow intakes are quite loud. Ever hear one of those honduhs take off under heavy acceleration? Its very much louder. Often times its drowned out by fart can mufflers so its not as noticable. But its still there. Even with the hood down.

Also, a lot of the "gain" in vehicles comes from wishful thinking. If you THINK it is more responsive, then by all means it "is". However, dynos will prove that wrong. Many people get drawn into believing that THEIR car gained the advertised 15+ hp, despite that number being for one type of car ONLY. (read the fine print ) The gain in intakes comes from better airflow via straighter larger pipes and better filtering elements.
Old 09-07-2008, 09:40 PM
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I had a 91 accord with a H22A transplant and striaght intake, it is not loud.
and yes, the air does go down into the ISR. An open ended filter will be loud with or without the ISR. Hell, stock would be loud with or without the ISR if the intake point wasnt burried in the fender.
Old 09-07-2008, 09:45 PM
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Originally Posted by NwRunner
I had a 91 accord with a H22A transplant and striaght intake, it is not loud.
and yes, the air does go down into the ISR. An open ended filter will be loud with or without the ISR. Hell, stock would be loud with or without the ISR if the intake point wasnt burried in the fender.
Noise levels are a matter of opinion. Generally the teenage crowd doesn't think a fart can muffler on their stupid honda commuter car is loud. Same crowd lulled into believing they are gaining 50hp with that fart can and a "Cold air intake"

As i said, the power benefit would be negligable at best. Its not worth the time or money to do it, unless you are building a race car where every 1/16th of a HP counts.

Last edited by DeathCougar; 09-07-2008 at 09:49 PM.
Old 09-07-2008, 09:59 PM
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Originally Posted by DeathCougar
Noise levels are a matter of opinion. Generally the teenage crowd doesn't think a fart can muffler on their stupid honda commuter car is loud. Same crowd lulled into believing they are gaining 50hp with that fart can and a "Cold air intake"

As i said, the power benefit would be negligable at best. Its not worth the time or money to do it, unless you are building a race car where every 1/16th of a HP counts.
Ahh resorting to lowblows now are we?


ISR mod does increase power over stock. it may be very minimal at best, but the little things add up. And not bad for a $10 peice of pipe.

and F.Y.I. My accord ran a 12.45 quarter, got 27MPG, and did it all looking and sounding like stock, hubcaps and all. I never was into the import scene...
Old 09-07-2008, 10:09 PM
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No low blows here. I really have no interest in what your accord can or could do. I run 19.1's on the figure 8 track. Really has no bearing in our discussion.

Little things ad up sure, and like I said it might make a difference on a race car where every HP counts. I know several people who have undone their ISR mods because they are pointless mods that merely made their intake noisier.
Old 09-07-2008, 10:14 PM
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and i have no interest in your funny car.

It does make a difference. A small one ill admit, but still a positive difference.
Old 09-07-2008, 10:15 PM
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Funny car? Nothing funny about T-boning a honda at 60 in the intersection Ask the dummy who tried to run me lol
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