Exhaust from the manifold back

mocpac · Post by **mocpac** » Mon Dec 29, 2003 2:12 pm

You need just a hi flow cat and will have no problem w\ performance. I don't know if in AU is legal but here in Puerto Rico you can't remove the cat.

Maximus · Post by **Maximus** » Mon Dec 29, 2003 2:45 pm

mocpac_ser wrote:You need just a hi flow cat and will have no problem w\ performance. I don't know if in AU is legal but here in Puerto Rico you can't remove the cat.

We also canot remove the cat, but who cares

I have thrown out my cat a long time ago.

Right now I now that I will make 2" pipes and only one prolem is schould i put in rezonator + one high flow muffler or just the high flow muffler.

I am also wandering if a straight through exhaust with only one muffler will not couse less power than two mufflers

Post by **Efratech** » Mon Dec 29, 2003 3:38 pm

im using a 2" with an RSracing muffler i do have TWO yes you read it right two 2" resonators... i had the 2" straight with the muffler it was loud... i mean VERY loud...

Maximus · Post by **Maximus** » Mon Dec 29, 2003 7:21 pm

maniac16v wrote:im using a 2" with an RSracing muffler i do have TWO yes you read it right two 2" resonators... i had the 2" straight with the muffler it was loud... i mean VERY loud...

And that's what I have wanted

thanx

Daew0Leganza · Post by **Daew0Leganza** » Mon Dec 29, 2003 8:22 pm

where can i buy a resonator?

Maximus · Post by **Maximus** » Tue Dec 30, 2003 9:03 am

Daew0Leganza wrote:where can i buy a resonator?

You have one in your car

and you can buy it it every exhaust shop

Maximus · Post by **Maximus** » Wed Dec 31, 2003 7:54 am

I feel lucky

my friend is selling his car today and yesterday he was pulling everythng that he could out of the car. He sold me he's 4-2-1 header for 100$

so all I have to do is do the rest of the exhaust and I'm finished with exhaust

I was also talking to a friend yesterday (he's a mechanic) and he told me that 2" pipes can be to big...

gti_7 · Post by **gti_7** » Thu Jan 01, 2004 12:36 am

thats true, if your running a straight-through system.. but with the proper mufflers and a cat you should have the right amount of back pressure so you wont loose any torque!

my brother has an A2 Jetta Gli its a 1.8 and he installed a 2.25" exhaust on it.. man that thing flew! not to mention the increase in top end from the stock 1 7/8" to the 2.25".. 2" for our 1.6 is good. you wouldnt want to go less. .

think efficiency, not quantity

Bernard

Maximus · Post by **Maximus** » Thu Jan 08, 2004 2:36 pm

This is my new Header

mocpac · Post by **mocpac** » Thu Jan 08, 2004 4:43 pm

Nice man is a 4-2-1 header. How much?

And what about a little cleaning in that engine space? :twisted:

GsiTurbo · Post by **GsiTurbo** » Thu Jan 08, 2004 5:57 pm

and the 'Lech' beer (one of my favourites) is a great way to provide some alcohol-injection lol. By the way, are you planning to put some sort of ceramic coating on the header? Looks good otherwise!!!

Maximus · Post by **Maximus** » Thu Jan 08, 2004 6:04 pm

mocpac_ser wrote:Nice man is a 4-2-1 header. How much?

And what about a little cleaning in that engine space? :twisted:

Thx

bought it for only 100 $ from my friend who was selling his woo. Now I'm thinking of wraping the header with thermo isolation what do you think ?

As to cleaning... My engine is always very clean but now in winter when roads are always wet and full of salt one cannot keep his engine clean for a long time

Maximus · Post by **Maximus** » Thu Jan 08, 2004 6:08 pm

GsiTurbo wrote:and the 'Lech' beer (one of my favourites) is a great way to provide some alcohol-injection lol. By the way, are you planning to put some sort of ceramic coating on the header? Looks good otherwise!!!

Yeah Lech is my favorite as well

the photos were taken in the new years eve

As to the coating you mean the thermic isolation tape right ?

damian007vk · Post by **damian007vk** » Wed Jan 28, 2004 3:12 am

hi, i have 4-2-1 ceramic coated headers, and a mandrel bent exhaust all the way to the muffler with a high flow cat and a magnaflow muffler and resonator....my question is this...the size of the pipe is 2.25 inches...is this too big? a mechanic i met the other day said it was too big, and that i had to change it to 2 inches...i really dont want to (though he is considered a master mechanic and will be workingon the performance of my car) Would wrapping the entire exhaust in header wrap help solve some of the problem?? Also, I am currently spraying a 55 shot of nos through a dry zex nitrous kit....i read that his messes up the cat.....should I remove the catalytic converter then and just replace it with another straight through resonator??? thanks...

Post by **PrecisionBoost** » Wed Jan 28, 2004 3:55 am

Ok.....here is a tiny little bit of math

Flow rate (2.25") X area of pipe diameter(2.25")= Flow rate (2") X area of pipe diameter (2")

(FR 2.25") X ( 3.976 sq inch) = (FR 2") X ( 3.1415 sq inch)

So ( FR 2" ) = (FR 2.25") x ( 3.976 / 3.1415)

Flow Rate 2" = 1.2656 X Flow Rate 2.25"

So by decreasing the diameter from 2.25" to 2" you decrease the cross sectional area of the exhaust by 21%.

But the flow rate increased and the 2" now flows 21% faster to make things equal out.

Given the exhaust gas density is primarily based upon the temperature of the exhaust gas you can bet that by getting it out of the pipes 21% faster ensures that it cools down less.

Cooler exhaust = More Restriction than Hot exhaust

So your mechanic just wants to make sure that the exhaust gases stay hot all the way out to the end of your muffler.

The best alternative is to insulate the larger pipe so you get rid of this "cooling" down of the exhaust and you have a 21% larger exhaust which equates to less restriction.

Sorry for the technical junk........ just remember that 2.25" insulated will be better than the 2" non-insulated.

I don't know if 2" insulated would beat 2.25" insulated......these kind of flow dynamics are best left to be modeled on supercomputers.

For us mere humans simply trying different sizes and using the one that makes the most horsepower is the best.

The original daewootech forum

Exhaust from the manifold back

I have 4-2-1 headers