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  #16  
Old 06-04-2008, 06:52 PM
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svxfreq svxfreq is offline
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Hey guys, I don't know if anyone is actually following this thread any more, but I've been sick for the past like 2-3 weeks, I got my tonsils out and was in a REDICULOUS amount of pain.

Now that I'm back up to speed I'm gettin back to my project.

I've got my exhaust parts in, I decided to go the the 2.25" true dual exhaust, I'm going to eliminate the third O2 sensor as it's just for emissions purposes anyways and it's going to throw a code probably without the cats anyways.
Expensive as it may have been I got two 4x14x2.25" resonators, two 4x9x14 2.25" mufflers, and 2 SWEET polished 3" dual tips.

On top of this I'm still working on the header design, I'm running into a few problems since I realised how small the current headers actually are (it's been a while since the last time I crawled under there) I've been thinking about going with a single 6-2 crossover header, and I'm wondering if someone could tell me the firing order of the engine, I'm going to see if I can tune this right, it's going to be a bit more work, but we'll see what happens.
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'97 Ebony Pearl SVX Lsi
Current Mods: K&N Filter,
-18x8" Konig Hotswaps with Nexen Tires
-Polyurethene swaybar bushings
-iRotor Drilled/Slotted zinc plated rotors, ceramic disc pads, stainless steel braided blue covered brake lines, powder coated calipers.
Soon - Custom Headers, Cold Air Intake, and Custom Magnaflow Exhaust
*New addition*2000 Volkswagon Golf TDi
(don't worry, it's my new winter beater, gives me more money in my pocket(less gas) and I can park my car for longer periods of time giving me time to work on it and less damage to the SVX from winter driving)
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  #17  
Old 06-07-2008, 11:52 AM
Nomad Nomad is offline
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I'm interrested in this thread so , continue your project and I might buy a kit from you !

http://autorepair.about.com/library/...bl-fo-8242.htm

thats for the firing order they say ... I didnt know so , i searched it !

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  #18  
Old 06-07-2008, 11:53 AM
Nomad Nomad is offline
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sorry , that was just the cylinder numbers ...
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  #19  
Old 06-07-2008, 02:53 PM
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The research done by others in the past came up with results to build 36" primaires for the headers... Considering the brute size of these means a lot of tubing and a lot of space is needed...

I have built two sets of headers. Both using 1 3/4" tubing for the primaries. first set was equal length give or take 3/4" collecting into a 3-1 10" collector out to a dual 2.5" exhaust. Granted these exhaust systems were made with using the stage 3 in mind so thats why they were so big...

Personally, I believe 2.25" duals might be too large for a N/A engine. 2" pipes would be better fitted to reduce turbulance down the system and to maintain a higher velocity. BUT 2.25" shouldn't be too much of a damper and will leave open some room for further modifications in the future.

Ideally a N/A header should be 1.25-1.5" primaries 30-36" in length. The bigger (longer) the collector the better. True duals also will make a lot of noise. I have done it and never liked to sound (tone) so I used a single flowmaster 40 series as an H pipe with 4 magnaflow resonators to make probably the best sounding SVX I have ever heard...

Good luck with the system and let us know how it turns out

Tom
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  #20  
Old 06-08-2008, 07:40 PM
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wow ya your numbers are VERY close to what I have found. From my calculations the headers will be 36.9 inch primaries, and the I.D. should be as close to 1.55 in as possible which would be 16 gauge 1 3/4" pipe.

Yes this is going to be very hard to fit under the car since the current headers are REALLY small, but I am planning on just pushing the exhaust back as I am removing the precats anyways.

I am also making the exhaust in such a way that I can add in an H or X pipe later, I want to see how the car will run and sound without it for now.

Lastly, I was thinking about making the exhaust 2" but A) I found it easier to find parts in 2.25", B) even for a venturi collector system it is suggested not to make the venturi less than 1/2" more than the primary pipe size, which is already 2.25", so 2" would be like putting a really small venturi on it, but I'll look into this deeper. C) Like you said, most of the rest of my car may still be stock now, but not for long, I wanted to leave a little (but not too much) leeway for MORE POWER

I am building the system in CAD to get some really close tolerances, and I'll also be testing the model in Flowworks, so once I've got it designed I'll post a picture of what they're going to look like.
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'97 Ebony Pearl SVX Lsi
Current Mods: K&N Filter,
-18x8" Konig Hotswaps with Nexen Tires
-Polyurethene swaybar bushings
-iRotor Drilled/Slotted zinc plated rotors, ceramic disc pads, stainless steel braided blue covered brake lines, powder coated calipers.
Soon - Custom Headers, Cold Air Intake, and Custom Magnaflow Exhaust
*New addition*2000 Volkswagon Golf TDi
(don't worry, it's my new winter beater, gives me more money in my pocket(less gas) and I can park my car for longer periods of time giving me time to work on it and less damage to the SVX from winter driving)
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  #21  
Old 06-09-2008, 12:15 PM
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RallyBob RallyBob is offline
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Quote:
Originally Posted by TomsSVX View Post
Personally, I believe 2.25" duals might be too large for a N/A engine. 2" pipes would be better fitted to reduce turbulance down the system and to maintain a higher velocity. BUT 2.25" shouldn't be too much of a damper and will leave open some room for further modifications in the future.

Ideally a N/A header should be 1.25-1.5" primaries 30-36" in length. The bigger (longer) the collector the better. True duals also will make a lot of noise. I have done it and never liked to sound (tone) so I used a single flowmaster 40 series as an H pipe with 4 magnaflow resonators to make probably the best sounding SVX I have ever heard...
FWIW, a single exhaust pipe (as opposed to true dual exhaust) almost always makes better torque. This is why we went with a single 3" exhaust on Jack's EG33 Impreza, even with a bone-stock engine. I made the downpipes 2.25" feeding into the single 3". Even on 600+ hp SCCA Trans-Am cars, they tended to merge both sides of the V8's headers into a single 4" exhaust pipe.

I recently built a custom stainless exhaust for my Nissan Pathfinder (3.0 litre V6), and extended the primary tubes downtubes (2" OD) compared to stock by about 24", then merged into a single 2.5" exhaust (stock was 1.875"). The torque and horsepower improved drastically via this mod, and that engine is only 160 hp stock. I suspect a stock EG33 would respond accordingly.

Regarding the Flowmasters....without exception, they made the lowest power of any muffler I've ever seen tested on a dyno! On a Mustang, a Corvette, STI's, Jack's Impreza, an SR20VVL-powered Sentra, etc, they were horrible for power.

HTH,
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  #22  
Old 06-09-2008, 12:19 PM
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granted this may be true... But more or less I couldn't stand the sound the other mufflers were making. I knew the flowmaster was going to be the only muffler to make the sound I wanted... I love the way it sounds and it responds just as well as the magnaflows did. I am sure there was some lost with this muffler it was nothing substantial and the gains of a sweet sound over a ricer on crack definately outweight the couple ft/lbs i may suffer.

Hey Bob, did Andrew get into that motor yet?

Tom
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  #23  
Old 06-09-2008, 12:30 PM
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RallyBob RallyBob is offline
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Quote:
Originally Posted by TomsSVX View Post
granted this may be true... But more or less I couldn't stand the sound the other mufflers were making. I knew the flowmaster was going to be the only muffler to make the sound I wanted... I love the way it sounds and it responds just as well as the magnaflows did. I am sure there was some lost with this muffler it was nothing substantial and the gains of a sweet sound over a ricer on crack definately outweight the couple ft/lbs i may suffer.
Well heck, that just means you need to build the motor to sound better!

On some cars they REALLY hurt power. The 215whp VVL-powered Sentra lost 13 hp from the 3" Flowmaster!

Quote:
Hey Bob, did Andrew get into that motor yet?

Tom
Probably not, he just got back from STPR yesterday. He's been bouncing around all over the country lately. This weekend STPR, last weekend Tennessee, the weekend before Oregon!

I told him to start the mockup work on the chassis (engine fitment, tubing the front end, cooling system plumbing, etc), then I'd get involved. He's going to bake the chassis, have it sandblasted, then seam-weld it/cage it, and finally have it powdercoated. So he needs to get the engine fitment issues out of the way first. Looks like he's going with a straight-cut 6 speed C/R dogbox as well...
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  #24  
Old 06-09-2008, 02:26 PM
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TomsSVX TomsSVX is offline
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Quote:
Originally Posted by RallyBob View Post
Well heck, that just means you need to build the motor to sound better!

On some cars they REALLY hurt power. The 215whp VVL-powered Sentra lost 13 hp from the 3" Flowmaster!



Probably not, he just got back from STPR yesterday. He's been bouncing around all over the country lately. This weekend STPR, last weekend Tennessee, the weekend before Oregon!

I told him to start the mockup work on the chassis (engine fitment, tubing the front end, cooling system plumbing, etc), then I'd get involved. He's going to bake the chassis, have it sandblasted, then seam-weld it/cage it, and finally have it powdercoated. So he needs to get the engine fitment issues out of the way first. Looks like he's going with a straight-cut 6 speed C/R dogbox as well...
Yikes!! Thats quite a tranny With that I am growing more curious as to the plans for that motor. /hijack

Tom
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  #25  
Old 06-09-2008, 04:44 PM
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Trevor Trevor is offline
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Great thread.

At long last we have some data/ideas being set down by persons who clearly know what they are doing, rather than only having read about it, then quoting accordingly on a basis of absolute knowledge.
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