Quieting a front-engine bus
Just some ideas...skoolies are noisy, but they can be quieted.
First, the universal stuff:
Seal all openings in the firewall & floor! They let in noise, dust, and engine heat. Don't forget the plases where the pedals & throttle cable pass through.
I added lots of sound deadening matting to the firewall (may require engine removal...I had to repower) and top of the bonnet, which made a HUGE difference.
Make sure the cab-area windows & the door seal properly.
Hunt down those squeaks & rattles...they can make a big difference.
Engine stuff:
Don't run headers. Manifolds are quieter & more durable.
Dump that big fixed-blade fan. Clutch fans are probably best, but I use a flex fan since there are no parts to wear out. An auxiliary electric can keep things cool (especially an automatic transmission) in traffic & climbing hills.
Turbos can actually help to quiet diesels.
Open-element air cleaners can be VERY loud...I use a dual-snorkel silencer with air intake ducts taking in air beside the radiator.
Check your engine mounts--worn out rubber can transmit lots of vibration.
Manual transmissions (like my Spicer) tend to whine in high gear...autos are quieter, but then you're stuck with a slushpump. The noise can't really be eliminated, but insulating the floor above the trans can at least keep it out of the bus.
Older buses on 9.00-20 or 10.00-20 tube tires are brutal...9.00 or 10.00R20 radials are a huge improvement. Tubeless 22.5 radialss are quieter & smoother, but pricey. For the quietest highway ride, run rib tires on all wheels...this makes traction on dirt pretty bad, though. I will run rib tires in front & traction Bandags in back (I have factory 22.5" Budds).
On flat-nose buses, engine noise is magnified. Insulate the inside cover, and make sure the gasket where it seals to the bus floor is in good shape.
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Jarlaxle
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Optimism is a mental disorder.
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