Turbine housing, divided or single?

[Grant Monkhouse]

As the title, who is running what? The benefits of each?

From being at AET turbos on Friday and discussing my new turbo and what works best for my application, drag racing, divided is better for street use but for full throttle in drag racing a single entry is better for higher revs as you have higher exhaust flow giving better top end.

Now the owner of AET was saying that most of the guys using t51 kais and t70s run a single housing? And one of the main reasons people go for divided is because most people use garret and they only come with divided due to their origins of being truck turbos.

[Turblown]

I agree with most of the above. On one vehicle I tested we had a divided turbo manifold, swapped from a .96 open volute to a 1.0 divided and picked up 300rpms spool.

Higher velocities tend to lead to faster spool( keep each rotor completely divided).

I find that having the least amount of bends in a turbo manifold, a big exhaust, big ignition, and a good tune will lead to stupid fast spool on a any size rotary with any turbo under 66mm inducer if with an open entry turbine housing. The car below used to spool 1000 rpms faster on the stock ports. If you watch the video it spools pretty fast as is for a undivided turbo manifold with a 1.15 turbine housing.

If you are driving on the street tires is no sense in going any bigger turbo, you will never hook unless you are running drag radials anything past 20psi on the turbos less than 66mm...

For example a 61mm turbo;

http://www.youtube.com/watch?v=hHhyIK_uCtc

leads to spinning the new 285s @ 80+mph...

[Grant Monkhouse]

I agree with most of the above. On one vehicle I tested we had a divided turbo manifold, swapped from a .96 open volute to a 1.0 divided and picked up 300rpms spool.
 
Higher velocities tend to lead to faster spool( keep each rotor completely divided).
 
I find that having the least amount of bends in a turbo manifold, a big exhaust, big ignition, and a good tune will lead to stupid fast spool on a any size rotary with any turbo under 66mm inducer if with an open entry turbine housing. The car below used to spool 1000 rpms faster on the stock ports. If you watch the video it spools pretty fast as is for a undivided turbo manifold with a 1.15 turbine housing.
 
If you are driving on the street tires is no sense in going any bigger turbo, you will never hook unless you are running drag radials anything past 20psi on the turbos less than 66mm...
 
For example a 61mm turbo;
 
http://www.youtube.com/watch?v=hHhyIK_uCtc
 
leads to spinning the new 285s @ 80+mph...

i cant believe this site just wiped a whole reply that i have just spent the last 5 minutes writing!!!!
 
anyway start again,
 
i have got an s300sx3 Borgwarner turbo, 66mm inducer 73mm exducer, rated at 320-800 HP, so 640 HP max on a rotary? you can find all of the other details at www.borgwarnerboosted.com
 
let me know what you think turblown, i am going to be using this on a bridgeported 13B, hopefully achieve 450HP
 
Project Z is running 2 of the BW400 series of turbo and is aiming for 6\'s to hopefully match its sister car in the states.

[Grant Monkhouse]

I agree with most of the above. On one vehicle I tested we had a divided turbo manifold, swapped from a .96 open volute to a 1.0 divided and picked up 300rpms spool.
 
Higher velocities tend to lead to faster spool( keep each rotor completely divided).
 
I find that having the least amount of bends in a turbo manifold, a big exhaust, big ignition, and a good tune will lead to stupid fast spool on a any size rotary with any turbo under 66mm inducer if with an open entry turbine housing. The car below used to spool 1000 rpms faster on the stock ports. If you watch the video it spools pretty fast as is for a undivided turbo manifold with a 1.15 turbine housing.
 
If you are driving on the street tires is no sense in going any bigger turbo, you will never hook unless you are running drag radials anything past 20psi on the turbos less than 66mm...
 
For example a 61mm turbo;
 
http://www.youtube.com/watch?v=hHhyIK_uCtc
 
leads to spinning the new 285s @ 80+mph...

 
Am i right in saying that car peaked at 491 HP?
 
was that at the wheels?

[Turblown]

I don\'t know the BW series that well. Sounds like it should be able to do 450rwhp with those compressor specs. You just want to run a bigger turbine a/r with the bridge to let it breath where it wants to make power. Why are you running a bridge for such low power levels anyhow? When you say 450rwhp what kind of fuel consumption is that? To me this is the easiest way to compare power levels, as dynos read all over the place. That dyno is the only one in town I trust, and yes its 491rwhp, 22 psi streetport, TD61( gt35R P trim), dual walbros, 550/2200cc @ 77 percent.

[Grant Monkhouse]

I don\'t know the BW series that well. Sounds like it should be able to do 450rwhp with those compressor specs. You just want to run a bigger turbine a/r with the bridge to let it breath where it wants to make power. Why are you running a bridge for such low power levels anyhow? When you say 450rwhp what kind of fuel consumption is that? To me this is the easiest way to compare power levels, as dynos read all over the place. That dyno is the only one in town I trust, and yes its 491rwhp, 22 psi streetport, TD61( gt35R P trim), dual walbros, 550/2200cc @ 77 percent.

i say 450 hp because thats what i have been told i will acheive on 14 pounds of boost, we could make up to the region of 600HP but want the engine to last a long time, what would you rekon would be more realistic on a bridge?
 
i am currently contemplating on a haltech ecu rather than the apexi because so much more can be done with the ecu, anti-lag, launch control etc, but all comes down to expense at the end of the day.
 
what do you mean fuel consumption? going to be running 2x 550\'s 2x 1680\'s, bosch 044 fuel pump, aeromtive fpr

[PGiljevic]

Any single turbo at less than 20psi is just pointless, use the turbo the way god intended and you don\'t need to .... up your power band by bridging your engine :Thumbs-up

1.5 bar minimum boost
1.7 bar nice power setting
2.0 bar for real amazing street car
2.5 bar for "I can destroy any supercar on the roads"

1.0 bar is just to low a boost level :Hammer
Divided housings ALWAYS will make more power than a non divided type, so you got some bum advise from your shop you spoke too about it too

[PGiljevic]

i say 450 hp because thats what i have been told i will acheive on 14 pounds of boost, we could make up to the region of 600HP but want the engine to last a long time, what would you rekon would be more realistic on a bridge?
 
i am currently contemplating on a haltech ecu rather than the apexi because so much more can be done with the ecu, anti-lag, launch control etc, but all comes down to expense at the end of the day.
 
what do you mean fuel consumption? going to be running 2x 550\'s 2x 1680\'s, bosch 044 fuel pump, aeromtive fpr

If you want your engine to last a long time then you will need to water inject it.

You will run less peak pressure stress at 700bhp water injected than what you will on 450bhp without it peak pressure and combustion temperature = death on rotary engine seals, long term.

[Grant Monkhouse]

Any single turbo at less than 20psi is just pointless, use the turbo the way god intended and you don\'t need to .... up your power band by bridging your engine :Thumbs-up

1.5 bar minimum boost
1.7 bar nice power setting
2.0 bar for real amazing street car
2.5 bar for "I can destroy any supercar on the roads"

1.0 bar is just to low a boost level :Hammer
Divided housings ALWAYS will make more power than a non divided type, so you got some bum advise from your shop you spoke too about it too

2.5 bar! Now that is insane. Is that what you run to on your car?

[Grant Monkhouse]

After looking on the Internet last night for differences between single scroll and twin scroll. The info that came up was that twin scroll spools earlier but not by a huge amount.

With a twin scroll on a rotary Is it far superior due to the fact that there is no pause in the exhaust pulse driving the turbine? Essentially per rotor you have three pulses straight after each other, per rotor and then repeats.

Does keeping the exhaust pulses divided at high rpms not have a restriction of the exhaust gas flow due to there being less area for the gases to go through the turbo?

From my researching last night, a single scroll creates mire back pressure, preturbo? But does this only have an effect at low rpm? As at higher rpms there is less time for the pulse to return to the exhaust port?

A it like the overlap on a bridge or peripheral port? Where the overlap creates the brap and pushes some exhaust around to the intake? But when on the throttle, high rpm, it doesn\'t haven\'t the chance.

[suba]

2.5 bar! Now that is insane. Is that what you run to on your car?

I\'s like to know more about this also - most UK rotaries seem to call it quits at a bar or so of boost to be reliable, whereas over in the US they go way higher on the boost level!

Are the higher boost levels only for WI?

[Grant Monkhouse]

Rice is using WI and has spent a lot of time developing his car with it and uses commonly used parts by the rotary community. HKS twin power etc.
 
but i didnt know he was running that amount of boost, thats just crazy.

[Grant Monkhouse]

I\'s like to know more about this also - most UK rotaries seem to call it quits at a bar or so of boost to be reliable, whereas over in the US they go way higher on the boost level!
 
Are the higher boost levels only for WI?

i think a lot of rotary owners leave it at 1 bar due to the fact that you dont have to use a lot of boost to gain HP with a big turbo, and with increased boost comes increased intake temperatures, one thing that happens when running a lot of boost on the standard twins is the heat goes through the roof, before i changed my FD to a large front mount IC the intake temps were in the region of 55*C! which was rediculous, put the front mount on ond they rarely go above thirty sat in traffic. cruising is below 20*C, and im running at .95 bar for the last couple of years with no problems.
 
so if you turn up the boost with a big turbo and want to get the intake temps down to what they were then WI is used to do that.
 
well that my understanding of things anyway, im sure some people will have better explanations of why they dont use more than 1 bar boost and the explanation behind WI

[suba]

I dont want to drag this off topic for the original poster, but I am very interested in why UK rotaries dont ever seem to run that much boost.  On a GT30 or bigger turbo I can\'t imagine that intake temps are going to be much of a factor, as the turbo will still be efficient at 2 bar +, and when using a decent front mount I would have thought intake temps would be the same anyway.

I can see how there would be more heat generated by the turbo(s) themselves - but I doubt much of this would be transferred to the housings and rotors.  I would have thought the reasons would be more related to how much the rotor tips and seals can reliably take....

[Grant Monkhouse]

I startedthe thread so not too bothered what direction it goes in as long as there is useful information given.

I think the amount of boost people comes down the fact that rotaries have bad rep for blowing up so people want the engines to last without worrying about throwing a tip, but if people don\'t try then we will always lag behind the Aussies and Americans when it comes to rotaries achieving huge power.