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Discussion Starter #1
Let's get technical here guys.

The Supersprint had a cowley box fitted in the centre pipe. It also has a resonator, very, very small. And then the back box. Those were the restrictions in the Supersprint.

It has NO cats.

Recently I had that cowley box in the centre pipe removed and OMW!:eek: The sound is amazing, and the pull...is it just my butt dyno or...? The car feels much more alive at high RPM even so that I push it hard nowadays not only to hear the pop at 6500rpm but also to feel the sudden rush after 5000rpm...

Many would remember I stated the car feels pap after 4500rpm...now with this box out and a nice straight ss pipe with same diamter, it feels VERY strong high up. Can a restriction such as a high flow cowley box, cause a dip in power at high rpm?

Remember with the Supersprint on the 1st time we made 226whp...which was largely contested.

We are planning to do some more dyno's with the car in stock mode to see what the Supersprint does now without software and exhaust only.

Then we'll load software again and dyno again.

talk to me.
 

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Can a restriction such as a high flow cowley box, cause a dip in power at high rpm?
Yes. It depends on your pipe diameter, where the box is situated (boxes to the front offer more restriction due to higher gas velocity as the gas is hotter and has greater volume).

The resonator also plays a role in the butt dyno (not saying your car has been butt dyno'd!). Part of your experience of higher performance can be due to the more vocal resonator allowing some more racy soundtracks and pops at 6500rpm.

A very experienced exhaust tuner once noted that exhaust design is as much a black-art as a skill. Sometimes you know what will work through experience, and no amount of sciance can explain why it works...:rolleyes:
 

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did you take the box and the resonator out?

if so how on earth are you enjoying the drone inside the car?
 

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Discussion Starter #4
Lol, I thought the same Ian.

But after driving it alot more at those revs I can litterally feel a difference.

This is not like my 2.0TS 147 that had a free flow in, and the moment I started it since the free flow I thought it gained 20kw, started racing G5 GTi's and got schooled...bad! LOL
 

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Discussion Starter #5
Only the box is out, resonator is still in.

No drone at 120/140/160/180/200/220/240/...didn't go past 240 yet.

Had family in the car to JHB this weekend for the 1st time since the box was out...didn't notice a thing. From outside, you can hear!
 

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