I have a scion tc that is too be supercharged in the spring or summer. I have the blower (TRD) mmw headers and trd exhaust. I also plan to install my web cams and forge 007 bpv and nst pulley. A friend of mine has a tc and he told me with his megan midpipe he felt a loss of power when using the trd supercharger. He said there was not enough back pressure. He bolted on his stock midpipe and claimed that the increase in back pressure helped out alot. He was running with a megan header, downpipe, and midpipe with a trd exhaust, nst 9.5lb pulley, agency power crankpulley and turbosmart 50/50 bpv.

My question is if I boost higher then 9.5lbs for example like 13 or something should I change the midpipe or leave it?

 

Did he actually lose power or did it just feel different?

 

he said he felt like he wasn't boosting at all. He felt no mid and low end

 

tell your friend "felt" means nothing.

what did the gauges say? what did the dyno say? what did the track time say?


fwiw, trd exhaust adds very little in diameter. and megan midpipe only, with stock header...i'd be surprised it that did anything at all. you need to release the bottleneck...thats covered by your mmw header. the mid and axleback are marginal at best, only serve to be loud and obnoxious.

and further info that your friend needs to buy a clue before a midpiper...there is no low end power with the s/c period. you don't start making boost until 3k+.

 

it was weird his boost guage stayed negative but when he reved it would top out at zero

 

You just can't rev it at a stand still and pretend to show boost... I felt a difference when i swicth my header and the whole exhaust system 2.5 inches all the way... It also showed on the dyno...

 

Back pressure is required in most cars bcuz the factory cam setup allows the exhaust valve to open before the piston has arrived at the bottom of its stroke. The continually expanding gas exert force in all directions following the path of least resistance. As the cylinder walls and head will not move the gases will continue to push down on the piston and out thru the exhaust. When you up grade the cams, the after market cam is designed to keep the exhaust valves closed until the piston reaches the bottom of its stroke. At this point back pressure is useless and will actually hinder the performance of the motor, whether the it is force induced or not.

 

so since I plan on installing s/c cams I should upgrade my midpipe then

 

then he has other problems, and its not backpressure.
is it possible he was only reading vacuum? check the gauges. and was this at idle or while driving?

 

get the ptuning 3 inch header back exhaust. they tested it and proved whp gains.

 

Oh sorry they tested it on a supercharge tc. 5spd.

 

will it work out though?

 

;both 05-06 use v5f superchargers and have the same displacement and stuff

 

Your friend and I shared a similar experience. I was running the mmw header/spipe combo and noticed a serious drop in low end torque. I hated it. Tried the dme header and i got some of it back but still wasan't happy. In the end i went with the stock header and spipe and the car feels great now. Just my experience. I will never throw another header on this car.