Engine/Transmission (1998.5 - 2002) Turbo exhaust housing question

[Ramafid]

Would switching from a 12cm housing to a 14cm affect fuel mileage in any way? I've heard it will raise the EGT's when just cruising down the road. Doesn't higher EGT's equal lower fuel mileage? Are there any other downsides to switching to the larger housing besides more lag? For those of you that have changed, are you happy? Thanks in advance.

 

[jlccc]

Originally posted by Ramafid

Would switching from a 12cm housing to a 14cm affect fuel mileage in any way? I've heard it will raise the EGT's when just cruising down the road. Doesn't higher EGT's equal lower fuel mileage? Are there any other downsides to switching to the larger housing besides more lag? For those of you that have changed, are you happy? Thanks in advance.

A. Yes, it may improve it by lowering restriction in the exhaust system.



B. Yes, it may raise cruising EGT's but not enough to hurt anything. Higher EGT's don't mean lower mileage.



Your total boost may drop a couple of psi by using the larger housing. But since you are opening up the exhaust side, the net effect is a reduction of EGT's (75-100F)when under load (cruising empty is not 'under load'. )