View Full Version : Water injection to silence exhaust


matoakley
06-12-2011, 11:29 AM
Hi

I know water injection is used to cool charge on forced induction motors, I also know it has been used to alter the apparent length of a 2 stroke pipe to improve mid range.
I also believe it is used to silence the space shuttle on launch.

Would it be an effective way of silencing my 6.2 LS3 TVR Griffith.? Due to space restrictions I struggle to pass noise tests.

How much water would be needed per sec? Has any one done this?

Many thanks

Matthew

Ethan[ws6]
06-12-2011, 01:55 PM
Muffler?

matoakley
06-12-2011, 04:23 PM
Hi
Yes I have Muffler/silencer as big as I have space for but big engine and tight regs

chuntington101
06-13-2011, 08:27 AM
matoakley, have you condiered fitting bolt on silencers for when you are a the track (im guessing you are in the uk?)? More and more people are using them on UK tracks with the low noise levels.

Just and idea. :)

matoakley
06-13-2011, 06:35 PM
Hi

Yes that would be sensible. However in a fit of stupidity I fitted engine as low as possible with dry sump to improve handling, so I have to run side pipe. This is now about 4 foot long and there is no room for any thing else.

I have designed some inserts that I will test on Wednesday, but an insert I bought, was less than useless!

chuntington101
06-14-2011, 08:14 AM
Hi

Yes that would be sensible. However in a fit of stupidity I fitted engine as low as possible with dry sump to improve handling, so I have to run side pipe. This is now about 4 foot long and there is no room for any thing else.

I have designed some inserts that I will test on Wednesday, but an insert I bought, was less than useless!

Hmmmm a side piped Griffin? you need to post some pics or links to the car! :)

Chris.

matoakley
06-14-2011, 05:43 PM
Hi chris

Pics in my "garage" Just click the link below my name

Matthew

stevieturbo
10-11-2011, 06:33 AM
Is that not a 4ft long silencer on the LHS side the car ? How is it designed ? What diameter ? What internal diameter ?

Isnt there room for a rear exit exhaust ?

And a properly designed bung inside the silencer should quieten noise down a bit.

or even reduce the internal diameter of it, and enlarge the OD.

What sort of power is the engine making ?

ZMX
11-29-2011, 04:08 AM
You can definitely lose a few dB from water injection.

lol responding 3 weeks later.

1CAMWNDR
12-02-2011, 04:06 PM
Why not reconfigure the exhaust with a 4ft long 3" diameter silencer on both sides of the car? Wouldn't that be quieter?

mypoorLS1
12-12-2011, 07:13 PM
Boats do it. Jet skis do too. BUT, any gains from lowering your engine would be offset by the weight of the water. And, It takes quite a bit of water to do so. I don't think you could burn it all before exiting the tailpipe.

ZMX
01-03-2012, 03:15 AM
Boats do it. Jet skis do too. BUT, any gains from lowering your engine would be offset by the weight of the water.

Wrong kind of water injection.

And, It takes quite a bit of water to do so. I don't think you could burn it all before exiting the tailpipe.

Water doesn't get burnt in the first place. How much he uses would be up to him.

Monzsta
01-07-2012, 12:54 PM
One thing I noticed since tuning my car with a megasquirt stand alone, was the noise of the exhaust. During cruise where I run between 16.5:1 and 17:1 with a ton of timing (+40 degrees light cruise) you almost can't hear the engine at all. When I switch back to the stock pcm (14.7:1) the car has an annoying drone and a very audible exhaust note.

I don't know how they're testing you but if it's a cruise drive by, lean it out and throw a ton of timing in the map at that point. If it's a dynamometer or WOT, well, I guess you could bolt a turbo in there. It'll help the noise. :D

My6speedZ
01-08-2012, 01:15 AM
Why not reconfigure the exhaust with a 4ft long 3" diameter silencer on both sides of the car? Wouldn't that be quieter?

Seems like this would work? From the looks of it I don't know if you could but how about some time of turn down? I know a lot of Porsche Club guys have clamp on tips for when they are at a track with DB restrictions.

Mako77
02-09-2012, 04:30 PM
Boats with open headers use water injection as a muffler.

chuntington101
02-10-2012, 08:05 AM
Boats with open headers use water injection as a muffler.

Hmmm im not sure they use it for that reason! I think they use it to help keep the header temps down more than anything. Could be wrong though. :)

Also they have a rather larger supply of water than a TVR Giffith. ;)

CharlieB53
02-20-2012, 02:22 PM
Boats with open headers use water injection as a muffler.

NOT!

Have you checked out the vids of engines on the dyno with the exhausts cherried?

Engines under load create extreme exhaust temps, boats use substantial water flow thru the jacketed exhaust manifolds to keep compartment temps from igniting.

Oh, and those nice chrome headers are also water jacketed, dumping all that cooling water into the exhaust is an easy way to get it over-board.

Simply adding a stream of water to a load exhaust 'could' reduce noise levels, except the sheer volume of water could become an issue as water is heavy when used in large quantities.

I'd sooner check out the small quantity water injection unit, you may find an increase in torque and a 'slight' exhaust benefit.

UMD_Jesse
03-06-2012, 08:51 PM
You might want to do some research on gun silencers. I know they are sometimes filled with water to accomplish the same thing youre trying to do...help cool the expanding gasses.
http://en.wikipedia.org/wiki/Suppressor
https://dimensionalfirearms.com/blog/ar15-information/silencers-101-part-1/