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I was just wondering if anyone running this turbo was noticing any compressor surge at low RPM's. I was plotting my specs on some efficiency maps and it looks like alot of T3/T4's are way over the surge limit. My calculations could be off, but I've been checking my work and I don't see any errors. It looks like the best T3/T4 is the T04E 46 or 54 trim. All the maps for the T04B housings were WAY over the surge limit. I was plotting maps at 7, 9, 11, and 15 psi.
The T3 60 and super 60 look good for all of these different pressures, though. (T3-60 looked so/so at 15psi but super 60 still looked good) I am about to buy a turbo, so I was hoping someone with some 'real-world' experience could share some insight.

 
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talk about an in depth question there, i have the t3t04e 54 trim, alot of people have the super 60 on here but i dont know about anyone with a 46 trim, wouldnt the 46 spool quicker, must say i really dont know how to answer what u asked

 
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Well, from what I've been seeing, that turbo on our engines would probably stumble until 3500 to 4000 rpms. With the curve of it's compressor map that would probably happen at any psi (it might be slightly better at real low pressures). I plotted from 2000 to redline and almost half of the points were over the surge line. (this was one of the better T3/T4's too) On a high note the top end did land right in the 'sweet' spot. Who knows how accurate my plottings have been, though. I'm just worried because alot of compressor surge could take out your thrust bearing.

 
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But EVERYBODY runs these turbos, so I'm sure if that was a real concern people would stop using them.

 
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I'm running a t3/t04b, no complaints....still tuning though, only at 4 lbs of boost atm and it pulls hard....I would probably go with a super 60 though if I had the choice just b/c of slightly faster spool...
Compressor surge is gonna vary with the kind of bov you get....I have the Greddy Type S and I have been adjusting it a lot....under full boost there is no compressor surge but under smaller loads sometimes it does surge a bit...

Brandon

 
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Get an electronic boost controller, and properly tune your wastgate settings so you eliminate surge (vitrually). My T04B/T3-60 is fine.

 
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I thought I read somewhere that recirculating your BOV helped also.

 
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Madwheel, weren't you running a super 60 compressor before? Which do you like better? Does it feel like your new turbo performs less? I only ask how it "feels" because I'm sure you don't have dyno sheets. It just seems to me that the Super 60 would outperform the hybrids on our cars.

 
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I had the base T3, never had the supper 60. The T3 felt nicer in mid rpms but couldn't handle power near redline as well. Thing is, for low boost a T3 super 60 would be better. But as the boost climbs, the potential of the hybrid is beyond what my engine would ever handle.

Once I get my built motor from DH, I'll get it all tuned to have just over 300Whp. Im looking for 12s on street tires with a daily driven setup. My Blitz EBC came in today, I'll be installing it soon.

 
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Here ya go, check em against your numbers. I caluclated before and calculated again.

Based on Turbonetics Compressor Maps:

@2000rpm
T3 "40" - Surge at over 9psi
T3 "45" - Surge at over 8psi
T3 "50" - Surge at over 8psi
T3 "60" - Surge at over 6psi
T3 "Super 60" - Surge at over 6psi
T04B Std - Surge at over 3psi
T04B V1/V2 - Surge at over 3psi
T04B H3 - Surge at over 3psi
T04E "40" - Surge at over 3psi
T04E "46" - Surge at over 3psi
T04E "50" - Surge at over 4psi
T04E "54" - Surge at over 4psi
T04E "57" - Surge at over 4psi
T04E "60" - Surge at over 3psi

@5000rpm
T3 "40" - Surge at over 22psi
T3 "45" - Surge at over 23psi
T3 "50" - Surge at over 18psi
T3 "60" - Surge at over 16psi
T3 "Super 60" - Surge at over 16psi
T04B Std - Surge at over 11psi
T04B V1/V2 - Surge at over 8psi
T04B H3 - Surge at over 8psi
T04E "40" - Surge at over 11psi
T04E "46" - Surge at over 11psi
T04E "50" - Surge at over 10psi
T04E "54" - Surge at over 9psi
T04E "57" - Surge at over 10psi
T04E "60" - Surge at over 10psi

@7000rpm
T3 "40" - Surge >30psi
T3 "45" - Surge at over 31psi
T3 "50" - Surge at over 27psi
T3 "60" - Surge at over 21psi
T3 "Super 60" - Surge at over 19psi
T04B Std - Surge at over 17psi
T04B V1/V2 - Surge at over 13psi
T04B H3 - Surge at over 10psi
T04E "40" - Surge at over 16psi
T04E "46" - Surge at over 17psi
T04E "50" - Surge at over 14psi
T04E "54" - Surge at over 14psi
T04E "57" - Surge at over 14-15psi
T04E "60" - Surge at over 13psi

Obviously, this is for our engine only, or any engine with the same displacement.

You have to account for a couple things though. The fact that you can reach some of these pressures at the given rpms. You also have to account for the fact that engines are not volumetrically efficient. So, if any of you say, I've hit that pressure before at that RPM with no problem, nobody is going to doubt you. Because in reality, those surge limits are pushed up. There are a ton of factors.

EDIT: Note, this says nothing to a turbo's efficiency really. But I can always list efficiencies at Xpsi if anyone is interested.

 
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Nice job Alex

 
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lol... that really reads: "You need a life Alex". I know

 
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Theoretical Efficiencies (70-75%) for the D17:

Using 4 and 7psi because they are common, here they are with the common trims.

T3 Super 60:
4psi - ~70% Efficient @ 5000rpm, ~75%+ Efficient @ 7000rpm (or redline)
7psi - ~70% Efficient @ 4500rpm, ~75%+ Efficient @ 6000rpm
Optimally Efficient: 12psi@~8500rpm

T3 "60":
4psi - ~70% Efficient @ 3500, ~75% Efficient @ 5500rpm
7psi - ~70% Efficient @ 3000-3500rpm, ~75%+ Efficient @ 5000rpm
Optimally Efficient: 12psi@~8500rpm

T3 "50":
4psi - ~70% Efficient @ 3500rpm, ~75%+ Efficient @ 7000rpm (doesn't reach 75%)
7psi - ~70% Efficient @ 3200rpm, ~75%+ Efficient @ ~4700rpm
Optimally Efficient: 13-14psi@~7000rpm

T04B S-3:
4psi - ~70% Efficient @ 5000rpm, ~75%+ Efficient @ 6500rpm
7psi - ~70% Efficient @ 6000rpm, ~75%+ Efficient @ 7000rpm (or redline)
Optimally Efficient: 11psi@~8000rpm

T04E "40":
4psi - ~70% Efficient @ 5500rpm, ~75%+ Efficient @ Doesn't Reach
7psi - ~70% Efficient @ 5000rpm, ~75%+ Efficient @ 7000rpm (actually 73%)
Optimally Efficient: 18psi@~10,500rpm

T04E "46":
4psi - ~70% Efficient @ 3500prm, ~75%+ Efficient @ Doesn't Reach
7psi - ~70% Efficient @ 3600rpm, ~75%+ Efficient @ 7000rpm (76%)
Optimally Efficient: 17psi@~10,500rpm

Garrett T25 0.80A/R 60 Trim
4psi - ~70% Efficient @ 3500rpm, ~75%+ Efficient @ 5000rpm (72%)
7psi - ~70% Efficient @ 4500rpm, ~75%+ Efficient @ 6500rpm
Optimally Efficient: 11psi@~8500rpm

:::And just for fun!!!::::

T76 on a D17:
4psi - ~70% Efficient @ Above the surge limit, ~75%+ Efficient @ 10,500rpm
7psi - ~70% Efficient @ Above the surge limit, ~75%+ Efficient @ 12,500rpm
Optimally Efficient: 15psi@23,000rpm


None of the T04's account for hybrid combinations, so I'd expect the numbers to be a good amount more efficient with properly matched exhaust housings and wheels.

 
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That is very true about the turbine housings and wheels. That had crossed my mind, but I haven't looked into calculating how turbos perform when taking the turbine side into account. From my understanding, you just don't want one side way bigger than the other. I was sold on a T3/T4 before I started looking into this. I figured I could deal with some lag for the benefit of not having to worry about buying a new turbo if I was to upgrade engine internals in the future. I don't know now, though. I've been seeing alot of T3/T4s for very cheap.

 
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Thanks for your posts Boosted2k2 and Madwheel. I'm gonna go with a T3/TO4E. I can get a really good deal on one right now. I'm gonna buy it. Oh, I made an Excel spreadsheet that will plot an efficiency map if anyone wants it. Just PM me with your email address. (It's on my computer at work. I have a government job so there is alot of free time at the office. haha)

Hey, out of the T3/TO4E what do you think......46 or 54?

 
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Madwheel, I'm gonna personally pay your way on a vacation for 2 to Vegas Madwheel if you run 12s....
I just don't see it happening....got love for ya , but I don't see it happening

1 I don't think the gearing is good enough for it, you will be in fifth gear by the time you
are going that fast(at least my 4th gear is quite short)
2 Open diff....spin spin spin spin spin, may make the trap speed for 12s but never the time
3 Tranny isn't gonna hold 300+ hp for long


Brandon

 
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Man I'm looking forward to that trip lol. I guess I have my motivation. So I have to be on street tires no matter what then? Im installing my blitz ebc tomorrow, along with corbeau seats. Looking to lower my weight while adding traction and power (DUH).

either way, it's all with tuning. with the amount of engine mods done (over 10k on the engine alone if the dh block is included (still waiting for it)), if i cant hit a 12 i'll cry, cuz i know its hard but damn if i got the wrx i initially wanted i would have had 12s 3 grand ago...

The open diff is gone this summer, I bought the phantom grip but returned it because of reliabity concerns. No more open diff, and hopfulley stronger axels at the same time...

 
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i duno what car u drive.. but in the manual. Well alteast mine. i Hit 120 at the end of 4th gear. Since ive been boosted, i really cant remember the last time i even used 5th.
Madwheel id like to come to vegas wit ya just to see his face.

 
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Yeah man sounds like a trip lol. I'll give you a holla when I make my pass, which will be on video tape, and I'll scan my timeslip.

 
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I drive the same car as you osoboosted, built my own turbo kit, tuned my own kit, I have many many many knowledgable friends....seen the Jotech 350z? He is from our club at UF...you don't belive me check out www.IMVfilms.com....and I don't think it is possible to hit a 12 in our car....Madwheel is one of my friends and knows that I will be the first one to congradulate him and personally pay his way to vegas

I do agree with you on 120 at the end of fourth....my bad

Brandon