Check this out:

http://www.ozhonda.com/forum/showthread.php?t=34542

 

saw ur pix. the important thing in boring the TB is increasing the size of butterfly. they usually bore it out to 2mm. the boring out must not have steps that create turbolence and that not good. also to benefit from boring out, you must mod the engine ie racing cam, higher comp piston etc. w/o this better leave ur TB stock.

 

I didn't install bigger butterfly, you don't need to have race cam. This mod is to have more free flow in the TB, and after I made it I felt there is gain in power, better pick up, and it will work a lot better with free flow air like open pod, and at the end it just cost me $5.

 

I would also doubt you really made any good gains with this mod. You probly affected the torque curve somewhere or shifted the curve and actually lost power. So since the curve moved to a different spot it feels like you gained power.

And yes, all mods should be viewed as a whole. One thing needs another thing (cam, exhaust) to actually get the full benefit from it. Many times just doing one thing will throw something off balance and you will either be using to much fuel or to little, ect.

Atleast your thinking and trying though, thats the only way to learn!

Kevin

 

Why I lose power if Spoon also bored TB without changing the butterfly. Many have done what I did and gained.

 

I could argue all day but basically nothing can be proved without a before and after dyno. So congragulations on the couple HP!

Kevin

 

Ok check this:

http://forum.sg-fit-jazz.com/viewtopic.php?t=8902

 

Looks like the same discussion only his cost a lot more. Your the smart one then lol.

 

 

http://www.spoon.jp/jp/products/line...php?category=4
You saying that SPOON doesn't know what they're doing?
Can't wait to see your Tokyo based Honda tuning expert's rebuttal....

 

? I am confused now

 

If Spoon doesn't understand then who

 

Spoon bores out the stock throttle bodies on Fit's and gets more power PERIOD end of story - their expertise is NOT questionable
...and they do have the dyno numbers to prove it.

 

Yep

QUOTE=Jonniedee]Spoon bores out the stock throttle bodies on Fit's and gets more power PERIOD end of story - their expertise is NOT questionable
...and they do have the dyno numbers to prove it.[/QUOTE]

 

spoon sells very good products. they sell bored out TB. but puting a bored out TB on a stock engine wont give u more power. in fact you will lose torque. the improvement that u feel is the result of a bigger opening on TB compared w/stock on the same pedal travel, ergo more power. but if u mod the engine like cams PnP etc, you realize actual HP gain.

now boring the front and back of TB leaving the butterfly stock. IMHO it wont achieve anything and maybe make it worse.
Honda spends tremendose amount of money on RnD to get the best power on least gasoline.
this is only my opinion and i can always be wrong.

 

Given That formula there's no argument - put looking for the most power without consent to fuel consumption is another ball game....

Also true just randomly boring out a throttle body may or may not improve go, but the argument that additional CFM flow or increased venturi action without other mods does not increase power is a crock of ****.

Back in the Carburetor days numerous manufacturers upped HP ratings on various models with nothing more than an increased CFM carb....no exhaust, cam or other changes.

 

SPOON bores only the front of TB not the back, this way you will have more pressure. People bore their TB to have more CFM of air, of course with other mods will work better. I think if you have free flow air filter will be even better for more CFM of air. In my case i felt the response is better, and the car picks up faster, I don't think I gained much but with the cost that I paid is a lot better than nothing.

 

wow, that is horrible for aerodynamics
for the air to hit a wall like that is horrible
if your going to do a bore, you should do a taper bore

that it starts out large, and tapers off to the size of the butterfly
also, you should never bore the exit of the throttle body larger than the butterfly

all the velocity you gained from taper boring the throttle body is instantly lost by boring the other side

 

this is how it should be done



start off big, and taper down slowly to the butterfly
that way you get a gradual increase in air velocity
this is how every reputable tuner would do it

 

also, because you bored out the back of the throttle body
now the air will hit another wall
since the intake manifold's inlet is smaller than the throttle bodies


extremely inefficient....sorry to tell you