[sdstatestud88]

From another thread...This is about TWINS...not any SINGLE talk...There are threads for that

GT28RS (i.e. disco potato) or GT2871R? What do you guys think? Let's discuss some options...

Here's the current idea to get this done quick and on a budget (not me doing it by the way, someone else):

1) Twin Log style manifolds (much easier and cost effective than tubular and will work very well for up to 800hp)
2) Twin GT28RS or Twin GT2871R (both are dual ball bearing)??
3) Preserve water/oil lines. Oil lines will have restrictors built in as ball bearing are rated up to 40psi oil pressure, N54 runs twice that under any load
4) T25??
5) Which ar would work best? .63?
6) Oil drains must remain gravity based
7) O2 sensor bank situation remains just like stock, with the sensors in the downpipes instead of hot manifolds

I'm leaning heavily towards the twin disco potato setup on this car (GT28RS) for a neighbourhood of 600-650whp...Twin GT2871R would be good to 800wheel.

Yes, there are always other options (single turbo single/twin scroll), this thread isn't about that. Nor is it about a pic from cp-E of their work that they never finished. Would love to get some info what you guys think based on displacement of this motor how this particular setup would perform and what the ideal setup in terms of housing, ar would be in your opinion. Also, how do you think it would spool and how early each of them would hit full torque.

[saxon]

honestly if your taking the manifolds off and making new manifolds, it would be cheaper and easier to just make a single (and most likely spool faster, and create as much if not more power)

if they could bolt up to the stock manifolds then it would be a great "cheaper" option but since new manifolds would have to be made I dont think its a viable option

[rader1]

Originally Posted by saxon

honestly if your taking the manifolds off and making new manifolds, it would be cheaper and easier to just make a single (and most likely spool faster, and create as much if not more power)

if they could bolt up to the stock manifolds then it would be a great "cheaper" option but since new manifolds would have to be made I dont think its a viable option

I really like the idea of true upgraded twins, assuming there is room in the engine bay. A pair of BW EFR 6262s would be INSANE. Not only that, but it would preserve O2 sensor locations.

[Jake@MOTIV]

The best way to decide what setup you want to go with is to figure out how much power you want to make - and be realistic with it. Turbos work best in their efficient "island". Once you determine what you want you can pick what "tools" you will use to achieve that goal.

Another factor is to think about spool. I understand this thread is about twins and not singles but for the most part - upgrading an inline 6 is typically rather efficient with a twin scroll single. Now the reason I bring this up is because the gt28rs and 2871 are great upgrades for the s4 as it is a v6 motor. It is a bit more complicated to run an efficient single on it.

When you think spool - 6 cylinders - high(ish) compression motor - 3.0L will get a decent small A/R t4 or large t3 (twin scroll or standard scroll) spooling in a decent range. With twin 28rs (smaller than the 2871 so it will spool a LITTLE earlier) you have to remember that you will only have 1.5L and 3 cylinders of exhaust gas to spool them up. On my 2.3L 4cylinder I had a 28rs, a 3076, and a 35r throughout the years. The 28rs ispooled in the midle-ish 2k rpms. With almost a liter less and 1 less cylinder I can estimate it will spool a bit later (obviously not too much). I don't follow the s4 v6 motors much so I am not sure where they make full boost at with these setups.

Long story short - figure out your HP goals, figure out approximately where you would like to have full boost by, and choose your turbo. If you want 600whp with a fast spool, a large A/R turbine housing with twin scroll in the t3 flanged family may be a great choice. Going twin t25 flanged turbos is just as much work as going single t3 or t4. You will need two manifolds and two turbos and two downpipes. That can get just as expensive if not more expensive than going single. I am all for either - I will go custom with mine as I have been doing this stuff for years - I just haven't decided exactly what I will use for hardware in a year or so when I have the time and motivation to start the project.

[BQTuning]

Just to let everyone know, so later its not said that the idea was hijacked, there is goign to be a TWIN TURBO upgrade for the N54 and yes the turbo on the table are prefixed with GT accompanied by a new turbo manifold.

Thats all I can say at this time, but yes, the idea by the OP and the original person, dzenno - that brought it to surface is already being planned and to be executed soon.

[jippii ensio]

Originally Posted by sdstatestud88

From another thread...This is about TWINS...not any SINGLE talk...There are threads for that

GT28RS (i.e. disco potato) or GT2871R? What do you guys think? Let's discuss some options...

Here's the current idea to get this done quick and on a budget (not me doing it by the way, someone else):

1) Twin Log style manifolds (much easier and cost effective than tubular and will work very well for up to 800hp)
2) Twin GT28RS or Twin GT2871R (both are dual ball bearing)??
3) Preserve water/oil lines. Oil lines will have restrictors built in as ball bearing are rated up to 40psi oil pressure, N54 runs twice that under any load
4) T25??
5) Which ar would work best? .63?
6) Oil drains must remain gravity based
7) O2 sensor bank situation remains just like stock, with the sensors in the downpipes instead of hot manifolds

I'm leaning heavily towards the twin disco potato setup on this car (GT28RS) for a neighbourhood of 600-650whp...Twin GT2871R would be good to 800wheel.

Yes, there are always other options (single turbo single/twin scroll), this thread isn't about that. Nor is it about a pic from cp-E of their work that they never finished. Would love to get some info what you guys think based on displacement of this motor how this particular setup would perform and what the ideal setup in terms of housing, ar would be in your opinion. Also, how do you think it would spool and how early each of them would hit full torque.

Just out of curiosity, are you the person planning to do this since you copied Dzenno's post word for word?

[cstavaru]

I am a total fan of a twin-turbo upgrade and I really think that a single turbo upgrade takes most of the N54 qualities (but adds power).

If you can find the space to fit the two turbos into the engine bay (and have the money), I would say do it, and go for the smaller AR, in order to keep the engine torque characteristics.

I made a software program with which I can do calculations on theoretical maximum power obtainable from a turbo setup, given the turbine efficiency maps:

http://www.e90post.com/forums/showthread.php?t=698432

So if you have a target power in mind, you can choose the turbos based on that power. I know that GT28 are the smallest Garrett turbos with ball-bearing shafts but maybe even smaller turbos may be sufficient.

If you are really serious about this, I can run some numbers for your turbo setup (it does take like an hour to input the data though )

[jippii ensio]

Originally Posted by FlyLow335i

The best way to decide what setup you want to go with is to figure out how much power you want to make - and be realistic with it. Turbos work best in their efficient "island". Once you determine what you want you can pick what "tools" you will use to achieve that goal.

Another factor is to think about spool. I understand this thread is about twins and not singles but for the most part - upgrading an inline 6 is typically rather efficient with a twin scroll single. Now the reason I bring this up is because the gt28rs and 2871 are great upgrades for the s4 as it is a v6 motor. It is a bit more complicated to run an efficient single on it.

When you think spool - 6 cylinders - high(ish) compression motor - 3.0L will get a decent small A/R t4 or large t3 (twin scroll or standard scroll) spooling in a decent range. With twin 28rs (smaller than the 2871 so it will spool a LITTLE earlier) you have to remember that you will only have 1.5L and 3 cylinders of exhaust gas to spool them up. On my 2.3L 4cylinder I had a 28rs, a 3076, and a 35r throughout the years. The 28rs ispooled in the midle-ish 2k rpms. With almost a liter less and 1 less cylinder I can estimate it will spool a bit later (obviously not too much). I don't follow the s4 v6 motors much so I am not sure where they make full boost at with these setups.

Long story short - figure out your HP goals, figure out approximately where you would like to have full boost by, and choose your turbo. If you want 600whp with a fast spool, a large A/R turbine housing with twin scroll in the t3 flanged family may be a great choice. Going twin t25 flanged turbos is just as much work as going single t3 or t4. You will need two manifolds and two turbos and two downpipes. That can get just as expensive if not more expensive than going single. I am all for either - I will go custom with mine as I have been doing this stuff for years - I just haven't decided exactly what I will use for hardware in a year or so when I have the time and motivation to start the project.

The pulses of 6-cylinder drive twin scroll nively due to the angles in between pulses being quite optimal. For the same exact reason 6-cyl engine drives twins nicely as well.

[jippii ensio]

OP, just try them both and report back the difference

[jippii ensio]

Originally Posted by BuraQ

Just to let everyone know, so later its not said that the idea was hijacked, there is goign to be a TWIN TURBO upgrade for the N54 and yes the turbo on the table are prefixed with GT accompanied by a new turbo manifold.

Thats all I can say at this time, but yes, the idea by the OP and the original person, dzenno - that brought it to surface is already being planned and to be executed soon.

Why can't you say more?

I've been reading about the plan, and there is a plan to execute it, but we do not really know if the plan will be executed until it has been executed.

[sdstatestud88]

Originally Posted by jippii ensio

Just out of curiosity, are you the person planning to do this since you copied Dzenno's post word for word?

No I just brought it over to this to get additional input from people. I said I was not the one who thought of this

[plague]

im subscribed to anything turbo upgrade N54 related. some big twins would be cool to see.. like they do on the gtr when upgrading turbos, bigger twins as opposed to switching single. im cool with either, i just want to see 650-700 whp consistent on pump gas and methanol. imo its not worth going to a big single to make only 550whp when rb's are making 500.. shiv's car is making 644 SO FAR, but no reports if customers cars making that yet so.. just waiting to see things develop...

[sdstatestud88]

Originally Posted by jippii ensio

OP, just try them both and report back the difference

Paypal me a few grand and ill test them haha

[The Morkinator]

Originally Posted by saxon

honestly if your taking the manifolds off and making new manifolds, it would be cheaper and easier to just make a single (and most likely spool faster, and create as much if not more power)

if they could bolt up to the stock manifolds then it would be a great "cheaper" option but since new manifolds would have to be made I dont think its a viable option

It's cheaper to make two cast Iron manifolds, by a lot.

[TwinTurboXI]

Originally Posted by BuraQ

Just to let everyone know, so later its not said that the idea was hijacked, there is goign to be a TWIN TURBO upgrade for the N54 and yes the turbo on the table are prefixed with GT accompanied by a new turbo manifold.

Thats all I can say at this time, but yes, the idea by the OP and the original person, dzenno - that brought it to surface is already being planned and to be executed soon.

That would be great if it ever actually happened. Sadly, many have attempted various turbo upgrades that never really got anywhere.

[sdstatestud88]

Originally Posted by The Morkinator

It's cheaper to make two cast Iron manifolds, by a lot.

Agreed

[vereak82]

500-550whp TT n54 with 500+ft lbs or torque would def net some nice 60-130 times as well as 1/4 et's man i need more power like yesterday!!!!

[sdstatestud88]

And for all of us with Auto transmissions...You gotta pay to play....Hopefully someone besides level 10 can do an upgrade of some sort

[cityazndan]

IPT is better. Level10 has some horrid customer reviews (Coming from a Suby AT)

[benzy89]

Originally Posted by cstavaru

So if you have a target power in mind, you can choose the turbos based on that power. I know that GT28 are the smallest Garrett turbos with ball-bearing shafts but maybe even smaller turbos may be sufficient.

If you are really serious about this, I can run some numbers for your turbo setup (it does take like an hour to input the data though )

Since turbo size is an issue, and the RB/ASR turbos are already seeing 400-450 WHP (no meth), what would it take to get a 500 WHP N54 upgrade? Feel like the aftermarket turbos for that power range would be a lot more feasible then a 600+ WHP TT upgrade (at that point you're better off buying the single-turbo & turning your car into a Dyno/Drag Strip Toy).

Originally Posted by sdstatestud88

And for all of us with Auto transmissions...You gotta pay to play....Hopefully someone besides level 10 can do an upgrade of some sort

Does anybody know if the 1M transmission is A) for sale or B) just an upgraded 135/335 MT?

[Fundahl]

If you wanna get really good spool, try to fit a medium-small frame Borg Warner EFR twin-scroll with a properly build manifold. (right runner lengths and proper cylinders per scroll)

With the EFR you can even eliminate the Diverter/Bypass/Blow-off valves. Boost recovery post shift would be awesome!

[MDORPHN]

Originally Posted by Fundahl

If you wanna get really good spool, try to fit a medium-small frame Borg Warner EFR twin-scroll with a properly build manifold. (right runner lengths and proper cylinders per scroll)

With the EFR you can even eliminate the Diverter/Bypass/Blow-off valves. Boost recovery post shift would be awesome!

But aren't they unobtanium?

Neil