GS back boxes on 4200?

FIFTY

Member
Messages
1,710
OK, I get you. But, how does GS loudness (valves open) compare to 4200? And for that matter, with valves closed? Quieter? Does std 4200 sit between the 2 modes or is it quieter than both?
Is everything else stock on the exhaust?

Further down stream I have "sports cats" and un-silenced X-pipe...

The stock 4200 boxes had quite a deep gargle to them, made a brutish sound in comparison

GS boxes immediately sounded more high pitched and the gargle was more of a rasp... I think it has something to do with the exhaust outlets being narrower and a different (better) grade of steel.

Obviously as the GS boxes are much smaller it goes without saying that with the valves open they do let out more sound than the stock 4200 boxes. Valves closed I would say it is about the same maybe a smidge quieter at low RPM but louder as the revs build.

With the above modifications my car with valves open it is around 100db - roughly the same as a 4.7 GTS also with valves open. The sound is quite epic with a lot of burbbling pops and bangs on the over-run, if I gently feather the throttle the engine makes the air/fuel mixture rich briefly and the exhaust goes "pop-pop-crackle-pop-pop-bang" which is quite entertaining... drawback is an ear rumbling drone zone from 1800-2100rpm but that is totally cancelled out by closing the valves

Valves closed my car is much quieter, no droning or booming at low RPM (which C was hinting at earlier), the noise with the autoshield x -pipe is a nice metallic rasp that turns into a scream at higher revs. The odd pop and bang but no crackling... overall much more composed especially at lower revs.


If you have a totally stock exhaust then then fit the GS boxes and see how you go with the valves open, you may be happy enough not to bother with the extra hassle of fitting the valve kit. In my case it was needed as the exhaust was already quite loud prior to fitting them and with the valves stuck open my wife would have quickly got fed up of the drone on long journeys (I don't mind it)
 
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FIFTY

Member
Messages
1,710
Did I mention they look great on the 4200? I was surprised how good they looked on my pre-facelift 4200, the sleeker tips actually look more in place on less cluttered design of the classico style bumpers

59372
 
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Delmonte

Junior Member
Messages
215
Is everything else stock on the exhaust?

Further down stream I have "sports cats" and un-silenced X-pipe...

The stock 4200 boxes had quite a deep gargle to them, made a brutish sound in comparison

GS boxes immediately sounded more high pitched and the gargle was more of a rasp... I think it has something to do with the exhaust outlets being narrower and a different (better) grade of steel.

Obviously as the GS boxes are much smaller it goes without saying that with the valves open they do let out more sound than the stock 4200 boxes. Valves closed I would say it is about the same maybe a smidge quieter at low RPM but louder as the revs build.

With the above modifications my car with valves open it is around 100db - roughly the same as a 4.7 GTS also with valves open. The sound is quite epic with a lot of burbbling pops and bangs on the over-run, if I gently feather the throttle the engine makes the air/fuel mixture rich briefly and the exhaust goes "pop-pop-crackle-pop-pop-bang" which is quite entertaining... drawback is an ear rumbling drone zone from 1800-2100rpm but that is totally cancelled out by closing the valves

Valves closed my car is much quieter, no droning or booming at low RPM (which C was hinting at earlier), the noise with the autoshield x -pipe is a nice metallic rasp that turns into a scream at higher revs. The odd pop and bang but no crackling... overall much more composed especially at lower revs.


If you have a totally stock exhaust then then fit the GS boxes and see how you go with the valves open, you may be happy enough not to bother with the extra hassle of fitting the valve kit. In my case it was needed as the exhaust was already quite loud prior to fitting them and with the valves stuck open my wife would have quickly got fed up of the drone on long journeys (I don't mind it)
I do have a larini X pipe but cat and everything else, is original.
Ta for the detailed insight, I’ll consider options.