burn4005

as with anything, shit in = shit out. if you have enough fit for purpose sensors (fast response, high accuracy) that are correctly calibrated, know your injector flow ACCURATELY (which is the difficult part of this) there is no reason to doubt the result. A VE model is just an abstracted correction function using physical models. you could convert all the corrections to ms and have no difference, and would suit your "motosports". they're fully interchangable. the advantage of a VE model is you can have single variable corrections as things are coupled in the model, whereas in a ms map they would be multivariate. sure, its not going to be within 0.01%, but in a dynamic real time system its not neccessary to go to that, its only a compressor map, and its a visual tool. The log I have above, the compressor stonewall flow vs turbo speed matches to within 0.8% of the BW supplied compressor map. if you are telling me that isn't useful data then by all means keep "intending" to set up a test bench. OEM manufacturers go to extreme levels to accurately model engine characterists because they REQUIRE it. emissions are getting incredibly tight. motorsport engine control is basic stuff by comparision, especially on the fuelling side. those advanced motorsport ecus aren't doing anything clever, they are just very reliable, don't change constantly, come with excellent datalog analysis and professional support, and often retardedly complicated licencing requirements on top of the hardware cost, but that's another story. the torque control and gear shifting is what you're paying for. the Bosch motorsport ecus (even as old as MS5's etc) use a relative fuel mass to lambda target, the air temp correction is based in a NTP relative ideal gas model and the final fuel charge is converted to an injection time later from the Q-stat flow so get off your high horse.

does the life racing calculate a VE model derived mass flow? a good plot is mass flow vs boost pressure with turbo speed as color. makes it easy to compare with a compressor map.

lol at the redacted plot.. anyone have ASIO clearance that can make sense of this for us? the Y axis can be fully extrapolated from the data in the bottom left corner (117.61) for the cross hair value. so you're overspeeding it by ~4%, good for you.

Yea split pulse manifolds and 1.05 housings on both.

I'll have a 9174 result on a 2.6l rb26 in the next few days. Running at same boost (180kpa) my 8374 hit Max speed at to compare. but should be interesting against my 8374 result on the same Dyno. Have turbo speed sensors on both engines and emtron kv8s so logging should be pretty comprehensive

You have to use much lighter return springs on the itb shafts too.

yea listen through exhaust, listen through plenum and listen through oil filler hole.

What cams is the motor running? Compression is on the lower end of acceptable but cams can make a big difference.

Full race guys seem to have an inside line on the EFRs

yea they would be, but if you want a more agressive cam ramp they won't do the job. duration and lift doesn't tell the full story about cam design. there is another metric of the cam that is the average lift over the duration that tells more of the story about the cam profile. also, worth noting the Tomei cams quote the lobe height and kelford quote the net lift. so they're both a 10.8mm lobe cam.

Let's rephrase that to more development in the last 15 years. Tomei are of the vintage of t51 and t04e turbos and old heavy dual valve springs . The world has moved on and cars are now running ethanol, single beehives and extremely efficient turbos. I'm not saying kelford has changed the game but things like the split lobe 274s would likely suit the modern engine better.

That's strange. The catelog quotes the same inducer/exducer measurements so I'd be very interested in why the map is different and off the wheel or housing is different. I had assume it was the same for 9274 and 9280 without checking.

you won't have the same midrange punch. the 8374 will be much snappier as spool range on a 2.6-2.8l engine is in a higher efficiency area, and every % increase in efficiency here compounds the spooling effect.

if you're only chasing 550awkw, on paper the 9174 looks to be a better fit, but you do buy a bit of surge margin with the 8474 over it. How the rotational inertia of the ligher compressor of the 8474 helps for transient response vs the 9174 we'll see i guess. the new releases are really top-end power turbos but the midrange performance will suffer a bit.

as promised, here are the efficiency curves at pressure ratios of 3.0 (29psi)

I'm sitting on a plane after a 4am start looking at these on my phone so your probably right. I'll plot out the efficiencies at various PRs when I get some downtime to see what's what.

I'm a bit disappointed with the 8474 to be honest. The loss of compressor efficiency to increase the flow potential at the same exducer size seems to be a poor trade-off. It'll be more responsive than the 9174 with a more forgiving surge margin but worse at everything else. I think I would have rather have seen an 87mm compressor sized between the 83 and 91 that was better optimised to fill the 850-900hp power target, but there is no denying the 8474 will have a pretty crazy to end its still pulling like a train when the 83 compressor has fallen o. It's face.. The switch over in efficiency vs the 8374 happens at about 60lb/min at 2bar. I guess we'll see when they start getting into the wild. Here is the link to the new catalog. https://cdn.borgwarner.com/docs/default-source/default-document-library/bwts_performanceturbosgeneral_1892_2130.pdf?sfvrsn=3098b63c_2

I thought the new turbos had larger inducer diameters to increase flow (92 compressor is 73.7/91 instead of 67.8/91 for the 91. wouldn't that increase the trim from 55 to 65 and push the map to the right? or is the 9274 a different compressor again? because otherwise that is going to be more likely to surge not less. will hold judgement until I see a final product catalog with the comp maps and specs on it.

the press release says the 2019 turbo catalog has been published, but I can't find it anywhere.. still the 2018 one on the BW site. https://www.borgwarner.com/newsroom/press-releases/2018/10/24/borgwarner-releases-new-high-performance-turbochargers-catalog

Also what the hell is a 9274 going to be useful on? That is going to be rediculous comp flow for such a turbine.

Full race Geoff I'll take one 8474 supercore thanks

There is a reason all the new tech compressors come with anti surge housings and it isn't for looks.

You'd be pretty game to be making a main cap out of a dissimilar metal to the block. I'd expect there would be issues/fretting due to thermal expansion coefficients?

is the integrated main cap version made from Steel or are they all Aluminium?

I'd like to test that theory about turbine flow, Geoff could I place a standing order for an 8474 supercore [emoji4]