Herbs

I tried a "search" this topic with no success, so if it's been discussed and you can direct me to the thread I'd appreciate it.

Is it true that hp is created by the tips of muffler being faced downward? (i.e. 5th gen Max's) I'm trying to figure out the best setup for added hp in the y-pipe and exhaust system area with minimal additional sound? I understand that upgrading the y-pipe but not the exhuast system might do that? But if I can upgrade my muffler, gain some hp, and still keep the sound down, I'd like to do that.
I know you guys have discussed this, but I can't find it anywhere. Input please!!! Holla...

mzmtg

iTrader: (11)

I dont know which 5th gen muffler you're talking about but...the angle of the tips has nothing to do with horsepower...

96sleeper

iTrader: (4)

Dave B. was the one that made the post about that. The theory behind it is that by having the tips pointed downward makes the air flowing under the car create a vacuum at the tip and helps draw out the exhaust. I don't know if it actually does anything, or is just a thought. I know Dave had a tip put on that faced downward becuase of the idea. I wouldn't plan your exhaust around it, I don't see how it could give more than 1 or 2 hp, if that.

y2kse

iTrader: (1)

Perhaps, but the massive exhaust flow resulting from your high-performance engine operating at WOT would tend to make your back end rise up, resulting in less control at high speeds. You'd definitely want to install a larger spoiler or put sandbags in your trunk to offset this effect.

mzmtg

iTrader: (11)

You're on the right track. In a street situation this would be true. But, at the drag strip this lifting jet of exhaust gas would help minimize weight transfer and help your 60 foot times.

As usual this is a situation of trade-offs...

y2kse

iTrader: (1)

Dave B

These tips are referred to as scavenger tips. The tips help scavenge the exhaust by using the air underneath the car to draw the exhaust out. These tips do work. As you've probably seen on many cars of today, the trend to to use this setup for both performance and asthetics (sp). Nissan's doing it, Mercedes, Audi, VW, etc. The amount of power gained is minimal, but every little bit helps. I had one on my car, but I couldn't get over the look because the stock bumper cutout made the tip look way too low (as if I backed into a curb and bent my tip).


Dave

NisMoMAX01SE

how much are those tips, like $40 or $50 , thats quite a lot to spend to gain like 1-HP.

y2kse

iTrader: (1)

I'm not buying it, Dave. I just conducted a Yahoo search under "scavenger exhaust tips" and couldn't find a single reference. With all due respect, I'm putting scavenger tips on the same list as the Tornado Air Management System and the Electric Supercharger. The tips are fine if you've got them. But spending money to have them installed for any reason other than aesthetics is just plain silly in my estimation.

LoveSick

I know that Mercedes have their exhaust looking like that! It looks ugly though.

Dave B

Ever heard of Robert Sikorsky? He's written many books on automotive maintenance and performance. Scavenger tips were very popular back in the late 60s and early 70s during the muscle car era. The gains of the tips, like any mod, is directly related to the displacement and max rpm of the motor. On a VQ, you'd probably get 1-2hp. There is a science behind this. Auto makers just don't bend the exhaust tips down for the heck of it. Take a look at a Impala SS, Crown Vic, V6 F-Body, any Saturn, I30 or AE Max.

BTW, these tips cost about $4 at any auto store.


Dave

AznWontonboy

hmm.. weird..

y2kse

iTrader: (1)

Super. Then perhaps you'd be willing to refer me to the book on automotive maintenance and performance that contains Robert's reference to the advantages of using scavenger tips. And if it's not too much bother, would you please provide the specific page numbers on which the reference appears?

Thanks.

Dave B

Y2KSE
Do you think I'm lying and making this up? I really don't need to prove anything to you. This guy has been around for a long time and does automotive tech write ups in many city new papers.

*yawn*

"Drive It Forever" 1995
Robert Sikorsky
Intake and exhaust, p.127, 2nd paragraph


Dave

Jeff92se

iTrader: (82)

Hey Dave, can you explain something to me?

Why would downward pipes extract any better than a pipe that is straight? Wouldn't both be extracting the same? Both would have the air passing by the tips correct?

y2kse

iTrader: (1)

Never, Dave. I'm just interested in looking up the information for myself.

Dreizehn

iTrader: (4)

I just put my downward tip on today... Damn!!! You should all check into it!!! Unbelievable.
It did nothing.
j/k

Herbs

From a looks perspective, I can see the issue with 4th gen.

From a cost perspective, if the "scavenger muffler" does provide 1 to 2 hp, and it costs $40 to $50 maybe not. But if it costs $15 or less, like Dave suggests, that would be cheaper then most of other upgrades that we purchase for our cars.

I had entirely too much time on my hands one day and figured out that on average, we spend somewhere between $15 and $30 per 1hp when we purchase an aftermarket product. Just something to think about.

Dave B

Nope. Ever seen a wind tunnel test on a car? A pocket of stagnet air develops right on the rear on the car. Air goes over the top, around the sides, and underneath. The tips take advantage of the air passing beneath.

Think of it this way. You've got a pool of clockwise rotating water. On the outside edge of the pool you have a pipe discharging water towards the clockwise rotation. The water will flow out much easier as it "rides" the flow. If you were to change the rotation of the pool to counter clockwise, but kept the pipe in the same direction as before, the water would discharge at a slower rate because it is having to work against the rotation of the pool. The same basic principle applies to these tips.


Dave