Borg Warner EFR Series Turbo's V 2.0

[Piggaz]

11 minutes ago, Ben C34 said:

Nitrous

Buy a R35 and wind it up on stock snails OR a 911 Turbo. DONE!

[acsplit]

+ 1 buy an R35 or travel the world doing coke and bitches

[fatz]

Put Efr on 35

 

in for coke n bitches

[sneakey pete]

Had something come off and go through my turbine wheel at the track yesterday.

turbo was making that wonderful turbo scraping noise, couldn't rotate it by hand forward, went back and it unbound and would then spin freely, drive, make boost etc. Rather odd. Also sounds like i have a manifold gasket leak and the EGT's on cylinder 1 are sitting at 150ish instead of 4-500ish at cruise. So NFI what has happened. Hopefully turbo is fine though...

Can't pull it down for a fortnight as i'm back out to site today but will be interesting to see the damage.

[afb312]

Air filters fitted? 

[sneakey pete]

Yeah i'm not that dodgy.

leading thought in my mind is gasket failed and part of it went into turbo? Note I have OEM gaskets, are they a nono?

What do people use? (also for the split T4 gasket while is out)

 

The only thing in my mind is that it doesn't really explain why the EGT's on that cylinder are 250C lower.

[Dose Pipe Sutututu]

On 9/2/2018 at 6:29 PM, fatz said:

in for coke

In for coke too

[afb312]

On 9/4/2018 at 5:40 AM, sneakey pete said:

Yeah i'm not that dodgy.

leading thought in my mind is gasket failed and part of it went into turbo? Note I have OEM gaskets, are they a nono?

What do people use? (also for the split T4 gasket while is out)

 

The only thing in my mind is that it doesn't really explain why the EGT's on that cylinder are 250C lower.

I was thinking more about a double cone type of air filter. I heard a while back that they can loose the internal end cap. I have never seen this personality though. I was curious. As for the temperature difference, is there any chance of a bad instrument reading? 

[sneakey pete]

Yeah there certainly could be a failure of the probe (the probe could even be what's gone into the turbine?), however i'm 99% sure it wasn't the filter as I had it off to inspect.

Flying visit home this Friday to take care of some other stuff might try get the turbo out at least to assess damage and get more time to figure out out to fix whatever it is, see what happens

[Lithium]

Because SAU went full potato with my first post, and won't let me delete it

Edited September 14, 2018 by Lithium

[Lithium]

On 8/31/2018 at 9:32 PM, Nismo 3.2ish said:

Paul , you have had the 1.45 on for a while now and at first you were sort of thinking about switching back to the 1.05.

You have had a few runs now and one today with Dan , have you made your mind up yet ?

 

 

On 9/1/2018 at 12:09 AM, Piggaz said:

1.45 has its place. Did the Huntley hill climb today and just doodling through it at a corner that I had huge issues with the twins, it was ready to turn tyres.

I won’t be going back to the 1.05. Sub 3000 RPM there is Definately a penalty to pay, it feels a bit “soft”, from 4000 RPM it’s fine. If you’re “driving it” it’s all there. The 0.92 IMO should be made redundant IMO. No need for it.

Still well infront is the -5’s that we’re on it either way. 

I wish I hadn't been so busy since I got back to NZ, I would have liked to have commented on this while the iron was still hot but life just hasn't been quite compatible with doing online rants - though better late than never, right?

First off, f**king sweet to catch up again Piggaz - and thanks again for the catch up and E85 burning session, was a day well spent and my liver still even functions!  

Next, this is my best effort at giving an impression of the EFR8374 with the 1.45a/r hotside.... considering I've not been in a vaguely comparable car in AGES, and I never experienced this car with the 1.05 hotside I have no choice but to rely on inference to build any kind of review about how this would stand up to any alternative.

I had actually had talked quite a bit with Piggaz from the point the car was tuned and the point he picked it up, and been in common cars (including this one) so I had a general idea of how his perspective of delivery compares to the real world so almost disappointingly - it basically behaved how I expected it to.   Disappointing in the fact that there wasn't a huge surprise, not that the performance was disappointing at all - I can just see how someone who hadn't been "primed" could go in the same car and be like "holy f**king shit, what just happened then?".    

Below 4000rpm as expected - it fell short of the initially descriptions I'd had from him and others of how it performed when it had the 1.05a/r hotside, which to be fair - a lot of people would not have believed if they didn't know the car and people in question... basically amounting to "it is ALWAYS on", almost like a totally undersized turbo which woke up at the whiff of the throttle.   What I was greeted with was actually felt like it was turbocharged, but with a fairly conservative turbo setup.  More like something which when he leaned on it could realistically have someone convinced that it was running something along the lines of -7s or -9s - the bigger hot side had clearly taken a bit of the low rpm windmilling/induction whistle effect you may expect at the very bottom end with a responsive single turbo setup.  Between 3000-3500rpm it was starting to go from a slight boost climb into an aggressive ramp, and if still in it by 4000rpm - in pretty much any gear, the boost climb felt like it was going pretty vertical... basically by just over 4000rpm "full boost rpm" becomes academic, even if it is still building the car is accelerating hard enough that you're getting somewhere in a hurry - so hardly laggy by any stretch of the imagination, definitely one of those cars where looking at the boost curves on a dyno plot are very misleading.

The trick here, is the ability for ANY Skyline GT-R to accelerate at that kind of rate in that part of the rev range is really impressive... let alone being under 3litres, and let alone with a car which has >500kw @ wheels.   I've been in a few 10s GT-Rs, and this thing pulls the whole way through the rev range much harder than any which I've been in that run mid/high 10s at low 130mphs.  For something that spools and responds the way it does, it's pretty mind bending stuff... even if rationally you know whats coming.  Lets put it this way, imho if most people went in this car and the rpm were kept below 4000rpm and you thought you experiencing which was making mid 300kw @ wheels it would be something you'd not have to lie to say that how it drove in that rev range was pretty impressive, let alone if you consider that the car actually has ~50% more power than that and delivers in with a FAT delivery.  

I guess if anyone wants a real world way of quantifying this themselves, we did a "time exposed to danger" test - acceleration from 80-120kph, starting the timer when the throttle goes down at 80kph/~4200rpm in 3rd and stopping it when 120kph was reached.  The elapsed time was in the 1.xx second range, which when you factor in the fact there was no "run up", no brake boosting or anything - just stomping the throttle at 4000rpm I think that is insane, considering the car is still not even in it's happiest part of the rev range at the END of the pull.   Try stomping the throttle from ~4000rpm in 3rd in your own car and see how much speed you accumulate in 2s from the moment the foot goes down, gaining >40kph is not pissing around from those kind of rpm with a car that's making >180wkw/litre.

 So what do I think?  The car is an insane setup, the engine package is simply awesome - and this speel doesn't even account for the fact it has a sequential gearbox (holy crap this makes the car that much more capable than the dyno plot suggests), amazing suspension and braking etc, I'm simply focussing on trying to communicate how the turbo works.   The turbo itself is clearly pulling it's weight in a setup where the expectations are high.  There are natural question marks for me, more for curiousity than the feeling there is any reasonable expectation for more.   So thinking through the EFR options I feel there could be an argument for on this car:

1) 1.05 EFR8374

I would have loved to have experienced that.  I understand the desire to move on from it as there were mid/low rpm surge issues with it, and those have been resolved by going to the 1.45a/r housing.  What I don't know is if the 1.45 has fixed it purely by allowing the engine to breath better, or purely by introducing enough lag than the turbo doesn't cross the surge line anymore just to getting to higher rpm before hitting that boost level, or if it's a combination of the two.  I am guessing it's a combination, but a combination which is particular to this particular engine setup - so not necessarily one that would apply to all setups.   
    
The idea of the car as it as at the moment with a softer boost curve down low to avoid the surge but with the extra life between 2500-4000rpm sounds interesting for academic reasons, it would just be hilarious - especially considering I at this stage can't see a reason it shouldn't be able to make up around 500wkw if the owner didn't mind EMAP starting to climb.   
    
 One way or another, this is the smallest EFR I'd consider putting on a car like this - clearly it is running out of compressor at only ~23psi as it is, and it's spooling fast enough to get into the surge zone so for various reasons the .92 is just not an option I'd consider on a good RB... personally.   

 2) 1.45 EFR8374 - The current turbo

This spools very well for a setup which is able to make this much power on a 2.8, it doesn't surge even with an aggressive midrange boost curve (ie, hitting ~30psi and bleeding back to manage turbine speed), and it allows the compressor to basically max out without an excessive EMAP/IMAP ratio.   It basically is able to use the full width of the compressor map with no big work arounds and isn't laggy, that has to count as a very good match.    The car is just so exciting to go in, again - there are a lot of pieces to the puzzle which allow that to happen... but the way this turbo and the engine interact is just spectacular.   For what Piggaz uses it for, I'd say (well I already have said) leave it here.   A few years ago I'd say neither of us would expect that what his car does now would have been possible with the parts it has.

3) 1.45 EFR9174

I don't really have enough data from this car but I am starting to entertain the idea that this could be a very interesting alternative to the EFR8374.   I wouldn't go any smaller on the exhaust side as it obviously already had surge issues with the 74mm compressor, the 91mm compressor's surge line is ~6lb/min to the right so would likely only be worse with the same hotside - however given the setup is already not surging with this hotside running lots of boost in the midrange, the 91mm compressor should add a little more lag so I'd hope that should dance around the surge line while also not adding too much lag - I do like the idea of the 74mm turbine having a much lower MOI than the 80mm turbine.    I know the natural question to this will be "what about exhaust manifold backpressure with all that extra flow?" - I really don't have enough real world data, but I am starting to suspect one of the things which is giving EFRs the rep of falling over at higher rpm/getting high EMAP is Borg Warner's decision to print compressor maps using an rpm as the cut off - not compressor efficiency.  

Looking at the boost level Piggaz car is running at peak power with the current turbo it would need an extra 7000rpm of shaft speed to increase flow by ~1lb/min.   The energy to increase the shaft speed that much comes from the exhaust, so less wastegating, so higher exhaust back pressure, and negligable change in boost pressure.  Not a great mix.   It may seem counter-intuitive, and I may be full of crap, but part of me wonders is this turbo with the exact same boost curve may actually result in lower EMAP than he has right now at full rpm - and also better power.  

I tend to think of 65% compressor efficiency as a point where you start going "ok, we're pushing it now" territory and realistically the EFR9180 compressor is already going to be under that efficiency if he tries to hold mid/high 20psi to redline so with his engine setup the 91mm compressor is not what I'd call a comfortable 95lb/min compressor.   If it were mapped to stay within the >60% compressor efficiency parts of the map then I'm not sure if EMAP would actually take off like one may assume, turbine rpm would stay safe as houses and everything should be pretty comfortable.  I suspect it could be a nice way of allowing the engine to operate a bit freer in the higher rpm without sacrificing too much down low, we're talking taking nearly 20,000rpm off the turbine speed and actually gaining power.  

Does it NEED the extra power up high?   Not really, in the real world this car is FAST.  Very very fast, everywhere.  If there was any other option that I'd be VERY curious to see how it worked on this car, this is it - mainly because if my speculating is right it'd be working a little less hard and give a little more at minimal cost.   In a world where there seems to be no perfect "sweet spot" match from the EFR range for this engine package, this could be the best alternate reality compromise from the 1.45 EFR8374.

4) 1.05 EFR9180

The idea of these make me feel happy in the pants, and I'd love to see how one behaved on the car.... but I know what Piggaz likes and again, with the overthinking above - I'm really not sure it's something he needs or would even necessarily suit his setup as well as other options, even though realistically if he put it on and anyone who hadn't experienced the previous configurations went in it with the current engine/trans setup and this turbo it'd not be surprising if it felt "perfect". 

5) "The others"

I think the .92a/r EFR8374 would be beyond pointless and would actually be a complete fail, and the 1.45 EFR9180 potentially just adding lag for sport.

  
So yeah, I've overthought the shit out this and given a TL;DR post for people to take or leave - but given I started the whole bleating about EFRs in this forum and have often expressed frustration on the lack of input on how they work I felt obliged to share some thoughts now that I'm in a position to have been able to vicariously experience the process Piggaz has gone through and the result of it.

Nice work mate, the thing is nuts - it's come a hell of a long way from the already potent machine it was when we first met.     

Edited September 14, 2018 by Lithium

[burn4005]

My car is tuned with EMAP compensation and my ignition table has the load axis in g/cyl so I'd really love to play around with a few combinations to see what happens with very minimal tuning required.

 

shame the 1.45 is so physically large. I think the dump pipe would need a fair amount of rework compared to the 1.05 i have on there now. (and for some reason the 1.45 housing on its own is massive dollars (~$1300 just for the housing!)

but based on that info you've posted, yea I reckon if you're shooting for over 500awkw a 1.45 9174 would be unbeatable, but a sequential box certainly hides away a turbos lack of response.

[Piggaz]

8474/1.45

BW, HURRY UP!

[SimonR32]

2 hours ago, Lithium said:

So yeah, I've overthought the shit out this and given a TL;DR post for people to take or leave - but given I started the whole bleating about EFRs in this forum and have often expressed frustration on the lack of input on how they work I felt obliged to share some thoughts now that I'm in a position to have been able to vicariously experience the process Piggaz has gone through and the result of it.

Nice work mate, the thing is nuts - it's come a hell of a long way from the already potent machine it was when we first met.     

TL:DR... PTE 6262 still better

But videos I get sent of said car do look very much fun

[fatz]

Summary So 8374 goes hard 6262 better and faster

[Piggaz]

22 minutes ago, fatz said:

Summary So 8374 goes hard 6262 better and faster

Says th bloke that has a 8374 hanging off his donk. ?

[acsplit]

Precision turbos are basically for knuckle draggers who only want to go in a straight line and brag about numbers.

For intelligent people who want a quick street car, tarmac rally or circuit car EFR is the right choice

[acsplit]

Probably can't even get an invite to coota these days without a precision

[fatz]

Lol will report back once 8374 is on seeing as the engine had a 6262 on it which was pretty epic before

 

unlike you kunce I ain’t bias to either will report back which is better after I hit all the same tracks

 

[fatz]

I only bought one cause Pissbin went from -5 to 8374 and said it was epic, and that is as a internal gate so let’s face it=shit

he probably would have said the same if he dumped a 6262 on as well