Looking for ideas to make the car quieter

[Davegt74]

89 CRX ITA car

I have the standard DC header with a cherry bomb muffler that ends in the center of the car
Has anyone tried anything else that knocked the sound down without the loss of power?



David

[mossaidis]

Talk to tGA. I think he runs a back to back resonators and is around upper 80 db.

[Greg Amy]

Talk to tGA. I think he runs a back to back resonators and is around upper 80 db.
I'm running a pair of these Walker Bullet Mufflers (http://www.summitracing.com/parts/wlk-24236) in series with a center dump in front of the tank, and I'm usually low- to mid-90s at NHMS. Dyno numbers are "very good".

[Flyinglizard]

How much power is lost? How about lost top RPM?
Thanks, MM

[Greg Amy]

How much power is lost? How about lost top RPM?
Versus what? I've never tested it any other way. No desire to get into any kind of significant development expenses, just wanna race.

But when you do, please pass along the results!

- Greg

P.S., and no, I'm not spending money at Burns' Stainless; eBay China copies work good enough for me!

[Davegt74]

The only info I had was from David Vizard's book "how to build HP vol. 1"

He goes into how to test and which brand names had the best results

Walker dynomax, Cyclone sonic, Thrush turbo (all V8 testing)

Stuff like that

Also hot rodding 101 was never use a cherry bomb muffler they are laud and they kill power

David

[ajmr2]

What about earplugs? :024:

[Chip42]

I like Hushpower by flowmaster. they shut the noise down enough and don't pull the dyno numbers down, at least on our MR2s. not the cheapest option out there, but they work. and they fit in absurdly tight spots, like the tunnel in a civic or anywhere in an MR2.

[Davegt74]

Thanks everyone for the input

Hushpower by flowmaster

http://www.youtube.com/watch?v=Zd4e8htvEfc

borla xr-1

http://www.youtube.com/watch?v=r3pzr-MtZQo


David

[trobbins]

We always used two shorter thrush cherry bombs in series much like TgA's setup
on our ITA CRX Si. Seemed to keep the car quiet enough for Waterford Hills 75DB rule.

[ajmr2]

Don't forget about the weight consideration! I've had a Magnaflow universal muffler under there for several years and it gets the job done, well built and inexpensive. Although a bit loud, 100db, it passes sound restrictions. Besides, Mario likes them.

Check out the 4" 5" & 6" round.

http://www.magnaflow.com/02product/universalmuffler.asp

[Davegt74]

We always used two shorter thrush cherry bombs in series much like TgA's setup
on our ITA CRX Si. Seemed to keep the car quiet enough for Waterford Hills 75DB rule.

Wow a 75DB limit that’s like less then stock

I ended up buying a Borla XR1

The plan is to put flanges on and run it in series with the cherry bomb

I plan on completely redoing the system so this will do for now



Davegt74

[Flyinglizard]

All of my data/research shows the cherry bomb/straights to hurt power the most.

Thrush 16755, (Discount/auto) is quiet and cheap. Runs about 90db with 10.5/1 engines.
Nothing can touch the megaphone on the dyno or track tho.
My Son's next research is to look into the rules for Prod and mufflers and see if we can fill in the rear lower valence with a " muffler" consisting of the megaphone into the diffuser.

[ITA_honda]

I dont run any muffler's..mine just follows the tunnel and dumps down/slight bend to the right before the fuel tank. Given the day usually end up in the mid to high 90's for sound. Granted the tracks I race at all have the standard 102DB readings. Go to a place like Waterford hills and Id be kicked out :happy204:

[trobbins]

Yup. Waterford Hills is situated right next to a subdivision that has been competing for the same groud for the past 55 years. Our rules read that the cars must meet the 75db sound requirement at the property line and must run a muffler that is readily available to the public. There are ways to get creative to quiet a car down.
There were some races that I'd have to pedal the car past the sound tower and other days I'd ding sound from across the track. Some cars exhaust might not be the problem, it maybe the whine of the gears or the intake sucking air. Some days the car will make sound if it is clear skies and some overcast "low ceiling" days the car won't pass.