Hi,

I was wondering if anyone is running a btb stainless exhaust on their 500A? I have recently aquired one of these exhausts second hand. It has the valve that opens under pressure. I've noticed it has/needs a vacuum hose for this to operate. Any idea where this is fed from?

Photo attached.

Thanks !

Hi MMM


I don't have any experience with the Abarth systems but there is a similar system on the VW Golf GTI and R as well as the Scirocco R and my guess would be that they work in a similar manner.


But I could be wrong


With the VW system the valve is held open in the "at rest" position and the hose is simply connected to the inlet manifold.
When manifold vacuum goes high the valve closes and as the turbo spools up and manifold pressure goes to boost the valve opens.
Thus you get more noise (nice noise) when under acceleration but at idle and in cruise with small throttle opening the valve closes for comfort


With the DSG Scirocco, and I guess the same with the other Golf models when you put it into "sports" mode the valve stays open, even at idle. You can click the gear selector in and out of "sport" and you can hear the exhaust note change. I guess there is a solenoid valve in there somewhere that stops the vacuum going to the actuator in sports mode


A lot of people just kink the hose when the engine isn't running and lock it with a cable tie so it never shuts - nice noise all the time


Hope this helps and apologies in advance if I'm wrong.
Cheers

Hi,

Thanks for your reply, I'm sure that the valve is shut in the rest position as I can move in manually with a bar/screwdriver. I'm also now pretty sure that its fed by pressure not vacuum. Surely someone is running one of these exhausts that could help? a few photos would be great to give me an idea.

Thank you

Hi,

I'll double check our BTB, my father-in-laws car has the prototype which was built to his requirements with the bypass valve. With his years in working on rally cars all over the world and then engine development work for OEM manufacturers he had a specific set of requirments that none of the systems offered by others including Fiat/Abarth met. Iirc there is a T piece in the vacuum pipe under the bonnet with some silicone vacuum tubing running the length of the car so that it opens under boost.

It is a beautifully made system that we ran back to back on the same dyno and the extra torque and bhp it made is pretty impressive. In fact our 500 Abarth with the SS map and the BTB exhaust makes more power and torque than teh new 180ps 500.

I know Adrain Newey of F1 designer fame, runs a BTB on his Jaguar E-Type race car, and I would guess he could pretty much get any exhaust builder to make his up for him. He choose BTB as they had the expertise to put his very unique design together.

That's fantastic thanks for posting! I would really appreciate a photo of where its T'd into if you can that would be awesome. That's an impressive list of cars you have there too!

Hi, I put an Ulter exhaust on mine as it has a lower resonance that the stick one, it's not loud at tick over but does come alive once you get up the Rev range and is really comfortable on motorway ??

MoltoMeglioMultijet said:

That's fantastic thanks for posting! I would really appreciate a photo of where its T'd into if you can that would be awesome. That's an impressive list of cars you have there too!

Click to expand...

I'll try and get a pic this weekend, but it's my daughters 4th birthday and may be bit tight on time.

We do love our cars, but your comment reminds me I've sold the Megane and bought a MINI for my daily.

I have just had a powermotive exhaust fitted to my A500. If you remove the engine top plastic cover, there is a vacuum hose on the right hand side which connects to a plastic pipe level with the the back of the head. This is where you connect your t piece. I ran my silicone vacuum hose along the brake pipes as they are under a cover and it is a tidy job. However, my exhaust also came with a one way valve, actuator and a remote control. My valve is open when not in use. You could try emailing powermotive or akropovic to see if they sell the fitting kit seperatly.

Actually, these valves operate on pressure not vacuum. This is rare as most other systems operate on vacuum. (I have the valve but not the full exhaust – for a possible future project)

Drop BTB an email, I found them exceptionally helpful and they have photos available for the install

Sorry for such a long time since this thread was last posted on, as I forgot. School holidays and kids does that when you're planning activities to keep young ones amused.

Anyway the 'T' piece as described by someone else just fits in the pipe at that the back of the inlet manifold to the breather. It is the only pipe you can use and is obvious when you look at it.