How many 458 Italias with original ecu and exhaust crackles?

There is no reason to install an aftermarket valve controller when I can program the ECU to control the valves exactly the way I want them to. With an aftermarket valve controller you toggle between always open or always closed. You can't program them to dynamically change with respect to RPM and Engine Load. Nor can you program Rain/Sport and Race/CST modes individually. Currently, in Race/CST I have the valves always open. And in Rain/Sport I have them constantly adjusting with respect to engine conditions. I much prefer the latter approach better because the exhaust is loud when i want it to be load (accel and decel in manual mode) and quiet when I want it to be quiet (highway cruise in auto mode). I don't have to fiddle with any aftermarket valve controller key fobs either.

Below is my exhaust valve mapping for rain/sport and race/CST respectively. 0=both valves closed, 1= 1 valve open, 2 = both valves open. X axis is RPM. Y axis is Throttle Position. Of course, everyone will have different ideas on how their exhaust should sound. And with the ECU being infinitely adjustable, it's possible to get exactly what you want!
Image Unavailable, Please Login

 

Now I know what to get you for Christmas!
Image Unavailable, Please Login

 

Here's where the Lambo engineers get their inspiration...
Image Unavailable, Please Login

 

Shiv
FYI, my 458 has the Capristo valve controller. It has two modes - one is valves always open, the other let's the ECU control valves open/close. So, I think the best of both worlds. There is another product out there by Forza, which has always open, always closed, and maybe ECU control as well, but I'm not sure. Your mapping should work as intended when in ECU control mode, and I can open the valves full-time (which is my normal behavior) when I want to. Personally, i find the on/off toggling of the exhaust sound when on the trigger rpm annoying.
The rest of my stuff is stock.
Another question. The closest track to me is Laguna Seca, and I really love it, but the sound control there is oppressive. 90-92db for track days. Not a chance the 458 with open valves gets by that. There might be some possibilities with the OTF to deal with that. Maybe setup an ECU program that keeps the valves closed all the time. I could load that before going to the track and use the Capristo valve controller to switch to ECU mode when going up the hill by the sound booth. Just not sure if keeping the valves closed all the time would cause problems when driving hard at high rams.
See you Sunday.
Mike

 

It's easy to solve that annoying on/off behavior with the standard Race/CST exhaust valve mapping by setting the throttle threshold a little higher. With the standard setting, there is a very low RPM transition point of 2650rpm and a ridiculously low throttle threshold of 2%.

It's easy to keep the exhaust valves completely closed as I have inadvertently done that while trying to figure out how these tables work. It absolutely kills power though. The engine struggle and strains as the revs/load rises. And I suspect it can also cause some damage to the valve due to exhaust pressure at high RPM. The only solution is to do what i do is just upshift to 7th gear up the hill and loaf by the sound meter. Sucks, I know!

 

The Forza controller has three modes of operation.

1. Normal ... ECU control ... this is the default mode
2. Always Open ... as the name implies, the bypass valves are forced open at all times
3. Always Closed ... again, self explanatory.

Typically, one would not use option 3 very much. If you want to quiet the car down, just use the default mode and as long as the throttle position / and engine RPM is low, the ECU will maintain the valves closed.

The Always Closed option is generally used by those people who want the valves closed when the ECU would otherwise open them. For example, when tracking the car and you are entering the noise monitoring zone. During the brief period time you are in the noise monitoring zone, you could switch the valves closed and then back open or default when you are outside the zone.

Steve

 

I wonder if anyone knows the actual risk to motor damage if the valves are closed completely at high heat/rpm on a track day. At my level of driving, if it is only reduces power output a bit, it would be more enjoyable for me to have "full" output, whatever that might be, for the whole lap.
That 'loafing by the sound booth' at Laguna Seca just sucks, and I've heard, though not experienced, that they sometimes have a roving sound meter to catch those who know how to beat the sound booth.
I guess that's what you get when you build a great track out in the boonies, but then people start building homes closer and closer, and then the track ownership changes over to the county parks department and the new neighbors don't like the sound. It is what it is.

 

Very good point.

A very good friend of mine once told me that in the event of excessive stress/failure, the valves are designed to lock in the "open" position until car is serviced and problem inspected (if car is fully stock). Is this true?

Kind regards,

Nuno.

 

An engine being choked by exhaust back-pressure will run hotter and will experience exhaust gas reversion which will make in-cylinder temps skyrocket. This can induce detonation which will results in the ECU retarding excessive timing. Which will lower the engine's thermal efficiency and increase exhaust gas temps. That won't be good for catalysts and general engine health for that matter. Can't see if damage would occur in minutes or in hours. But it's definitely not something you want to do

 

Exhaust gas reversion occurs if at the point in time that the engine intake valve starts to open, that the pressure inside the cylinder is lower than the pressure outside the cylinder. There are a several things that may cause this condition:

* Mid RPM operation and oversized headers
* Improper valve timing
* Too high back-pressure in exhaust system

Exhaust reversion can occur if the the back pressure is too high, but generally this effect will be minor and the effect will be to reduce the evacuation of exhaust gases by lowering the exhaust velocity. This will reduce the horsepower ... BUT, only at very high engine RPM.

On racing cars / engines, this effect can be very detrimental. On street cars, much less so. Unless one is running the engine at WOT for long periods of time, it is not reasonable to believe that keeping the exhaust bypass valves on the car will be truly detrimental.

My thought is that one should NOT wire closed the exhaust bypass valves. But, using an exhaust controller to close the valves for a short period of time when running through a noise trap at the track is not going to cause any harm to your engine.

Steve

 

How'd it go today?

 

Good. Mike and I went for a test drive in both his 2013 Spider and my 2010 Italia. Verified that his car, even with his Capristo exhaust valve controller in full open mode, didn't burble at all during coasting. While mine, with no add on controller, gave sustained burble during coasting. Both cars have 100% stock exhaust systems so it was a good and fair comparison. Mike will be dropping his car off at the shop soon so I can back-up his ECU data. Then I will flash it with the desired tuning changes and will provide a video showing before/after our flash on a 2013 car that has never burbled before

 

GOOD GOOD GOOD! Looking forward to hearing the results - quite literally!

 

Sounds great! (no pun intended)

We're all extremely anxious and excited, Shiv!

Kind regards,

Nuno.

 

In the process of scheduling shop time early next week. I'm excited as all you guys. Mike has a Spider so, even with the top up, the rear window can roll down. So the before/after will be very obvious to him and in the GoPro video I'll be producing

 

Be sure to mount the gopro centered right above the exhaust tips with the valves in the open position. Your prior videos didn't quite sound like an original ecu car.

 

Yep. I'll spend a few hours recording sound from various locations (in cabin, rear bumper, etc,.) Over the weekend, I did restore my ECU back to one of the earliest 2010 calibrations as a test. While the burbles were present, they were noticeably more subtle than what i have now with the updated (but modified) sw.. The 2 main reasons being at the original ECU calibration only extends the decel fuel delay to 1 second and that it also keeps the exhaust bypass valve shut during these conditions. In comparisons, my personal calibration extends the delay to 2.55 seconds and keeps the valves wide open during these conditions. So the burbles are stronger and longer lasting. Sounds like a ED drug commercial, I'm sorry

I think the videos with the super loud crackles and bangs are from cars with old SW and exhaust mods (race cats, cat deletes, mufflers, etc..) and aftermarket exhaust valve controllers. No way you are going to make that much noise with a 100% stock exhaust system. Rightfully so because it would be hell on the OEM catalysts and factory bypass valve.

 

I have a 2010 and I am pretty sure it was never updated because first gear shifts are very rough and it pops and gurgles on backoff noticeably. I tried tried to record it to post here but all I get are wind noise in the cabin.

Like it so much I told the dealer to not flash any updates. Around here you can seldom drive fast but just a little bit of spirited driving and it sounds fabulous.

 

I pulled the oldest calibration out of my database and ported over the mapping data into my current calibration.