Borg Warner EFR Series Turbo's V 2.0

[RB335]

I do have a spare set of coolant/oil lines suit EFR 1.05 rear mounting on 6boost if anyone wants,   Also downpipe suit EFR on Skyline w 6boost.

Edited October 1, 2023 by RB335

[StubbyFoil]

RB335, I would be interested but I'm using the Full-Race EWG manifold that sits differently than the 6 Boost. 

[MiSTI]

On 29/09/2023 at 3:25 PM, StubbyFoil said:

Man, I got the email from Full-Race that the 8474 was back in stock! Not even 30 minutes later when I checked, they were all sold out. I really wish to get my hands on one of these once my car is up and running with the Precision. I'm even pre-fabbing up coolant lines/fittings and running them looped so its just a downpipe change away from a turbo swap once I finally get one. Bump for more real world info on the 8474. I'm looking at the 1.45 housing for my Nitto 2.8/mild port head, GSC S1 cams, shimless bucket setup. ::Fingers crossed::

Hello guys, 

I am a new user and I have been following this thread for a very long time. I have  just checked with my supplier (I deal with tuning parts through my company) and I would be able to supply 2 x 12747100017 (EFR8474). Shipping from Austria to Australia is not an issue.

In case someone is interested feel free to send me a PM. 

[CowsWithGuns]

I've been trying to source an EFR7163 TS for a couple of weeks now (for not $5000+) and it's just non existent. Anyone know what's the deal with this or know any SECRET STASHES of this rare loot?

[Full-Race Geoff]

On 11/23/2023 at 9:12 PM, CowsWithGuns said:

I've been trying to source an EFR7163 TS for a couple of weeks now (for not $5000+) and it's just non existent. Anyone know what's the deal with this or know any SECRET STASHES of this rare loot?

Full Race is getting these turbos in small amounts and we always keep the housings in stock.  Let me know exactly what you are looking for - depending on the configuration we may be able to help in some capacity. 

 

Worth noting we have a good amount of EFR 7670, 8370 and 8374 (for the first time in 2 years)

Edited November 29, 2023 by Full-Race Geoff

[burn4005]

are 8474s hens teeth or are they generally available?

[Full-Race Geoff]

we have (2) 8474 in stock, dont know of any other distributor with inventory. Full Race has a couple 9280 and 8374 as well.  Dont know how long until we see more

[Komdotkom]

While this isn't strictly a Borg Warner turbo question, does anyone know if you can use the very helpful Matchbot software to simulate a turbo restrictor? It's got a line item for inlet air restriction which is for airboxes/filters and so on but if I ramp up these numbers to suit a 38mm restrictor does anyone know if the software will model correctly?

 

[Lithium]

5 minutes ago, Komdotkom said:

While this isn't strictly a Borg Warner turbo question, does anyone know if you can use the very helpful Matchbot software to simulate a turbo restrictor? It's got a line item for inlet air restriction which is for airboxes/filters and so on but if I ramp up these numbers to suit a 38mm restrictor does anyone know if the software will model correctly?

 

I think it should do a reasonable effort so long as you put the right values in and the results will only suit the conditions you are applying the numbers to suit.  

[Duncan]

4 minutes ago, Komdotkom said:

While this isn't strictly a Borg Warner turbo question, does anyone know if you can use the very helpful Matchbot software to simulate a turbo restrictor? It's got a line item for inlet air restriction which is for airboxes/filters and so on but if I ramp up these numbers to suit a 38mm restrictor does anyone know if the software will model correctly?

 

What a specific question

I am pretty sure the rule of thumb is that your maximum HP is restrictor diameter x10hp....therefore you should should size your turbo for max 380hp (ie, tiny/fast spooling). 

Unless you follow the tried solution of an accidental air leak downstream from the restrictor of course

[Lithium]

6 minutes ago, Duncan said:

I am pretty sure the rule of thumb is that your maximum HP is restrictor diameter x10hp....therefore you should should size your turbo for max 380hp (ie, tiny/fast spooling). 

Trick is that the airflow through an orifice loosely speaking increases by square of the diameter, so a 76mm restrictor (lol) will support *quite* a lot of power.  The other issue is the pressure ratio across the compressor will go up significantly as pressure drops below ambient between the restrictor and the inducer, so that starts doing funky things with compressor efficiency and also how hard the turbine needs to work... things I assume someone using Matchbot are hoping to try and anticipate.

[Komdotkom]

It's a very difficult thing to get right. When the car had a smaller turbo on it (GT2860R .64) it would make more power past peak torque with the WG open. The current turbo GT2971R (not a typo) .86 does not, but that seems mental to me. All that air can't be going through the turbine without EMAP being 11ty billion PSI.

I was reading an article about the old WRC compressors and they were saying that they ran a larger overall wheel but with a smaller inducer to allow for a 7 degree taper from the restrictor. The turbine was shallower/thinner but had a larger exducer to work at higher PRs.

Car makes 220 ish kw on E85.

[Komdotkom]

I want to add a map sensor between the restrictor and the compressor to see what that looks like, not my car though so that's up to the owner.

[Lithium]

4 minutes ago, Komdotkom said:

The current turbo GT2971R (not a typo) .86 does not, but that seems mental to me. All that air can't be going through the turbine without EMAP being 11ty billion PSI.

I'm pretty fn tired right now so fair warning I may say something really stupid without realising it - but the way I read this it basically covers what I mentioned above.

I might have to run into matchbot to illustrate what I'm getting at, but basically the pressure ratio across the compressor will be going through the roof and compressor efficiency potentially getting completely rooted.   What will happen there is the thing has to shut the gate to keep driving the compressor but the compressor is not moving enough air to drive the turbine any harder than it already is, which is essentially what I was getting at when I said "how hard the turbine needs to work".   Even though the absolute pressure in the inlet manifold is not super high, the pressure ratio across the compressor is MUCH higher than the pressure ratio across the turbine.  It almost wouldn't shock me if a tighter hotside would work better, lol. 

I'm going to have a fiddle with matchbot now because I'm curious.

[Komdotkom]

I had a crack with matchbot earlier but without having much information on what the intake restriction is I was getting some pretty wild numbers.

It still generates 30psi MAP so I'm assuming it's still spinning pretty hard, or is this in fact choked up exhaust gas? This has all come about because the engine is apart at the moment and the intake ports are covered in partially combusted E85 jelly stuff.

As soon as the air becomes supersonic through the restrictor and it chokes the PR is going to spike massively, is the object to bypass more air through the WG to keep the compressor right on the edge of the restrictor stall?

 

[Lithium]

39 minutes ago, Komdotkom said:

I had a crack with matchbot earlier but without having much information on what the intake restriction is I was getting some pretty wild numbers.

Yeah I've hardly ever tried doing math for this exact thing and suspect I may be going quite wrong, or maybe matchbot DOES need some work for this kind of thing.   I decided to calculate the maximum airflow through a 38mm orifice with a .9 discharge coefficient (I have no idea what was reasonable so went for something big while not sounding completely impossible) and with standard ambient temp/pressure I have ended up settling on 6psi below ambient at the compressor inlet for ~31lb/min mass airflow.

With this I put the -6psi line in to Matchbot using the "Default" 2litre setup, and ended up needing to run a boost curve that looks kinda like "5000rpm = 23psi, 6000rpm = 15psi, 7000rpm = 11psi" and ending up with 300hp.

This results in matchbot estimate 54lb/min corrected mass flow (so what you look up in the compressor map as opposed to the actual mass flow), and a compressor pressure ratio of 4.46:1 at 5000rpm dropping back to "only" 3:1 at 7000rpm.   Kinda doesn't seem toooo shocking to me, the 71mm Garrett GT series compressor is basically "topped out" at 46lb/min so it'd not be surprising at all if any amount of "gate shutting" was going to be in vain to a degree.

Now matchbot DOES estimate a pretty terrible amount of EMAP for that boost, but from what you say you're not actually seeing that.   Matchbot "assumes" a given amount of power needed to drive the turbine and I wonder if it's factoring in the fact that you may not actually need as much power to drive a given pressure ratio across the compressor if the intakeP is a LOT lower than ambient.  Basically a lot less resistance on the compressor, kinda a trick that was used in early F1 for antilag (a pre compressor throttle that closes with the actual throttle to bump the PR and reduce drag on the blades).

At this point if I were to guess, I'd say that the compressor can't even move enough air to get you to a point where the turbine is choking the engine - if I were going to be ruthless I'd try fitting a smaller a/r housing, possibly much smaller so you can bring the drive pressure enough to spin that compressor will a relatively unimpressive amount of exhaust flow.  Probably a good idea to get a compressor that is more efficient at high PR as well, lol.

 

Caveat: I'm still bloody tired and this could be nonsense, but may or may not have said something that could prove useful!?

 

Edited January 17, 2024 by Lithium

[Komdotkom]

Thanks for your insights @Lithium, much appreciated.

I was thinking G25-550, at least they're good at high PR's unlike the GTX2971R which is surprisingly poor. It's currently running an IWG (I know I can't believe it either) so I'll see if we can get a Mamba .64 rear for the GTX29 on a V-Band and see how it goes.

Edited January 17, 2024 by Komdotkom

[Komdotkom]

Sorry, I should have mentioned this is God's Tractor Engine, SR20DET (not VE)

[Lithium]

4 minutes ago, Komdotkom said:

Thanks for your insights @Lithium, much appreciated.

I was thinking G25-550, at least they're good at high PR's unlike the GTX2971R which is surprisingly poor. It's currently running an IWG (I know I can't believe it either) so I'll see if we can get a Mamba .64 rear for the GTX29 on a V-Band and see how it goes.

No worries, please don't take it as gospel - I wouldn't I don't have direct experience with this kind of thing and it just got my curiosity, though I'm sure you can decide whether stuff I've said seems nonsense or not as you look into it more.

Out of interest, the Xona/FP turbos are pretty expensive but they do work to unusually high pressure ratios. I think they have got a bit more common with "restrictor classes" in various forms of motorsport for that

 

[discopotato03]

One thing I can add is that I'd say what you mean by GT"29"71R  is that it probably has that ancient cropped GT30 turbine in it .

If so these were a GT30 UHP turbine that had the blades shortened - trying to fudge a turbine size in between GT28 and GT30 . The idea was to make effectively a smaller more responsive turbine than a GT30 . It doesn't work because having the GT30 sized turbine hub with shorter blades isn't the same as having a purpose designed turbine with the same inducer and exducer diametres . Long story short these GT29 turbines were never efficient in any turbo . Too much hub mass and volume for too little blade area .

I think as mentioned the G25 should be a step in the right direction . 

Something else to think about is the turbo tech used in the Group A rally days of inlet restrictors . A huge amount of research went into their turbos and they were very different to virtually everything else . From what I remember they were trying to get the things to come on as early as possible and make ginormous torque over a reasonably narrow rev range . The numbers were something like 650 Nm of torque from 2000cc and it was all over at 53-5500 revs .

I think early on manufacturers started doing the twin scroll thing ie some EJ20s and most 4G63Ts but in the end it was simpler to use anti lag systems with more conventional style open manifolds and turbine housings .