Exhaust restriction - later TD5 D2

**Graeme** · 16th December 2008, 08:00 PM

As JC pointed out, there is a significant restriction in the bellows-type exhaust flexible joint that is in the later TD5 D2s, as was in my MY03 TD5. The opening is only 1.75", reducing the cross-sectional area of the 2.5" OD pipe to just 54%. There is now a mesh-type joint that has no internal obstructions. After only 1 outing, I feel that the engine is smoother under medium throttle at lower to medium revs. Where I previously ran between successive tight roundabouts in 3rd, 3rd was only used for a few seconds whilst negotiating the roundabouts then 4th pulled well until the next one. I have a test section of road that heads uphill after a roundabout in an 80 zone and I was able to get to 5th earlier and with much less fuss than previously, still heading uphill.

The annoying exhaust reverberation is gone, which was the reason for the change.

**Mundy** · 17th December 2008, 07:18 AM

Graeme,
Where can you get the mesh type joint and how much? Part numbers too please.

Mundy

**Basil135** · 17th December 2008, 08:35 AM

As a wise man once said - "It didn't happen if there are no photos"

**Urban Panzer** · 17th December 2008, 06:34 PM

The mesh type joint is actually the "earlier" type and are a LOT more prone to failing / splitting, the modified / updated later one is the "bellows" type as you called it. Both types provide a good flow for discoveries, removing the cat on later ones would be a better option imo to "Improve" performance.

**Slunnie** · 17th December 2008, 06:38 PM

If the bellows type reduces the internal cross sectional area by 50% how can it still be providing good clow compared to the mesh type that maintains a full diameter throughout.

**Graeme** · 17th December 2008, 07:36 PM

Originally Posted by Mundy

Graeme,
Where can you get the mesh type joint and how much? Part numbers too please.

Mundy

Purchased from Macperformance.com through e-bay. Its the 2.5" x 6" version (overall length but considerably longer than the one on the early D2s so might last longer) and cost $12.50 US which converted to around A$60 incl postage. I cut out the bellows and tack-welded the new one in place then had the joins mig-welded locally for a neat job for $16. The length very nicely allows the reduced sections of pipe above and below the bellows unit to be cut out totally. An exhaust shop had quoted $150 plus fitting.

The bellows were fully extended and pulled down against the internal stop by the weight of the rest of the exhaust system and IMO this would have been causing the vibrations and cabin drone that I've been chasing for around 18 months.

There is a significant/major improvement in response to light and heavier throttle and to engine smoothness. Yesterday afternoon I re-installed the harmonic balancer that was removed some time ago with the idea of cleaning-up the last remains of what had been a bad vibration around 2500-2600 rpm, but after today's driving that's coming off again as some drone returned.

**Graeme** · 17th December 2008, 07:59 PM

The restriction can be seen in this picture.

**Slunnie** · 17th December 2008, 08:10 PM

What were they thinking when they changed to that!

**justinc** · 17th December 2008, 09:44 PM

Thanks for bringing this up again Graeme. BTW, I have seen way more bellows ones vibrate and fail than the mesh type. I just fitted another one recently, about $90 for the 2.5" stainless flex, and the whole job took less than an hour, including removal and refitting of crossmembers etc.

Again, smoother, vibrationless Td5 D2 =

people.

JC

**Redback** · 18th December 2008, 06:55 AM

Originally Posted by Urban Panzer

The mesh type joint is actually the "earlier" type and are a LOT more prone to failing / splitting, the modified / updated later one is the "bellows" type as you called it. Both types provide a good flow for discoveries, removing the cat on later ones would be a better option imo to "Improve" performance.

I have 200,000ks on my TD5 without any problems with my flex joint, trust me this Disco gets a hard time

I had a look at one of those later bellows type joints, they look very restrictive compared the the early flex joint.

Mundy any muffler place have them for $60, i just paid $145 for a 3" flex, 1mtr of straight 3", 1 3" mandrel bend 2, 3 hole 3" flanges and gaskets and 1 2 hole 3" flange.

Best Mufflers in Hurstville is a good place to get them.

Going 3" back to the second muffler

Baz.

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