Lost power after exhaust set up

[hex999]

Lol just realized his from sabah.

 

[^pomen_GTR^]

i would say 2" pipe all the way and delete 1 midbox should be good enough

 

[pangyau]

Veloc,
Feel bad about the result of the modification.
Another try an error/experiment will cost you along the route.
Just sit back & relax for awhile.
Maybe can discuss with the tuner/expert on this.

I feel you bro...

 

[Veloc]

Veloc,
Feel bad about the result of the modification.
Another try an error/experiment will cost you along the route.
Just sit back & relax for awhile.
Maybe can discuss with the tuner/expert on this.

I feel you bro...

Haha... Touge mate. We always feel one another other. Yes learning curve. I think im going to buy a stock header and reinstall.

 

[vr2turbo]

Each curves at header plays a role, be it inlet diameter, how long the curve is and how long is section of 4/2/1. Without proper understanding an output of the engine a simple mod could just contribute loss rather gain. For your engine, i recommend FGK 4-2-1, improves almost all range from low to high rpm even for a stock heart. Private me if you interested.


Not possible unless bro Veloc willing to ship to car over from Borneo just for sake of exhaust.

Your stock header was cut out, not removed?

 

[Izso]

Veloc - my take on this is this :

Last time I had my power band shifted up like you was when the flow of the exhaust was too 'smooth' or 'slow'. I had to add restrictions like a S-flow muffler to normalise it. So to me it sounds like you might have the same issue. 4AGE being a 1.6L, I'm thinking the 2.3" piping probably is too large. Like what most of the sifus said here, I think your issue is the large piping. I don't see a problem with adding the additional mid-box, but this is just my personal opinion.

What is the piping size from header right to the back? The mid-boxes are the same size as well or step up/down piping sizes?

 

[Veloc]

Veloc - my take on this is this :

Last time I had my power band shifted up like you was when the flow of the exhaust was too 'smooth' or 'slow'. I had to add restrictions like a S-flow muffler to normalise it. So to me it sounds like you might have the same issue. 4AGE being a 1.6L, I'm thinking the 2.3" piping probably is too large. Like what most of the sifus said here, I think your issue is the large piping. I don't see a problem with adding the additional mid-box, but this is just my personal opinion.

What is the piping size from header right to the back? The mid-boxes are the same size as well or step up/down piping sizes?

Yes bro after some thinking, I came to the same conclusion too. Piping. Mid boxes are same size. But slightly bigger shouldn't be a problem right? Since it will taper off back tot he same piping size shortly.

The header piping at the "1" section (after the 4-2 section) is only about 2". And the most noticeable part is the squashed design like in the picture. Then, catback onwards I am using 2.1" piping which works beautifully for me all this while. I didn't change that part. All I did was change the "1" section to 2.3" and without squash, and added another midbox to minus the drone..

 

[vr2turbo]

Looks like you need to trail and error to get the best fit......

 

[Izso]

Big taper down to small will cause some scavenging loss I think. Better to have all same size la.

 

[Veloc]

Big taper down to small will cause some scavenging loss I think. Better to have all same size la.

Really? I thought big to small is actually good coz it speed up the exhaust gasses?

 

[vr2turbo]

Really? I thought big to small is actually good coz it speed up the exhaust gasses?

Big to small not bottle neck meh?

 

[Izso]

Back pressure la.. it's restrictive.

 

[vr2turbo]

Back pressure la.. it's restrictive.

Restrictive same like bottleneck but mention back pressure sometimes we need a little back pressure for low end....

 

[Veloc]

Big to small not bottle neck meh?

Back pressure la.. it's restrictive.

Restrictive same like bottleneck but mention back pressure sometimes we need a little back pressure for low end....

I have come across so many different theories and advices. Some say small to big.

Some say big and gradually go smaller as the exhaust approach the back. Because as the exhaust gasses travel, it cools down and loses velocity. So by going, the gasses are force to speed up, hence maintaining velocity. This helps in maintaining scavenging.

I would say NA exhaust tune is one of the hardest and most expensive systems to learn in terms of theory and trial and error besides suspension.

 

[vr2turbo]

So far I have not heard from big to small. Most have them of equal size all the way. Only heard from one of my turbo friend with modded engine, from 2.5" all the way the near rear end go to 3". Even my turbo is 2.5" all the way. NA depending on CC can be from 2" to 2.2"......:rolleyes: