NSW Corvettes
Technical Tips => Engines - Carbies - Exhausts - Dissys => Topic started by: demonx on July 15, 2008, 06:19:17 PM
-
The title says it all. I was curious if anyone here has Hooker Side pipes with stock hooker mufflers and has had them tested for noise compliance?
-
Do any side pipes pass noise compliance?
-
Being a small block you might fair a little better but its hard to make it comply! What mufflers are you putting in the tube? Most exhaust places will weld together a tube with holes and supports attached then stuff in heaps of fiberglass. I was thinkin of getting Spiral turbo baffales. http://www.spiralturbobaffles.com/products.html just cause you get less horsepower loss.
-
The mufflers that are in them some "bubba" welded in. They have the Hooker stamp so I'm assuming they are stock.
I havn't taken a picture yet but they look like a 4" tube that narrows down to a approx 2" hole ?? (Going from rough memory the last time I looked at them in the shed!)
-
Try these they are made for the sidepipes and are quietest ones.
http://store.summitracing.com/partdetail.asp?part=HOK-21002HKR
I am running them in mine.
-
They are pretty much the standard versions.... the glasspack is basically what i said an exhaust shop would do and the other is quieter but is reverse flow, so your trying to push 4in through 2inch pipe that just folds back on itself, and sounds like you've captured Tweety in the pipe. Both are very restrictive and are touch and go with noise but they probably the best option for reducing noise. They would also end up being cheaper than getting them made locally? I've got the glasspak muffler homemade version and I reakon I'm losing at least 20-40hp
-
i made a set for a mates 77.....made the way dirty rat said....internal baffle pipe with glass packing around the inside....gives a nice DEEP rumble,but is loud........
here they are on video.....
http://s68.photobucket.com/albums/i7/nifty_2006/?action=view¤t=021-1.flv
-
Just shove a few wads of steel wool up there the day you get it registered.;39
-
Shhhhhh! I know of that trick! but I blew a lot out. Just be aware that most Engineers and RTA know of this trick!
-
What is done on the bike pipes is the use of a small pack of washers with gradually decreasing center diameters...one well known brand was super trapp....the harleys straight pipes are known to use a similar restriction system(particularly about rego/roadworthy time!).....the other trick that does help is to turn down the outlet on the pipes towards the ground.....those that have heard my small block at full bore(6800 rpm) on the track will know how loud it is,but surprisingly it passes the noise tests at 2500 rpm with the same system....it is very very unrestrictive at higher rpm and surprisingly quiet at lower rpm...john;35;35
-
Originally posted by jdunne
What is done on the bike pipes is the use of a small pack of washers with gradually decreasing center diameters...one well known brand was super trapp....the harleys straight pipes are known to use a similar restriction system(particularly about rego/roadworthy time!).....the other trick that does help is to turn down the outlet on the pipes towards the ground.....those that have heard my small block at full bore(6800 rpm) on the track will know how loud it is,but surprisingly it passes the noise tests at 2500 rpm with the same system....it is very very unrestrictive at higher rpm and surprisingly quiet at lower rpm...john;35;35
can you decribe what you have done on yours then? Have you done this washer system on the Vette? Our db levels are measured at 3200 rpm are yours 2500rpm? and is it 95db in Vic?
-
When mine did the test it was static,45* from the pipe end at 1 metre.....it is supposed to be at half rpm....my tacho has orig redline at 5500...guess they allowed me some leeway as it should have been 2750....my system is custom long tube headers,Xpipe,and single magnaflow muffler on each side....the pipes are 2 1/2" duals,i deliberately got the mufflers with offset inlet/outlet rather than centerline inlet/outlet.....the tips are turned down(as they were in 74 anyway as standard)......i vaguely recollect the test as being 93 or 94db......RHD69 has more recent experience and his is with a bigblock...what ever it was the tester said i was well under the limit....i know at phillip island on the main straight they warned me that i was right on the limit which i think is 96db but that was measured at some distance from the edge of the track and i kept as far as i could to the other side of the track!!!! i was trying very hard in second and third gear so i was well over 6500 rpm.....sadly i was going far too fast to hear it but was told by those in the stand it sounded really good to hear a small block fairly bellowing up the straight....john;35;35
-
The reason I was asking is I'm getting my 70 vert ready for a RWC and VASS inspection.
At the moment it has sh*tty/leaking header gaskets and other exhaust leaks underneath the car which they'll probably knock. On top of that it has no mufflers, only a pair of huge hot dogs and the car is louder than Hooker pipes as it sits.
I also have a set of Hooker headers and pipes sitting here, but I have no idea if they'll pass a RWC and VASS.
If the Hookers fail than its a big job to put all the other crap back on to get the ticket just to take it all off again after the ticket!!!!!
-
If you dont go the sidepipes to get it registered & get some good mufflersfor an underbody exhaust that would fix it! Other Big Blocks I know make 95db @ 3000rpm so a SB should do it easy. Its just sidepipes are hard to get under control! Another method to quieten the sidepipes is to only connect 1 or 2 of the sidepipes and block the others ie 4 -1 pipes off engine then into 1-2 pipes of the sidepipe, but again I think that would decrease power!
-
Heres a pic of the mufflers I got with them. They are stamped hooker.
As you can see, "Bubba" has welded them in and cut off the flanges. Didn't know that till after they arrived from interstate.
Either way, I have absolutely no idea what these mufflers are and how loud they would be.
Looking into them they seem to be just a 2" maybe 2 1/2" tube?
(http://i174.photobucket.com/albums/w95/vettesofballarat/hookermufflers.jpg)
-
The photo is confusing me, are they sidepipes? or are they the hotdog mufflers you spoke of that goes under car? got somemore pix, it looks interesting!
-
Originally posted by demonx
Heres a pic of the mufflers I got with them. They are stamped hooker.
As you can see, "Bubba" has welded them in and cut off the flanges. Didn't know that till after they arrived from interstate.
Either way, I have absolutely no idea what these mufflers are and how loud they would be.
Looking into them they seem to be just a 2" maybe 2 1/2" tube?
(http://i174.photobucket.com/albums/w95/vettesofballarat/hookermufflers.jpg)
Those look more like motor bike trumpet mufflers such as we used to have on triumphs and nortons....;-);-);-)john
-
Originally posted by jdunneThose look more like motor bike trumpet mufflers such as we used to have on triumphs and nortons....;-);-);-)john
Yep, I was thinking something similar.
-
Definately side pipes - heres the headers
(http://i174.photobucket.com/albums/w95/vettesofballarat/hookerheaders.jpg)
As far as more photos - theres not anything else I can take a pic of that will show you anything! The muffler is just a straight pipe that "Bubba" welded into the header, cutting off the flange which is a pain in tbe arse but easy to work around.
The muffler is definitely stamped with the same hooker stamp as the headers.
The muffler is probably half a meter long, if not possible a little bit longer and that photo is obviously the outlet.
-
about the only drawback i can think of with using the washers with decreasing holes is the heat factor.....when i used to race go karts they used a similar restrictor plate for the joung kids to decrease power.....ALSO makes them run a LOT hotter,as evidenced with the young kids blowing up a lot more motors than the adults...(same engine...one with restrictor one without)
-
The other thing I did with mine is put an extra muffler inserts in the small section between the 4 -1 and where the pipe joins the long muffler!
-
just worked out what angle the pic of the mufflers are.....can see it better in the brain now....the mufflers are leaning against the post of a garage and you took the pic standing over the top of them.....any pics of the whole unit laying down?
-
Originally posted by nifty
the mufflers are leaning against the post of a garage and you took the pic standing over the top of them.....any pics of the whole unit laying down?
Yes - that's it. You can see my feet standing on the other muffler! They are solid. Fairly heavy.
I'll have to go down to my shed a bit later and I'll snap some more pics. I just used these as I already had them.
-
Ok - heres those pics you guys requested.
I laid them out next to the car so you can get a rough idea of dimensions.
Also - I want to correct myself, after inspecting the mufflers again, they are NOT stamped hooker. Sorry for stating that before. It'd been a while since I'd looked at them.
(http://i174.photobucket.com/albums/w95/vettesofballarat/19072008401a.jpg)
(http://i174.photobucket.com/albums/w95/vettesofballarat/19072008402a.jpg)
-
Still reckon that looks like a hacked motorcycle exhaust.
These are conical like Dunstalls, but you get the idea.
http://www.woodstock-ny.com/allynair/item940.jpg
-
I think its a 2in pipe surrounded by glass inside? I'm not sure what you should do? apart from trying them on + add some more steel wool to get through rego then get rid of the wool? But whether thats good enough?
-
As to the original question, from what I can see, I would guess that they would be very loud.
-
am i correct in thinking the bent bit slips OVER the bit that looks like a motorbike muffler? thats what im thinking happens,so will just look like any other side pipe....
-
(http://i174.photobucket.com/albums/w95/vettesofballarat/19072008402a.jpg)
Where the pipe is laid out is where it would clamp up. So the muffler is about 3/4 the length of the pipe.
If they were actually motor bike mufflers, why would they be straight/cylindrical the whole length? Wouldn't they be tapered.
I'm assuming they are not motorbike mufflers based on that alone, but I know little about motorbikes so correct me if I'm wrong.
-
It's true that bike mufflers of that style taper down to meet the header pipes.
What you've got there simply resembles a bike muffler. I've Googled around trying to find a similar "hotdog" style muffler but none of the ones I found had a radiused end like that --- they were all in-line types.
Are they straight through, or baffled?
-
so thats the inner with the tapered end.....will look fantastic when hooked up.....but damn they get hot demon.....burnt my leg bad on a blown 76 with sidepipes.....the 76 is my avatar....
-
Originally posted by gtc
Are they straight through, or baffled?
From the pics you can see as much as I can. looking down the hole just looks like a tube. Cannot see any holes etc.
Originally posted by nifty damn they get hot demon.....burnt my leg bad on a blown 76 with sidepipes.....the 76 is my avatar....
I guess thats why they're called "calf burners" ;53