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Discussion Starter #1
Picked up the car yesterday after having had a custom 3 inch exhaust fitted. The work was done by Julian Robinson of JR Fabrications. As you can see, it's a true work of art :) Obviously all the bends are mandrel bent but in addition, all the welds are back purged to ensure totally smooth inner surfaces. Also, JR likes to use v-band clamps. These are stronger than normal flanged joints and are much less prone to causing 'chuffing' noises. They also make it dead easy to service/remove the exhaust components. The downside is that they cost a little more and require very accurate machining/welding to make sure eveything aligns properly.

The close up shot of the end of the Toda manifold/decat shows how Julian modified the Toda. In the original, there's a pinch point right after the secondary pipes - the bore drops down to 50mm before flaring out to 60mm. Now this intersection has been reworked; the 2 x 50mm secondary pipes have been swaged out to ensure perfect gas flow into the 76mm (3") decat pipe :)

Mapping at TDI North tomorrow but even without, the midrange feels noticeably stronger :D

Click on pics for bigger version







 

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Looks good.

But that transition from the TODA Flange to the 3" should have been alot Smoother. Its not like the FD2 doesnt have the space for this.

From 55mm to 76mm its a big step to have ...
 

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Looks good.

But that transition from the TODA Flange to the 3" should have been alot Smoother. Its not like the FD2 doesnt have the space for this.

From 55mm to 76mm its a big step to have ...
I could be wrong, but I believe it's been done that way so the OEM cat can be refitted.
 

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Awesome Andy, looks good looking forward to see the performance gains.


Sent from my iPhone using Tapatalk 2
 

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I could be wrong, but I believe it's been done that way so the OEM cat can be refitted.

Could have been done just the same.

I Must add that the Work looks very very good!!!

I would pay them a visit if I lived near by for sure!!
 

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Discussion Starter #20 (Edited)
Thanks for all the kind comments guys :) Sorry for not posting earlier on this - got back quite late last night after being stuck in a thick M6 jam :( Then today, been really busy catching up with work.

Well, there were gains, but if I'm honest, not as much as I'd hoped. Bearing in time that the last time the car was mapped, it made a peak power of 270.1bhp. This time it made 270.6bhp (ie no change). BUT, the last time it was mapped, it was a very cold day whereas yesterday was around 10C warmer in the workshop. All things being equal you'd expect a little less power in warmer conditions, which indicates that we did get some peak gains. More interestingly, we got quite a lot of gains in the 3K-6Krpm area. This surprised me as I thought I might gain some top end but perhaps lose some midrange. Paul commented how he needed to add quite a bit of extra fuel in this rev range, which shows there were real gains. It also goes to show that the frequently heard claim 'a bigger bore exhaust slows down gas velocity and loses midrange torque' is complete ballocks!

Paul thinks that the reason we didn't make much more peak power is simply that the A3 cams are pretty much maxed out at this kind of power on a 2L capacity, which means that the extra flow offered by the 3" exhaust couldn't really be used. Having said that, as some of you know, my plan is to add a bigger bottom end later this year (probably a 2144cc through boring but not stroking). Then, the exhaust (and all the other bits) will really show their mettle.

I have got any dyno prints here but will get Paul to email me so I can post them up later :)
 
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