Sports Cat VS Decat Downpipe Boost Graphs
 

I recently switched over from Sports Cat --> Decat downpipe, thought it would be useful to share some boost data for general info. The below graphs show boost with a Cobra sports 'sports cat' and a (what I think is an unbranded) Japspeed decat downpipe.

I use a dawes type MBC for the boost control, and I tried to collect the data as back to back as reasonably possible but the ambient air temp was different later in the day and it was boosting slightly higher.

Engine is a forged STi 2.5 with hybrid VF43 turbo, using a billet 7+7 compressor and stock intercooler. You can see the spool is improved, and you can certainly feel it when driving! :D

Sound wise it's a bit deeper on idle, not obviously louder otherwise but you can hear the turbo and recirc more, and no more droney on the motorway than before, which is a bonus!



https://cimg8.ibsrv.net/gimg/www.sco...62f4e338e0.png

Looks good, what gear was that log done in ?

4 gear for these ones. Driving it normally, the difference in the lower RPMs is pretty significant!

Yeah looks nice spool and must be nice to drive.

When would you roughly expect peak torque if a VF43 was used on a 2.0? (ported standard headers)

At the time mine was hitting peak torque about 3900 ish but mine is a 2.5.

Difficult to compare. From what I understand it would spool slower a 2.0l pressumably because the volume flow is lower.

out of interest what sports cat were you running before?

Cobra sports, 200 cell I think.

3900... damn a 2.0 will be a fair chunk after that then. I take it from the graph your hybrid version was spooling around 3k, that's a huge difference!