converted to 2.5" exhaust on my rear mount
05-05-2007, 10:16 PM
#1
converted to 2.5" exhaust on my rear mount Just got my exhaust wrapped with the DEI wrap from the manifolds to over the axle. I had previously just had some insulation on the y-pipe.
I also had the exhaust redone to 2.5" piping all the way, 2.5" y-pipe, 2.5" I-pipe to the turbo over the axle. I had my friend fab it in 2.5" so it was easy to route and it also has less overall surface area.
If we assume there is about 20' of total exhaust piping the difference is pretty big.
20' of 3" piping = about 20 square feet of surface area
20' of 2.5" piping = about 13 square feet of surface area
The 2.5" piping he used also had a slightly thicker sidewall.
The results are awesome, the turbo reaches full boost about twice as fast as it was previously, it really hits HARD now. I'm suprised that it is this big of a difference considering my previous y-pipe was insulated.
I don't think the 2.5" will hurt the performance at all, but I'll find out when I take it to the track on wed. It should trap around 130mph at 16psi like it did previously (if the weather isn't too much hotter than before).
I also had the exhaust redone to 2.5" piping all the way, 2.5" y-pipe, 2.5" I-pipe to the turbo over the axle. I had my friend fab it in 2.5" so it was easy to route and it also has less overall surface area.
If we assume there is about 20' of total exhaust piping the difference is pretty big.
20' of 3" piping = about 20 square feet of surface area
20' of 2.5" piping = about 13 square feet of surface area
The 2.5" piping he used also had a slightly thicker sidewall.
The results are awesome, the turbo reaches full boost about twice as fast as it was previously, it really hits HARD now. I'm suprised that it is this big of a difference considering my previous y-pipe was insulated.
I don't think the 2.5" will hurt the performance at all, but I'll find out when I take it to the track on wed. It should trap around 130mph at 16psi like it did previously (if the weather isn't too much hotter than before).
05-05-2007, 10:57 PM
#3
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Good to hear! And interesting calculations on the surface area...I hadn't thought about that previously, but it makes sense. I'm currently having my piping fabbed up in 3.00", both compressor and turbine sides. I did worry about creating lag with the 3" but talked at length with another GTO/rear-mount owner that did the same and has had amazing results, so I just went with it over the 2.75" I was leaning toward. Like you, I will be Jet-Hot coating and wrapping the entire hot side as well...need get the turbo in to have the turbine housing done too.
Recently bought one of the new turbo blankets from Jose at forced induction...hoping that all of this will optimze the rear mount efficiency.
Recently bought one of the new turbo blankets from Jose at forced induction...hoping that all of this will optimze the rear mount efficiency.
