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pulling the trigger on an EFR9174. Fullrace Geoff, maybe you could chime in here.

should I be going an alloy or cast iron bearing housing? need a $80usd kit for a retainer ring for the alloy housing to turbine flange otherwise costs are the same.

thanks!

Alex

its not a billet chra, it is cast alloy with the necessary machining.

going on a revvy 2.7L nitto engine with a big flowing head.

have an 8374 but its close to max speed. not very keen for the turbine wheel to remove itself from the shaft. Its a simple (and relatively cheap) supercore swap. all external dimensions remain identical. a few 9174 results in FG falcons seem to handle 800 hub horsepower at ~5600rpm on a 4 litre at 26psi, so i think it should be ok on a 2.7 @ 8500rpm.

matchbot reckons I'll have to delay boost onset for about 300rpm later than the 8374 was happy at to keep it out of surge but it's worth it for the extra legs of the compressor. the 8374 was over in the 65% efficiency area where the 9174 will be around 74% for the same flow. this alleviates back pressure by some margin, without having to go to a larger A/R turbine so VE should be improved also. from my calculations we can run 45kPa more boost to achieve the same pressure delta accross the engine at the very top end.

I had some concerns about the strength of the alloy cartridge really.. on a racettrack with a 105 degree water temp and a 900 degree exhaust side pumping in the heat. (this is obviously worst case scenario)

yield stress of some aluminium alloys really drop away in the 120-140 degree range (especially 7075). I'm not sure what this CHRA is made of but that was my concern.

it will obviously be water cooled in this application.

Edited by burn4005
  • Like 2
On 18.1.2017 at 10:10 PM, blah_blah said:

So we are saying then a 7670 wont fit stock position in an RB25?

Not sure on that, but could be possible.

 

On 19.1.2017 at 4:06 AM, discopotato03 said:

Mothot I thought of the T3 single scroll IW version too and it will be very interesting to see your results .

I had this running from mid 2015 till mid 2016.

Short spec list:

RB25DET Neo (OEM pistons, Eagle con rods, ARP head studs, Cosworth metal head gasket)
Borg Warner EFR 7064 T3 IWG
OEM intake & exhaust manifold
big FMIC (noname?)
Apexi pod air filter
OEM R35 GTR injectors (570cc)
Walbro in tank fuel pump
Z32 AFM
Tomei Poncams Type B (260° In/Ex, 9,15 Lift In/Ex)
custom 3" stainless steel downpipe
100 or 200 cell cat (not sure which, very budget piece nonetheless)
Blitz Nür Spec R exhaust

 

Results from a roller dyno mid 2015, see below.

Its all german, so i'm gonna help you guys out a bit:

DIN-Leistung = crank HP

Rad-Leistung = wheel HP

The rest should be pretty obvious.

This run was with max boost of about 1.5 bar / 22 PSI. Dropping off to around 1,3 bar / 19 PSI at max RPM.

Did another run on low boost (1 bar / 14,5 PSI) that yielded 353 PS / 260 KW / 474 NM at the crank, 314 PS / 231 KW at the wheels.

The graph doesn't really show how it drove on the street:

Boost coming on from about 2K RPM and 1 bar / 14,5 PSI at 3K RPM, full boost before 3500 RPM.

Exactly what I wanted :-)

DSC_1241b.jpg

 

On 24.1.2017 at 5:25 AM, VFRegal said:

@MotHot Are you having any issues with controlling boost ?

As you can see from the dyno sheet, after 6K RPM boost is falling off.

Probably because the exhaust side is too small for the RB25.

  • Like 1

Should have comparison between the PT 6266 Gen 2 and the 8374 in few weeks, that should be interesting as they are both rated around 800 BHP.

Trouble is they will be done on different Dynos so not a real back to back comparison.  But worth a look I think.

 

  • Like 3

i think the most interesting part of that comparison is the transient response, which a dyno isn't very good at showing.

boost threshold graph need to start at same load (Id say completely off the thottle at 2500rpm, then WOT. and use similar ramp rate)

transient boost needs time on the X axis rather than speed. you want to be falling to 5000rpm completely off the throttle, then WOT.

outright power is more difficult if the dynos are totally different, and to me, far less important.

  • Like 1
2 hours ago, burn4005 said:

i think the most interesting part of that comparison is the transient response, which a dyno isn't very good at showing.

boost threshold graph need to start at same load (Id say completely off the thottle at 2500rpm, then WOT. and use similar ramp rate)

transient boost needs time on the X axis rather than speed. you want to be falling to 5000rpm completely off the throttle, then WOT.

outright power is more difficult if the dynos are totally different, and to me, far less important.

I too,  find Dyno Graphs to be confusing , I thought 300KW would be 300KW on all of them all

Then I am told it depends whos dyno and how they do the runs, I think they just give you an idea and they are tuning tools.

I will wait until the car is done and see what I think, more importantly the boys will let me know what they think and I value there opinions more than a Dyno,but I guess at the end f the day there is only one bloke that has to be happy , me :)

I will put the results up, some may find the comparison helpful, but ??

I would like to take it to a few other shops to see what the Dyno differences are, now that would be interesting !

 

I have found my car spools at lower rpms on the street consistenly over what it does on the dyno. Dyno makes it seem laggy when compared to street logs. But I don't have access to a load bearing dyno yet.

 

 

 

 

3 hours ago, HarrisRacing said:

I have found my car spools at lower rpms on the street consistenly over what it does on the dyno. Dyno makes it seem laggy when compared to street logs. But I don't have access to a load bearing dyno yet.

 

 

 

 

That would be interesting to see both the inertia and the load bearing Dyno Graphs to compare them

3 hours ago, HarrisRacing said:

I have found my car spools at lower rpms on the street consistenly over what it does on the dyno. Dyno makes it seem laggy when compared to street logs. But I don't have access to a load bearing dyno yet.

 

 

 

 

I thought all dyno's were load bearing?

2 sorts.  One has a LOAD CELL.  The other is an inertial type.

The type with a load cell does not "bear" any load.  it simply has a means to measure the torque (with the load cell) while dissipating the power in a brake.  The inertial type work by spinning up a heavy mass and calculating the power put in by the time taken to spin it up (hence, inertial type).

 

/rocket surgery.

41 minutes ago, Nismo 3.2ish said:

From what I found out the load baring type has an Eddy Brake that sort of mimics driving on the road

What GTSBoy said - but to add here, there are different kinds of load bearing dynos... an eddy brake dyno is one of the options (which the Oz manufacturers use). Dynapacks use a hydraulic brake.

1 minute ago, Lithium said:

What GTSBoy said - but to add here, there are different kinds of load bearing dynos... an eddy brake dyno is one of the options (which the Oz manufacturers use). Dynapacks use a hydraulic brake.

Hi Dan, why do the different Dynos read power on the same car differently?

Do they just play with it to look better to bring the customer back ?

 

from my understanding it's like any 'tool' in which you use to measure...

It comes down to calibration...then the method used to calibrate...

 

As has been mentioned many times take dyno readings with a grain of salt and use them primarily as a tuning tool..

1 hour ago, Nismo 3.2ish said:

Hi Dan, why do the different Dynos read power on the same car differently?

Do they just play with it to look better to bring the customer back ?

 

Different methods used to measure power and different calculations for correcting the results to try and eliminate influence by conditions on the day.

As a result there are totally dynos which read higher or lower figures for the exact same setup, but in most cases it's not to try and pull the wool over people's eyes- naturally competitors will suggest otherwise if someone else's dyno reads lower than their own though sometimes that claim is actually bollux. 

I think those workshops who continously tell customers their dyno reads low (or otherwise) are the worst - just be straight up about the result and what it means in context.  

 

Sooner or later it's going to become clear if the car is fast or not so why let the dyno dictate that? It's just a tool.

 

Fwiw the dyno I use to tune reads on the high side compared to average and you can't get more straight up than I am about what is going on - for better or for worse.  It happens to be a tool I have the privilege of getting to use and I love the fact that there aren't tyres involved to add an extra variable to try and track and control when trying to repeat conditions when tracking the effect of changes 

Edited by Lithium

My workshop of choice has a Dynotech (by Dyno Dynamics) that reads a bit lower than most in the local area. They don't claim their figures are lower. It simply punches out the data and whatever power it makes is what it makes.

I have been pleasantly surprised, on a couple of occasions, at dyno days when my car (both my R33 and Golf GTI Pirelli) has produced 18kW and 21kW more than at my workshop of choice. I could probably take my R33 to a workshop with a dyno that is a touch more optimistic and get a 500+kW figure. But there's no point, I know it won't have gained anything in the real world.  

A mate in the industry was telling me about a situation recently where a car was tuned at one workshop and produced 400kW at the rear wheels. It was then taken immediately to another workshop where it recorded 295kW. I used to think most dyno readings were within 20-30kW or so regardless - hub dyno aside.         

2 minutes ago, whatsisname said:

A mate in the industry was telling me about a situation recently where a car was tuned at one workshop and produced 400kW at the rear wheels. It was then taken immediately to another workshop where it recorded 295kW. I used to think most dyno readings were within 20-30kW or so regardless - hub dyno aside.         

Yes, this definitely happens. With rolling road dynos even the exact same setup can get different results with different tyres, or different ways of tying them down etc.  That's one of the reasons I am not a fan of them pesronally.  Ironically, the highest reading dyno I know of (won't mention names) in NZ is a rolling road dyno... I have no idea what they've done to get the readings they get but it's insane - but it's repeatable enough to gauge comparisons so I guess it suits the purpose, at least so long as people don't believe that their car with a much higher figure than anyone else with the same setup is actually that much more powerful.

Just now, Nismo 3.2ish said:

Gee Dan , my tool has been dictating to me forever :/

Your dyno is the hub type ?

Do they read high because there is no tyres to loose traction

Lol Pete, touché :)

Yeah, the fact the tyres aren't a solid link means there is less wasted energy - not to mention having to spin the wheels around etc. It's also a thing which makes the data more precise and therefore it's much easier to trust the data you are getting from the dyno software.  If I had more money than I had anything to do with I'd have a Mainline hub dyno :)

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