Open T3 vs Twin-Scroll T4

[JayB12]

Okay, I've been searching around a bit and I just cannot get a definite answer. I've been doing some research on my next turbo and have come to a point where I cannot decide.

I have been debating on a Ball-bearing Precision 6266/6466 in a .82a/r T3 or a similar sized Borg-Warner in Divided T4 (probably a 1.0 or 1.1 a/r housing.)

I was going to use a Borg-Warner because of the price difference to offset the cost of going to a TS T4 Manifold.

I've seen big numbers from both Turbos but, was wondering why even bother with a more expensive manifold/exhaust setup?

I've heard that the larger Twin scroll housings spool fast for the size and have less back-pressure, which would be suitable for me since I plan on using the car on the street running primarily 93 Pump.

FWIW I'm currently making 470whp with an HX35 on 93. and looking to make 550-600 on pump and higher with some type of race gas eventually.

 

[CrackedDSM]

It depends on preference. I'm a twin-scroll fanboy because I love having retarded fast spool, and great top end just like an open housing. Best of both worlds. It's expensive, but worth it. However some people don't mind the laggyness of an Open housing, and it's cheaper. So it's all in what you prefer.



The difference between an Open T3 .82 a/r 6266 and a twin-scroll equal size BW will be absolutely night and day. Just when the 6266 is starting to come into play and get into it's stride, the BW will have been at full boost and tearing ass down the street.

 

[bastarddsm]

I've had several twin scroll setups on my car, and I've never had one come even close to the hype. Sure they had great response compared to a open setup, but they don't make any power.

I had a HX35 in a true correct twin scroll setup in both a 12cm and 18cm housing I saw 30psi at 3500 and 4000 respectively, that just straight standing on the gas at 2000 in 3rd, none of the brake boosting shit. Neither setup made over 450whp no matter what I did.
Even with the 18cm housing it had over 2:1 boost to drive at 30psi and 8000RPM

I ran the HX35 open with both housings the 12 and the 18, full boost 30psi at 4500 and 5000 I never tracked or dynoed the 12cm, but the 18 made over 500 at 25psi, and plenty have seen close to 600 on the 12cm.

I've also ran an S362 in both a .7A/R T3 TS and a .84 T4 TS. They both sucked. Sure it spooled fast but it didn't make any power at all.

I have a couple SAE papers that if you read between the lines you can see that for housings sized to spool identical, the open beats out the twins scroll in flow.

When I see some twin scroll 35R's, 6262, HX40, or S362 making 700-800hp and making 30 by 4500 I'll believe it's magic. So far all I'm seeing is guys getting a little better spool than my HE351 makes, and making 100whp less.

I think on big turbos like 42R sized, T/S can be a benefit when you have exhaust flow to spare, but on the 35r Hx40 sized stuff nope.

 

[Steve93Talon]

I've also ran an S362 in both a .7A/R T3 TS and a .84 T4 TS. They both sucked. Sure it spooled fast but it didn't make any power at all.

I have a couple SAE papers that if you read between the lines you can see that for housings sized to spool identical, the open beats out the twins scroll in flow.

When I see some twin scroll 35R's, 6262, HX40, or S362 making 700-800hp and making 30 by 4500 I'll believe it's magic. So far all I'm seeing is guys getting a little better spool than my HE351 makes, and making 100whp less.

We ran the S362 in the .85 TS T3 housing and made 708 whp with full boost under 5k. This was on E70 with BC280s, there was probably another 50+ whp in it.

 

[JayB12]

I was under the impression that twin scroll housings worked better for pump gas. Not sure why, I was guessing back pressure and lower EGTs. I'm not really too worried about spool.

I guess what I'm asking is if a 300sx fmw going to be the better turbo based on a 1.10 a/r housing vs a 6266 in an open .82?

 

[Steve93Talon]

Twin scroll works better on pump gas because it prevents reversion of the exhaust gas. This can help prevent knock and also allow more aggressive tuning. You're also comparing two different turbos so it's hard to say which would be "better" for your application. The 6266 is also available in a divided T4 housing, so if your intent is to try going twin scroll, don't let the turbo choice be a factor.

 

[bastarddsm]

What manifold is that s362 on? Keep in mind that the reversion is only helped if the cam timing is just right.

 

[CrackedDSM]

Personally JayB12, I'd take advice from someone whose actually made 700+awhp from a TS setup. They can be super pricy though.

 

[bastarddsm]

The powerband on that 362 sucks. That's defiantly not full boost by 5000, and it falls off at high rpm. Turn it up and it will be worse. A 6266 in a .82 will do better than that.

 

[lasthope05]

I'd listen to Steve. He's been playing with/knows people that have been playing with BW turbos for years before it got big. GV auto salon, an old local dsm shop were big on BW turbos back then.

 

[CrackedDSM]

I'd listen to Steve. He's been playing with/knows people that have been playing with BW turbos for years before it got big. GV auto salon, an old local dsm shop were big on BW turbos back then.

Agreed.

 

[Steve93Talon]

The manifold was the first TS T3 manifold by JMF, which had a single gate with a crossover tube. With dual gates and truly divided passages, spool might have improved slightly. Logs are on my old laptop, but full boost in 3rd on the street was a bit sooner than the dyno indicates. 30 psi was around 4700 if I remember correctly. Here's another friend's S362 setup with the TS .76 hotside. 30psi under 4500 and 60 lb/min up top. Also, the word you're looking for is "definitely".

 

[bastarddsm]

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Makes 500ft lbs 400rpms later, and look at that top end. Single scroll. I don't think 60lbs/min out of a s362 is anything to write home about. I'm sure if I worked at spool my car would make 30psi by 4500, and it still flows for than 60lbs/min, and it's a cheap pos setup. Trust me I really want this t/s stuff to work like the magic it's promised to be but I still havnt seen one that was enough better to even count. It's a big expense for the manifold and extra gate and I feel that lots of private guys are very disappointed with there setups. I'm pretty sure I saw jmf saying t/a is a waist of time.[DOUBLEPOST=1417145400][/DOUBLEPOST]http://www.dsmtuners.com/threads/bw-s362-log.330712/

There's s362 in a bep .7 same boost response and the car traps 137 breaking up, that defiantly mid 600s.

 

[JayB12]

Okay, maybe I need to ask a different question..

I just want to be clear so I understand. What is really better T3 or T4 TS.

For simplicity sake, what differences would be seen comparing the same turbo in the .82a/r T3 to one in a 1.0 or similar T4 Twin-Scroll Hotside?

 

[ceedawg]

Okay, maybe I need to ask a different question..

I just want to be clear so I understand. What is really better T3 or T4 TS.

For simplicity sake, what differences would be seen comparing the same turbo in the .82a/r T3 to one in a 1.0 or similar T4 Twin-Scroll Hotside?

There is great info on the difference between T3 and T4 TS housings in the evoltionm.net forums.

I know Steve got great results with his T3 TS setup however alot of the Evo guys use T4 TS setups with 1.0 A/R housings and bigger. You will also find many comparisons open vs TS mani setups with different housings.

Checkout #82 in this thread. When you get a chance read the whole entire thread

http://www.evolutionm.net/forums/ev...monster-spool-fact-fiction-6.html#post8265015

 

[bastarddsm]

The 1.0 T4 T/S is probably going to spool faster, and not make as much power.

 

[DSM Chase]

Trying out a 4094R with .85 twin scroll next year.

 

[bastarddsm]

That's probably going to be on the small side to get maximum power out of it. Twicks69 on here was on a 4088 in a .96 divided with a 2.3 and a dnp header, and I think it was about the right size, but the dnp doesn't keep the wastegate runners seperated so it behaves more like an open manifold in my experience.

An s366 is close in wheel size to a 4094, and that is usually run in a 1.1 or bigger divided housing.

 

[TalonSpeed]

Do you really need turbos that big to make 550-600hp? That is HX40 in bep 55 or 70 AR housing numbers.

 

[bastarddsm]

. So I was just reading an SAE paper from FOMOCO, about the effects of the uneven firing order of a v8 on blowdown interference. The 180* blowdown interference we expereince is non existant by the time any decent sized turbo starts making boost. The time it takes for the pulse to travel, the exhaust valve is allready closed. Even on a log manifold.

As suspected, some armchair engineer took a tiny bit of information out of context and blew it up as the gospel.

Then the johnny come lately shops say you have to have this to make power, and everyone buys it, and is dissapointed.

Funny though, in the ford paper, they make no mention of quick spool and massive flow. It seems as if the pumping loss stays the same when they goto twin scroll.....

 

[Seamus]

You want to see a wealth of info on the power potential vs. Spool look at some rotary dyno sheets. Divided setups have been common on rotary street cars for 20 plus years and you can see the equivilent divided housingss always are down at least 5 percent power often more with no other changes. 5 percent can be a lot on a powerful car. The ex garret engineer in friends with had always told me its worse than the difference between tangential and non tangential. This is the sane guy who 15 years ago turned me onto the schwitzer line of turbos that became Borg warners s300's when they bought them out.

 

[rvaughn]

Fwiw: Having gone TS on a smaller charger (hta3076 w/ 1.04 ar) on my current setup, there is no way in hell I would do it the same again. Old school 3052 / 3065s are pulling down similar results to my setup in spool with better power. In talking to many gurus it has become apparent I was sold on a tech that isn't worth the hassle. Imo I would get a single scroll setup and spend my money elsewhere.

 

[bastarddsm]

Man it feels good to be right. I love all the guys on here that can't even get a 16g to run good pushing the t/s.

 

[Seamus]

I've had dived setups in the past. The term twin scroll was hardly even used till they recently got popular. I've had just small turbo 100% street beaters the past 7 or 8 years. At the end of the day in drag racing or dyno racing divided setups are never going to look attractive because they are going to flow less and cost more. And with the advancements in automatics and ecu launch strategy its even less important.

 

[ceedawg]

Alot of the EVO guys swear by the TS setups. Alot of them are using T4 exhaust housings with t4 TS manis with 1.0 A/R's and bigger. I have a T4 TS mani (1.5inch runners) and .96 A/R housing. Using a BW 88-75(BW S363) turbo. I hope to get this car running soon so that i can see what the EVO guys are talking about. Car will be sent to ATL and tuned by Keltalon so hopefully we will see what this setup can do.