BBS and ported intake runners

[jonheese]

I've already disassembled my intake once when I painted it & did my 60k. I have no idea what you are talking about... and what are "metal velocity stacks"??

Does anyone have pictures they can label for me? I know I"m making myself sound stupid but I don't care, I have no idea what you guys are talking about.

You can't see them at all from the outside, but when you disassemble the intake, when you take off the butterflies assembly from the surge tanks, you should see six little curved tubes (3 on each side) pointing into the tanks that look like this:

If you they aren't there, then someone already removed them.

Regards,
Jon Heese

 

[FOMOCOTOSHO]

You can't see them at all from the outside, but when you disassemble the intake, when you take off the butterflies assembly from the surge tanks, you should see six little curved tubes (3 on each side) pointing into the tanks that look like this:

If you they aren't there, then someone already removed them.

Regards,
Jon Heese

Thanks for the info & picture. That's perfect. Now I know what you are talking about.

So removing this well help allow the secondaries to open @ a lower RPM then? That's good right?

 

[Phoenix]

The only purpose to remove them is when you install BBBs. You wont improve anything if you remove them "for fun".

 

[jonheese]

Thanks for the info & picture. That's perfect. Now I know what you are talking about.

So removing this well help allow the secondaries to open @ a lower RPM then? That's good right?

No, you will not change the secondary-opening RPM at all. The secondaries open at a programmed RPM, totally independent of any feedback from the physical engine/intake. The only way to change the secondary-opening RPM is with a computer mod, like a TwEECer, LPM, etc.

Removing the horns is a good idea if you're installing BBBs, since the horns are smaller in diameter than the butterfly units themselves. In other words, if you install BBBs and leave the horns, you're not getting the full flow out of the butterflies, since the horns are relatively restrictive.

My point about the RPM tuning had to do with the optimum RPM that the secondaries are "tuned" for, which has to do with the physics of air moving in a column, nothing to do with EEC computer tuning.

http://en.wikipedia.org/wiki/Variable_length_intake_manifold

Regards,
Jon Heese

 

[jonheese]

The only purpose to remove them is when you install BBBs. You wont improve anything if you remove them "for fun".

Agreed. However, whether you remove the horns for a BBB install or not, you will change (lower) the points in the RPM band where the engine makes peak power and peak torque (possibly lowering the peak power and torque numbers themselves in the process). Not that anyone would want to do that, but it is what it is.

Regards,
Jon Heese

 

[jedhead]

Thanks for the info & picture. That's perfect. Now I know what you are talking about.

So removing this well help allow the secondaries to open @ a lower RPM then? That's good right?

The ECU determines when the secondary butterflies open up. You can change the rpm for the butterflies to open via LPM or Tweecer. Mine opens at 3400rpm vs. 3950 stock.

Bob

 

[-DVP-]

The ECU determines when the secondary butterflies open up. You can change the rpm for the butterflies to open via LPM or Tweecer. Mine opens at 3400rpm vs. 3950 stock.

Bob

Why so low? Just curious.

 

[jedhead]

Why so low? Just curious.

I think it makes the power transistion when the butterfiles open smoother. When the secondaries opened at 3950, torque came in with a bang and when powering out of the corner, pre-quaife days, it caused the inside front wheel to up in smoke.

Bob

 

[formersho]

Quite a few years ago this was a big topic. There was a fellow that dyno tested this theory. On a stock car it made 4hp on top, but it curiously lost about the same on the bottom end. I always remove them.

 

[92MTX]

I am keeping them, and drilling several 1/4 inch holes in them..

 

[formersho]

I am keeping them, and drilling several 1/4 inch holes in them..

what is that going to do for you? Just take them out.

 

[mike25]

would you be hurting a stock sho by removing them i am about to do my intake and was curious.

 

[frosho]

would you be hurting a stock sho by removing them i am about to do my intake and was curious.

Yes, leave them.

 

[illSHOyou]

We deleted the secondary butterfly's in James (St. Louis SHO) car, but left the horns. I think he should chime in here with his opinion. Sure he has taken a hit on the bottom end, but he might be making more top end power than SHO's equiped with BBB. Becuase the intake horn is a good silencer that in itself is a indicator of a well working intake port. Take for exmaple a ported speaker. Say you have two ported speaker inclosures, one with a flared port and one with out. The flare port not only has less port noise, but increases the power of the said speaker by creating less turbalance.

Air likes to move in a pattern that raises it off the port floor and do a "S" bend into the intake horn. This is why many turbo intake manifolds have trumpets in the inside.

Bottom line with good hard data you could debate this both ways. James car has no bottom, but runs very good on top vs. highly modified SHO's.

Something to pick your brains about...

 

[St Louis SHO]

My car has good low end. I really didnt notice a huge loss by any means. It has the most unique sound. At the convention, you could hear my car over all the other ones out there. Its fast too.. lol

 

[formersho]

It will not hurt a stock SHO, we had a 93 ATX completely stock and I put a Cone filter on, and pulled the horns and it was a monster for being stock. They are just there to quiet the sound. The long runners do not have them and I think if they were an important part to how the intake works they would have them as well.

 

[jonmon6691]

It will not hurt a stock SHO, we had a 93 ATX completely stock and I put a Cone filter on, and pulled the horns and it was a monster for being stock. They are just there to quiet the sound. The long runners do not have them and I think if they were an important part to how the intake works they would have them as well.

No. Intake runners are tuned to a very specific length to make peak torque at a specific rev point. The reason the SHO has long and short runners is so that it can peak in two places, therefore increasing driveability.

Take a look at this, its the intake manifold of an s62, the V8 from the BMW M5:


Those runners are NOT for noise reduction.

 

[93rev2sev]

I've always been of the quiet opinion that the horns should be modified to work with the BBBs. It does not seem all that hard to do, but it would take some fabrication skills, including welding.

As far as I know, SHOBill is the only one that has done this. I'm surprised he hasn't commented in this thread.

 

[Toolman]

On my intake, I plan on removing the entire butterfly assembly, and then fabbing some new larger horns. I have two EH intakes, so I could dyno a stock intake, an EH/BBB intake with horna, then my monster no BB's/EH intake with big horns (in fact, I am right now laying claim to the name BIG HORN INTAKE!!!)

 

[BlackonBlack89]

I've always been of the quiet opinion that the horns should be modified to work with the BBBs. It does not seem all that hard to do, but it would take some fabrication skills, including welding.

As far as I know, SHOBill is the only one that has done this. I'm surprised he hasn't commented in this thread.

nova SS has some and they are very nice.