Open downpipe or straight pipe PROS and CONS

kalibwenm

Member +
Hi guys,

Just as the title says, what are the advantages and disadvantages of running an open downpipe, or straight pipe exhaust on a stock 4efte, with a stock CT9 turbo?...once my exhaust blew at the flexible, and i remember it felt a little sloppy at the low ends, but the power was quite fun at the top ends, and the sound was awesome...lol

Lets discuss this for a while, as i see lots of people do it lately.

Cheers...:rockon:
 

dac69er

Super Moderator
no downside of having a striaght pipe apart from the excessive noise as long as its not a huge bore. on a stock ct9 i would say you want between 2"-2.5". any smaller would restrict the top end, any larger would effect the lower rpm.

open downpipe would be a similar issue, you have less length to work with to get the gasses flowing well.
 

kalibwenm

Member +
no downside of having a striaght pipe apart from the excessive noise as long as its not a huge bore. on a stock ct9 i would say you want between 2"-2.5". any smaller would restrict the top end, any larger would effect the lower rpm.

open downpipe would be a similar issue, you have less length to work with to get the gasses flowing well.
Thanks mate...so no increase in fuel consumption nor EGT?...what are the actual gains for these setups? (mind you i use my GT as a daily)
 

dac69er

Super Moderator
i dont monitor EGT. just changing the exhaust bore wont make any difference to EGT as long as you are sensible. again, fuel consumption wont really be affected. my GT driven as a daily is pretty much as economical as a uk spec non-turbo if you drive it off boost.

as for gains, read the many millions of threads on this forum or info online.
 
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