Exhaust Cut out....Wank or Works?

[TUFFIE]

In recent times a few on here have been installing exhaust cut outs to their vehicles, do they actually work with a gain in Power or are they just a wank factor, so you can sit in the car park and see who's has the loudest car????

Does anyone have any hard evidence regarding this? IF there is any, what gaines have ppl seen with them? I am very interested to know peoples experiences, if it works I may consider doing the mod to the barge.

AND yes I am very aware that they are not legal.

[O.N.]

ok i had 2.5in badlandz cutouts on the 5.7L the exhaust set up was 1 3/4in tri y headers 2.5in system.

Cut outs were installed on both sides just after the cats both on remote control.
The only proof i have was it felt like it had more power and when shifting into 3rd it skidded for a little longer but thats it, as far as the theory goes for getting gasses out with less resistence it would have to make a difference.

I did see a USA dyno which said 18HP on a stock exhuast system, so again its a restrictive exhuast.

If you are already running a 3in or something large i dont think it will make much of a difference.

Mine were nice and loud when open just after the cats, on decelerating it would burp out flames though. Other than that if you open em up its very loud and can be heard from really far away.
Also they easily set off car alarms in carparks...lol

[Wonky]

Hopefully Andy (SSV8TE) will soon do back to back runs with his on Chev's dyno as I'm sure lots of people are wondering. Anybody who did it for sound only reasons would (IMHO) be a real wanker as to me they sound terrible when opened - loud and horrible.

[O.N.]

i actually wonder if you lose power by installing them when they are closed as you dont have a free flowing pipe anymore you have a pipe with a y piece that is blocked off. Exhaust gas will hit the y pipe and create back pressure and maybe effect reversion??

What do you guys think? you might lose power when closed compared to not having anything installed into the pipe.

[VYSHSV8]

Hopefully Andy (SSV8TE) will soon do back to back runs with his on Chev's dyno as I'm sure lots of people are wondering. Anybody who did it for sound only reasons would (IMHO) be a real wanker as to me they sound terrible when opened - loud and horrible.

I hope for Andy's sake it produces more power.

I can't see it making sweet FA difference our cars well most of them aren't really that powerful..

Hey Andy your a Wanker :lol: :hide: ya can blame Gaz on that one:)

[TUFFIE]

i actually wonder if you lose power by installing them when they are closed as you dont have a free flowing pipe anymore you have a pipe with a y piece that is blocked off. Exhaust gas will hit the y pipe and create back pressure and maybe effect reversion??

What do you guys think? you might lose power when closed compared to not having anything installed into the pipe.

Exactly what I am thinking too, thts why I am interested to see what the difference is, I reckon it would cause more restriction when closed. Spend a lot of money getting a free flowing exhaust and then go cut it up and cause a possible restriction. WHY?:confused:

[TUFFIE]

Hopefully Andy (SSV8TE) will soon do back to back runs with his on Chev's dyno as I'm sure lots of people are wondering. Anybody who did it for sound only reasons would (IMHO) be a real wanker as to me they sound terrible when opened - loud and horrible.

Wonks 100% with you re the sound :spew: but its a matter of taste I guess..
as for the Dyno runs, yes hopefully it will answer my questions..

[justin_d]

Hopefully Andy (SSV8TE) will soon do back to back runs with his on Chev's dyno as I'm sure lots of people are wondering. Anybody who did it for sound only reasons would (IMHO) be a real wanker as to me they sound terrible when opened - loud and horrible.

Wonks you probably were in a tunnel next to Steve when he opened his up and gave you a little fright! :jester:

On the cruise to Woodend when my house mate and I were behind Steve the car sounded great! Crackling, popping and sounding nuts, especially on the downhill sections. It'd be interesting to see Steve or Andy post up here how they sound on the freeway with drone and cabin noise. I'd consider going it in the future but then again, I am a wanker. :rofl:

[SirNemesis]

I had these installed on my old twin 2.5" DF exhaust. I did back to back dyno runs with them open/closed and there was absolutely no difference in power. The noise, shocking. Sounded like a bushpig ute and leaked a little bit when they were closed. Mine were QTP cutouts.

[duke5700]

Its a more normal thing in the turbo circles... the least amount of pressure after the turbine the better. As for n/a, a well designed exhaust with the right balance of gas velocity versus flow yeild better results.

I could see cutouts working if the exhaust was restrictive, but I don't think it will be the case in this situation. I think there may be more bark than bite after the dyno run.

[STATIE]

Unless you've got a really really crappy exhaust system/cats etc it will make jack shit difference - the gains guys get by doing it at the drags are mainly due to less weight - a few years ago Nathan Higgins when he was running low 9's even put a partial exhaust back on his drag car with a muffler etc as it made more power that way.

[BadSeed]

I had some on my last exhaust system, they were mainly a wank factor when I was NA, but they made a difference to me "seat of the pants" meter when I was supercharged. I've got full 3" kpm system now, no plans for more cutouts.

[VX2VESS]

Unless you've got a really really crappy exhaust system/cats etc it will make jack shit difference - the gains guys get by doing it at the drags are mainly due to less weight - a few years ago Nathan Higgins when he was running low 9's even put a partial exhaust back on his drag car with a muffler etc as it made more power that way.

would need a tune to suit the change to get a difference. would need two tunes as you switch from one to the other.

would be more noticeable on a stock system with them

[swingtan]

Open Exhausts:


Do they work? Yes, they certainly do.
Are they "optimal" in all applications under all conditions? No, they certainly are not.


Let's talk street cars, as that's what the original question is about.

The complete exhaust system is not just about "passing the most gas" ( innuendo intended.... ). If it was, you could run with no exhaust manifold at all as that, in theory, is the least restrictive. The exhaust have many more tasks than to just flow exhaust gas.

The exhaust system needs to provide a certain amount of "back pressure" to help the intake cycle of the motor. Too little back pressure and you may loose intake charge out the exhaust. Too much back pressure and you may leave exhaust gases in the cylinder, contaminating the next intake cycle.

At the near end of the exhaust system ( near to the motor ), the exhaust gases flow as defined pulses. These pulses or pressure waves flow along the exhaust pipes and diminish in intensity the longer they flow in the pipe. The pulse has a "high pressure" region followed by a low pressure region, basically exhaust valve open vs exhaust valve closed ( putting it roughly ).

Tuned length headers aim to join the individual header pipes at a length where no two exhaust pulses will be a high pressure state at the same time. In fact, if you get the length just right, you can have the low pressure region of one pulse at the merge to help "suck out" the exhaust gases of the other pipes. This is called "scavenging" and when it works well improves not only the exhaust cycle but also the intake cycle. Most would know of the debates on "kiss pipes", "X pipes" and "H pipes". These are used for a reason, and it's not just to help the exhaust note. They further work on the scavenging principle to improve the overall engine efficiency. Again, they rely heavily on the "pulsing" nature of the exhaust gases.

The effect of removing the back pressure in the exhaust is that it allows the gases to flow much faster through the pipes. This can have a few effects...


The pulse speed is results in over scavenging, sucking intake charge out the exhaust.
The pulse speed may be high enough to effectively "de-tune" the tuned length headers.
The open ends of the exhaust result in pulse reflections in the pipe, which can cause high pressure points at critical points in the exhaust.


All this and we haven't even looked at how the increased air flow "may" lean out the motor if not catered for in the tune.

Personally I wouldn't worry about doing it on the street, though there are times I'd like to have a seriously loud exhaust, just for fun..... If I was racing, I might try setting up an exhaust that retained the merge and then exited just in front of the rear wheels, but I'm not sure if it would help or harm over all power.

Simon.

[Millsy]

Where's RonSS when you need him :D


In all seriousness but, I wouldn't bother with them

The gains wouldn't justify the hassle/cost of fitting them to a street car IMO

Just my 2 cents Tuff :)


Cheers,


Millsy

[O.N.]

I'd like to see 3 back to back dyno runs. With a decent exhuast 1-7/8in headers with twin 3in.

Dyno runs like so:
No cutous
Cutouts installed and closed
Cutout installed and open

As Far as theory goes i think when they are closed you will have less power compared to having no cutouts at all. It has to be doing something weird in gas flow with that extra pipe about 1/2ft to a full foot in length off shooting.

imo some of the gas will be hitting into the y pipe causing more back pressure and becoming trapped while the other part of the gas will be escaping but at a lower pressure than normal.

The only way i can see no restriction would be if you can put the cutouts flush against the exhuast main pipe and then have it dumping with a turn down pipe.

[HRT 8]

Wank or Work?

Seriously, why would you even bother except to "stroke your own pipe".

Some blokes need to put the crack pipe down long enough to see the smoke clear.

[SSV8TE]

In recent times a few on here have been installing exhaust cut outs to their vehicles, do they actually work with a gain in Power or are they just a wank factor, so you can sit in the car park and see who's has the loudest car????

Does anyone have any hard evidence regarding this? IF there is any, what gaines have ppl seen with them? I am very interested to know peoples experiences, if it works I may consider doing the mod to the barge.

AND yes I am very aware that they are not legal.


Wank or Work?

Seriously, why would you even bother except to "stroke your own pipe".

Some blokes need to put the crack pipe down long enough to see the smoke clear.

Guess im a wanker and a crack pipe smoker then hey?

[HRT 8]

Guess im a wanker and a crack pipe smoker then hey?
Dont know you from a bar of soap mate.
Perhaps you can explain your methodology behind fitting them into a nice free flowing exhaust which is fitted to a street car.

[fishla]

For someone like Andy (SSV8TE) it could be beneficial on the track when he next races.

The big restriction in the VE V8 exhaust (as most people know) are the rear mufflers.
So maybe it works, maybe it won't. I'm not exhaust expert, but i know a free flowing exhaust works well :teach:

I don't think it's a wank, coz if you were a real wanker, you'd just have open pipes all the time.

[SirNemesis]

For on the street, these are a wank. I ran them for about a year before I got over it...

For a street car that occasionally goes to the drags though these do have benefits. I used mine at the drags because it makes it easy to hear the engine, which was helpful for me changing gears at the right time. I find when racing with a helmet on, you can either see where you are going, or the dash, not both.

[Uncle Tone]

Guess im a wanker and a crack pipe smoker then hey?

Dunno about that.

From what I see in your photos, you've basically made a straight exit from the headers, bypassing the first bend leading to the centre section with your cutouts.....and indeed all the bends and mufflers in the exhaust. I reckon there would be some merit in that. I'm interested to see the results when you stick it on the dyno.

[zorro]

For on the street, these are a wank. I ran them for about a year before I got over it...

For a street car that occasionally goes to the drags though these do have benefits. I used mine at the drags because it makes it easy to hear the engine, which was helpful for me changing gears at the right time. I find when racing with a helmet on, you can either see where you are going, or the dash, not both.

or you ask your exhaust builder to make a removable section and still retain the back part of the exhaust on hangers. for the average jo you arent going to worry about 5-10 extra kgs when going to a test and flog and chasing low 12s............proper tires Id spend money on before silly exhaust mods

Boosted F/I applications definitly an advantage for track applications, the experts might want to say if yay or nay for N2o use or not.

street use I agree a big :jerk:

[SirNemesis]

or you ask your exhaust builder to make a removable section and still retain the back part of the exhaust on hangers. for the average jo you arent going to worry about 5-10 extra kgs when going to a test and flog and chasing low 12s............proper tires Id spend money on before silly exhaust mods

Boosted F/I applications definitly an advantage for track applications, the experts might want to say if yay or nay for N2o use or not.

street use I agree a big :jerk:

Removable section vs. switch on the dash. Lazyness wins.

[spank]

i dont your exact application TUFFIE but back in the days when VN commos were new i had an ex cop bt1 5.0 auto, i must have done 200 pases in that thing at heathcote , i used to drive it there and back home, and i found by removing the catalytic converter over and above whatever other mods i did it dropped et by 3 tenths consistantly, so when i went there with a mate in a m6 vx r8 we did a few runs and then removed the cats of it, straight away 3 tenths of the et, and no i cant remember what it did to mph except that it went up, but not by a great deal. i dont know what you have now but id be leaning to a nice set of di fillipo's !!!!

[TUFFIE]

Guess im a wanker and a crack pipe smoker then hey?

Andy, This is not directed towards any individual...I am curious. No need to be so defensive....

1.as to if the money spent doing the cut out is worth the gains. Its like any mod I do, I like to be able to feel that its money well spent.

2.What Gains IF any there is.

[Stevieboy34]

I'd like to say I got little dump pipes made to simply get rid of the rear resonator on my duel 3 inche for Summernats and the difference it makes in sound purely is great. I drove around town and home before putting back on and I thought it was unreal in a cammed car. Obviously its probably not as loud as having a cut off that far up and it was only for the noise but i reckon I would have them open occasionally if I have the electric cut out, I reckon it sounds great. I dont think its a wank, whilst I wouldnt want to have it start up in the morning at my apartment block you find nearly all Harley riders these days have straight through pipes making their bikes a lot louser.

[FLASH-0889]

I'd like to say I got little dump pipes made to simply get rid of the rear resonator on my duel 3 inche for Summernats and the difference it makes in sound purely is great. I drove around town and home before putting back on and I thought it was unreal in a cammed car. Obviously its probably not as loud as having a cut off that far up and it was only for the noise but i reckon I would have them open occasionally if I have the electric cut out, I reckon it sounds great. I dont think its a wank, whilst I wouldnt want to have it start up in the morning at my apartment block you find nearly all Harley riders these days have straight through pipes making their bikes a lot louser.

I have the same only canned ve ute. Straight pipes all the way through from the cats back. No middle mufflers and no rear resinatiors just two 5 inch cannons, one on each side. The sound is amazing. Deep as when it's just siting there but when you open her up she just screams!
An I gotta say I love the look of 2 big dump pipes coming out the back of the ute.. It's different

[Stevieboy34]

I have the same only canned ve ute. Straight pipes all the way through from the cats back. No middle mufflers and no rear resinatiors just two 5 inch cannons, one on each side. The sound is amazing. Deep as when it's just siting there but when you open her up she just screams!
An I gotta say I love the look of 2 big dump pipes coming out the back of the ute.. It's different

Dare I say i would love to see a pic, or a clip... But back to the topic, for practicality most people couldnt get away with that, I know I couldnt where I live. (although I wish I could). Hence where the cutouts come into their own if you want a proper hoon drive :driving:

[FLASH-0889]

Dare I say i would love to see a pic, or a clip... But back to the topic, for practicality most people couldnt get away with that, I know I couldnt where I live. (although I wish I could). Hence where the cutouts come into their own if you want a proper hoon drive :driving:

I'm sure I have a pic somewhere but I'll have to get a clip with the cam. I haven't done one yet.
Well isn't this where the varex comes into play? I no it's not just past the cats but if you remove the centre mufflers then it's a straight through exhaust. When the varex is open the mufflers at the rear are straight through.. Correct me if I'm wrong of course.

[Stevieboy34]

I'm sure I have a pic somewhere but I'll have to get a clip with the cam. I haven't done one yet.
Well isn't this where the varex comes into play? I no it's not just past the cats but if you remove the centre mufflers then it's a straight through exhaust. When the varex is open the mufflers at the rear are straight through.. Correct me if I'm wrong of course.

Mate I have a Varex on my ute now, it works great for startup as I am in a unit block and it stops the crazy cammed car BARK and SCREAM when it starts lol. Hence I would still need to keep it.

[hsv-105]

In recent times a few on here have been installing exhaust cut outs to their vehicles, do they actually work with a gain in Power or are they just a wank factor, so you can sit in the car park and see who's has the loudest car????

Does anyone have any hard evidence regarding this? IF there is any, what gaines have ppl seen with them? I am very interested to know peoples experiences, if it works I may consider doing the mod to the barge.

AND yes I am very aware that they are not legal.

Good question Fluffie :goodjob:

In comparison to fitting aftermarket daytime running lights to a 5 year old Grange :spew:

I would say no :teach:

[ATOMIC MALOO R8]

:lmao::lmao:

[HYMEY]

the dumpers sound the best, especially with a carbed L98 with 250s cam;)

[MTC]

Good question Fluffie :goodjob:

In comparison to fitting aftermarket daytime running lights to a 5 year old Grange :spew:

I would say no :teach:
:goodjob::lmao::lmao:

[O.N.]

ok i did a home jobby wind tunnel test today...lol

I have a set of 3in cutouts waiting to "maybe" go on still unsure if i want to use them or not.

anyway i put thinly cut long bits of paper around both opening on 1 of the cut outs.

i put the main end onto the fan and turned the fan on, i watched as the main pipes paper flaps would move really fast as the main direction of air is directed at the main straight through section of piping, the cutout section did flap about but no where near as much as the main pipe. at a guess 20% of the air went out the cut out section, when i put my hand on the cutout section to simulate the cutouts being closed the flaps on the main pipe didn't "appear" to gain much air speed although the wind sound changed slightly.

my guess is about 20% of exhuast gases escape out of the cutout when they are open. The design of the cut outs have their faults i think they would be much better if instead of a throttle body design if you had an internal flap which moved to block off the rear muffle section diverting all gases to flow out of the cut outs that would work alot better.

At the moment majority of the gases flow through the main pipe as it is straight and in the direction of the flow of the gas and very little escapes through the cutouts as the gases have to alter direction.

i think if someone could design a flap type system this would be way way better diverting all gases to an alternative route.

[RARASV8]

i'm watching with respect, who knows they could be the latest equivalent to the otrcai from a few years back.

now if you don't have an otrcai your not making enuff POWER

sometimes thinking outside the norm is what it's all about, like most of the mods we run.

Garry

p.s still not loud enuff Andy:stick:

[hsv-105]

ok i did a home jobby wind tunnel test today...lol

I have a set of 3in cutouts waiting to "maybe" go on still unsure if i want to use them or not.

anyway i put thinly cut long bits of paper around both opening on 1 of the cut outs.

i put the main end onto the fan and turned the fan on, i watched as the main pipes paper flaps would move really fast as the main direction of air is directed at the main straight through section of piping, the cutout section did flap about but no where near as much as the main pipe. at a guess 20% of the air went out the cut out section, when i put my hand on the cutout section to simulate the cutouts being closed the flaps on the main pipe didn't "appear" to gain much air speed although the wind sound changed slightly.

my guess is about 20% of exhuast gases escape out of the cutout when they are open. The design of the cut outs have their faults i think they would be much better if instead of a throttle body design if you had an internal flap which moved to block off the rear muffle section diverting all gases to flow out of the cut outs that would work alot better.

At the moment majority of the gases flow through the main pipe as it is straight and in the direction of the flow of the gas and very little escapes through the cutouts as the gases have to alter direction.

i think if someone could design a flap type system this would be way way better diverting all gases to an alternative route.

Did it sound Fluffie or Tuffie :)

[TUFFIE]

Good question Fluffie :goodjob:

In comparison to fitting aftermarket daytime running lights to a 5 year old Grange :spew:

I would say no :teach:

:rofl: LOL Mark..Fair Point.....But I like it.....:smilesandbanana:

as much I like to think it is..Its not all about me at this time....

Now lets stay on topic ....:)

[O.N.]

Looks like jegs have made a manual version of what i was talking about diverting 100% gas flow out the cut outs.

http://www.jegs.com/i/JEGS+Performance+Products/555/30862/10002/-1

http://www.jegs.com/images/photos/500/555/555-30861.jpg

------------Cut out closed----------------------------- Cut out opened
http://www.jegs.com/images/photos/500/555/555-30861_2.jpghttp://www.jegs.com/images/photos/500/555/555-30861_3.jpg

------------Cut out closed----------------------------- Cut out opened
http://www.jegs.com/images/photos/500/555/555-30862_2.jpghttp://www.jegs.com/images/photos/500/555/555-30862_3.jpg

[HYMEY]

Pat G tested them 10hp peak on 500rwhp LS1, and 10 foot pound tq loss at the peak picked it back up top, Id rather drop the ex and save the weight. worth 1 mph if that.

[TUFFIE]

:lmao::lmao:

NOW NOW Kiddies......make sure you and little Mikey don't wet your nappies from laughing too much...Daddy will have to spank you again..

[MTC]

NOW NOW Kiddies......make sure you and little Mikey don't wet your nappies from laughing too much...Daddy will have to spank you again..
Hey Jeremy just stick with the Theme you already have going & do it.
I think there a Wank so would suit your personality to a tee.

P.s no spanking for me little fella im not part of your Back Door Club:wave:

[TUFFIE]

PPL wonder why this forum is turning to shit......I started a thread trying to gather information and create a discussion....then you get PPL like Mike that turn it personal.:goodjob: Mike

[MTC]

Aww poor little Fluffie

[TommyVTss]

Piss poor form lads,

How about we keep things grouse and on Track,

[Nidz]

PPL wonder why this forum is turning to shit......


Best thing you've ever said and I agree with that... Oh and wasn't this question asked back in 2005 somewhere? :confused:

[Rub]

:popcorn: :popcorn:

[justin_d]

Oh boy oh boy oh boy! After spending the arvo at Chev's and hearing Andy's ute I think it sounds great and as he said, he wants to hear his motor when he's dragging it. With the helmet, windows up and every second person running open headers, it's hard to hear the motor. Tuff, based on the evidence from the few people who've made constructive comments here I'd say don't bother. The barge weighs enough and it's an auto. The gains would be negligible and the fact your's is an auto there's not as big a need to hear the motor when dragging as you don't need to manually shift gears. Andy, your ute sounded great today mate. :goodjob:

[Roonstain]

This style is a little different to the ones most here are talking about

http://www.quicktimeperformance.com/OVAL/lightbox/photos/shot4c.jpg

Probably would let out more of the exhaust than what O.N found with the other style because of the orientation of them compared to the exhaust flow

This is the more common style used on VE's, G8's, camaro's etc because their low profile gives better ground clearance on these cars

[zorro]

I don't know about the whole hearing your car thing. I've run my old ute bot with my own custom made drag exhaust and with full exhaut and I knew where my motor was at. Also to note when running 12s there is plenty of time to take a quick look at your gauges, oil pressure I checked religiously when over 4k.

Each to their own I say but when you run as for fun $ for ETs I'd say money better spent elsewhere. And as with all forms of motorsport you can have all the HP in the world but the mug behind the wheel has to know how to use it 10 out of 10 to get 100% out of what the vehicle is producing.

[TUFFIE]

Agreed Zorro...thats why we have tacho meters and shift lights...IMO if you have time to listen to the engine and change gears you are not going fast enough.

Hopefully we can have some input regarding dyno results.....

[SirNemesis]

Agreed Zorro...thats why we have tacho meters and shift lights...IMO if you have time to listen to the engine and change gears you are not going fast enough.

Hopefully we can have some input regarding dyno results.....

Didn't you see my post Tuffie? Dyno'd back to back. 0 gain. Also, I disagree about the tacho comment. You just can't see it if you have a helmet on, well, I couldn't anyway. I added a shift light to compensate for this, but it really isn't bright enough during the day either.

[FLASH-0889]

Dare I say i would love to see a pic, or a clip... But back to the topic, for practicality most people couldnt get away with that, I know I couldnt where I live. (although I wish I could). Hence where the cutouts come into their own if you want a proper hoon drive :driving:

I tried to get a pic of the cannons coming out the back of the ute but it's hard to see through the photo. In real life u can see it clearly.
I'll throw it up anyway.
http://184.72.239.143/mu/3ab24ebc-cf28-7318.jpg

[katlad]

I have also been thinking about these, watched a video on You Tube with them on a GTO in the States & personally I thought it sounded great.

Back in the day when I had a XD with a 351 Cleveland & other guys had Commodores we used to always drop our pipes off @ the collectors for the drags.

Funny this thread popped up as I am thinking about dropping my pipes for the drags on Sunday in Warny.

Just for a bit of fun & interest sakes.

[blu ute]

Personally I love them. But I couldn't help my self if I had them.
Sounds ace. :goodjob:

[VYSHSV8]

The biggest prob with tacho's is that if you are reving higher than 7000rpm on VZ and models prior the tacho stops :(:( they should come with a 9000rpm tacho in them :):) also the tacho being analogue there is a bit of delay so if you are revving to 7000rpm you need to shift at about 6800-6900 otherwise ya hit the limitter :(

[Stevieboy34]

I tried to get a pic of the cannons coming out the back of the ute but it's hard to see through the photo. In real life u can see it clearly.
I'll throw it up anyway.
http://184.72.239.143/mu/3ab24ebc-cf28-7318.jpg

Looks good flash, I'll pay the points for something different!

[FLASH-0889]

Looks good flash, I'll pay the points for something different!

Thanks mate. The pic really doesn't do it justice tho. It does fill the cut outs on the bumper alot better. Hopefully I will get some sound clips and put them up aswell over the weekend

[FLASH-0889]

Any more news about this system? Anyone had a go with it yet? Or found a shop that will do it?

Cheers
Flash

[Lincoln87]

i like my diff dumpers (after the middle mufflers... basically running no rear resi)

and the car has the "feel" of being faster.. but i doubt it is.

i love the real offending the car does. and the burble and bumble when backing off.






only reason i would run cut outs would be if i had a really quite restrictive exhaust system.

so you could have it quite around town n what not.. basically stock dB
then when you want to open her up.. you can let all hell break loose!!
obvs have it tuned for maximum performance while the cutouts are open

[FLASH-0889]

Yeah I pretty much have the same system mate. I got no rear resonators aswell but I also have no middle mufflers either so I have alot of burble and bark aswell. But I was thinking I there if u could put cut outs right up the front just past the cats then when your in the mood and u want them open.. It will be stupid loud, which is what I want. And then when your not in the mood you can just shut them and cruise.
Something I have been thinking about..

[Martin_D]

Also to note when running 12s there is plenty of time to take a quick look at your gauges, oil pressure I checked religiously when over 4k.

You got that right, No-Doze is needed at that level :)
Anything slower than a low 11 gives you the time to read the competitors 60 foot etc in the other lane at Heathcote :lol:

[zorro]

You got that right, No-Doze is needed at that level :)
Anything slower than a low 11 gives you the time to read the competitors 60 foot etc in the other lane at Heathcote :lol:

I almost needed an alarm to wake up to change into 4th :lol:

I got to drive a mates Altered a couple of years back, a consistent quick car that set the national index 3 or 4 times, low 7's. Im no John Force but managed a high 8 with too much thinking about if the diff blowing I would lose my meat & 2 veg. Its not until you do that you realise how slow we actually are in street cars...

Also riding shotgun with Gentleman Jim at QR on a Porsche club day was an eye opener.

[Soopy]

I have to say, if you're that worried about having a noisey exhaust system on the street that you're considering cut-outs once you're off it, what ever happened to the old one bolt trick?

Unbolt the exhaust, pull it across untill the bolt hole on the right hand side of the exhaust pipe is inline with the left hand side bolt of the extractor and stick a bolt into it. Ditto for the otherside.

Wallah, free flowing exhaust for no money and 10mins effort.

[Martin_D]

One bolt always worked a treat, however it has no Uleh factor. You cannot let the most hated sample your 'dumpies' during a midnight fly by. Its serious business :cool:

[FLASH-0889]

I have to say, if you're that worried about having a noisey exhaust system on the street that you're considering cut-outs once you're off it, what ever happened to the old one bolt trick?

Unbolt the exhaust, pull it across untill the bolt hole on the right hand side of the exhaust pipe is inline with the left hand side bolt of the extractor and stick a bolt into it. Ditto for the otherside.

Wallah, free flowing exhaust for no money and 10mins effort.

Will the one bolt on each side hold the exhaust in place properly?

Also will it be safe to unbolt the exhaust and start the car up? I've always been a bit iffy about touching anything like that on my car cause it's got a custom tune. I doubt taking the exhaust off with harm it but still a concern for me.

[Soopy]

If you do it up tight it will stay there.
As for the tune, couldn't comment I don't know enough about it. I shouldn't think its going to cause too many drama's though. No more then what cut outs would anyway.

To me, cut outs are like lockers. Everyone that has one has every excuse under the sun as to why they're awesome. Everyone else has to hold back the tears of laughter.

[zorro]

just undo the exhaust and cable tie it to your tailshaft :jester:

[FLASH-0889]

Was thinking about this today.. I'm really keen to do this to my ute but don't want to do a bodgy home job. I was thinking maybe you could fit a cut out into a cat and have it wired up so that you can open it and close it as you please. Although in saying this I understand it's not as simple as it sounds.

I wonder if any shops in Sydney would be willing to give the cut outs a go..?

[boggers007]

Was thinking about this today.. I'm really keen to do this to my ute but don't want to do a bodgy home job. I was thinking maybe you could fit a cut out into a cat and have it wired up so that you can open it and close it as you please. Although in saying this I understand it's not as simple as it sounds.

I wonder if any shops in Sydney would be willing to give the cut outs a go..?

Do i read it right in saying you want to basically gut a cat and make it into a cutout?

[FLASH-0889]

Do i read it right in saying you want to basically gut a cat and make it into a cutout?

Well maybe not exactly the main body of the cat, maybe an extended cat where infront of the body the cut out could sit?
Just a thought

[boggers007]

ah ok, was gonna say messing with the cat itself is a big no no emission law wise and if a reputable shop was to help u and they were caught big fine for both.

[FLASH-0889]

ah ok, was gonna say messing with the cat itself is a big no no emission law wise and if a reputable shop was to help u and they were caught big fine for both.

Nah was never inteding on touching the cat itself. I should have worded it better, I was thinking if you could make a section inbetween where the headers and cats meet with an electronic butterly dumping out to a little cut out could do the job.

Just not sure if you could find anyone who would be up to it. I remember reading about one someone on here done themselves and it was very good and seemed to work

[Soopy]

So is a Mafless tune and OTR. As is a cam and 100cpi cats... If you're going to worry about illegal stuff, don't modify a car.

[Spectrum dude]

Here is my old setup, was great fun.

http://i1180.photobucket.com/albums/x408/dd0021/DSCF0475.jpg

http://i1180.photobucket.com/albums/x408/dd0021/DSCF0477.jpg

[VYClubby]

You can buy exhaust cutouts off Ebay. They are not motorised, but you just undo 3 bolts per side and away you go.

[Spectrum dude]

Knew I kept a vid somewhere, was fun flickin the switch at the lights :p

http://i1180.photobucket.com/albums/x408/dd0021/th_idlewithcoutoutsonnoff.jpg (http://s1180.photobucket.com/albums/x408/dd0021/?action=view&current=idlewithcoutoutsonnoff.mp4)

[FLASH-0889]

Here is my old setup, was great fun.

http://i1180.photobucket.com/albums/x408/dd0021/DSCF0475.jpg

http://i1180.photobucket.com/albums/x408/dd0021/DSCF0477.jpg

was this done yourself mate?

Im still keen to do the cutouts.. i have been looking at the ebay ones but i cant see how they will really work well. Anyone have a rough idea of what it would cost to do something like the cutouts?

[SIR_SKITZ]

Nah was never inteding on touching the cat itself. I should have worded it better, I was thinking if you could make a section inbetween where the headers and cats meet with an electronic butterly dumping out to a little cut out could do the job.


No! ...

If you seriously want to do this, then i'd suggest after the cat, that way you wont corrupt the readings obtained by the O2 sensors ... Before cats = bad


Personally, its not for me, money could be better spent elsewhere, but I once put a pair of bodgey dumpies on my SS where I unbolted the breadboxes from the exhaust
http://i12.photobucket.com/albums/a207/cmk3/dumpies.jpg

Sounded great, until the fun busters lightend the wallet by 100$ for having them fitted ...
Might be cool to have the noise, but seriously, IMO is it really worth the hassle and expence?

[FLASH-0889]

Yeah I will not be doing anything to the cats. If I do it, it will be just after the cats. I no how I want it done in my head it's just accually doing it..

[Toast]

Pardon my thread mining.

Been having a similar discussion/argument with a mechanic mate on exhaust's dumped at the diff. My car is cammed and tuned with a full exhaust. Does dropping the rear pipes throw the tune out so much, that it's dangerous? Is it imperative that you have a different slightly different tune to run "diff dumpers"?

[Wonky]

I'm no expert but unless the rear mufflers were very restrictive I'm guessing it would make 2/3 of SFA difference ...............

[duke5700]

It will be fine.


Pardon my thread mining.

Been having a similar discussion/argument with a mechanic mate on exhaust's dumped at the diff. My car is cammed and tuned with a full exhaust. Does dropping the rear pipes throw the tune out so much, that it's dangerous? Is it imperative that you have a different slightly different tune to run "diff dumpers"?