Custom turbo back questions

[davyboy]

Before I get flamed, I know I've asked similar but I've read many many posts and seen that many people do it differently so I'm going to ask specifically what I want. Also decided against ordering a full set up simply due to international shipping etc.

1. I'm only going to try to get 200-240 awhp on this, daily driver, do you guys think I should go 2.5 or 2.75 mandrel bent turbo back?

2. I want to build a custom down pipe and need to know the angle from engine bay to the rest of the exhaust, thinking its a 45 degree?

3. I want to have as few bends as possible, will a straight pipe (with res) work running from dp to rear axle?

4. Best angles to run over rear axle? I'm thinking 4 45 degree bends should get over and to proper position for a small section of straight and a short muffler.

5. What are the largest size of tips that fit in the stock bumper opening? Gonna go slightly smaller to look better in my opinion.

6. Should I keep from the dp back as one piece or would it be better to throw a flange on before the rear axle to be easier to work on?

7. I forgot to ask, what is the angle bend in the stock cat? I would love to build a 1 piece test pipe/down pipe for easier access without that damn hidden mount that you can't reach without attempting to win the cuss-limpics...
And if it's not showing up in my sig, 2001 Audi A4 1.8t Quattro

[DoesntCare]

2.5" is more than large enough for those HP goals.. In all honesty you don't need a 3" exhaust unless you are trying to get closer to 300hp

As for the rest of your questions, your best bet will probably be to look at what is on your car and go from there.

[davyboy]

bring it to a shop

I WANT to build a full custom setup.......

2.5" is more than large enough for those HP goals.. In all honesty you don't need a 3" exhaust unless you are trying to get closer to 300hp

As for the rest of your questions, your best bet will probably be to look at what is on your car and go from there.

Thanks, I figured that 2.5 would be more than sufficient and offer a nice sound. Would you happen to know the stock exhaust exit size of a k03-/k04 turbo? I can't remember if it's 2.5 or 3 with reduction?

[apmech]

Do you have access to a mandrel bender? It's my understanding that the suggested exhaust sizes based on HP, are mandrel bent systems. If you were to do crush/press bends you would have to go up a size or two, to achieve the same flow.

Do you have much experience in bending pipe? You could easily start eating up your savings in bad bends.

As far as the degree of the bends. If you aren't sure, start conservative, test fit, and work your way there. This will limit the size of your scrap pipe pile.

[DoesntCare]

Do you have access to a mandrel bender? It's my understanding that the suggested exhaust sizes based on HP, are mandrel bent systems. If you were to do crush/press bends you would have to go up a size or two, to achieve the same flow.

I figured he would buy pre-bent pieces and weld them together, which is why he's trying to figure out what angles he needs.

[apmech]

I figured he would buy pre-bent pieces and weld them together, which is why he's trying to figure out what angles he needs.

That would make more sense, than what I was thinking.

[davyboy]

Yeah the plan is to buy pre bent, wanting to build in three sections and weld myself.

Want angles
1. Turbo to down pipe, down pipe to flex.
2. Straight as possible
3. Over axle to exit

Hoping to find someone that's done this, I remember one post where someone used straight pipe and two 180 bends but the pictures are no longer showing up.

[Avant Nate]

I did this, but with 3 inch with slip fittings. 2.5 would be easier. I would build the down pipe as one piece . I did not, as I was using a psi concepts pipe. Use Vbands. I have a vband at the base of the down pipe, and one before the back s.

[davyboy]

What's gonna be the cost difference for v-band vs standard three bolt exhaust flanges?

I want to build test pipe and down pipe as one piece. From looking I was thinking two 45 degree bends one off the turbo and one at the bottom should fit but I want confirmation. Also wondering about over the axle and if any are needed along the length or if I can just use a single straight pipe?

[Avant Nate]

There's a little dog leg in the middle.

[SteveAudi99]

Use the old one to make a jig for your new one? Accommodate for the larger diameter.

[VanCityA4Q]

I bought a Flowmaster universal kit when I did my 3" exhaust. For the downpipe I just bought a cat delete pipe and stayed with the 3 bolt flanges, but there's more than enough pipe in the kit with the proper bends that you could make your own easily. Also don't forget to install a flex pipe of some sort after the downpipe.

Here is a link at the bottom to the kit I used if you're interested, it comes with 2 lengths that have 2 45 degree offset bends that fit perfectly through the zig zag by our transfer cases. I know it's a dual exhaust kit and I did use just over 50% of the kit, but for the price, it's not bad at all. They also have an aluminized steel kit that's $50 cheaper but it's not cheap enough to justify at all.

http://www.jegs.com/i/Flowmaster/389/815936/10002/-1

[Avant Nate]

I have the Flowmaster 3inch kit as well, but Aluminized. You will have a lot left over. I don't have any experience welding Stainless, so if you do that's up to you. I also like mandrel-bends.Com
http://www.mandrelbends.com/builder-...timate-bk.html

[davyboy]

That ult kit from mandrel bends looks pretty good, should be able to do turbo back with it right (supposing I wanted nothing but pipe all the way back?
Would I have to cut some of the 180s to make it all fit?

[Avant Nate]

To be honest, looking at the kit again, a bunch of those bends wouldn't really work. Don't hold me to this, as I did this about 3 years ago. You basically need 2 45s for the downpipe, a U that you can cut to make the S at the back and then something for the dog leg in the middle. Google image some aftermarket exhausts to get a better idea.

[VanCityA4Q]

I would just get the Flowmaster kit, I remembered I did make a downpipe with it as well, and welded the mounting bracket to it as well. I'll take some pics tomorrow and post them up if you like.


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[GrapeBandit]

why go through all this trouble? a cx racing or ssac can be had for cheap. if you dont like the sound, swap out the mufflers. hell, scan the classifieds and you will find something

[melomandn]

Buy a milltek exhaust, they're only like $700 brand new now and they sound beautiful on the 1.8t

[tar]

Buy a milltek exhaust, they're only like $700 brand new now and they sound beautiful on the 1.8t

Link?

[Rodgman15]

Meh. I have a 2.75" Milltek and with the resonator, it doesn't make a sound, without the resonator, it drones like nobody's business. Can get better for the price.

[tar]

Apr is 2.5 inch right? Currently I have a cx racing and borla and not sure if I want 2 keep either. The borla is 2 small and cx requires modding which makes the the cost of a better system. Debating on miltek or 42draft

[Dan[FN]6262]

why go through all this trouble? a cx racing or ssac can be had for cheap. if you dont like the sound, swap out the mufflers. hell, scan the classifieds and you will find something

I'm running the SSAC exhaust. Picked it up for $300 brand new, just had to post an online review to a forum.

I have no complaints. I honestly like how it sounds.

[redline380]

I finally found a good video showing the difference exhaust sizes can make. Obviously not apples to apples considering this a BBC, but it should hold more true than you think. This engine is doing about 83.8hp per liter. Multiply that by 1.8 (our engine displacement) and that is only 150hp, so a stock engine! Couple that with back pressure on the turbo, and I think you might be surprised what a bigger exhaust can do for you

[Dan[FN]6262]

Even more so with a turbo. The exhaust manifold sees roughly 1.37 times the pressure that the intake manifold is seeing. So if you're running 30psi, the exhaust manifold is seeing pressure in the 41psi range. If your exhaust system is too restrictive, it'll actually cause the whole exhaust system after the turbo to pressurize. The best exhaust for a turbo is a 2 foot pipe routed up through the hood

[GrapeBandit]

^it is apples to apples, if you are discussing exhaust sizes. you would be comparing flow, not the actual hp gain for the given test engine because every engine is different, so hp figures will be +/- , only concentrate on the flow.

i always say no exhaust is the best exhaust, but for street car, you have to have an exhaust system. bigger is better.

heres a thread on backpressures. .. .
http://www.audizine.com/forum/showth...kpressure-fail

[Dan[FN]6262]

Lmao I know what I'm talking about. Keep keyboard tuning

[redline380]

Lmao I know what I'm talking about. Keep keyboard tuning

pretty sure he was agreeing with you.....

[GrapeBandit]

Lmao I know what I'm talking about. Keep keyboard tuning

yea, calm down there danny boy, my arrow was trying to point to redline, but you replied as i was drafting my message lol

pretty sure he was agreeing with you.....

my post did agree with him, although i didnt even see it as i was replying to you

my apples to apples statement was to you

[nynoah]

The main thing is 3in takes more skill to make it work. Less room for error in alignment.

3in is also WAY louder than 2.5in. So if you don't need to push more than 300 whp, 2.5 will work and not be stupid loud.

034 stopped making and selling the 3in for our cars because they got sick of the complaints that the system did not line up (very little room for variation error between car and pipe) and that the system was too loud.

So food for thought.

[Dan[FN]6262]

Lolololol 100% my bad

[Dan[FN]6262]

The main thing is 3in takes more skill to make it work. Less room for error in alignment.

3in is also WAY louder than 2.5in. So if you don't need to push more than 300 whp, 2.5 will work and not be stupid loud.

034 stopped making and selling the 3in for our cars because they got sick of the complaints that the system did not line up (very little room for variation error between car and pipe) and that the system was too loud.

So food for thought.

This man speaks truth, 3 inch is a whore to hang and not have it knocking on something.

I personally like how a smaller diameter exhaust sounds vs a big one. Less drone.

[redline380]

This man speaks truth, 3 inch is a whore to hang and not have it knocking on something.

I personally like how a smaller diameter exhaust sounds vs a big one. Less drone.

M 3 inch is very difficult to avoid rubbing on the body or the front hanger. I will hopefully fab something up soon.

I am talking about my 3 inch exhaust, not penis BTW.

[Dan[FN]6262]

I may not have 8 inches, but I can get friction on a pickle jar

[davyboy]

Believe me I know about back pressures and fluid (yes gasses are considered fluids) flow rates.
And I have zero intention of going to a big turbo or pushing 300 ponies on my daily driver so I know 2.5 inch is sufficient in size and thank you all for the mention of fitimint. Personally I like the sound a 2.5 makes as well, it's an l4 motor not a V8 lol.
My intention was to get angles as I want to do full mandrel bent right from the turbo.

Big props and thanks to Avant Nate for the pictures, big help.
I also have been looking underneath at all the unnessicary tiny bends that Audi put in, and at the bends in just the cat. I will def be taking pictures and recording all the angles I use when I do this, I'm just gonna go through my local auto stores to see if I can find any universal flanges and o2 bungs or if I need to order them as well before I place my order.

To everyone that's posted helpful tidbits, thank you muchly, to everyone who keeps saying just buy aftermarket I'll say it once more....
I WANT TO BUILD A FULLY CUSTOM EXHAUST....

[melomandn]

Link?

http://www.g-werke.com/audi/a4/b5-19...attro-catback/

Perfect sound for the b5 IMO. Zero drone, great sound level, got tons of compliments. May be a little quiet for some, but loud exhausts on a 4 cylinder always sound ridiculous to me.

[tar]

Meant a 700 link. All their manual are 850 like usual

[melomandn]

Meant a 700 link. All their manual are 850 like usual

They're the same exhaust besides the transmission bracket on the dp. Lop off the bracket and save yourself $150.

[tar]

Tip doesn't come with a down pipe...

[melomandn]

Tip doesn't come with a down pipe...

Never even noticed that haha. Welp my bad, that explains why they left the downpipe out of the picture

[carel]

Do I need a resonator in or can I just run one box with silencer

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