4th Gen OEM 2.2Vtec Exhaust Manifold

Post by **vanzep** » Tue Apr 29, 2025 2:37 pm

thanks wurly - im going to get under the car tomorrow and have a good look
in the meantime im busy overly preparing to cover any eventuality from engine mounts to gaskets
Ive lost count how many exhaust systems ive gone through over the years - i was hoping that going back to oem from cat back would reduce noise and vibration. The fuji mani fitted up to the oem catback very nicely so didnt think there would be a problem like this.
Hopefully it is something simple and that any fix will stand up over time and resist speed bumps and potholes etc.
Will try and get video of whats going on.
Thanks for all help and suggestions

Post by **Drax** » Wed Apr 30, 2025 9:10 am

i'll get some measurements tonight. i also run a fuji manifold & downpipe and i've never had vibration issues, only eating through mani-downpipe gaskets for breakfast lol

i would likely guess its a worn engine mount myself, they can be easily cracked over time - i use sikaflex to fill mine to be stiffer too

Post by **Merlin** » Wed Apr 30, 2025 9:54 am

Drax wrote: ↑
Wed Apr 30, 2025 9:10 am
i also run a fuji manifold & downpipe and i've never had vibration issues, only eating through mani-downpipe gaskets for breakfast

Same and same.

Post by **vanzep** » Wed Apr 30, 2025 9:48 pm

yeah.
well replaced the mani to downpipe gasket and sorted a few other related small issues but to no avail

its buzzing like a dentists drill
its very central in the dash/stereo/gearstick area - and seems very noticeable starting around 3800rpm - could it be butterfly valve related?
So next step is refit the air intake resonator and check the engine mounts
Any thoughts/input appreciated
Not sure how to upload vid

Post by **Vtecmec** » Wed Apr 30, 2025 10:37 pm

Could it be the large heat shield that sits above the exhaust? The large one that covers the cat under the gear stick?

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Thu May 01, 2025 8:18 am

Can you take a hide and show us what it’s like?

Post by **vanzep** » Thu May 01, 2025 10:44 am

https://1drv.ms/v/c/77fd1947baba4547/EQ ... w?e=2S7fxA

hope that works

Post by **vanzep** » Thu May 01, 2025 10:46 am

Post by **Merlin** » Thu May 01, 2025 10:52 am

Some pics from last night.

Post by **Merlin** » Thu May 01, 2025 11:22 am

The vibrations do seem to come from the middle of the firewall, and only occurs at ~3,800rpm (from what I heard/felt when taken for a passenger ride).

IMO it is likely to be the exhaust, as it only happens at that specific RPM. One way to test would be that we remove the exhaust completely, leaving only the manifold on, rev it and see if it still vibrates.