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I am currently running a bnr stage 4 on my FC at 340rwhp. I recently picked up a parts car with a to4s. I am pretty new to turbos so excuse me if i throw out some numbers that dont make sense. Im told its got a 1.00 hotside divided housing with a 60-1 on the front. Greddy manifold with external wastegate.
I was wondering how this would compare to the BNR on spool time and power at 12lbs on both turbos?
I think that both turbos are especially efficient at 12psi, but let me post some compressor maps to show you what you've got:
T04"S" is likely a T04E w/ 60-1 Compressor Wheel:
T04E "60"
The T04E "60" is one step up from the "57" and is the largest T04E compressor wheel available. This is also one of the more popular compressor sizes for the 13BT. The box easily clears the surge limit line. Over 3/4th's of the box is within the 70%+ efficiency plateaus - very nice. With it's top efficiency plateau over 78%+, the boost ratios are from 1.5 to 2.5, so this compressor wheel is designed to make best power from 7psi all the way up to 22psi - a very wide range of boost. With such good matching for the 13B, no wonder this compressor wheel works very well. Like the 60-1, this turbo can make 400hp at the wheels on a DynoJet.
If it's a T04B w/ 60-1 Compressor Wheel:
Turbonetics T04B 60-1
This is a very popular turbo for the 13B. Notice how the "box" lands almost in the center of the concentric rings of the efficiency plateaus. One big thing missing is the efficiency plateau ring numbers, so we have no clue how efficienct the turbo is; this basically makes the compressor map useless. The "box" is clearly away from the surge limit line. Through experience, this compressor is good for 400hp at the wheels on a DynoJet at around 18psi.
BNR Stage 4:
Here's where it gets interesting. Your BNR is a T04B CHRA already with a 60-1 Compressor and a P-Trim (74.1mm ~ 3") turbine wheel. It's exactly what the above map is... SO, compare that top map of the T04E (likely the T04S that you have) to the bottom one (the BNR Stage 4 that's on the car) and that's your result. The boxes are 30-40 lbm - air/min on the X-axis and absolute pressure in BAR on the Y-Axis. 12psi / 14.7psi = 0.816 + 1 BAR for the atmosphere we live in = 1.816 BAR Absolute. I would look at it as you're mainly changing from IWG to EWG and the Pros and Cons of that should be considered.
I believe the factory divided housing (depends on S4 or S5) is something like 0.91 Area/Radius. Lower the number = faster spool. Higher = more peak power.
My T04B w/ 54mm Compressor Housing and P-Trim Turbine wheel came with a 1.15 Area/Radius Divided Manifold to make up for the smaller compressor. At some point, you can only flow so much out of that compressor though (and mine will be just be turning hot air around 18psi).
1.816 BAR (Absolute) is your Target Y-Axis!
My advice would be to upgrade to a better IWG-75 dual port unit and maximize an internally wastegated setup with porting. I live in Kalifornistan where modifications are illegal, so I have to conceal things. If that's not the case for you and you don't mind the noise of EWG, go for it. Turbine Housings are cheap too, so swap to your heart's content until you find a balance you are looking for. Tight Mountain roads -> Faster Spooling Setup. Highway pulls -> More Peak Power.
Last edited by RGHTBrainDesign; 10-24-16 at 11:42 AM.
Actually, a T04S looks huge...so ignore the top one. Search for a compressor map and compare to the T04B 60-1 that you have on your car now. That'll answer your questions with my given explanation above.
Well I'm actually looking for a faster spool than my current bnr. It makes good power but I feel it's pretty laggy. I mostly use the car for autocross or curvy roads.
So with the to4 I have I could just swap the exhaust side housing to something like a .84 to get a quicker spool? Also is there a way to route the ewg back into the exhaust instead of into the atmosphere?
if you want 400hp and stock spool a hybrid will never get you there. you can get that with an EFR 7670. and maybe pretty close with the SXE 7670.
hell i havent had or seen a hybrid that made 350 hp with better then 4k spool.
I'm about to do that on a streetported S5 motor with 54mm Compressor, P-Trim Wheel Hybrid S5 Turbine Housing ported by G-PopShop. 350whp on e85 @ 18psi. Should have full boost by 3400 RPM and pull like a freight train to 7-7.3k.
sirlaughsalot, when you saw just swap compressor housing and wheel are you talking about on the t04s?
I really only want/need 300-340wph. im currently at 340 so i dont really want to go down but would be willing to trade for faster spool time. The BNR does not spool fast enough for me.
So my best option might be to sell the BNR setup and modify the to4s for my specific purpose? Am i understanding correctly?
sirlaughsalot, when you saw just swap compressor housing and wheel are you talking about on the t04s?
I really only want/need 300-340wph. im currently at 340 so i dont really want to go down but would be willing to trade for faster spool time. The BNR does not spool fast enough for me.
So my best option might be to sell the BNR setup and modify the to4s for my specific purpose? Am i understanding correctly?
im gonna give you the reciept for the best 330 hp setup imaginable.. are you ready for this?
I'd tend to agree with him here, except for I don't think the S5 Turbine Housing and factory S5 exhaust manifold will clear this turbo against the intake manifold...
Actually, come to think of it, how the heck is your BNR Stage 4 clearing the IM? Did you change exhaust manifolds on that thing? It's a T04B 60-1, so I wonder if that's the same OD as my compressor housing, but just less internal area with a larger compressor wheel???
I meant to just use the BNR Stage 4 and change to a 54, 56, or 57 trim compressor housing and compressor wheel. Bolt on different compressor setups and RE-TUNE!!!
If you think you can just swap turbo stuff and not retune, you're out of your damn mind...
The BNR Stage 4 uses the smaller "Hi-Fi" housing that flows 10% less than the T04S compressor housing even though they use the same 60-1 compressor wheel (should spool the same with same exhaust sides AFAIK).
That is how the BNRs clear the TII lower intake manifold.
I happen to have a couple EFR 7163 and a BNR Stage 4 right here.
The EFR 7163 is a bit smaller in width and a bit shorter from turbo housing to the point of interference on the BNR Stage 4- it would fit no problems.
The BNR Stage 4 and the T04S are basically the same turbos. Unless the T04S is the ball bearing variant- then it is journal bearing vs ball bearing.
If you have a S5 BNR it would spool better than the T04S on a T4 divided or undivided aftermarket exhaust manifold. The S5 stock exhaust housing and manifold have smaller passages for more velocity/better low rpm spool.
If you have a S4 BNR, they do spool slowly on the stock manifold and going to T04S on undivided manifold would probably be the same spool and going to a T04S on a divided manifold would probably spool better.
One easy thing that helps the BNRs spool is to put a stronger WG actuator spring on or give the one on there more preload.
Also, if you want better spool you can get a more free flowing exhaust and intake and IC, etc. Exhaust and intake has a huge effect on spool.
Thanks for all the help and not flaming me everyone I'm learning alot
i realize I will have to retune that's why I am doing my homework before I go swapping turbos around. Steve kan tuned the current setup with the bnr to 340rwhp. It's a ton of fun but I hate the lag. Like I said I have a complete setup of a parts car I bought with a to4s. Greedy manifold with external wastegate and mandrel bent 3" exhaust. However I dont really want more power than the bnr I want better spool.
The the bnr fits very closely against the intake manifold, I think it actually touches when tightened down.
Im looking to go away from stock maifold to something more modern. I'm thinking my best option would be to use the to4s platform just buy a .84 turbine housing instead of the 1.00 that's on it not to get it spoiling faster? 94 am in totally off?
Heres a pic of my engine bay I'll get one of the turbos tomorrow.
Yeah my bnr is s4. And the to4s is divided housing. Like I said 1.00ar right now I'm thinking I need .84. Wouldn't that help spool be quicker? Everything is free flowing on my current setup and I did put a stronger wastegate spring on which helped some.
The journal bearing and ball bearing T04S might fit different exhaust housings (usually the center section and hat are different on BB turbos)- so make sure you get the right exhaust housing for the turbo.
Other than that, you need a housing that is already bored for the exhaust wheel on the T04S, so you will want to pull the exhaust housing off that turbo and measure to be sure.
A divided 0.80AR T04S set-up should out spool the S4 based BNR by a little bit and is a good turbo for 340rwhp.
Is your manifold divided? Sounds like a set-up off an FD which would typically not fit an FC...
Good points Blue and thank you for the info! Undivided, ugh, guess I can't blame Kan on everything. LOL. Regardless of what you do, a divided manifold and turbine housing will yield what you're after.
Depends on how deep your pockets are.
Blue, I have a question about what you said up there, "Should spool the same with the same exhaust sides". If that's the case, then why isn't everyone running TINY turbine sides and HUGE compressor sides since we have such strong exhaust pulses that occur so frequently? Can that really be exactly the same?
*I guess I need to shop for a 9174 w/ 0.92 Divided IWG!* 3" to 5" downpipe megaphone to 4" full exhaust.
Blue, I have a question about what you said up there, "Should spool the same with the same exhaust sides". If that's the case, then why isn't everyone running TINY turbine sides and HUGE compressor sides since we have such strong exhaust pulses that occur so frequently? Can that really be exactly the same?
He's comparing slightly different housings, same wheel, same mass/inertia. The larger housing can flow a bit more up top, but at spool up RPM there is (probably) no flow impediment with the smaller housing.
Blue, I have a question about what you said up there, "Should spool the same with the same exhaust sides". If that's the case, then why isn't everyone running TINY turbine sides and HUGE compressor sides since we have such strong exhaust pulses that occur so frequently? Can that really be exactly the same?
My BNR Stage 4 is 60-1 compressor wheel and P trim exhaust wheel in a T3/T4 CHRA.
The stock S5 exhaust housing is 1.00AR. There is no tiny exhaust side on the turbo.
You can get a journal bearing T04S that will be exactly the same turbo as the BNR except for the larger 0.70 compressor housing (that the T04S gets its name from) and then the fact that what makes my BNR a BNR is the (modified) stock exhaust housing and manifold.
The exhaust wheel size and AR have the major impact on how much a turbo exhaust housing can flow. The stock S5 exhaust housing is 1.00AR.
The turbo frame size (T2, T25, T3, T4, T6) has a much more limited effect on how much the turbo exhaust housing can flow.
Why? Because even if you take a huge T6 1.00AR exhaust housing if you just cut the T6 turbo and weld on a stock ~T25 size S5 TII turbo flange where the T6 exhaust runners are the same size as the T25 flange you now have a T25 1.00AR exhaust housing.
Does it flow any less with the T25 flange? The flow choke point is closer to the exhaust wheel where the runners are even smaller...
AR is the ratio of area to radius from center so it does not change with turbo frame size.
*I guess I need to shop for a 9174 w/ 0.92 Divided IWG!* 3" to 5" downpipe megaphone to 4" full exhaust.
Now, you have another problem. The compressor surge line.
The 91mm compressor wheel cannot make boost at low engine rpm without surging no matter how much exhaust energy it has. Hell, you could spin the compressor with the engine (centrifugal supercharger) and it would still surge trying to boost below 3,500rpm on a rotary.
There is exhaust side induced lag and there is compressor side induced lag.
The EFR 9174 would be more responsive than an EFR 9180 with the same exhaust side/set-up (would get up to the same max boost it can per engine rpm), but it could not make any more boost per rpm than the 9180 can and so wouldn't make any more low end power.
Here are pics of my turbos. Bnr is on my current car, the to4s is on the parts car I picked up.
Please excuse the horrible picture qaulity
i guess what I still am wondering.... is there a way to use this turbo off my parts car To
meet t e goals I have specified I am looking to accomplish? Or am I better off selling both turbos and buying a new one that will bolt up to the greedy manifold that suits my needs?
Okay, i guess i will look into some s5 turbos to make a hybrid, from what i am understanding the s5 manifold/turbine should have quicker spool responses than the s4 counterpart? then from there i just need to pick a compressor side that will match my hp goal and still get quick response. Thanks guys for all your help!!!
do the indy versions come iron centers? i thought it was a good idea to stay away from the aluminum center section on the rotary.
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No, they are Aluminum centers on the IRL EFR 7163 and on the old Honda IRL EFR 9180 too.
Cast Iron center would be preferable, but I am hoping to find out how the rotary treats the EFR with the Aluminum center.
Borg Warner strongly recommends water cooling on the cast Iron center housings and says water cooling is mandatory on the Aluminum center housings.
This tells me the Aluminum conducts heat better and will cook the oil in the bearing into carbon and varnish too easily if it is not water cooled.
Further, Borg Warner states you must be careful to correctly torque the exhaust housing to the Aluminum center housing or the bolt will fret into the Aluminum and cause it to crack.
I have read that early on in the IRL EFR turbos were having issues with Aluminum center housings (but that is the only reliability issue I have heard of with EFRs). I am betting it was the cracking, but never read just what the issue with the Aluminum housings were.
10-23-16, 08:55 PM
