[Pesto]

Has anyone had any experience with Stebro exhaust systems on 550 Maranellos'?My car has had the valves in the factory rear units wired to be permanently open, but the sound is still a bit subdued formy taste. I have been considering replacing the center muffler with the one offered by Stebro but am not sure that this is the right solution. There are several aftermarket systems available but I have not heard any of them. I would like to have a more agresive sound without making the car obnoxious and unplesant to drive. Can anyone offer any advice?

Many thanks,

DAB.

 

[Andrew]

Has anyone had any experience with Stebro exhaust systems on 550 Maranellos'?My car has had the valves in the factory rear units wired to be permanently open, but the sound is still a bit subdued formy taste. I have been considering replacing the center muffler with the one offered by Stebro but am not sure that this is the right solution. There are several aftermarket systems available but I have not heard any of them. I would like to have a more agresive sound without making the car obnoxious and unplesant to drive. Can anyone offer any advice?

Many thanks,

DAB.

Hello and welcome to the site. I know our sponsors can offer assistance. Try to contact them. DexM is located in Michigan and I know Tubi USA is as well. They maybe able to offer their advice.

I know of the following aftermarket exhaust:

Tubi
Ansi
Lanari (not sure if they have it for the 550)

Most owners choose the Tubi, however, I have heard the Ansi on a 360 and it sounds incredible (deeper than a Tubi). If I were going to choose one this is what I would choose. Best of luck and let us know what you decide to get.

 

[joel benatar]

550 exhaust

hi
Just to let you know that I recently installed a Tubi exhaust on my 1998 550. I needed to get a little more sound from the car. With the tubi the idle has a nice burble to it. On full acceleration the sound is awsome. Also prior to the install we measured the horse power on a dyno. At the wheels prior I was getting 388 and after the install we are getting 418. Also must mention I installed the end units only. Got a great deal from a web site called HG parts in Germany. Great to deal with.
Thanks
Joel

 

[Andrew]

Joel,

I agree with you that the 550 is a little too quiet for Ferrari. I've been trying to convince a member on this forum he needs to do the same upgrade, but he insist you cannot improve upon Ferraris design.

If you happen to have a video clip of your 550 exhuast sound could you post it in the Video section. Thanks and welcome to Ferrari Forum, I hope you will enjoy the site and share some of your knowledge.

 

[ze_shark]

Re: 550 exhaust

hi
At the wheels prior I was getting 388 and after the install we are getting 418.

30hp at the wheels from Tubi cans ?
Come on ... would be interesting to post the dyno charts !
I have Tubi cans as well, I can recommend the post-2002 version, prior models produced unbrearable resonnance from idle to 2000rpm. Makes up from the bland OEM exhaust note, but arguably too loud at low revs.

 

[joel benatar]

With regards to the extra horse power I also agree that it is substantial. Please note that when we did the test we tokk measurements at the beginning of the service and then did the following: Tubi change, new oil and put in a K& N Airfilter. I am a believer that the airfilter does not give you more horsepower if the car i breathing properly, however if the orriginal airfilter was dirty(as it was ) then this left room to get the horse power back to normal. Having looked at other results the figure of 415 - 425 at the wheels are feasable for the 550. I will try and find a scanner to send the dyno chart. Also agree with you that the burble at the low RPM is loud, however the growl on open throttle is great. Happy New Year.

 

[stephen550]

With regards to the extra horse power I also agree that it is substantial. Please note that when we did the test we tokk measurements at the beginning of the service and then did the following: Tubi change, new oil and put in a K& N Airfilter. I am a believer that the airfilter does not give you more horsepower if the car i breathing properly, however if the orriginal airfilter was dirty(as it was ) then this left room to get the horse power back to normal. Having looked at other results the figure of 415 - 425 at the wheels are feasable for the 550. I will try and find a scanner to send the dyno chart. Also agree with you that the burble at the low RPM is loud, however the growl on open throttle is great. Happy New Year.

The performance improvement you saw is soley the air filters. I replaced my 550 flters with BMC units and saw a similar gain. The ECU in the 550 is one of the first generation Bosch OBD2 units, it is not adaptive like current models, so the airfilter with less restriction causes the air fuel ratios to lean out. At wide open throttle AFR's at peak power are running a 12.0 to 1 with standard airfilters, with BMC/K&N you will find it is around 12.8-12.9. It is acknowledged that peak power is produced at 13.2-13.4 to 1. There is horsepower improvement available in the exhaust system, it just isn't the rear muffler. Changing the mid muffler alone is worth another 10-15RWHP.

 

[ze_shark]

If a leaner full mix helps peak power, what happens with torque a lower revs ?

 

[stephen550]

If a leaner full mix helps peak power, what happens with torque a lower revs ?

HP is a calculated function of torque. You can increase HP by either increasing torque, or decreasing the rate that torque falls away as revs rise. This is another way of saying that the improved mix increases both torque and hp.

 

[ze_shark]

I know that power is the product of torque times rpm, so let me reformulate: if a leaner mix helps increase torque at higher rpms or extend the torque curve before it dips, what effect does this leaner mix have on torque at low revs ?

 

[stephen550]

At all rpm the leaner mixture produces more power. Any mix richer than 13-1 on a naturally aspirated motor loses power.
On my Ducati race bike peak power drops from 155rwhp to 130 simply be richening the AFR from 13.4 to 12 to 1. Granted this is an extreme example. Leaner mixes than 13.5 to 1 do not really lose any power, but increase chance of engine damage.