New gears and exhaust...Killer!!

[Thasian1]

Well i finally finished like 20 projects and got around to my svx. :D I replaced the wheel bearings up front and well...decided that maybe the gears are worn out...lol...and maybe i should replace those too! So i decided to replace them with 4.11's. Well since i had to take the exhaust out to take the diff out i also decided to replace the exhaust from the headers back. They looked like maybe in the next 10 years that i could have an exhaust leak.....so why wait replace it now. Man let me tell you how heavy that freakin tranny was doing this by myself! Can't imagine doing a awd one.
Well everything is together and i lost the diff. plug so i can't fill it with liquid until monday and get a new plug. The exhaust looks and sounds so sweet i couldn't help but redlline it like 20 times. We eliminated all three cats, made two duals into one highflow magnaflow cat, single three inch magnaflow race muffler along with a second straight through race muffler(through the area made for the rear awd) and split again for two dulas with dual square tips on each side. It looks too sweet and sounds like Ferrari f40!!! I actually had a couple guys come from the garage next door to find out what it was, they tought it was a turbo porsche or something along that lines. (and they work on turbo cars.) We are going to start putting together kits for 2wd and also awd svx's and installing them. I'll post pics tommorrow night. Can't wait to drive it monday!

[justiceSVX]

Sounds sweet. :)

[mbtoloczko]

Very similar to what I'm building. Which of the Magnaflow cats did you use, the 94047? 2" OD tubing from the manifold to the cat? How far is the cat from the manifold?

[Chiketkd]

Welcome to the 4.11/4.44 club! :cool:

-Chike

[BordeauxComet]

sound clips would be awesome!

[Bxsvx]

How did you replace the front hubs? I need to swap out my abs ring. any suggestions/steps and tools to use? anywhere I can rent it from?

[SilverSpear]

when I first installed my exhaust system without the middle cherries (only the high performance dual end mufflers), all the ground was shaking, even when i pass near cars, all their alarms go on.... then I realized I should calm the beast, so I put the cherries, and i have now like BMW M5 sound.. veeeerrrrrrrrrry niiiice

[sharky512345]

Originally posted by BordeauxComet
sound clips would be awesome!

:)

[Thasian1]

Well from the headers back it is dual 2 1/2" straight pipe then behind the (don't forget this is 2wd) Tranny it goes into a two into one 3" pipe. Then it has a magnaflow race muffler than a standard high flow which then splits into dual once again for the finisher of two dual square tips. It sounds mean. Very close to stock at idle until you get past 1100rpm then it just sounds very twin turbo porschey. Although now i have everything complete and toke it on test runs today. The heat sheild seems to rattle around 3000 to 3500rpm, otherwise than that full throttle at 25-30 mph breaks the front wheels lose into a torque steer monster. LOL. man i can't say enough about getting gears in this car, i change the whole feel of the car. The car seems to just shifter better, response is like day and night, and when you kick it down to pass or just whatever, it just plain goes!! Love it to death. Next up is the stage 2 computer, upgrading the brakes, and finishing the tunes. This car may be for sale soon, i know i know why, but i've had my sites set on a wrx. I vowed that i was getting one this summer so projects are getting finished and booted so i can go plunk so cash down for one. But you never know, i might decided to keep this and still get the wrx. Love my svx!

[Thasian1]

Ya i can admit if you don't have a presh those hubs are a bit of a pain. I had to use our tubing bender with some jerry rigged plates to hold the spindle and presh the race out with a pipeexpander adaptor. The hub actually pounded out with a large socket, although the bearing and seal where still attached and end up very careful grinding it down until it was easy enough to come off.

[Thasian1]

Lmao, presh......press that is.

[mbtoloczko]

Originally posted by Thasian1
Well from the headers back it is dual 2 1/2" straight pipe then behind the (don't forget this is 2wd) Tranny it goes into a two into one 3" pipe. .... The heat sheild seems to rattle around 3000 to 3500rpm, ...

Ah, your setup is similar to what I have now (vs what I'm building next). I think you'll find that the "heat shield" rattle is not from the heat shield. Its a resonance setup in the exhaust system by using a 2-into-1 y-pipe on the H-6 motor. I have the exact same problem. I've got a 2-into-1 merged y-pipe at the same location. When I first fired up the car, my buddy and I were sure that it was the resonator that we installed about 18" after the y-pipe. I changed out the resonator, and still had the exact same sound. I considered a bunch of different possibilities, and in the end, I decided that because there are equal time intervals between each cylinder firing in the H-6 layout, a resonance sets up at 3000-4000 rpm with the layout you and I have. I'm planning to dump the y-pipe and put a 2-into-1 Magnaflow cat in its place. The separate entrances into the cat should minimize the resonance.

[want-a-fast-svx]

Im not too sure thats gonna happen though unfortunately mychailo...I have 2in pipes going into a high flow magnaflow cat 2in in 2.5 out to a flowmaster. There is no resonator and it resonates like crazy right at 3000-3900 sounds horrible. This made me believe i needed a resonator. Now your saying you basically have the same thing except I have a cat and you don't and with a resonator the sound is still there? I was planning on just chopping out the cat for now until i have more money for another one because, this one was shot in aproximately 4months. However i have been throwing a 02 sensor code the whole time so i was running rich.I still can't believe it toasted the cat that quick though. Either way i was gonna chop the cat and run dual straight pipes till i fix it, might be a little louder but it can't sound any worse.

[mbtoloczko]

Well that's lousy news. Yep. I've got a resonator in there but no 2-into-1 cat. Seems that we have the same sound. I guess I'm going to have to change my game plan again. elninoalex said that he got good results by placing resonators in the primary pipes before the y-pipe/2-into-1. I may have to go with that setup afterall. At least you saved me the trouble of determining this the hard way.

[want-a-fast-svx]

i wish it werent true but i guess it saves us both in the long run....Do you think cutting the pipes will make them too short and have possible problems with my valves getting burned?

[Thasian1]

So i see this is a big issue as well with everybody else. So if i install a resonator on each side(Where the old cats where) Before the 2into1 pipe this noise will go away? It sounds good all up until the resonating starts, then it sounds like a cat stuck in a tin can.:mad:

[SVXRide]

What's the engine at (rpm-wise) when "the cat gets stuck in the can"? You may just have to extend the length of the primary pipes before you join them together with a "Y"
-Bill

[mbtoloczko]

Originally posted by SVXRide
What's the engine at (rpm-wise) when "the cat gets stuck in the can"? You may just have to extend the length of the primary pipes before you join them together with a "Y"
-Bill

I think that Bill has the correct idea. This may be one possible way to stop the resonance from forming.

[odepaj]

haha, i have that same problem on my car. im thinking about running duals, but i read somewhere that that creates a "two raspy 3cyl. engines running at the same time" sound and i deffinetly dont want that. any suggestions?


dustin

[SVXRide]

Originally posted by odepaj
haha, i have that same problem on my car. im thinking about running duals, but i read somewhere that that creates a "two raspy 3cyl. engines running at the same time" sound and i deffinetly dont want that. any suggestions?


dustin

A couple of us are playing around with different exhaust theories that drive the final design of the exhaust system and the final verdict is still out. Right now I can only suggest that you extend the duals to at least 60 inches back from the engine block and then tie them together with a preformed piece of Y pipe. 2.5 inch pipe from the pipe back to a magnaflow muffler (or similar) would be a start.
-Bill

[mbtoloczko]

It may have to be a bit more than 60 inches. I'm at 58 inches right now, and the car sounds like crap from 3000-4000 rpm (and there is a slight drop in power too). I think 70 inches or so will be necessary... about the location of the factory pre-muffler.

[mbtoloczko]

I just looked at my notes. If this is a constructive interference phenomenon occuring with the next cylinder firing, then the way to minimize the interference is to either place the y-pipe at about 120 inches from the manifold (past the back of the car?) or place it at around 24 inches from the manifolds.

[SVXRide]

Originally posted by mbtoloczko
I just looked at my notes. If this is a constructive interference phenomenon occuring with the next cylinder firing, then the way to minimize the interference is to either place the y-pipe at about 120 inches from the manifold (past the back of the car?) or place it at around 24 inches from the manifolds.

Would you make up your mind already?:D ;) :p
-Bill (almost done reading the 4cyl aircraft exhaust system article...)

[odepaj]

i looked up some pictures of the stock exhaust, and it turns out i basically have the stock exhaust with two resonator tips at the very end instead of the stock secondary muffler. dont blame me if this is a bad thing the previous owner had this done. opinions about this?

http://www.subaru-svx.net/photos/files/odepaj/24082.JPG


dustin


ps. i was wrong earlier, my exhaust doesnt resonate at the same rpm's as yours do, i just have a rattle somewhere at 2500-3000 after you let off the gas.

[oab_au]

Connecting the two engine pipes together with a Y pipe, is not the best way for engine performance.
The two pipes should enter a box of some kind, to drop the gas pressure, before they join. If a Y pipe is fitted to the engine pipes, the high gas pressure from one, is going to enter the other pipe, to cause a high pressure in the other exhaust manifold.

The way they join now is the two pipes enter the space in the front of the second cat, where the gas pressure drops. This has the pipes joining in a low pressure area, to prevent one from affecting the other.

If you are dividing the system into two pipes, the dia of the pipes should stay the same as they are now. The idea that because there is only three cylinders on the pipe now, it can be smaller is wrong, as the cylinder size, is what sets the pipe size, not the number of cylinders. Only one cylinder's exhaust is using the pipe at a time.

Harvey.;)

[SVXRide]

Harvey,
I should have been more specific...the Y connection I suggested would feed into the stock (or aftermarket high flow) secondary cat, thus achieving what you've noted (given that the primary cats have been replaced by straight pieces of pipe). Just trying to keep the air a little cleaner and minimize the chance of anyone not passing their state's emissions testing.;)
-Bill

[mbtoloczko]

Originally posted by SVXRide


Would you make up your mind already?:D ;) :p
-Bill (almost done reading the 4cyl aircraft exhaust system article...)

Well, I had the resonator (expansion box) removed from my exhaust line today. The expansion box was in the location of the OEM expansion box. The expansion box I was using was a hollow box (7"W x 3.25"T x 14"L) with a single "V" deflector towards the rear. With the expansion box removed, the resonance at 3000-4000 rpm was greatly reduced in loudness. I think that the exhaust pulses were slamming into the "V" deflector and making a hell of a lot of racket. I also think that if I put a standard muffler style resonator in the position of the expansion box, the exhaust will sound pretty nice.

BTW, removing the expansion box had zero effect on the butt-dyno HP estimate.

[SVXRide]

"OEM expansion box" = OEM resonator??
-Bill

[SVXRide]

Originally posted by odepaj
snip*

dustin


ps. i was wrong earlier, my exhaust doesnt resonate at the same rpm's as yours do, i just have a rattle somewhere at 2500-3000 after you let off the gas.

Dustin,
The rattle could just be from your heat shields. Do you still have the stock primary cats? You might want to get the car up on a lift and see if anything is loose.
-Bill

[mbtoloczko]

Originally posted by SVXRide
"OEM expansion box" = OEM resonator??
-Bill

Yep.