599 vs HGTE vs GTO Mufflers

George

I went back from Tubis (which were on the car when I bought it) to stock after installing Fabios 6-1 and cats, because the car was not really silent with closed valves and the valves opened too early which was the main reason.
With stock mufflers the loudness with the Tubis was OK and the sound was good.

I can make a scatch from the schematics of the stock and Tubis today.

Daniel

 

I've just had the Quicksilver mufflers added and now its bedded in and done 1k miles its a nice rich rumble now !

 

Stock vs Tubi

Daniel

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At the stock, the HGTE and the GTO mufflers, in the outside end pipe, you can see a much smaller tube.
So I think, the muffler function is the same at all 3, the differences must be inside with more or less baffle plates and/or insulation.

The tubis function different.

Daniel

 

Worth too much $$ to cut open. I switched from stock 599 muffler to HGTE. Nicer, deeper tone than stock. The tips, with the black chrome, have a nice, unique look to them as well. Image Unavailable, Please Login

 

Just like mine and they doo look great.

 

You could go inside with a visual sonde.

Daniel

 

After installing the 6-1 headers, the Tubis were too loud with closed valves, and after installing stock mufflers, I saw that the valves are closed to higher revs than the valves from the Tubis (up to about 4000 instead up to about 3000).

The sound with the Tubis is fine, with stock headers, also with 6-1 headers.

Daniel

 

Daniel- Changing mufflers and valves should not affect the opening schedule of the bypass solenoid. Especially since 599 valves are fail open.

 

Hi Terry

I know what you are mean, but it is different with the Tubis and the stock.
I was very surprised that this happened.

With the Tubis, it was not possible to get more than 3500 rpm with valves closed, and very difficult to let them closed with more than 3000 rpm.
A little bit to much throttle and they opened.
Now it's no problem to get the engine to about 4000 rpm with valves closed, and you can drive in city very normal.
So I can drive very silent.

Perhaps the different back pressure has an affect to this ?
I don't know.

Perhaps I can sell the Tubis, I don't use them in the future, and I don't change back from the 6-1.

Daniel

 

Probably it is due to a different actuator (diameter or stroke) - requiring less vacuum, hence opening the valve before the stock exhaust?

 

In the case of the 599, vacuum is used to close the valves and springs keep them open. The solenoid actually cuts off vacuum flow to open the valves. I guess it is possible one has stronger springs on the bypass valves and opens more readily, even if both received the same signal from the solenoid and the vacuum was cut off at the same time.

Cannot argue with empirical data.

 

Hello Daniel, i have a quastion if you sell the tubi cat back how much do you want for them ?

Marco