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9174 iwg vs 6766

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Old 04-26-18, 09:47 AM
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9174 iwg vs 6766

I currently have a 6766 dbb setup. I love the setup, but I'm wanting to simplify things by having an internal wastegate. Way back I originally tried to purchase a 9180, but they were on indefinite back order so I decided on purchasing the 6766. Now that I'm refreshing my entire build, I'm thinking of trying to purchase a 9174 iwg setup. How does it compare to a 6766 in spool characteristics and ultimate power? My 6766 setup is a T4 1.0 divided hotside and I run it at 25psi and higher. Will the 9174 be quicker? Will it hold boost to redline? Will I see any advantages besides being a cleaner/simpler setup? Is it worth getting over a 9180 especially if I'm mainly focused on street driving and fun back roads (I would like to stay in the 67mm turbo range so I'm not interested in the smaller 8374)?
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Old 04-26-18, 11:10 AM
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How much power were you making on the 6766?

I have seen the dyno of that turbo make over 700rwhp on an RX-7 when maxed out.

If that kind of big power is your goal my opinion is there is no way you should go with the EFR 9174 instead of the EFR 9180.

If you are looking for the 500-600rwhp range then maybe the EFR 9174 for better response than the 9180 (but still the same limited low rpm power because of the compressor surge line).

I am sure you don't want to hear it but I still think a 500-550rwhp 8374 would rape a 600rwhp 9174 because of the response and low end/midrange power from the smaller compressor/compressor surge line.

Basically, I think the 9174 is for 2.0L piston engines with limited exhaust availability trying to swing that big compressor and not for the rotary.

Disclaimer:
I have never even seen a car with any of the turbos mentioned so I am just writing from what I have seen of dyno sheets and a basic understanding of physics. But, I'm not trying to sell you anything either.
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Old 04-26-18, 12:49 PM
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I was in the 600s with a slipping clutch at 32psi on a mustang dyno. I never went to the drag race track to find out what it trapped on high boost though. Low boost (18ps) made 450whp on the same dyno and was beating cars that trapped 132mph in the quarter by around 2 cars with me slow shifting into 3rd. I was even able to instantly jump that same car (procharged 2012 5.0 making 700whp) from a 45 roll without brake boosting.

Basically the main reason I'm thinking of changing my setup is to simplify/clean up. I figured/hoped the 9174 would make close to the same power as the 6766 on high boost, spool up significantly quicker for even more fun around town (resembling the response of the previously mentioned 8374), and have a nice tidy package with essentially less maintenance items to worry about.
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Old 04-27-18, 08:19 AM
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Do you have a dyno sheet or datalog( 4th gear) showing your current response?

The 9174 makes similar power @ the low boost for sure. I just tuned one that made 480rwhp @ 20 psi on a mustang dyno. You said you were making 450rwhp @ 18 psi. I haven't tuned one at high boost yet, literally assembling one today. Should have results from a ewg 1.05 setup at 30 psi next week also.
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Old 04-27-18, 10:42 AM
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Do you have a dyno sheet or datalog( 4th gear) showing your current response?
^^
This brings up a good point in that we have to separate the limits of the compressor surge line (how much boost a turbo can make at xx engine RPM) and how quickly a turbo RPM comes up to speed (how close the turbo rpm follow the throttle input).

When I use the term "response" I am talking about how quickly the turbo rpm picks up as you tip into throttle. That is a transient state that does not show on the dyno graph.

When I use the term "Spool" I am talking about how many PSI of boost a turbo makes at xx engine RPM at WOT and full load. This does show on a dyno graph.

Important distinction when discussing EFR 9180 and EFR 9174 as both turbos at high boost will be limited in spool to the same compressor surge line, but the difference in exhaust wheel diameters can affect transient response.
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Old 04-30-18, 10:17 PM
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It's hard to beat a 6766. I hope you have a good set of tires if you want more low end power than what you're getting with the 6766
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Old 05-01-18, 02:05 PM
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I'll try to get a hold of the datalog. I like peak power, but I'm really thinking about simplifying the setup (I currently have my wastegate plumbed into the downpipe, but it's a hassle to change anything out). I figured if I was thinking this far ahead I might as well make the setup more responsive while have similar power up top. Also, I'm on 295 r888s so I know the meaning of needing traction with the current setup. I'm upgrading to r888rs with the new wheels so I'm hoping it will help as well.
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Old 05-01-18, 02:56 PM
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It should hook up better with more low end power and less top end power (EFR 9180 versus 6766). That has been my experience with the EFR turbos.

The "late" spool of the 6766 doubles its torque in 1,000rpm (from 4,500rpm to 5,500rpm) going from ~250lbft to 500lbft and that abruptness from low torque to tons of torque is what really breaks the tires loose.

The early spool of the EFR 9180 has it doubling its torque down around 2,500rpm to 3,500rpm going from 150ftlbs to 300ftlbs which isn't as bad as there is a lot less torque to double. From there the EFR 9180 torque gain will be more progressive and you will be pressed to get more than 600rwhp out of the IWG version.
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Old 05-02-18, 09:14 PM
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Here are some E85 dyno results from the T4 1.5 EFR 9174. Lucky7Racing built this car( half bridge). ECU showed 28 psi fading to 26.
606rwhp/473rwtq. This was our welded design. They are building another identical setup with our new cast manifold too. Will be neat to see that overlayed...
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Old 05-02-18, 09:18 PM
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Better shot showing the scaling etc
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Old 05-03-18, 05:52 AM
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Hmm, interesting... I wonder how the 9174 looks with just a streetport and modest to low boost (for reliability and longevity).
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Old 05-16-18, 07:44 AM
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At those power levels I'd advise you stick with an external gate setup regardless of which EFR you go with. Being stuck with a .92 housing will cause a high backpressure condition which will translate into higher egts and make it more difficult to hold high boost levels as the pressure in the manifold will force the gate open if the differential is large enough. You'd have to use a 4 port controller to get around it, but even then you would just be putting a bandaid on the real problem being the turbo is a pressure choke and heat trap.
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Old 05-17-18, 10:04 AM
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Yup, I picked up an EWG 9174 last winter and plan on running dual 38mm MV Tials. My motivation for getting the 9174 wasn't to chase power, but rather to chase reliability (through lower boost) while still maintaining a modest power range and good spool through the 400's.

I'm closing on a house this month, so unfortunately I won't be able to supply my own numbers and figures for a while since that's going to take priority through the near future..
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Old 05-17-18, 09:38 PM
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Originally Posted by Skeese View Post
At those power levels I'd advise you stick with an external gate setup regardless of which EFR you go with. Being stuck with a .92 housing will cause a high backpressure condition which will translate into higher egts and make it more difficult to hold high boost levels as the pressure in the manifold will force the gate open if the differential is large enough. You'd have to use a 4 port controller to get around it, but even then you would just be putting a bandaid on the real problem being the turbo is a pressure choke and heat trap.
Hmm, interesting. For all that, I'll just stick to my current setup. I was really trying to get away from ewg and have the simplicity of iwg. I'm not necessarily chasing numbers anymore, I was way back when I originally started. I figured if the spool of the iwg 9174 was way faster and overall peak power was close, I'd consider selling my current setup and getting a simpler setup. I guess this is just the universe telling me to stop spending money on unnecessary things and concentrate more on overall dynamics.
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Old 05-18-18, 04:58 PM
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I've never had to use a 4 port mac valve. The above dynos are only on 3 port mac valves. With a bigger exhaust system I've never had to go above 75% duty cycle to get to 30 psi either. We also have several customers making 600+rwhp on the 9180 kits in the low 20 psi range, and carrying power past 8000rpms.
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Old 05-19-18, 11:21 AM
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Originally Posted by Turblown View Post
I've never had to use a 4 port mac valve. The above dynos are only on 3 port mac valves. With a bigger exhaust system I've never had to go above 75% duty cycle to get to 30 psi either. We also have several customers making 600+rwhp on the 9180 kits in the low 20 psi range, and carrying power past 8000rpms.
Making 600 in the low 20 psi range wasn't a problem. The problem was that low 20 psi range becomes you cap due to the .92 turbine combined with the turblown cast mini manifold. Its a major choke at those power levels and regardless of post turbine exhaust size you're going to have extremely high egts due to the high pressure and low flow pre-turbine. Sure you can get away with forcing it to hold higher boost through use of a mac, but doesn't change the fact that the manifold a .92 combination is essentially a pressure cooker. With a side port engine, the high pressure and egt's aren't as dangerous as a peripheral port where the intake chamber is directly open to the exhaust port and all exhaust pressure when the seal crosses over the peripheral, so it was a horrid choice for my application. I don't see the point of going with a 9180 over an 8374 if you won't be able to run more than 20lbs without hitting the egt ceiling.

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