chuntington101

just a note to the TS fans, how many WRC cars are running TS these days?.......

Not trying to start anyhting here, just ilistrate that altoguh TS is useful, the extra engineering isn't always required, even in top levle motorsport! Also TS has been arouns since the early 80's at least. I have seen 1.5ltr turbo F1 motors of the eara running both twin scroll and V-band SS housings (obviously not together)

Chris.

Sarg

iTrader: (6)

They have anti-lag to spool the turbo

98Z28CobraKiller

iTrader: (17)

Again, the twin scroll magic is just a reduction of exhaust housing volume. If the turbo spools faster it comes at a penalty up top. The only real benefit to it is that you can use a quickspool device to block off half of the housing and increase exhaust velocity to get it going. Useful in a rear mount application.

dcblackss

Craftmanship is awsome!!

3800SII

I would have to only agree with you to a point where you are truly using a TS turbo that is smaller than what is actually necessary. It is very, very useful in non-divided setups also. Most of the divided turbine setups are larger. In my case my turbine selections are .84 AR on the GA and .70 ar on the Firebird. The typical turbo to fit a V6 would be .63 ARThe typical turbo to fit an LS based V8 should be no less than .96AR to 1.05AR.
If you do the research you will find that TS sytems have anywhere from 5% to 10% more peak HP and torque than regular single scrolls as well as faster spool, and this is without a spool valve using the same amount of boost!

ablakez28

iTrader: (9)

I made 975/930 on 18psi with my twin scroll setup earlier this week.

3800SII

Awesome!! Those numbers would speak for themselves

ClimberD

Do you have a boost plot and/or dyno printout of some sort? Boost plot would be ideal

ablakez28

iTrader: (9)

I don't have a boost plot. The graph mostly looks like any other on here I have seen. My turbo is huge though and I am going to be going to 21-22psi soon.

http://www.youtube.com/watch?v=F0kpj..._order&list=UL

ClimberD

WRC is definitely not something you want to compare to street cars. The antilag results in one turbo per service. The Subau car I saw had a giant water tank to spray the tiny FMIC continuously. The cold-side piping became massive near the throttle body, with a perforated inside pipe to guide the air, such that more compressed air would be in the piping when the throttle body would shut, and then that air would rush into the intake manifold when the throttle body would open up again after the momentary shift, so response would truly be instant. That and the antilag would be blowing up the exhaust. 2.0 liters. With a restrictor plate to limit airflow. And they're still stupid fast. Yes they use twinscroll because they need the entire power band to be a powerful as possible. But all that other crap on top makes for no possible way to compare.

I have a twinscroll car, though it is not my Subaru. My Subaru makes power 3500-7000rpm. My Twinscroll volvo makes power from [lowest rpm you can get the engine]-to redline.
An individual with roughly the same Subaru and same modifications, but twinscroll version of my car and turbo, is making power 2000-7000rpm. His transient response is faster after shifts. Riding is his car was just plain nuts. No matter how low the rpms are, he would hit the gas, and there would be boost.

I'm trying to come up with an analogy to explain that twinscroll in no way limits top end, at least I've never seen it do so, unless the person putting the system together had to be all special and mix and match non-compatible parts to produce a system that performed poorly. How about the single big exhaust pipe vs dual exhaust example. Let's say your big single exhaust is 3", and your duals are each 2.25". Someone on here who knows everything about LSx exhausts please tell me which one will make more power, or will they be the same?

ClimberD

When you're driving it on the street, can you make a mental note of what RPM in 3rd gear you hit your peak boost?

P.S. What turbo are your running, and pics of engine? Cool car!

ablakez28

iTrader: (9)

I have a build thread on here. Boost comes on really hard and fast on the street. I wish I would have went WOT on the dyno at a lower rpm to give it more time to spool.

ClimberD

Street loads better than dynos anyways, maybe 500rpm better.

Took me a while to find your graph and turbo info (awesome thread, love the pictures). S88? Don't know anything about it yet, but I have seen some nice hybrid turbos for sure...

https://ls1tech.com/forums/15296226-post109.html

Turbo hits at what in 3rd gear, 3000rpm? Thanks for your help

ablakez28

iTrader: (9)

By hits you mean makes boost? On the street it is near instant. I have a log from last night I go wot in 2nd gear at 3100 and am over 105kpa(into boost) at 3300.

I will do a 3rd gear roll from around 2500 once it stops raining and see what I come up with.

chuntington101

And???? whats to stop ANY turbo guy on here runni9ng anti-lag? NOTHING! the BS you hear about anti-lag destroying turbos is only really apropiate if you are running SERIOUS anti-lag. Yes Group aA and Early WRC cars from yester year did used to run VERY aggresive anti-lag. I remember watching, rallying in the 90s. you could hear the cars coming from about a 1/2mile away through think forest. They sounded like machine guns when they bacced off the throttle.

Now if you want to talk about moderen WRC style combustor can anti-lag systems feel free. but all you need to know is they are MUCH easier on turbos than conventional 'bang-bang' anti-lag!

Also there are lots of people that run Anti-lag on the street. alot of the Evo gusy use it. you dont have to run it at mad nutter levels for it to still make a difference!

Chris.

chuntington101

I think you have been missed informed about some things used on WRC cars!

First of, as said above, the combuster can (or rocket box in the subaru world, sure you would have heard of them???? no??), is actually MUCH softer on the turbos than the old school bang-bang anti lag. This is bacuase the event is much more contolled and mettered. I have a thread in the advanced section talking about it. go take a look.

Secondly, although WRC cars DO spray the intercooler (they are NOT tiny, but properly sized with VERY effecient core and end tank design!!!), but the water is mainly used to inject into the engine to increase the deptination threashiold of the engines!

The increase in pipe diameter has nothing to do with helping the turbo spool. obviously you understand that the great the volume of the intake track the long it will take for the turbo to fill said pipework. Thats fundamentals. The increase in pipework diameter is actually to help reduce intake temps. By over boosting the air (ie running it at higher than needed intake presures) and then exspanding the air very rapidly (and thus getting presure back down to the intended intake presure) you can also reduce its temp.

rear bumber mounted tanks where roomored in WRC but i think they have been banned.

And NO WRC do not run TS. Look at the Ford WRC engine. They use a Tial style SS trubo housing. The same as the ALMS cars do! By the way the turbo is a Garrett GT30RS based usit (and cost about $15K each from what i have heard).

What people forget about turbos is you need to match the trubo to the requirements of the engine. you need to understand what RPM, airflow rates & intake preusre you will want the turbo to be operating at its most efficent in. you want low end power then you fit a smaller turbo and use less revs (turbo will choke at higher RPM). you want top end power you fit a bigger turbo but it will take long to provide boost!

Thanks,

Chris.

chuntington101

You have me thinking about this now! lol

If you want supper fast responce then you might want to look into compound boosting or even sequential turbo setups?

Compound would require running two turbos (a little one and a really big one) but can give you both fast responce and big power. Sequential would also require you to run two turbos but might be easier to package.

For the compound setup you could run a little T70 or something up front and then a much larger turbo in the rear of the car.

With the Sequenial setup you could run a more conventional TT setup with a balancer pipe. Behind one of the turbos you would need to run a valve to block exhaust flow. THis would force all the exhaust gases through one turbo which should spool very quickly. THen onece a pre set presure is reached the vavle starts to open and both turbos provide boost.

other thing to look into are:

flat shifting (reduces the lag between shifts)
N2O - amazing at boosting turbos
Quick spool valves - Speack to Zombie on here

mdbreaux

Here is a link in this forum to my twin scroll setup - 427 ERL with GT42R's. I had it for the street with a 402ci so I just kept it when I converted it to a drag only car. I also use twin scroll on my 86 Mustang SVO with a GT35R custome built and a 2.3L 4 cylinder engine. I would not do it for a drag car, but it is well worth it for a street car. https://ls1tech.com/forums/forced-in...-ls2-pics.html

lm1clive

I was wondering about TS, and how to plumb it on my LSX. Thanks for the info I'll be buying single scroll housings now..... Interesting and great Discussion info though boys keep it up with these informative topics......

Krom

holy zombie thread batman