I am looking at doing a carbon clean over the Christmas break and wanting some advice on to keeping the port separator vanes in or leave them out.
Are there any gains or side effects leaving them out or just clean them up and refit?
I haven’t heard of many if any leaving them out. I think if anyone was leaving them out for performance gains JHM would, but they don’t remove them. Do the guys with p&p manifolds remove them?
Although if your installing JHM intake manifold spacers, I believe they should be removed?? Although Don’t quote on that, definitely need to double check.
JHMs instructions are to remove them when installing the IM spacers. Mine are gone…
Sorry for the bum scoop, I learned something new today!
JHM says to ditch them when installing IM spacers, but they say nothing about that if you’re not (i.e. just doing a carbon clean)
I can attest to this (leaving them in vs. removing). Leaving them in causes a choke of flow once the spacers are in. Felt like my car was flat above 5K’ish rpm. I mean really flat. Yanked the I/M, removed them and put it back together. HUGE difference. Yank them if doing the spacers.
*I learned the hard way, I had a shop do this for me and I instructed them to leave them in originally. So I paid for a I/M pull twice.
I won’t be installing any spacers this time, so looks like I will just clean and fit the separators back in.
Thanks.