Jump to content
dwightlooi

Why Bi-Turbo V6es ALWAYS suck.

Recommended Posts

2 hours ago, Drew Dowdell said:

Fiat make the following claim about the efficiency:

"MultiAir technology can increase power (up to 10%) and torque (up to 15%), as well as reduce consumption levels (up to 10%) and emissions of CO2 (up to 10%), particulates (up to 40%) and NOx (up to 60%) whe compared to a traditional petrol engine."

That is what they claim. Ask yourself two things. Firstly, how much of that is due to Multiair itself and how much of that is due to everything else Fiat put in the engine -- say Direct Injection or using tiny displacement engines (like their 1.4L). Secondly, how does cutting off the action of the intake valves partway through the cycle accomplish all those things better than VVL systems that... well... offer long and shorter duration valve actuation with advance and retard of the timing?

Share this post


Link to post
Share on other sites
1 hour ago, Drew Dowdell said:

@dwightlooi  Would a hot-V twin-scroll setup for the turbo help a V6? 

As explained in the original post, a Hot Vee SINGLE TURBO design will provide uninterrupted exhaust flow to the turbine. A twin-scroll turbine housing will be preferred for intake breathing efficiency. Hot Vee Singles are rare because the exhaust collector bridging both sides and a single larger turbo means the turbo sits really high and interferes with the desired hood line. It has been done though... the Duramax 6.6 is an example of a Hot Vee Single Turbo. It makes 445 hp @ 2,800 rpm and 910 lb-ft @ 1,600 rpm (it's a diesel).  Note: Notice how tall the entire turbo setup is and why it may be a problem in a sports car or a sedan.

However, a Hot Vee Twin Turbo design like Mercedes' M276 DELA30 (3.0L Twin Turbo; C400/C450/C43 AMG) provides no advantage apart from packaging (which is itself debatable). I find Mercedes' coining of the term "Pulse turbocharging" ironically laughable as it describes the interrupted exhaust problem of V6 bi-turbos so succintly. IMHO, conventional flanking turbos can be located just as close to the exhaust ports as a turbos in a Hot Vee, and flanking turbo designs like GM's LGW (3.0L Twin-Turbo; CT6) performs just as well.

L5P-front-full.jpg

Edited by dwightlooi
  • Upvote 2

Share this post


Link to post
Share on other sites

Note that the Duramax is a diesel, though.  Is anyone doing single turbos like this for a gas V6?

  • Like 1

Share this post


Link to post
Share on other sites
11 minutes ago, Robert Hall said:

Note that the Duramax is a diesel, though.  Is anyone doing single turbos like this for a gas V6?

I don't think so. And the Duramax does not have the hood heights issue. Pickups have lots of room under the hood.

  • Like 1

Share this post


Link to post
Share on other sites
16 hours ago, Robert Hall said:

Note that the Duramax is a diesel, though.  Is anyone doing single turbos like this for a gas V6?

Nope, but they should for a mid-engine sports car. I think ford wasted a good opportunity with the Ecoboost V6 Ford GT. These have a lot of height in the engine bay if you don't mind seeing the engine in the rear window. The Audi R18 Le Mans race car is a hot vee single turbo 3.7L V6. But that is (oddly enough) a DIESEL Le Mans race car, and that doesn't constitute a "production" engine.

The C8 is unlikely to use a hot vee single setup since it is a V8 and that is as good as an I4 which is good enough.

7.jpg

Edited by dwightlooi
  • Upvote 1

Share this post


Link to post
Share on other sites

I can't see flat as being any advantage.  

Share this post


Link to post
Share on other sites
2 hours ago, Drew Dowdell said:

Where do the turbos sit on the Subarus and is the flat 4 or 6 any advantage?

LOL... It sits in a terrible location that is unreachable, unserviceable and very far from the exhaust ports! Basically, it's behind the engine, below intercooler and above the transmission. VERY long pipes connect the turbo to the exhaust ports below the engine. If you straighten out the pipes the turbo is about as far from the engine as the front seats in a car. For emissions purposes, Subaru even stuck a small catalytic converter between the exhaust ports ahead of turbo for the further pair of cylinders. Another main catalyst is, of course, located after the turbo. It all amounts to a mess that is both inefficient and a nightmare to work on. Also, with the intercooler above the turbo and fed by a hood scoop, when the car is stationary, all the heat rises up to heat soak the Intercooler. Congratulations! BTW, if that pre-cat breaks all that debris goes turbine...LOL! (See photos)

That is why all the STi WRXes always have inferior turbo response compared to the Inline-4 Lancer Evolution. It takes 4,000 rpm for the STi to make full boost and it is rather placid 14.7 psi.

EJ25_turbo.jpg

tn_100_8527.JPG

Edited by dwightlooi
  • Thanks 1
  • Upvote 1

Share this post


Link to post
Share on other sites

Your content will need to be approved by a moderator

Guest
You are commenting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.




  • Social Stream

  • Similar Content

    • By William Maley
      Fiat Chrysler Automobiles is considering replacing the Pentastar V6 with a brand new straight-six engine. A source tells Allpar the new engine will be based on their new four-cylinder Global Medium Engine (GME) - what is found under the hood of the Jeep Wrangler and Alfa Romeo Giulia. This will allow FCA to build the engine alongside the four-cylinder variant.
      Not many technical details are known about the engine aside from it being pegged around 2.9L to avoid taxes in certain European countries. We might expect larger displacements for trucks and SUVs. Production could take place at FCA's Dundee and Trenton, Michigan plants. It is expected that Ferrari will use a variant of this engine for Maserati vehicles. No timeframe as to when this new engine could debut.
      Allpar also mentions in their report that FCA was considering adding some sort of boost to the Pentastar, but ran into issues with the size and power constraints.
      Source: Allpar
    • By William Maley
      Fiat Chrysler Automobiles is considering replacing the Pentastar V6 with a brand new straight-six engine. A source tells Allpar the new engine will be based on their new four-cylinder Global Medium Engine (GME) - what is found under the hood of the Jeep Wrangler and Alfa Romeo Giulia. This will allow FCA to build the engine alongside the four-cylinder variant.
      Not many technical details are known about the engine aside from it being pegged around 2.9L to avoid taxes in certain European countries. We might expect larger displacements for trucks and SUVs. Production could take place at FCA's Dundee and Trenton, Michigan plants. It is expected that Ferrari will use a variant of this engine for Maserati vehicles. No timeframe as to when this new engine could debut.
      Allpar also mentions in their report that FCA was considering adding some sort of boost to the Pentastar, but ran into issues with the size and power constraints.
      Source: Allpar

      View full article
    • By William Maley
      It is no secret Fiat Chrysler Automobiles has been dealing with a number of issues with the 2019 Ram 1500 launch. As we reported back in April, the  Sterling Heights Assembly plant was only operating at 60 percent of where the company wants it to be due to various issues. FCA announced that it would be investing $300 million to try and get production back on track, along with extending the production schedule to six days a week and running though Independence Day and Labor day.
      But as Automotive News reports, there is a new issue that is likely driving customers away from the 2019 Ram 1500. Currently, the 1500 is only available with the 5.7L HEMI V8. The 3.6L V6 and 5.7L HEMI V8 with the 48-volt mild hybrid system are no where to be seen.
      "I have customers looking for them and asking about them every week," said an unnamed Ram dealer in Michigan.
      It is unclear why neither one of these powertrains are available. Automotive News has two possible guesses. One is that FCA engineers are still doing some fine-tuning work to the mild-hybrid system before putting them into production. The other comes down to the EPA becoming more  stringent with automakers in terms of emission and fuel economy testing.
      While FCA is quick to point out that retail sales were up 18 percent in May to 27,011, we can't help but wonder if that increase is due to the massive incentives that are being put on the last-generation model. Through May, the average incentive on a last-generation Ram 1500 stood at $6.578 according to Autodata Corp. But the lack of new engines for the 2019 Ram 1500 is hurting, as year-to-date sales are down 8.4 percent. Dave Sullivan, a senior analyst with AutoPacific says the lack of V6 this long after the launch is becoming a problem.
      "In the old truck, the V-6 represented about 20 percent of sales," he said.
      Source: Automotive News (Subscription Required)

      View full article
    • By William Maley
      It is no secret Fiat Chrysler Automobiles has been dealing with a number of issues with the 2019 Ram 1500 launch. As we reported back in April, the  Sterling Heights Assembly plant was only operating at 60 percent of where the company wants it to be due to various issues. FCA announced that it would be investing $300 million to try and get production back on track, along with extending the production schedule to six days a week and running though Independence Day and Labor day.
      But as Automotive News reports, there is a new issue that is likely driving customers away from the 2019 Ram 1500. Currently, the 1500 is only available with the 5.7L HEMI V8. The 3.6L V6 and 5.7L HEMI V8 with the 48-volt mild hybrid system are no where to be seen.
      "I have customers looking for them and asking about them every week," said an unnamed Ram dealer in Michigan.
      It is unclear why neither one of these powertrains are available. Automotive News has two possible guesses. One is that FCA engineers are still doing some fine-tuning work to the mild-hybrid system before putting them into production. The other comes down to the EPA becoming more  stringent with automakers in terms of emission and fuel economy testing.
      While FCA is quick to point out that retail sales were up 18 percent in May to 27,011, we can't help but wonder if that increase is due to the massive incentives that are being put on the last-generation model. Through May, the average incentive on a last-generation Ram 1500 stood at $6.578 according to Autodata Corp. But the lack of new engines for the 2019 Ram 1500 is hurting, as year-to-date sales are down 8.4 percent. Dave Sullivan, a senior analyst with AutoPacific says the lack of V6 this long after the launch is becoming a problem.
      "In the old truck, the V-6 represented about 20 percent of sales," he said.
      Source: Automotive News (Subscription Required)
    • By William Maley
      Nissan and Toyota are outliers in the full-size truck market as they only offer V8 engines. Nissan had announced that a V6 was coming, but it hasn't appeared.  Michael Bunce, senior vice president-product planning for Nissan North America told Wards Auto said a V6 is still in the cards, but it will appear in the next-generation Frontier.
      “A new Frontier (small pickup) is on its way, and a V-6 is more geared toward that segment. Both (the Frontier and Titan) are built in the same plant in Mississippi, so that opportunity is being looked at for Titan also,” said Bunce.
      “I can’t give you any specific details on that, but we will be moving in that direction,” Bunce said when asked if the V6 would first appear in the Frontier before appearing the Titan.
      The V6 engine for trucks is mostly positioned for those buying them for fleet duty.
      Wards Auto reports that it is unclear what V6 engine will be used.
      Bunce also revealed the automaker is looking at a return to the off-road utility segment due to the resurgence of the segment due to models like the Jeep Wrangler.
      “We know (via research) the Millennial male, through devices they’re becoming more isolated. And they want to reconnect with friends, family, outdoors. And a vehicle is an expression, a way to do that. We’re doing a lot of work in the space to understand that customer very well.”
      Bunce also said the XTerra nameplate “is a great asset in terms of a name and a badge. It’s on the shelf right now, but it’s something we could utilize in the future.” The XTerra nameplate went away in 2015. Judging from these comments, it might mean the XTerra could be coming back.
      Source: Wards Auto

      View full article
  • My Clubs

  • Recently Browsing

    No registered users viewing this page.

  • Reader Rides

About us

CheersandGears.com - Founded 2001

We ♥ Cars

Get in touch

Follow us

Recent tweets

facebook

×