Challenge: reduce revs for that first 20 sec of startup?

[Lightknight0]

YES, LightKnight0! This is the sort of thing I have been looking at. If you go earlier in the thread you'll see the pictures I posted of my modified Harley Davidson mufflers (does ANYONE leave those on their bike? ;-) ). It helps a lot, but still not quite enough. Without them, my Mustang's exhaust is SUPER loud..... With them, it's gone from SUPER loud to very loud.... I was hoping to get to something close to normal....
Thanks so much for digging up those videos!!

Hope it quiets things down enough for you! If you were local, I'd see if I could find my extra pool noodles and just give it to you. I had to order a pack from amazon and when it arrived, I was too lazy to test it out so when I had guests, they always asked what the pool noodles by the door were for lol.

Sponsored

 

[MicksS550]

these are all the PCM parameters on my ecoboost that i can control with forscan. you can manually set the rpm to any level. Not very practical to hook up a laptop every time to get a quieter start though. Use at own discretion

ihasnostang, thank you - that's awesome, but it isn't the idle I need to drop - it's the *initial* 20-secpnd roar, before it drops to idle.... I don't see a setting for that (sadly) - just overall idle. Did I miss it?

 

[MicksS550]

You could also look into fitting the 2018+ active mufflers. The Quiet mode is really quiet. I believe there's a thread in the DIY area where you'll find the procedure and a list of components.

Thanks Vlad Soare. If I can't get what I need from a tune (at this stage, this seems like the most cost-effective option via Wengerd) then I may have to look at going that route, but it's a lot more expensive

 

[Vlad Soare]

Thanks Vlad Soare. If I can't get what I need from a tune (at this stage, this seems like the most cost-effective option via Wengerd) then I may have to look at going that route, but it's a lot more expensive

Yes, it's going to be expensive, especially as I had forgotten that the 2015-2017 had single exhaust tips, and the 2018+ has double tips, so you may also need to change the valance. And the 2018+ valance may or may not fit the 2015-2017 rear bumper... and so on. Sorry, it seemed like a good idea at the time, but now I'm not so sure anymore.

It is certainly possible to change the idle speed via a tune. You don't see the options in the above picture because ForScan isn't suited for this kind of changes. You need a proper tuning software. For instance, here's what I see in HPtuner's VCM Editor for my 2020 GT:

But there's something else I'm not sure about.
We know that cold starts are noisy, and that the cold idle speed is high. But are those two things actually related? I mean, is the engine noisy because it's revving faster? Or is it noisy because of the cold fueling strategy (i.e. richer mixture, etc.)? If it's the former, then I guess you can fix it with a tune, but if it's the latter...

 

[MicksS550]

Yes, it's going to be expensive, especially as I had forgotten that the 2015-2017 had single exhaust tips, and the 2018+ has double tips, so you may also need to change the valance. And the 2018+ valance may or may not fit the 2015-2017 rear bumper... and so on. Sorry, it seemed like a good idea at the time, but now I'm not so sure anymore.

It is certainly possible to change the idle speed via a tune. You don't see the options in the above picture because ForScan isn't suited for this kind of changes. You need a proper tuning software. For instance, here's what I see in HPtuner's VCM Editor for my 2020 GT:

But there's something else I'm not sure about.
We know that cold starts are noisy, and that the cold idle speed is high. But are those two things actually related? I mean, is the engine noisy because it's revving faster? Or is it noisy because of the cold fueling strategy (i.e. richer mixture, etc.)? If it's the former, then I guess you can fix it with a tune, but if it's the latter...

Oh now THAT'S interesting Vlad. The HP Tuner you have lets you change the Cold / Startup parameter....? And by default, Cold / Startup is 1250 vs 800 for a warm start?? Ok, NOW we're getting somewhere..... Which HP Tuner do you have, and which software did you need to get (I notice on their site that they sell the tuner and software separately). Thanks so much Vlad

 

[Vlad Soare]

The software is free and can be dowloaded and used freely, no restrictions, for everything except writing data to the car. You can connect to the car and read the tune, do live scans of various parameters, modify files, compare them, etc. But you need to purchase so-called "credits" if you want to upload a modified tune file to the car.
The number of credits depends on the vehicle model and year. An S550 Mustang needs four credits, which makes it quite expensive. Most other cars only require two credits, but I guess the Mustang's PCM is more complex, hence the higher cost.
The credits are linked to a specific MPVI2+ interface and a specific VIN, but there are no other constraints. That is, four credits will allow you to tune one particular Mustang, using one particular MPVI2+ interface, as many times as you want, indefinitely. If you want to tune two cars, then you need to purchase additional credits for the second car.

In short, for your purpose you'd need to purchase the MPVI2+ interface itself, plus four credits.

As for the parameters you can see in my screenshot, frankly, I'm not sure exacly how the car is using them to decide which rpm to idle at. I believe the actual rpm value may be a function of several parameters, depending on the current conditions. For instance, one parameter says it should be 1,250 rpm at cold idle, but another one says it should be 1,400 rpm when the heater is running and the car is cold. So the final result might be something like a weighted average of those two, depending on exactly how cold the engine is, and how big the difference is between the interior temperature and the target climate control temperature, etc. You may have to experiment a bit. I'm new to this tuning thing; I'm still trying to learn how it all works.

To further complicate matters, it seems that not everything that can be tuned in a US vehicle also works with a non-US one. I have changed some parameters in my 2020 Euro Mustang, and the car is simply ignoring them. It behaves exactly as it did before, as if nothing had happened. Strangely enough, it doesn't even behave in accordance with its original parameter values. So, which parameters can actually be tuned in a non-US vehicle and which can't, appears to be a crapshoot.

 

[TasGT]

If it’s an Auto, just pop it into drive, that cuts the revs back.

 

[mejohn50]

Yes, it's going to be expensive, especially as I had forgotten that the 2015-2017 had single exhaust tips, and the 2018+ has double tips, so you may also need to change the valance. And the 2018+ valance may or may not fit the 2015-2017 rear bumper... and so on. Sorry, it seemed like a good idea at the time, but now I'm not so sure anymore.

It is certainly possible to change the idle speed via a tune. You don't see the options in the above picture because ForScan isn't suited for this kind of changes. You need a proper tuning software. For instance, here's what I see in HPtuner's VCM Editor for my 2020 GT:

But there's something else I'm not sure about.
We know that cold starts are noisy, and that the cold idle speed is high. But are those two things actually related? I mean, is the engine noisy because it's revving faster? Or is it noisy because of the cold fueling strategy (i.e. richer mixture, etc.)? If it's the former, then I guess you can fix it with a tune, but if it's the latter...

There’s some cold start emissions reduction (CSER) strategies in addition to the high idle on cold start. Ignition timing is part of the CSER warm up strategy. It retards the timing to get more heat into the exhaust so it can light off the cats and heat up the O2s. On 2018+ cars it doesn’t work the same as it did in the 2017 and older 5.0s. It can be tamed down with a tune, but the info on how to do it is being held tightly. It used to work by changing all the CSER ignition timing tables to the same values across the board to match the hot start numbers (55° IIRC). Not anymore for some reason.

Maybe someone who knows how to do it on the 18+ cars is willing to share, becasue I haven’t figured it out.

 

[Vlad Soare]

There’s some cold start emissions reduction (CSER) strategies in addition to the high idle on cold start. Ignition timing is part of the CSER warm up strategy. It retards the timing to get more heat into the exhaust so it can light off the cats and heat up the O2s. On 2018+ cars it doesn’t work the same as it did in the 2017 and older 5.0s. It can be tamed down, but the info on how to do it is being held tightly. It used to work by changing all the CSER ignition timing tables to the same values across the board to match the hot start numbers (55° IIRC). Not anymore for some reason.

Exactly. And the question is: could this CSER strategy be responsible for the exhaust being noticeably louder when cold? In which case, reducing just the cold idle rpm may not solve Mick's issue (not entirely, anyway).
Personally, I wouldn't mess with this strategy. I'm sure the Ford engineers have devised a strategy that's the quickest, most efficient, and safest for the engine, cats and other components, and that changing it can only make things worse - unless you really, really, really, know what you're doing.

 

[sjmurphy34]

Your only option to change your cold start would be to get a tuner to do it. I'd be surprised if you could find one that would be willing to especially right now with the EPA cracking down on anyone that tries to bypass emissions rules. The cold start is trying to get the cats up to light off temps as fast as possible. Majority of your emissions come during that intial CSER stage while the cats are getting up to temperature. So if you delay that process by lowering engine speed or changing spark/fuel parameters you are going to increase emissions on the vehicle by a lot.

 

[MicksS550]

I had a similar idea when I was researching how to quiet down a cold start, however, couldn't find much info on someone who has done this and wasn't willing to go through R&D to see if this would work haha. I kind of remember an image of someone with a bunch of PVC pipes running through some container they had to quiet things down, but don't remember how effective it was (or if it worked at all)

Oh, totally. And see that's where I thought I had the PERFECT solution by jamming my Harley Davidson mufflers into the pipe ends....and it's better.....but it's still pretty loud. I suspect this is because a lot of the loudest sound is originating from the headers and cross pipes, so it's loud long before it gets to the pipe ends. I may be flogging a dead horse (pony?)

 

[MicksS550]

The software is free and can be dowloaded and used freely, no restrictions, for everything except writing data to the car. You can connect to the car and read the tune, do live scans of various parameters, modify files, compare them, etc. But you need to purchase so-called "credits" if you want to upload a modified tune file to the car.
The number of credits depends on the vehicle model and year. An S550 Mustang needs four credits, which makes it quite expensive. Most other cars only require two credits, but I guess the Mustang's PCM is more complex, hence the higher cost.
The credits are linked to a specific MPVI2+ interface and a specific VIN, but there are no other constraints. That is, four credits will allow you to tune one particular Mustang, using one particular MPVI2+ interface, as many times as you want, indefinitely. If you want to tune two cars, then you need to purchase additional credits for the second car.

In short, for your purpose you'd need to purchase the MPVI2+ interface itself, plus four credits.

As for the parameters you can see in my screenshot, frankly, I'm not sure exacly how the car is using them to decide which rpm to idle at. I believe the actual rpm value may be a function of several parameters, depending on the current conditions. For instance, one parameter says it should be 1,250 rpm at cold idle, but another one says it should be 1,400 rpm when the heater is running and the car is cold. So the final result might be something like a weighted average of those two, depending on exactly how cold the engine is, and how big the difference is between the interior temperature and the target climate control temperature, etc. You may have to experiment a bit. I'm new to this tuning thing; I'm still trying to learn how it all works.

To further complicate matters, it seems that not everything that can be tuned in a US vehicle also works with a non-US one. I have changed some parameters in my 2020 Euro Mustang, and the car is simply ignoring them. It behaves exactly as it did before, as if nothing had happened. Strangely enough, it doesn't even behave in accordance with its original parameter values. So, which parameters can actually be tuned in a non-US vehicle and which can't, appears to be a crapshoot.

Hey Vlad, thank you very much for all that. That's really useful info.

Whatever the case, I think the MPVI2+ is a good start, so I'll invest in that. Interesting also to note that the software to accompany it allows you to read values, but not write them, although this totally makes sense from a commercial perspective. We know they have to make $ somewhere, so I'm sure none of us begrudge them that (I say this prior to checking the price of 4 credits, so I am review that wording ;-) ).

This is becoming really interesting. I only just bought the car, and the mods had been done before I got it, but from what I was told (I'm yet to climb under there) it has headers, a cross-pipe, high flow CATs, and 2.5" pipes - all Borla.

I also had to research CATs a bit to be honest, because I hadn't really looked into them. For anyone else interested, I found these videos to be really good:
- YouTube: Catalytic Converter
- YouTube: What a Catalytic Converter looks like inside

I *CAN* always replace the cross-pipe with a resonator, but I really didn't want to do that - I'll loose all of that rich sound....all because of those first 20 bloody seconds...!

Anyway, with all of that said, it seems that the 2018+ Mustangs have a more sedate start-up. I know it's new Gen Coyote under the hood, but....how are they doing that?

I'm also wondering: (1) Revving hard and heating the CATs quickly (and lots of exhaust) vs (2) revving lower and heating them more slowly (but less exhaust) - there can't be TOO much difference in emissions, can there?

 

[MicksS550]

Your only option to change your cold start would be to get a tuner to do it. I'd be surprised if you could find one that would be willing to especially right now with the EPA cracking down on anyone that tries to bypass emissions rules. The cold start is trying to get the cats up to light off temps as fast as possible. Majority of your emissions come during that intial CSER stage while the cats are getting up to temperature. So if you delay that process by lowering engine speed or changing spark/fuel parameters you are going to increase emissions on the vehicle by a lot.

Thanks sjmurphy34 - the CSER aspect does sound right, and I feel like it's filling in a few gaps in my understanding. I appreciate your input.

Were previous generation Mustangs so much worse with their emissions? I do notice (in my relatively uninfiormed / informal observation) that very few cars take this start-up "rev hard for 20 seconds" approach. That said, I think Mercedes do.... Dammit.

Like I mentioned with Vlad: I'm also wondering about (1) Revving hard and heating the CATs quickly (and lots of exhaust in the process) vs (2) revving lower and heating them more slowly (but less exhaust) - there can't be TOO much difference in emissions between the two approaches, can there?

Anyway, I think I'm just thinking out aloud at this stage.....

 

[MicksS550]

Exactly. And the question is: could this CSER strategy be responsible for the exhaust being noticeably louder when cold? In which case, reducing just the cold idle rpm may not solve Mick's issue (not entirely, anyway).
Personally, I wouldn't mess with this strategy. I'm sure the Ford engineers have devised a strategy that's the quickest, most efficient, and safest for the engine, cats and other components, and that changing it can only make things worse - unless you really, really, really, know what you're doing.

I think if I got even a partial solution, coupled with me continuing to jam the two Harley Davidson mufflers I have into the pipes...that might just be enough....

 

[MicksS550]

There’s some cold start emissions reduction (CSER) strategies in addition to the high idle on cold start. Ignition timing is part of the CSER warm up strategy. It retards the timing to get more heat into the exhaust so it can light off the cats and heat up the O2s. On 2018+ cars it doesn’t work the same as it did in the 2017 and older 5.0s. It can be tamed down with a tune, but the info on how to do it is being held tightly. It used to work by changing all the CSER ignition timing tables to the same values across the board to match the hot start numbers (55° IIRC). Not anymore for some reason.

Maybe someone who knows how to do it on the 18+ cars is willing to share, becasue I haven’t figured it out.

Yes mejohn50 that would be REALLY interesting to see.... Thanks for what you posted.

Sponsored