um...i think someone did this and said there was no gain... as i am aware the TB is alreaddy matched to the intake manifold so that even if you port the TB it won't do anything cause no more air will get in the intake manifold...

 

Well, thanks... but I already have the second TB so I am going to do it, worth it or not. And besides, the TB does flange out after the throttle plate (on the intake manifold side) so I dont see how I wown't be able to effectively increase the size of the throttles opening area.

 

The limiting factor will probably be either the engine side of the intake manifold, or definitely the MAFS mount. The MAFS mount is 2.5" in diameter, so widening the throttle body any more won't do anything. You're only getting so much air into the engine, so widening anything beyond the smallest diameter in the intake system is pointless.

 

Okay, cool.
You answered my question BB. If the MAFS mount is 2.5" in diamter, and the stock TB is 60mm (2.32"), then the most I should widen it to is 63.5mm (2.5") to match the MAFS.

Thanks!

 

You could probably pick up a GT-S throttle body and yank the throttle plate from it. The GT-S' plate is almost exactly 2.5".

 

Hmmm, good idea. I might just try to machine one out of aluminum, or brass... the stock plate looks like it's brass.

 

One of the Spyder owners on here had seen a dyno proven consistent 2hp gain from milling the arm that holds the plate flat, so you might try that too. And please post results - I am very interested in doing this if it works!

 

Well, I'd love to post some dyno results, but I dont think I have the time or the money to hit up the dyno twice... but we'll see

But I'm not sure what you mean about 'milling the arm that holds the plate flat'....care to elaborate?

 

Originally posted by S|Lv3rBu||et
Well, I'd love to post some dyno results, but I dont think I have the time or the money to hit up the dyno twice... but we'll see

But I'm not sure what you mean about 'milling the arm that holds the plate flat'....care to elaborate?

Well, if you've got two throttle bodies, you can just swap them out in between runs.

If you look into the throttle body, the part that holds the throttle plate is basically a cylinder with a slit in the middle to hold the plate. If you flatten this cylinder out a bit, you'll gain a bit more airflow through the throttle body.

 

Originally posted by Blue Bomber
If you look into the throttle body, the part that holds the throttle plate is basically a cylinder with a slit in the middle to hold the plate. If you flatten this cylinder out a bit, you'll gain a bit more airflow through the throttle body.

Ahhh, I get it... good call, maybe I'll give that a try too

 

What Bomber said is right, and if I remember right it was Lilrocketspyder that mentioned it so you might PM him for details.

 

Originally posted by S|Lv3rBu||et
Well, I'm going to have my TB ported, polished and bored out sometime very soon. I believe it's a 60mm stock and I'm concidering increasing to about 62 or 63mm, if anyone has any experience or ideas as to what might be a good amount to bore out, please let me know. Thanks

Are you talking about the ID? I measured and found that it goes from 53mm (ID) at the butterfly plate, then it has a sudden enlargement to 56mm, and gradually tapers out to it's end at about 66mm. I did this with a telescoping gauge and a micrometer.

 

Originally posted by 143hawaii
Are you talking about the ID? I measured and found that it goes from 53mm (ID) at the butterfly plate, then it has a sudden enlargement to 56mm, and gradually tapers out to it's end at about 66mm. I did this with a telescoping gauge and a micrometer.

Okay, my qutoe of 60mm was a rough estimate that I got with a US micrometer (that doesnt telescope). But if the diameter at the throttle plate is 53mm.... then to get it as large as the MAFS housing, I'd have to enlarge it a full 10mm... does that sound a like a lot to anyone else?

 

2.5" = 63.5mm

 

Originally posted by S|Lv3rBu||et
then the most I should widen it to is 63.5mm (2.5") to match the MAFS.

Originally posted by Blue Bomber
2.5" = 63.5mm

Yeah, I know.
I'm just saying that if 143hawaii is right, and the stock diameter is 53mm, would widening it to 63.5mm be too much? I mean, don't most bored out TBs increase diameter like... 3-5mm?

 

Well, you can only gain so much from porting the throttle body. After that, the intake runners and/or head would be the final bottleneck. If anyone knows the total volume of air the intake runners can handle, matching the the throttle body to that would give you the most airflow. Not sure if you can safely port the GT intake manifold, though, since it's plastic.

 

Originally posted by Blue Bomber
Well, you can only gain so much from porting the throttle body. After that, the intake runners and/or head would be the final bottleneck.... Not sure if you can safely port the GT intake manifold, though, since it's plastic.

Yeah, I'm gonna take it one step at a time. However, depending on how easy it is to remove the intake manifold, I might give it a good cleaning before final re-assembly.
But thats a good call about the airflow capacity of the intake manifold.... if nobody on here knows it, any ideas of where I can get that info from? Maybe directly from toyota (thats assuming I can get someone from toyota to talk to me).

 

Originally posted by S|Lv3rBu||et
Yeah, I know.
I'm just saying that if 143hawaii is right, and the stock diameter is 53mm, would widening it to 63.5mm be too much? I mean, don't most bored out TBs increase diameter like... 3-5mm?

Boring it out 10mm is way to much IMO. If you take off your throttle body and compare it with your intake manifold, you'll see that there's a slight gain to be had by a mild boring to match it to the manifold. That is unless you're planning to port a plastic manifold also.

Then if you remove the intake manifold, you'll see that there's another restriction. The ports of the runners don't match up with the head. Then there's the head...just look at it. :bang: The 1ZZ was definitely not made to be a clean NA motor.

 

Okay, I thought boring 10mm seemed like a lot... but if you concider the 1.8l out of the integra (I know, a very different engine) companies sell TBs for that engine with a diameter of 65mm!! Thats the only thing that makes me think boring out to 63.5mm would be okay. But now I'm really not sure.

So if the stock size is 53mm, and MAFS housing is 63.5mm... maybe I should go for 58mm? 60mm?

 

did anyone ever figure this out?

 

I'm going to be putting a slightly used '03 1zz in my car within a month or so. The head will be ported and polished so I believe it will be a good application for a larger throttle body, so I am saving this project for that application. Unfortunatly, the results will not be applicable to stock 1zz heads but... eh....

In any case, so long as the walls of the TB are thick enough, I plan on going with 60-63mm to match the MAFS.

 

ehh, i forgot you had a GT. i wonder what the 2zz throttle body looks like. has anyone measured it?

 

Originally posted by jway83
ehh, i forgot you had a GT. i wonder what the 2zz throttle body looks like. has anyone measured it?

2.5" at the throttle plate.

 

cool. i guess i don't have to add that to my list of things i'll probably never get around to doing...

 

Originally posted by jway83
cool. i guess i don't have to add that to my list of things i'll probably never get around to doing...

:chuckles: