2G Is there anybody running an HX40 in a true twin scroll setup???

[Seamus]

The forum isn't displayings sigs for me now. It was showing times and wheel torque, but then it stopped. Its probably like that for some other too.

 

[jbeaton9292]

Yeah same here

The forum isn't displayings sigs for me now. It was showing times and wheel torque, but then it stopped. Its probably like that for some other too.

 

[CrackedDSM]

FWIW if beans car was 5-speed it would be trapping in the mid 140's, so I say again, this is the answer to the "it doesn't work" argument.

 

[Mr Peepers]

For what it's worth, I trapped 135.9 in a full interior AWD 5 spd with a 54mm twin scroll turbo at 30psi. With beans trapping 134 through an auto, I really don't see an issue with 140+ if it were a 5 speed. Hell, my car as it sits would likely be low 140 through a 5spd EDIT: I just noticed your post CrackedDSM

The impressive part is beans is getting the stock stall to light up with an hx40 and 2 liter. I'm not saying twin scroll is the end all setup but it certainly has its advantages and doesn't seem to give up much as far as power goes from my experience. Even if you're not auto, the point is that the boost threshold is almost always at a lower rpm with a wider torque curve.

 

[CrackedDSM]

Thanks for your input, Matt. Yours is another car that I've watched closely and modeled my build after as well. And it's auto too. What cm hotside was your HX35 on? The 12cm?

 

[Mr Peepers]

Thank you!

12cm hotside up until recently, and no good data to back the new 16cm and non recirculation wastegate (besides a pretty good 109mph in the 1/8th). Still gets on the stock stall with ease

 

[CrackedDSM]

Awesome. I have been thinking of going with T4 twin-scroll just like Bean has, same size hotside and everything but on my 2.4LR motor. I feel like it would spool incredibly but make very good power and not be like an "on/off switch" of power. 130-135mph traps in my heavy 2G pig would be plenty enough for me. I'm just spoiled and don't want to wait forever for boost to come on.

 

[Mr Peepers]

I've still seen some twin scroll setups spool somewhat slow, runner sizing (being too large) may be something to consider

 

[CrackedDSM]

1.25-1.5" OD tubing is best, right? I've got a fab guy that makes killer stuff so pretty much anything I can get made.

 

[Mr Peepers]

I wouldn't be able to say what is best, but the 1-1/4" schedule 40 pipe I used comes out to 1.380" inside diameter. I don't think I've seen a common aftermarket TS manifold even close to that small of a runner. 30psi before 3000rpm was easy in 5th gear. There are always other factors but extremely similar setups besides a larger runner twin scroll manifold have been noticeably laggier- and even made less power to boot(again, tons of factors but just illustrating a point)

 

[CrackedDSM]

Awesome. I've been researching it like crazy and been finding the same thing. Angle, sharp bends, too big of piping, etc. My fab guy is building a TS manifold right now for someone so he does have experience with it. We've been friends for awhile so I'm getting it for a steal. He's also building tubular subframes that I plan to utilize on my 2G, but I'm getting off topic. Because I plan to keep a/c, power steering, and drive this car on the street 98% of its life, an off the shelf manifold wasn't going to work anyway. I've got a lot of work ahead of me but it'll be worth it I feel. I appreciate for sure any/all input, and I take it to heart. Love picking the brains of the guys who have actually made power and gone fast on these TS setups.

 

[bastarddsm]

Peepers, I don't believe the auto is taking that much away. Your traps haven't suffered that much. I know your running it harder now, but it's not like it was gonna pick another 75-100hp with 5psi more boost.

Don't get me wrong I get that twin helps it come up, but I really do think if you could get a decent housing that was sized comparatively it would spool the same and make more power. The available suff other than holset kinda sucks cause it's a generic housing machined to fit. I spend a lot of time at my job reading about this subject, and every single paper suggests that in general twin scroll looses to and open. The whole "Pulse isolation" deal is bunk. Any decent header isolates it well at the Rpms we run.

This isn't no hater attitude either. I really wish it was as great as it perceived. I've played with the t/s as long as you guys have, and it just didn't work for me. T/s hx35 vs open hy35 airflow was way down on the hx. That's logging it externally with a GM maf. That doesn't lie. The spool. Difference wasn't horrible either. My manifold had big runners though. Right now I have a bw s362 on the car .84 t4 twin scroll it spools great, 35psi by 4000ish in 3rd gear with no brake boost foolery, but balls out it's 2-3mph slower than my hy, airflow and fuel flow shows it sucks too. There's several other people that spent the money for the t/s stuff and are badly dissapointed.

 

[bastarddsm]

FWIW if beans car was 5-speed it would be trapping in the mid 140's, so I say again, this is the answer to the "it doesn't work" argument.

Simple fact is, it hasn't done it.

 

[Mr Peepers]

It took quite a bit to get the trap speed back up to 132 with the auto. I went from gaining over 30mph on the big end to about 23, that's a huge difference; even with more boost, much more efficient intercooler, larger hotside, 2g head, evo3 intake etc. The info is here, how you want to interpret it is up to you.

I agree that a properly sized open scroll could make more power, but I don't think I would be doing what I'm doing now without it.

EDIT: I suppose I should be really clear. I probably sound like I think twin scroll is the best thing ever. Well, I did at one time, and it's not. Although I've had great luck, and it has been a benefit to my particular setup, it certainly hasn't worked for everyone, or fit into their goals, nor will it. I think it's something that should be considered, however.

 

[bastarddsm]

What did your 1/8mi goto? I just find it hard to believe that the auto sucks up 100hp more than a 5 speed.

What size housing is on your car now?

In the end I don't know, peepers your car is impressive, but it's a freak. It's just old having people that have not even ran one telling everybody how it will spool off idle and still make killer power.

You do know if it was a 5 speed and it really did trap 140+ it would be at least a couple tenths quicker that it is with the auto....

 

[LandSpeed-DSM]

Like so many other things.. if you don't know how to match components, the setup won't perform as it should.

Anecdotes on how "twin scroll is hype" seems to be just that.. anecdotal. Open and divided each have applications where they shine.

 

[bastarddsm]

I don't even think it comes down to matching things. By the time you size a t/s housing to flow like an open setup, all the spool advantages are gone.

As a further data point the diesel pull truck I tune recently went from an hx60 based turbo to an hx82 based turbo. We went from a divided 32cm with a 4" turbine reducer to an open 25cm setup with a 5" exducer. And a bit more compressor flow. Truck makes 300hp more with about 5psi less boost and 10-15psi less drive pressure. Spool characteristics stayed the same. Keep in mind this is on a maxed out application where it is not wastedgated ~60psi boost and 1700hp at 3800RPM.

 

[Seamus]

I've never seen favorable results when I was messing with it years ago on rotaries. But I also concluded to myself that the low pressures I was running(10-15psi) weren't letting me see the benefits.

I will say that the modern OEM twin scrolls seem to be pretty amazing. I've had a few generations of the vag 2.0t, both fsi and newer tsi. They literally peak off idle. But can still support a solid 300whp. So it seems that it may show more advantage on these very small turbos with very light rotating assemblies. The weight possibly multiplies any increase in drive efficiency. I guess no one but the OEM engineers no, but cause your unlikely to ever see one with a tiny open turbo standing in for duty.

 

[viperlp01]

I don't even think it comes down to matching things. By the time you size a t/s housing to flow like an open setup, all the spool advantages are gone.
.

That is False. I run a Borg S362 in a 1.1AR T4 TS housing(biggest they make for this turbo). Big cam 2.0L low compression(worst combo for spool) and make 30psi at 4k in 4th gear and make power up to 8.8K(furthest I revved it out). In 3rd gear if I start at 4k I hit full boost at 5k. I trapped 130 in a FULL weight evo at 27psi. This is the most responsive and most powerful setup I have ran single turbo and felt in other cars. 5th gear cruising is no issue to build boost and pass.

I also did a test on a Borg 1.0 AR T4 vs a BEP housing .55ar. The new setup beat it in spool and gained 80whp over the open scroll bolt on turbo.

Under Suzuki just beat the lap record at Tsukuba by 6 seconds by switching to a twin scroll EFR setup over a t3. The issue is your comparing OLD ass technology Vs. OLD ass technology in your statement. The new 9180 EFR housings are making 900+WHP in 1.05ar T4 TS and hits full boost in 4th at 4500rpm. They just released a 1.45 housing that should gain even more. The open scroll is convenient that's it.

 

[bastarddsm]

I don't know, I haven't seen a paper yet that shows a t/s being better for spool and power than an open setup. I'd suggest that the oems righting these papers have access to a lot better tools than us mortals have. I don't think that the bep housing is a fair comparison to anything. Plus why are you bringing up the efr stuff, this is about hx40s. The efr stuff might do ok, but that's a huge price to pay for a possible improvement in transient response. Also about your track reference, as we say in the science world, "correlation is not causation" I also feel like my hy35 has a very similar boost response, and had no trouble running 130 at 30psi in a heavy car with a tired engine. So let's spend $2000 on a turbo an manifold to do the same thing a $250 setup is doing? And my cast manifold has been dd for 4 years and about 30k mi, without cracking and it clears stock fans. I'm rambling, but the point is it's a whole lot of hassle for minimal gains.

 

[Seamus]

Shaving six seconds off a lap by switching to an entirely different turbo says nothing about twin scroll. And when you changed from a bep .55 to divided t4, that's a terrible example because the turbo has difficulty running out its map with that housing. Going from a .86 t3 to a larger divided t4 is a more appropriate comparison.

 

[viperlp01]

Same turbo, different housing plus I am sure everything else involved. Considering Borg warner refuses to make these big turbos in anything other than twinscroll I am lead to believe it works. I wish t3 was as awesome as T4 TS. Then the manifolds would be easier to make and I wouldn't have to spend an extra 300 bucks on another wastegate. Its just that much better from my personal experience.

 

[LandSpeed-DSM]

The major OE manufacturers (passenger/commercial) have overwhelmingly backed the twinscroll horse due to the criteria set by the need for meeting emissions by bringing airflow up quickly while also satisfying customer demand for response, efficiency and power density.

The cost and complexity premium being deemed worth it as almost every one of them appear to have reached the conclusion on their own.

Is it the objective best in every application, of course not.

Bastard - just got your PM, I'm always on mobile now and some quirk in my browser/hardware never shows my alerts.. I'll see what of those pdfs I can dig up. They were found under a paid subscription.

 

[Jst4Cyl]

Off topic at hand, but what's everyone doing for a T4 Twin Scroll manifold for 2G's?

 

[beansblacktsi]

Well I just got off the dyno and Im very pleased with the results. Ended up making 547hp @40-41psi and 14 degrees of timing. This was done on our local heartbreaker mustang dyno through an auto with a stock non lock up converter. It would of made more power if the control arm didnt break its bushing and pull out of its mount. From 13 degrees to 14 it picked up 20 wheel hp and ended up twisting the control arm going to 15 degrees.
Just for comparison I went 10.15 @134 making right around 400hp on this same dyno and pretty much the same setup.