GS back boxes on 4200

[Delmonte]

I’ve procured a pair of the above for my car. Just considering getting a remote operating thingy for the valves, I believe this can be done? Where do you buy the device? And also is this easier than setting it up to operate GS style, on the throttle? I think I’d prefer a manual switch if not too much aggro?

 

[Spartacus]

message BennyD . You can link them up to the aux air system with some t pieces and some rubber tubing as the Gs has

 

[CatmanV2]

Formula dynamics sell a kit, or they can be made simply from parts on ebay.

I think setting it up automatically would be virtually impossible.

C

 

[rockits]

I've got valves Larini's to put on the 4200 and Larini do a remote kit. Not cheap and I'm sure you can do cheaper but I might go that route but get AV to do it for me on annual service.

 

[hunta]

If I could have them open permanently on my GS (independently from sport mode) I would. It doesn't make an enormous difference, so you may want to consider fitting as is first, if you haven't already.

 

[Delmonte]

If I could have them open permanently on my GS (independently from sport mode) I would. It doesn't make an enormous difference, so you may want to consider fitting as is first, if you haven't already.

Nice idea, I was thinking maybe just do that. How much louder is the GS with valves open, than the 4200 anyway?

 

[safrane]

Not much TBH until you get to the VVT band.

It operates on the vacuum, so no vac then it defaults to Open/Sports.

 

[BL330]

I have the Larini's and the remote kit fitted. I forget I have the remote to make it quieter.

 

[Delmonte]

Not much TBH until you get to the VVT band.

It operates on the vacuum, so no vac then it defaults to Open/Sports.

So if I just put it on, leaving valves open, but I have no vacuum, will it be at permanently it’s max volume? Or am I missing some extra volume by not having the vacuum?

 

[hunta]

So if I just put it on, leaving valves open, but I have no vacuum, will it be at permanently it’s max volume? Or am I missing some extra volume by not having the vacuum?

That's my understanding - they'd be open.

 

[CatmanV2]

That's my understanding - they'd be open.

They would. And they'll seize that way....

C

 

[Lozzer]

message BennyD . You can link them up to the aux air system with some t pieces and some rubber tubing as the Gs has

You mean botched? Like the rest of it?

 

[Delmonte]

Formula dynamics sell a kit, or they can be made simply from parts on ebay.

I think setting it up automatically would be virtually impossible.

C

...and I’m guessing, if I put them on, and want to rig up a valve switch later, it would mean taking the boxes off again to do it.. so I should do it before putting them on, really... a pain because I won’t be doing that myself anyway...

 

[CatmanV2]

...and I’m guessing, if I put them on, and want to rig up a valve switch later, it would mean taking the boxes off again to do it.. so I should do it before putting them on, really... a pain because I won’t be doing that myself anyway...

Hmmm, not so much. It's only plastic hose to the boxes so you can pretty much add at will. But (and I can't really emphasise this enough) if you don't make the valves move somehow IME they will seize in their open position.

C

 

[Delmonte]

I have the Larini's and the remote kit fitted. I forget I have the remote to make it quieter.

Out of curiosity, does the valve closed position on the larini actually make it quieter? Surely it’s still exhausting via an unsilenced can anyway?

 

[Gazcw]

Out of curiosity, does the valve closed position on the larini actually make it quieter? Surely it’s still exhausting via an unsilenced can anyway?

If they are like the qp. Valve closed goes through small bore and wadding. Open is large bore and into an open chamber before exiting. Just bolt some straight through on. When you want it to be quiet lift off the loud pedal!

 

[Sanmiam]

I just did this earlier in the year. It is INSANELY easy if you have access to the underside of the car.

You will need ~7m of 4mm vacuum line (20ft of 5/16 to us Americans), two T fittings, a vacuum actuated valve, and a latching button.

The vacuum actuated valve for the gransport mufflers is actually the same as the one used on all 4200s secondary air system int he engine (315769) I got mine of e-bay for about $20. The harness that goes into the actuator is pretty universal, I am pretty sure mine came off a Volvo or some sort - I went by image alone and found a cheap actuator w/pigtail on e-bay. I tossed the volvo actuator and used the pigtail.

You will need to wire the actuator to an on/off switch located somewhere inside the car. I placed the button on the center console, but virtually anywhere will work. Now this is where it gets a bit interesting. The non-powered condition for the actuator is open (loud) but the powered position is closed. This would mean that on a latching button the latched position is quiet and the rest position is loud. If you are OK with that skip the next paragraph.

I was not, so I ended up getting a 12V latching relay module that would allow for the resting (startup) state of the circuit to be powered, and use a momentary switch to change this to non-powered. Again, if you are OK with a latching switch no need to be bothered with any sort of relay module.

The vacuum line comes right off of manifold in the engine bay - coincidentally where it pulls from for the factory gransport mufflers (not botched). On the US version there is even a barb connector that I was able to exchange for a tee without so much as cutting the vacuum line. I ran the vacuum line along the frame rail with the brake lines, and the electrical wiring came down the transmission tunnel to meet it 1/2 way and run the same path. I zip tied the actuator to a cross-member rail and ran the vacuum line through a hole in spare tire heat shield before tee'ing out to each muffler (again going through the heat shield on either side). I found this method of routing to support wires and vacuum lines sufficiently. This is a ton of detail on how I did it - you may come up with an easier or better way of routing.

The mufflers are easy to replace. A clamp for the exhaust pipe and four bolts per side. You will need to remove the wheel and fender liner in order to access the two most outward bolts. Don't try to do it blind - you will waste a ton of time (as I did). It may take a couple of times loosening and tightening to get the exhaust tips aligned where you want them to be.

My thoughts on the project - 120% worth it. The mufflers were pricey, but everything else cost about $50 and took about 3-4 hours to install. Admittedly I have a lift, but am also meticulous and slow in how I work. With the x-pipe, secondary cat deletes, and valves open it sounds like I am being chased by a thunderstorm when I let off the throttle. At a stop light I can turn them off and the drone is not annoying.

 

[BennyD]

I've got valves Larini's to put on the 4200 and Larini do a remote kit. Not cheap and I'm sure you can do cheaper but I might go that route but get AV to do it for me on annual service.

You don’t just put a set of valved exhausts on a 4200 and expect them to work. You need the pneumatic system of the GS installing as well. This comprises; a vacuum tank, (which sits behind the rear splash guard in the front near side wheel well), a pneumatic solenoid, about 15’ of rubber pipe, a T piece, about 15’ of wire and a switch. It took me about 2 hours to install. IIRC, to utilise the Larini remote kit, you need a vacuum source to operate the valves.

 

[Lozzer]

You don’t just put a set of valved exhausts on a 4200 and expect them to work. You need the pneumatic system of the GS installing as well. This comprises; a vacuum tank, (which sits behind the rear splash guard in the front near side wheel well), a pneumatic solenoid, about 15’ of rubber pipe, a T piece, about 15’ of wire and a switch. It took me about 2 hours to install. IIRC, to utilise the Larini remote kit, you need a vacuum source to operate the valves.

Why not? You can put all sorts of makeshift parts on a 4200 and they will work just fine. They just blend into the rest of it.....

 

[BennyD]

I’ve procured a pair of the above for my car. Just considering getting a remote operating thingy for the valves, I believe this can be done? Where do you buy the device? And also is this easier than setting it up to operate GS style, on the throttle? I think I’d prefer a manual switch if not too much aggro?

Tbh, fitting standard GS boxes to a standard 4200 system will be at best disappointing. You will get no real increase in sound. What you will get is an increase in bass at tick over, which gives the impression on more noise but it really isn’t. To get a noticeable increase in sound levels, you need to change 2 or 3 of the exhaust elements, these are:

1. Cats - change the standard 2 x 400 and 2 x 600 cell cats for 2 x 200 cells.
2. Centre resonator - change for an unsilenced H or X pipe.
3. Rear boxes - modify the internals to reduce the muffling effect. (Modifying GS boxes work well as you can still use the valves - if you have the pneumatic operating system fitted). Or, fit ‘straight throughs‘ which is basically a piece of pipe with 2 outlets on.

Changing only one of these elements will give a small increase, which might be enough for some, but changing 2 will give a much more noticeable increase. Do all 3 and you are looking at an ASBO if caught. That’s why I now have a 4 valve system on my back boxes in which 2 valves ‘fail’ open and 2 valves ‘fail’ closed. This set up gives a decently muffled quiet side or a barking mad fully loud side.