[vtp]

Currently my car has a ct20b, KO racing DP, Tanabe B-Pipe replacement going to the Greddy SP Exhaust.

My dyno numbers where a tad disappointing. After closer examination, I noticed I am getting a torque drop off, not unlike the ct26, but not as dramatic. My question is: since the KO is 2.5 inch going to the 2.75 inch tananbe and back down to 2.25 inch for the Greddy SP, is this SP piping my bottle neck? Is this the most likely source of my torque drop off?

If this logic is true, can I just have the SP piping replaced with 2.5, 2.75 or 3 inch piping and have the inlet into the SP muffler bored out to the matching Diameter? (as this would be significantly cheaper than purchasing a new exhaust)

My primary concerns is noise really. I love how the SP is quiet. I cam imagine with the modified bigger piping it would be a tad louder, but still very quiet in comparison.

Any input would be greatly appreciated.

~Vu

 

[lDeeZ lNuTz]

2.5" piping isn't a restriction until you start making power over 300rwhp. exactly where is the torque dropping off? are you holding consistant boost levels to redline? you may want to look into the fujitsubo single canister dual exhaust (similar to greddy sp), it's a full 3" CATBACK exhaust, i'm running an aussie 3" dp and a fujitsubo 3" catback and that bitch pulls until the engine screams for mercy

 

[vtp]

SP is 2.25inch.

~Vu

 

[SLOW2]

Sorry for bringing up an old thread but I searched around for a long time for this exact question. Can I replace the pipe that connects to the b-pipe with 3" piping on the SP

 

[JSPEC2]

i thought the sp was 2.5". i should be getting my sb .46 from KO racing this week with 3" downpipe but i had him make me a 2.5" b-pipe to mate up to my greddy sp exhaust.

 

[JSPEC2]

the greddy exhausts confuse me, let me make sure i have the same exhaust, is it the greddy sp that looks just like the stock muffler with bigger piping and tips, i know its not the power extreme because that has canister mufflers...i have the factory polished greddy muffler with duals and one big muffler

 

[sflmr2]

I believe the SP is 60mm, which is 2.36"

Right now your GReddy SP is the narrowest path (2.36"), followed by your 2.5" DP. Upgrading the SP and leaving the 2.5" DP in there is going to give you virtually no gain whatsoever.

If you post your dyno graph maybe some people can comment further on the cause of your torque drop.

 

[Nateness]

Ok guys... VTP lives pretty close to me, and this is an issue we took care of a long time ago lol. He ended up selling the tanabe bpipe and SP and got a custom 3" Greddy PE. The SP ended up being a VERY big restriction. We could tell tq was dropping off because on his electronic boost gauge, turbo pressure started dropping off before 7,000rpm.... somewhere in the 6k range.. loosing tq at that part of the rpm range = significant peak hp loss. I can personally vouch for the noticible increase in power and response in VTP's car after getting rid of the SP. w/ the SP he dyno'd at around 218rwhp... feels like he easily gained 15 or more rwtq w/ his new set up.

the Greddy SP netted a -1 hp gain on N/A's... so i can only imagine what the number was for the turbo version.. but it cant be good for the amount of money you spend on it =P

 

[SLOW2]

I'm going to have a 3" bpipe made and I just wanted to know if i could replace the 2.36" piping on the greddy sp with a 3" one so that it would be a full "3 inch exhaust"

 

[Nateness]

why dont you just get a real 3" exhaust system? i'm pretty sure it'd be cheaper and cleaner looking.. and perform better probably =P