Hamish71
29th September 2010, 10:14 AM
Have asked this question before, But got no real answer, so Im asking again.
http://www.aulro.com/afvb/technical-chatter/109587-td5-air-induction-pipe-replacement.html
I want to replace the Air Intake Hose on my D2A. Just so we are clear, it is the hose that runs from the MAF, to the turbo inlet. The stock hose is rubber, and has two "ports". One for the wastegate modulator, and the other for the crank case breather. In my case, both of these are no longer needed. I run a VNT which doesnt neet the modulator, and I am running my crank case breather to a provent, which I have now put an air breather filter on the outlet of.
The MAF is OD 80mm, the turbo inlet is OD 60mm. The original hose is hard to measure, but it appears it maintains close to 80mm right up until 25-30 mm short of the turbo air inlet. It also has a rubber bellows in it to allow for engine movement on its mounts.
I had been thinking about using an alloy pipe. I was thinking of a silcon reducer 80mm to 70mm at the MAF, then OD 70mm pipe, then a reducer from 70 to 60mm right at the turbo inlet. The alternative is an 80mm joiner, or hose, stepping down to 60mm at turbo. But a step of this size is hard to find. It was suggested when i last asked this that:
Stepping it is probably not the best option as you need a smooth transition into the turbo inlet. A stepped intake will create turbulent flow affecting the overall performance.
You may need to have a custom sheet rolled and welded conically to keep the existing profile.
But to be honest, Im not sure im buying it given the bellows in the original hose.
I have a couple of queries.
1. Does anyone know of a suitable replacement hose?
2. What approach, in terms of stepping, offers the best supply of air to the turbo?
http://www.aulro.com/afvb/technical-chatter/109587-td5-air-induction-pipe-replacement.html
I want to replace the Air Intake Hose on my D2A. Just so we are clear, it is the hose that runs from the MAF, to the turbo inlet. The stock hose is rubber, and has two "ports". One for the wastegate modulator, and the other for the crank case breather. In my case, both of these are no longer needed. I run a VNT which doesnt neet the modulator, and I am running my crank case breather to a provent, which I have now put an air breather filter on the outlet of.
The MAF is OD 80mm, the turbo inlet is OD 60mm. The original hose is hard to measure, but it appears it maintains close to 80mm right up until 25-30 mm short of the turbo air inlet. It also has a rubber bellows in it to allow for engine movement on its mounts.
I had been thinking about using an alloy pipe. I was thinking of a silcon reducer 80mm to 70mm at the MAF, then OD 70mm pipe, then a reducer from 70 to 60mm right at the turbo inlet. The alternative is an 80mm joiner, or hose, stepping down to 60mm at turbo. But a step of this size is hard to find. It was suggested when i last asked this that:
Stepping it is probably not the best option as you need a smooth transition into the turbo inlet. A stepped intake will create turbulent flow affecting the overall performance.
You may need to have a custom sheet rolled and welded conically to keep the existing profile.
But to be honest, Im not sure im buying it given the bellows in the original hose.
I have a couple of queries.
1. Does anyone know of a suitable replacement hose?
2. What approach, in terms of stepping, offers the best supply of air to the turbo?