i own a 4.2 with 4.7 boxes and 200cell cats. When i added 4.7 boxes it was a bit louder on WOT, but it gave a lot more rumble. When i added an x-pipe it was setting car alarms off. Then i added 200cell cats and it destroyed my ears. So now i run 200cell cats with oem central muffler and 4.7 boxes with remote control valves. This works for me since i can close valves with push of a button. The retrofit for remote control vaccuum valves is quite easy, and electric valves shouldnt be too hard either. The 4.7 boxes on a 4.2 to give it a drone at certain speeds. Just something with the 4.2 engine and exhaust tuning that doesnt work. So you need some sort of muffler or resonator. I think if you fancy a project, replacing the cats would be the best option in your current situation.
That’s really interesting, I have an x pipe fitted that came with the car and I wonder if sticking back a resonator and opening up back boxes would be better. I would have liked to get 4.7 boxes, but they are a fair bit of money and out of my budget at the moment. From what you say though, perhaps sports cat with 4.2 boxes and x pipe or resonator would be good. However again, from what I can see that would be 1700 for the cats. Of course I could just tear out the cats inner workings, I had a Peugeot 406 HDi coupe that I Defapped and that made a huge difference to performance, but not exactly legal I think… I will keep an eye out on eBay, sometimes stuff comes up at the right price (even for me!).
I have the exact same setup. I originally put on 4.7 valved boxes, then added xpipe. Then I installed larini sports cats, put stock resonator back on, and still have 4.7 quad valved mufflers.
@@SailingSVPipedream my cats went bad for some reason. So I had to buy ones anyway. Otherwise I wouldnt have done it. Same with my muffler. But yeah, pricy parts and she does sound great with just an x-pipe as well.
I just installed 4.7 mufflers on my 4.2 and the sound was incredible. I didn't connect the valves so they stayed open all the time. It's not as loud as long you don't floor it. So I drove away slowly in the mornings.
Someone stuck the internal plans for the 4.7 on the forum. I am planning on going into my boxes again and making them similar to the 4.7. Blimin valve is rattling a lot now, so it is moving up my priorities list once again!
Yes that is pretty much how I felt... Still I now feel comfortable with the idea of cutting out those valves, but I will have to drum up the enthusiasm first. At least cutting out all of that will take out a couple of kilos of weight.
My 4200 Coupe has straight through pipes from the resonator in the middle of the car, no back boxes. It's loud but not unpleasant and at cruising speed almost unobtrusive. The brand is Powerflow, they were fitted to the car when I bought it.
That’s interesting. I have no resonator (I have an x pipe that came with the car), I suspect mine would be too loud with stripped out boxes. However if I put a resonator mid box back in, that might balance it out.
@@SailingSVPipedream I think I'm right in saying the X-Pipe replaces the resonator, therefore you could be right. Not sure if the factory replaced the resonator with the x-pipe for the Granturismo.
@@francescorochira773 The Granturismo came with resonator from factory, but it seems to be the first people take out and replace with x pipe. Apparently some people use an X and some a H… no idea how much difference they make!
@@SailingSVPipedream Recently I've come to appreciate there's more to exhausts than just a pipe. In order to maximise engine efficiency and increase power, the ideal is to create a pressure wave that effectively causes a vacuum and therefore aids with the scavenging of the exhaust gasses,. Obviously this can only be tuned for specific engine revs (exhaust wavelength), although Yamaha developed a system on their 2 stroke motorcycles and later on 4 stroke in the 80's and 90's. Like your videos BTW, I like your approach.
@@francescorochira773 thanks very much and yes I do worry about tinkering too much with the exhaust design. Quite often, even though manufacturers have to meet emissions and noise regs, there is not much to gain but a lot to lose if you get it wrong. Having said that, I suspect the 4.2 exhaust was designed at speed (as was the car) and that is why the 4.7 was much different.
we are partnered with several exhaust companies however one in particular who make custom systems very cheap, back box mods, x or h pipes, sports cats you name it, happy to make an introduction for you if you still cant get it how you want
Yes, I was looking for them for a while, but they are like £1k for the pair and then I would need to add in valve controls or just wire it open. With these valves wedged open in my boxes, she does crackle more now. I do wonder what the 4.7 boxes look like inside.
@@patrickXWAY I would Larinis, but £2k… The stock exhausts are stainless, so if I can just get the internals right, I can do it for free (and a lot of work).
@@SailingSVPipedream @SailingSVPipedream I know the price, I have the whole line, X-PIPE catalytic converter, straight tube and silencer with valves, if you want a good compromise you can take just the X-PIPE. I advise you to change the catalytic converters as soon as you can, because they eventually clog up and the engine will breathe better. if you can do it yourself that's fine 👍
@@patrickXWAY That must sound great! My car came with a Larini x pipe and I have wondered about the sports cats. As my rear boxes are not that loud even with valves locked open, sports cats would probably give it that bit more without being too much and would give better performance too as you say. If I could just muster up the money!
i own a 4.2 with 4.7 boxes and 200cell cats. When i added 4.7 boxes it was a bit louder on WOT, but it gave a lot more rumble. When i added an x-pipe it was setting car alarms off. Then i added 200cell cats and it destroyed my ears. So now i run 200cell cats with oem central muffler and 4.7 boxes with remote control valves. This works for me since i can close valves with push of a button. The retrofit for remote control vaccuum valves is quite easy, and electric valves shouldnt be too hard either.
The 4.7 boxes on a 4.2 to give it a drone at certain speeds. Just something with the 4.2 engine and exhaust tuning that doesnt work. So you need some sort of muffler or resonator. I think if you fancy a project, replacing the cats would be the best option in your current situation.
That’s really interesting, I have an x pipe fitted that came with the car and I wonder if sticking back a resonator and opening up back boxes would be better. I would have liked to get 4.7 boxes, but they are a fair bit of money and out of my budget at the moment. From what you say though, perhaps sports cat with 4.2 boxes and x pipe or resonator would be good. However again, from what I can see that would be 1700 for the cats. Of course I could just tear out the cats inner workings, I had a Peugeot 406 HDi coupe that I Defapped and that made a huge difference to performance, but not exactly legal I think… I will keep an eye out on eBay, sometimes stuff comes up at the right price (even for me!).
I have the exact same setup. I originally put on 4.7 valved boxes, then added xpipe. Then I installed larini sports cats, put stock resonator back on, and still have 4.7 quad valved mufflers.
@@SailingSVPipedream my cats went bad for some reason. So I had to buy ones anyway. Otherwise I wouldnt have done it. Same with my muffler. But yeah, pricy parts and she does sound great with just an x-pipe as well.
@@christianvandewaart6913 I think I will save the pennies and maybe look at those in a couple of years.
Top job chap. I love your vids and being part of this journey. Si from Bath
Thanks very much!
I just installed 4.7 mufflers on my 4.2 and the sound was incredible. I didn't connect the valves so they stayed open all the time. It's not as loud as long you don't floor it. So I drove away slowly in the mornings.
Someone stuck the internal plans for the 4.7 on the forum. I am planning on going into my boxes again and making them similar to the 4.7. Blimin valve is rattling a lot now, so it is moving up my priorities list once again!
You can also hollow out the center muffler or replace it with an X-pipe to make it louder.
Ah, I have a Larini X pipe already that some previous owner installed. I do wonder if a hollowed out pipe would be better though to keep the tone.
Nice work for little reward IMO. 😀
Yes that is pretty much how I felt... Still I now feel comfortable with the idea of cutting out those valves, but I will have to drum up the enthusiasm first. At least cutting out all of that will take out a couple of kilos of weight.
My 4200 Coupe has straight through pipes from the resonator in the middle of the car, no back boxes. It's loud but not unpleasant and at cruising speed almost unobtrusive. The brand is Powerflow, they were fitted to the car when I bought it.
That’s interesting. I have no resonator (I have an x pipe that came with the car), I suspect mine would be too loud with stripped out boxes. However if I put a resonator mid box back in, that might balance it out.
@@SailingSVPipedream I think I'm right in saying the X-Pipe replaces the resonator, therefore you could be right. Not sure if the factory replaced the resonator with the x-pipe for the Granturismo.
@@francescorochira773 The Granturismo came with resonator from factory, but it seems to be the first people take out and replace with x pipe. Apparently some people use an X and some a H… no idea how much difference they make!
@@SailingSVPipedream Recently I've come to appreciate there's more to exhausts than just a pipe. In order to maximise engine efficiency and increase power, the ideal is to create a pressure wave that effectively causes a vacuum and therefore aids with the scavenging of the exhaust gasses,. Obviously this can only be tuned for specific engine revs (exhaust wavelength), although Yamaha developed a system on their 2 stroke motorcycles and later on 4 stroke in the 80's and 90's. Like your videos BTW, I like your approach.
@@francescorochira773 thanks very much and yes I do worry about tinkering too much with the exhaust design. Quite often, even though manufacturers have to meet emissions and noise regs, there is not much to gain but a lot to lose if you get it wrong. Having said that, I suspect the 4.2 exhaust was designed at speed (as was the car) and that is why the 4.7 was much different.
Finally!
Yes, I struggle with time a lot!
we are partnered with several exhaust companies however one in particular who make custom systems very cheap, back box mods, x or h pipes, sports cats you name it, happy to make an introduction for you if you still cant get it how you want
Thanks very much, I will see how it goes, but bare that in mind.
See if you can find a 4.7 exhaust cheap. It's a straight replacement and it will make your car sound like the 4.7 ie. much louder and with crackles.
Yes, I was looking for them for a while, but they are like £1k for the pair and then I would need to add in valve controls or just wire it open. With these valves wedged open in my boxes, she does crackle more now. I do wonder what the 4.7 boxes look like inside.
@@SailingSVPipedreamtake a LARINI the best, 👍
@@patrickXWAY I would Larinis, but £2k… The stock exhausts are stainless, so if I can just get the internals right, I can do it for free (and a lot of work).
@@SailingSVPipedream @SailingSVPipedream I know the price, I have the whole line, X-PIPE catalytic converter, straight tube and silencer with valves, if you want a good compromise you can take just the X-PIPE.
I advise you to change the catalytic converters as soon as you can, because they eventually clog up and the engine will breathe better. if you can do it yourself that's fine 👍
@@patrickXWAY That must sound great! My car came with a Larini x pipe and I have wondered about the sports cats. As my rear boxes are not that loud even with valves locked open, sports cats would probably give it that bit more without being too much and would give better performance too as you say. If I could just muster up the money!