EFRs r gud rite
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You are currently reading a thread in /o/ - Auto
A picture of a EFR 9180 in it's natural state. 808awhp @ 38psi on a dynojet on a Subaru.
Also Turbo thread.
>>14674503
>38psi
WHY WOULD YOU DO THAT?!
>>14674516
Gotta get to work.
>>14674503
>38 psi
Don't the EFR's have that gamma-ti turbine? The one that's supposed to be lighter but it's weaker so they kept breaking them until they made them heavier?
>>14674578
>implying that that's actually a lot of boost on a closed deck block with 1/2" head studs with orings, i beams, and 2618 custom JE pistons, billet 282 cams in a ported and polished head with a 2.5i long runner manifold
>also that shit subaru VE -- only made 808hp with 38psi
>>14674597
Correct, This one didn't actually have the turbine wheel explode though, the nut shot out the back of the exhaust @ 7200rpm @ 38 psi. Logs show that we were 16000rpm shy of the rpm limit of the turbo and now borg warner is giving us bullshit that we overspun it even with that sensor data.
The customer is now pissed and doesn't want to put the RMA'd turbo back on the car.
Oh, and it takes BW 3 fucking months to RMA a turbo.
>>14674605
apparently it is
>>14674617
Except the block didn't explode, the turbo did. Any Garrett, Comp or Precision turbo could do what this turbo did just fine without shitting itself.
Based on what the customer's power goals are (He wants 800-900hp without pushing the shit out of the turbo) I'm thinking something like a Comp CT43x 6871 or a 7075. He still wants it to not spool like shit which is already hard because of how long the runners are on a subuaru to begin with combined with their joke VE.
I would do a garrett but they make the least amount of power out of all of them for the same wheel size.
whoever can tell me the wheel sides of these two mid-frames wins
>>14674613
Interesting. I'll be honest, I'm an engineering student that wants to get into the automotive/motorsports industry after I graduate - I've been teaching myself some of the physics of engines and forced induction but I know jack squat about the market. What are the alternatives at that power level? Why did you (or the customer) pick the EFR?
>>14674665
On the right is a hurricane with a 66mm inducer I'm guessing and the one of the left is hard to tell because of the skew. 64-66mm inducer on that one.
>>14674675
First things first, ignore everything other than wheel size. Look at the inducer/exduser size of the compressor and turbine wheel and go from there.
From that you can see that the EFR 9180 is a 66.7/91mm compressor wheel and a 80mm turbine wheel
This means that comparable turbos will have a similar sized compressor wheel and the turbine wheel will need to be roughly matched either up or down depending on the volumetric efficiency of the engine. This means, a piece of shit subuaru motor needs a smaller turbine wheel because it can't breath up top but needs to keep wheel speed high to maintain a high boost level on the compressor side. You then adjust AR of the exhaust housing accordingly to get the desired backpressure ratio.
Comparable turbos to the 9180:
Garrett GTX4294R which is a 70/94 compressor wheel and a 82/75 on the turbine side. This turbo would make less power than the EFR with a smaller wheel just because of the geometry of the compressor wheel. There is nothing in the Garrett range with a 67mm inducer that can flow what a EFR can.
Comp CT43X with a 68/71 wheel combo. They will literally make the turbo custom to your specs. This one would have a 68mm inducer and 94mm exducer on the compressor side and a 79mm inducer and 71mm exducer on the turbine side.
Precision 6870 Gen2 - Everybody gets their dicks hard over this one, but it's a hair better than the EFR 9180 in terms of power at the expense of spool because of the heavy inconel turbine wheel and the forged 2618 compressor wheel.
Turbonetics - turbonetics are trash.
The customer chose the EFR 9180 because of the gamma ti turbine wheel which is significantly lighter than an inconel wheel. That combined with it's new generation compressor wheel (See Garrett GTW turbos, Gen2 Precisions SXE BWs) means that it spools quicker than other turbos in it's class.
Oh and one more thing, inducer/exduser terminolgy is swapped on the compressor/turbine side.
>>14674738
I gotcha, thanks for the write-up. So, for a given size turbine and compressor, the main differences between turbos are the wheel geometry and materials? And in this case, the lighter gamma to was chosen for spool up, whereas you might go for the inconel if your exhaust was super hot (anti-lag?). That's pretty nifty
>>14674617
i run 52psi in my dsm. its fine.
>>14674923
Correct. The max tip speed of the EFR's across the board is 560 meters per second which is a limitation of the gamma ti turbine wheel material choice. Inconel is definately the choice for anti-lag, 2step and pushing a turbo way past it's efficiency range.
It's also important to note that many people push turbos WAY past their efficiency range, and still make power for the tradeoff of increased IATs. As long as that's still under control, or you're running E85, you can often go pretty significantly outside the map and still make good power.
