Author Topic: free power on a stock aaz (Read 15619 times)

rov716y · « **Reply #45 on:** January 24, 2009, 02:37:28 pm »

Quote from: "Tony2ltr"

is the stock downpipe really that restrictive?
-Tony

it is if its a 1.6n/a on a 1.9td!!

Tony2ltr · « **Reply #46 on:** January 24, 2009, 06:23:43 pm »

I am only talking about the 4 bolt flanged, cast iron piece with the 90 degree bend coming to the front pipe from the turbo/wastegate housing with the graphite ring seal, is this a very restrictive piece?
The rest is all something that can be easlily modified. I made a 2.5 inch front pipe using the stock funnel flange. I have a straight pipe all the way back, and can hear the turbo spinning in the exhaust when it is sitting there idling (pretty cool). I wondered about that cast downpipe though.
-Tony

Smokey Eddy · « **Reply #47 on:** January 24, 2009, 07:10:19 pm »

yes! Look at the difference between three inch downpipes and the stock one. It's highest restrictive point is probably only 1.5inch in diam. It's brutal.

Tony2ltr · « **Reply #48 on:** January 25, 2009, 08:19:06 am »

I thought it might be a bit bigger... I never really looked at it really well. I have one more 90 degree stainless elbow from the 3" system on the vega. I will have to look at replacing this awful offender of free flow then!

-Tony

dillenger1 · « **Reply #49 on:** January 25, 2009, 10:29:50 am »

the hardest part is the square manifold to pipe weld.Its hard to be able to keep clearance for the nuts.I had trouble with 2 1/2".

Tony2ltr · « **Reply #50 on:** January 25, 2009, 05:10:49 pm »

I had the same trouble on the vega. It is not bad at all for flow to use a short 1-1/2 or 2 to 3 inch adapter that gives you room for the nuts, or heat it up with a flamewrench after to hammer in the nut areas for clearance. Using a different fastener to gain tool clearance can give you some options too I would imagine. If you read old turbo books, the best way to do this kind of thing is to use a large toroid shaped expansion chamber with your down pipe at some tangent. It helps to shape the flow of the turbulent gasses out of the turbo.
-Tony