KrazyKat

What do you mean Mitsu did it incorrectly? They didnt put a tubular steel crack prone turbo header on a production vehicle? Of course they didnt. Reliability goes to the cast iron or steel twin scroll manifold, power goes to the properly designed tubular steel header.

If you're comparing dyno's, make sure to compare same trans to same trans.

A twin scroll TD04HL-19T-8.5cm is expected to spool slower than a single scroll TD04L-13T-6cm. Unless you have pie in the sky expectations.

cris90

Thats what mean ... neither Hyundai or Mitsu did it correctly. As far as production goes "twin scroll" is only used to attract people, kinda like how saying "V-tech" in front of dumb honda ricers gets them all flustered but non of them knows what it means. "twin scroll" in production cars is just for show.

Thats my point in reality in production car... twin scroll TD04HL-19T-8.5cm is expected to spool slower than a single scroll TD04L-13T-6cm.

But go to the a sales floor and watch the sales rep say otherwise. I'm sure, just like when i went my first time to a hyundai dealership, there going to say to stupidest most incorrect crap all day long. And i'm sure if you ask "witch spools faster the 2013 or 2010-2012?" they'll tell you the 2013 spools faster.

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http://www.gencoupe.com/2-0t/94778-fuel-system-what-you-need-know.html
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http://www.gencoupe.com/2-0t/91199-compressor-maps-how-read-them.html

Fav. JT Quote

KrazyKat

You could have done a better job than their engineers designing a twin scroll setup that would last over 100,000 miles? Impressive!

I fail to see how the twin scroll setups in the Lancer Evolution and '13 Genesis 2.0T are not done correctly. They both spool much faster than an identical setup without twin scroll, so what exactly is wrong with them? 10cm-12cm turbine housings for the Evo's, and 8.5cm housings (hypothesis) on the Genesis..

And whats wrong with VTEC?

School me Cris90.

Quartermaster

I think what he's trying to say is that the twin scroll advertised by mfrs is not a true twin scroll in the sense that the custom fabbed manifold on my car is a pulse-matched twin scroll manifold with a divided housing turbo; whereas an OEM Genesis Coupe for 2013 uses a twin scroll in the sense that it has "two scrolls" but its not "truly" a divided housing pulse-matched twin scroll manifold AND turbo.

Debates about the nature of TRUE twin scrolls rage on for WEEKS on evo forums and often end in murders, rapes and assault cases that go to a grand jury.

The gist of what he's trying to say (I think) is analogous to Dodge advertising their newer line of "Hemi" engines, which are not truly hemispherical head engines in the classical sense of the original motors which were - honest to God - hemispherical, fully machined cylinder head space.

AKGC

If the AR trim was tighter, then it would of spooled better with less exhaust.

If they wanted to engineer it right, they would of done so with the turbine housing with a different AR trim for each port.

engineers that design OEM parts do so just to get things working within a range of efficiency. They aren't designing super cars. well the ones of relevance in this conversation anyways.

I mean look at the design of the exhaust manifold of the 10-12.

V-tech is use for engine/gas efficiency, why do you think all the auto manufacturers have been making their form of variable cams and shoving it into eco boxes?

whatnot

I agree with KK. Sure a nice tubular EM can help optimise a twin scroll, but twin scroll non the less is better than single.

And VTEC is also better than VVT or anything else. Twin scroll and VTEC isn't just for show, it is better. Sure some things can optimise it and it isn't factory optimised, but few things are when there is s 100k warranty.

Quartermaster

The mfrs job is to build something catchy and marketable that sells you on the idea of being whiz-bang-coll-high-tech, but in REALITY it only usually delivers a hint of the high techish stuff they suggest, while being built with the dark, ulterior motive of lasting a long time without breaking so the mfr doesn't eat sh*t and die on warranty claim losses over time.

AKGC

No honda came from the factory with a turbo IIRC.

And most of the high HP civic builds use the non vtec heads.

Quartermaster

There's a reason for this. Tuning a turbo on a VTEC head is a mongolian clusterf*ck from what I've been told.

AKGC

Yeah, same with me. It's just another thing to go wrong.

And the ones that do have vtec, tune it and have cams that make it run rough in low rpms because they mainly tune for the second cam profile (when vtec kicks in yo)

KrazyKat

But the factory stuff is pulse paired, true twin scroll. From exhaust port to turbine wheel.

And again, you AKGC, can do a better job engineering the factory setup? You know a better way to get all the compromises worked out? Just so I get this straight, the guy who says VTEC is for gas efficiency knows better than the Mitsubishi Evo X engineers? Sweet! What a wealth of knowledge we have here.

Truth!


RDX.

Where did you discover this? DOHC VTEC heads are the bees knees.

Not that bad LOL. Just need to learn it, like anything else! 2 engines in one, really.

That depends on the choice of cams. The whole advantage to VTEC on the DOHC's was the ability to have a super aggressive race like cam profile, while not suffering at the lower rpm ranges. So great idle, and responsive (relatively) low end, to ~5k rpm (or whatever). Then the VTEC switchover occurs, and the race like cam profile is followed. Fantastic top end power, right to ridiculous rpm levels (8400 rpm ITR, 9000 rpm S2K, CTR).. Compare to an older muscle car with a hot cam, and listen to that rough idle.

A 1.6L DOHC VTEC honda making 185 hp with no help from compressors is damn impressive!

darkvader0

Lots of incorrect information in the last three posts. High HP Hondas are almost always the VTEC engine variants.

Tuning a VTEC vs non-VTEC adds hardly any trouble at all. I have been tuning them for over 12 years.

Any properly tuned VTEC engine should never run rough in the low RPM as that is the very purpose of the system.

I haven't ever personally put my hands on a twin scroll setup, but from articles I have studied I think it would help if everyone understood the turbo as a "pulse energy" device. The twin scroll designs can keep this pulse energy seperated and optimized all the way to the turbine blades. The typical single designs just mash the pulses together not optimizing them at all as they enter the turbine housing.

The pulse energy optimized by the twin scroll design makes the turbo respond faster/earlier. Plus typically the twin scroll will have a larger overall AR for better topend breathing.

Is the 2013 "twin scroll" manifold not really a "real" twin scroll? Do we have that information already? I still can't decide if I want a 2012 or 2013 model.

[Oops KrazyKat's reply was not there when I first started typing. ]

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AKGC

You realize what goes into casting iron in an complex shape, and then machining it? There is no way in making molds for green sand or even produce dies without making it cost effective.




acura, not honda. "oh god its the same company." well the "i-vtec" uses almost the same variable came timing like our like our engines. it goes about doing so in a different way, because they use timing belts, meaning they can't touch oil, we have chains. The older vtec is basically an on/off switch.
It hits a certain rpm and then it engages the vtec cam profile. You try to tune for that.

get back you me when you've worked on 3 of the same vtec engine dohc or sohc, over the course of 3 months with so called race cams because the valve lash needed to be adjusted every single time and then the EGR ports needing to be cleaned out after 10k miles because it being clogged with soot.




Thats because its NOT TURBO'd. When you turbo a vtec system, you add another variable that is need to be tuned. Plus you basically need to tune for 2 fuel maps, and also to tune for the transition between the 2 profiles. If the the ecu applies the later map late, then lean and boom, especially if turbo'd. Thats the main reason why most of the actual honda track cars are supercharged, where boost is dictated directly from RPM, or why the people that are running turbos run fat down low.


Thanks for making me derail the thread

KrazyKat

LOL Finally a proper Honda guy. Thanks for setting the record straight.

And for the record, the 2013 are a 'real' twin scroll setup. Didnt know there was a fake kind LOL.

KrazyKat

Dude, you're killing me here. The more you write, the more misinfo you spew. Just shut off the flow. Please! Some guys in this thread have actually done that, with turbo Honda's and the VTEC. You think this kind of writing is going to go unchecked?

BTW, VTEC adds a variable that no Hyundai VVT has, and that is LIFT. That is a big reason why they can make such great top end, with excellent low rpm driveability. Just so you have your facts straight for the next post.

KrazyKat

OP, sorry for the mass derail. In a nutshell, the pros and cons:

Pros:

-Faster spool and overall response for a given A/R or Nozzle size (MHI turbo's in CM) compared to single scroll
-Top end potential of the larger A/R or Nozzle size

Cons:

-More expensive than an equivalent single scroll setup
-More complicated external wastegate setup, if done correctly. Not a concern if using an internal wastegate, as in the 2013.

whatnot

^^^ /thread

You guys can argue off topic all you want, but this really sums up the OP's question in KISS form, and I don't think anyone will disagree with.

Quartermaster

Ok well now that the Honda gais have stepped in and declared a twenty year old vvt technology superior to current computer controlled vvt systems, I guess we can go home now.

AKGC

CVVT has duration, in that the timing between exhaust and intake valves opening

vtec


ivtec

ECU controls more than just the cam to do the same thing that variable cams do. low load, it holds the exhaust valves closed a little longer to hold some of the exhaust gasses for fuel economy and emissions. High load, it lets the valves stay open longer whether lift or duration and lets some of the charge air, exit past the exhaust valve. It ivtec also controls the throttlebody by DBW to regulate torque load when it transitions.

As I said before, its the transition thats a PITA to tune properly with a turbo, because of the how quickly the torque it applied and the change of exhaust flow.

and I said track as in coursa, not drag.

SouthernGenesis

Thanks for all the info, on turbos and v-etc stuff lol. =D

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