Mod Proposal: Twinscrolling the GT

[OppoLock]

Small turbos don't have too much of an impact on noise (if any), just listen to any of the german luxury cars. As for blower, I meant turbo; I'm new to the terminology and I assumed forced induction was forced induction.

They absolutely do impact noise. Even the smaller twin turbo setup and twinscroll singles act as mufflers, so say goodbye to that sharp induction bark and crisp exhaust note. The past half-decade of motors coming out of Bavaria have made up for the lack of a complex soundtrack by at least sounding smooth throughout the range, or compensating with "active sound design", which is a pre-recorded engine track (or an actively-recorded track depending on the model) that gets pumped through the speakers. They sound good, but it's heresy to some enthusiasts. It's proof that F/I muddles the end product either way.

This is true. I drove a GT/CS which probably didn't have the Torsen. I was able to floor it in first from a roll without any traction issues which to me means two things:

1) Not a ton of torque (torque is what breaks traction, not horsepower)
2) Probably not the higher ratio rear-end

I don't see how the inclusion of a Torsen diff would make a noticeable difference in low-end acceleration. If traction issues are that bad, then the rate you're accelerating at should feel plenty fast. A diff wouldn't do much to help out in most instances, but more torque would give you that kidney sucking sensation if that's what you're referring to.

Personally I've always thought that if you want to go forced induction, buy the model that offers it. Why buy a 5.0 not setup for forced induction when you know there will be a model that offers it out of the box.

That's just my 2cents though.

100% agreed.

Just curious if you've driven the Audi's you highlight.

I haven't, but I have driven a BMW 335 (with the twin turbos) and I own a VW GTI. Both have relatively well respected turbo engines, and both make great torque down low, but both also have horrible turbo lag.

I drove the 335 at an AutoX, which admittedly is about the worst case situation for exposing turbo lag, and it was not a fun experience due to the lag. I think if I owned the car I'd adapt to the lag for track driving, but for street driving it is very annoying. The GTI is similar. Less power overall but the lag leaves a similar feeling of unresponsiveness.

The only time I really like the feel of the turbo is when going up a hill. That's when you have high, steady state load at a low RPM, and the turbo really works well in that case. When you have dynamic throttle application, the lag is very evident IMO and masks the low-end torque.

So, IMO, turbos look good on a dyno and provide good advertising numbers, but aren't very fun to drive due to the lag.

I think the positive displacement supercharger that's mounted right on top of the engine with the integral intercooler is a much better way to get the low-end torque. The Audi Supercharged V6 is a good example.

Anyhow, if I wanted to get more low end, with quick response, that's the way I'd be looking.

-T

Right, the N54's twin turbos have a huge plateau of torque across the general range of 1500-5500 RPM, which is great for DD'ing, but it's a shame that those little snails run out of breath as soon as you head above that range. Lag is relatively minimal, but the throttle response is still very rubber-bandy, so to speak. Heatsoak is also a huge issue with my 335i. And +1 regarding your supercharger input.

Yeah that's a fair point. Price is the main motivator; anything on the market that gives you mustang performance with a turbo costs at least $20k more.

I haven't driven either the rs5 or rs7, I just know their torque curves are flat starting around 1700 rpm or so. Being an engineer sometimes I do let the numbers get the best of me lol.

Well their TTV8's have low boost thresholds like the F/I motors from BMW, sharing a similar effective torque range from around 1.5-2k up to 5500 RPM, but they're still going to be affected by lag to some degree.

The bottom line is, short of increasing displacement, there's only so many tricks that can be employed to broaden the torque curve (substantially increasing the low end) without sacrificing the high end power too much. I believe all of the things that have been discussed will improve the S550 over its predecessors.

The question is whether it will provide a dramatic enough improvement in low-end grunt that I believe the OP is looking for. We can theorize all we want, but the only way to find out will be to wait and drive it. If it still leaves more to be desired, I think a positive displacement blower will be just what the doctor ordered...

Direct injection would be rather beneficial for low end improvements (and the fuel efficiency it brings with it would be an added perk). It's one thing that I'm afraid to miss out on by being an early adopter for the S550. I wish that we had some more concrete info on a timeline for upcoming powertrain enhancements.

I can relate to what the OP is talking about, but have no idea what is necessary to achieve it on the s550, because as many have mentioned we do not have the proper specs/analysis yet.


I have BMW 135is, (3.0 liter w/scrolling turbo).. & have roughly 350ft-lb of torque just off idle at 1,300 rpms..

I hardly ever see 3,500 rpm during daily driving..

I will be waiting for the first DFI V6 FI Mustang. I have no need for 500hp+, when I can have 400ft-lbs of torque at 2k rpms in a turbo stang.

Same here. I keep my 335i in the 2000-3500 RPM range all the time. It's fun to apply WOT in that range, short shifting and just riding the torque wave.

Do you guys really not take your car to redline on a semi-regular basis? It's good for the engine to get it up there every once in a while, and on the on-ramps makes for a ton of fun.

I wish I had more reason to. :( I only do it for the noise since it runs out of breath at high RPM...

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[Sterling Archer]

Well their TTV8's have low boost thresholds like the F/I motors from BMW, sharing a similar effective torque range from around 1.5-2k up to 5500 RPM, but they're still going to be affected by lag to some degree.

You're seriously reaching there. When was the last time you actually hung out below 1.5k rpm in a mustang outside of cruising on the highway? That's effectively zero lag.

 

[OppoLock]

You're seriously reaching there. When was the last time you actually hung out below 1.5k rpm in a mustang outside of cruising on the highway? That's effectively zero lag.

That's not turbo lag... that's boost threshold, i.e. the effective RPM range where the turbos have to "spool up" to in order to produce their maximum power. Turbo lag refers to the window of time when you press the throttle and receive that actual power.

Trust me, look at the car I drive. This was a whole thing on E90post.

 

[Hashbrownn]

I am planning to add twin turbos on 2015 5.0 if I'm not satisfied with it's performance.
If the turbos do not fit in under the hood, no matter. I'm sure someone can fit them in the rear.
If you want turbo torque out of the box go for the EB. I have a feeling it can be a quick sports car.

 

[burntire]

Someone will find a way to make twins fit up front. They may sit low or behind the fenders but I bet the will be up front.

 

[Fazm]

Every new body style people say there's no room, and every time someone finds a way

 

[Sterling Archer]

I guess one other thing came to mind, what if instead of turboing the coyote, what about enhancing the sound of the ecoboost? As an engineer I couldn't care less how the sound is generated, I just want the car to roar when I push the gas peddle (in fact being able to tune a synthesizer would have a nice set of perks to it).

 

[scottpe]

I guess one other thing came to mind, what if instead of turboing the coyote, what about enhancing the sound of the ecoboost? As an engineer I couldn't care less how the sound is generated, I just want the car to roar when I push the gas peddle (in fact being able to tune a synthesizer would have a nice set of perks to it).

Hopefully they will make it sound as good as a 4-cylinder can, but NOTHING they do will make it sound near as sweet as the roar of a V8.

 

[Sterling Archer]

Hopefully they will make it sound as good as a 4-cylinder can, but NOTHING they do will make it sound near as sweet as the roar of a V8.

I don't agree with that at all. As an EE I can guarantee you there exist sound symposiers that can perfectly recreate the sound, it's just a question of can they actually be successfully implemented into a muffler, and how much would it cost? If it takes $5k in electrical equpiment and modification costs to do it, the v8 would just be a smarter choice.

 

[JoeDogInKC]

They should just make an EcoBoost 5.0 and be done with it.

 

[Sterling Archer]

They should just make an EcoBoost 5.0 and be done with it.

I would be 100% down with that

 

[Nate408]

I don't agree with that at all. As an EE I can guarantee you there exist sound symposiers that can perfectly recreate the sound, it's just a question of can they actually be successfully implemented into a muffler, and how much would it cost? If it takes $5k in electrical equpiment and modification costs to do it, the v8 would just be a smarter choice.

Lol. The sound symposer that BMW and others use playback through the car's stereo currently. No way that sounds as good as the real thing to those with full hearing. Also if they tried to get close it would get expensive and complicated, seems really unnecessary.

 

[scottpe]

Lol. The sound symposer that BMW and others use playback through the car's stereo currently. No way that sounds as good as the real thing to those with full hearing. Also if they tried to get close it would get expensive and complicated, seems really unnecessary.

I've never heard BMW's implementation of this, but I'm guessing in any case, as soon as you roll the windows down, most of the illusion is lost.

I want my Mustang to growl inside AND out, thank you very much.

 

[williamwally]

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[5.0 Coyote]

An easy solution to this sound problem is don"t buy the Eco Boost 4 Banger,the 5.0 Coyote doesn't have an exhaust sound problem,and come to think of it, doesn't have a POWER problem either,I am still baffled as to all this hype over a 4 Banger Mustang:amen:

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