Rebuilding my intake, which way do the little metal pipes inside point?

[Devin]

Rebuilding my intake, which way do the secondary horns point?

Of course I didn't mark them when I took them out. Is there any real difference on which pipes I stick where? The middle ones can only go in the middle, but the two sides each have different lengths.

Thanks for the help!

 

[Devin]

So no one here has rebuilt their intake?

 

[HopefulSHO]

IIRC, the secondary horns (I'm assuming your talking about them) can only go in their certain spots - as in the 'knobs' won't let you put them in the wrong place.

I belive they point downward once installed.

 

[Red Baron]

They do point downward and I believe that the bolt pattern will allow them to fit in only one place....I'm trying to remember as to how they were when I removed them from my intake...

Do you have BBBs?

 

[Devin]

No, just normal butterflies. Secondary horns, huh? Wouldn't there be less restriction if I just didn't include them?

 

[wood_e]

They were put there for a reason...but I took mine out because I was told the sound is incredible without them. I cannot say at this point, my car's been apart for a week and a half...

 

[Huntervf]

Dyno runs have shown that with the air horns removed you generally get a very slight hp gain above 5500 rpm I believe, but you trade off more low end power. In short, they were put in there to help optimize low end breathing, which IMO is more important than a couple hp increase up high. I'd leave them alone, those Yamaha engineers knew what they were doing with this engine.

 

[Red Baron]

No, just normal butterflies. Secondary horns, huh? Wouldn't there be less restriction if I just didn't include them?

This has been a topic that has been discussed quite a bit. What answer you get depends on who you ask. Check this thread out....

...but you trade off more low end power. In short, they were put in there to help optimize low end breathing...

By low end power, do you mean when the secondaries initially open up until 5500 RPM? In other words, the curve in the power band moves up?

 

[Huntervf]

Honestly it's been awhile since I reviewed this; in fact I remember the dyno number coming up when I was still on the SHOtimes mailing list. IIRC it wasn't so much a change going forward as it was just lower torque number below 4k versus higher hp figures upwards of 5500. I'm hesitant to use actual numbers because it's been so long, but I want to say a 2-3 hp increase was seen up high while a loss of around 5 ft. lbs. tq was seen down low, and max tq was lower as well. Sorry I can't be more specific...I'll see if I can dig that info back up. All I remember is that I was going to remove the horns but after hearing & seeing the dyno numbers I changed my mind.

 

[Devin]

Now that I have them in, I'm not going to do anything about it, but...


The horns are on the butterflies, and therefore the short runners. Why would there be a loss of anything on the low end? I thought the butterflies stay closed until 4K?