8 stack noise

[Dave]

Got my EFI 8 stack fitted today.. I can't believe how loud the induction noise is. My ears where bleeding after driving along at 3000rpm for ten minutes. Sounds awesome but how freaking loud.

My TB's are 56mm diameter, I wonder if I got smaller ones say 45 or 40's if the noise would be less.

 

[roaldin]

56!!! Wow!

I have 50mm, used to have 44mm. To be honest, although they sound different, I don't think there is much difference in volume.. er.. loudness between my two setups.

Purely subjective, I haven't measured it.

Tim.

 

[Dave]

Yeah they are biggens alright. They where made by a Guy in the States that owned a cnc shop, they where for his 427w cobra. He took them off (probably because they are so loud) because he could not find someone to tune the car properly and now they live in West Australia.

All very nicely done with billet trumpets that could swallow a small child if they got to close.

Here she is outside the dyno shop.

 

[Randy V]

A Glass rear bulkhead window will help over Lexan.

Gads - 56mm????

 

[Dave]

Hi Randy
Got glass bulk head and rear clip.

 

[René]

maybe some airfilters would/could help a bit...

 

[Paul Thompson 'Hooligan']

Wear foam earplugs.... works just great!

Also seems to allow all mechanical noise to get through, so you can hear whats going on (right or wrong) without being deafened by induction roar...

oh - and worth a second or so off your lap times on track...:thumbsup:

Win win win...

 

[Mike Huddart]

Just for information, we were recently asked to quote for an eight stack EFI 427 Windsor. TWM did a feasability excersise for us to put their big block throttle bodies on a 351 W manifold. They could do it with some port matching and adaptor plates to reverse the bolt pattern. It means we can run their stock 56mm and 58mm TBs on a 351 based SB if you need to make 600HP or such and still retain the intake vacuum plenum built into their manifold for IAC, MAP, brake booster fittings etc.............We didn't get the order by the way !

Mike

 

[Jimmy P]

I agree with Paul....wearing ear-plugs will help a lot and like Paul also advisesd you can still hear what you need to and when I wear mine I think they do a lot to improve the sharpness of the sound of the engine. BTW I try to be a very polite guy so I also supply a set to any passenger who happens to come along. As far as I'm concerned its all part of the fun and gives them the race car experience they were looking for. Thats one mean looking engine you've got.

 

[flatchat(Chris)]

Nice lookin' car there Davo

 

[Mike Pass]

Too big - too loud. That's what we like! Just perfect!!
Cheers
Mike

 

[Dave]

Just realised firewall engine access panel was loose. Tightened up and noise has probably dropped by a third......Still loud.

Next thing I have to fix is my accelerator pedal, it's so hard to push..

Is this common with 8 stacks?

 

[Seymour Snerd]

Just realised firewall engine access panel was loose. Tightened up and noise has probably dropped by a third......Still loud.

Acoustics is a bit of a side line for me so I'm curious: is the too-loud sound RPM specific at all? I'm wondering if you're getting an "organ pipe" effect from the ITBs and stacks, since after all resonating is part of the idea. If so it might (in theory, at least) be possible to suck up some of that sound with an adjacent helmholz resonator (a box with a port, like a miniature subwoofer). NSXs have one in their air-cleaner ducting although I was never able to determine exactly what it was intended to do (I didn't try very hard).

 

[Jim Cowden]

Dave what size is your inlet valve.

When you had your first drive did the noise make your bottom lip quiver.

Jim

 

[Dave]

Hi Jim
I am not sure what size the valves are, the heads are GT40P's.

I had a set of 44idf webers on my FFR Daytona coupe and they sounded awesome. I just wish i could tune them properly.

 

[Troy]

56mm and noisy? Uh ohh, mine are 63mm... (sorry, old pics)

 

[Gus Richmond]

Troy, I see your engine has the go slow shaft poking out at the left hand side rear valey cover. Its not to late to trade it in on a blue oval :lipsrsealed: and get real performance!!:lol:

Kind regards, Gus.

 

[Doug S.]

Here she is outside the dyno shop.

My apologies for the thread drift, Davo, but I'm intrigued by your :thumbsup: side window setup.

Does the rear 3/4 of the window hinge outward, or am I seeing things?

Is that the standard DRB window treatment?

Rather than polluting this thread, perhaps you could post in the "Exterior, Interior, A/c & Trim" forum regarding your windows?

Thanks!

Cheers from Doug!!

 

[Dave]

The side window kit is available from drb. Works well and gives the car that finished look. There are threads on these already.

 

[Doug S.]

Thanks...I'll search that forum. I really like some of the touches DRB adds to its 40's...their outside mirrors that are attached at the upper edge of the door frame (like Pete has on his) are particularly attractive, IMHO, and now the window treatment. I've always thought you Aussies were fortunate for many reasons, not the least of which is the duration you were "blessed" with the 351C engine, now this is even more to admire about Australia!

Cheers, and thanks, from Doug!!