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Great numbers. Using this boost drop-off test to determine FI efficiency appears to be a great way to identify recommended highest boost level for engine longevity. Haven't seen this before, but seems like common sense now I've read it. Love your work!
As an aside, it would be interesting to see this "boost drop-off" test done on a Greddy manifold, and on Slash128's top mount setup.
I really think this behavior is peculiar to the Renesis and relates directly to effect the Siamese port has .
I don't think other engines would see such a sharp dropoff in performance like this .
Edit. As far as the breakthrough I mentioned earlier in the thread: hasn't really panned out as a true breakthrough otherwise the effect I'm talking about above would have disappeared completely. But I do see an improvement over previous attempts.
Thanks man .... It's actually at the point I can say it's a genuine 400whp daily now as the power/boost doesn't start dropping away till over 15psi so I know the engine is happy there.
Just did this comparison so you can see what I mean :
Assuming the base for an NA engine is 190whp
up to 14.3psi I get 14.6 whp for every psi of boost
from 14.3 to 15.9psi I only get 7.5 whp for each additional psi .
So the return from the extra boost is HALVED after 14.3psi !
BTW :we did another run at 14.3psi which netted 405whp
Hm.
Noticed something,
one atmosphere is 14.696PSI, being a bit accurate here just for fun. So relative to atmosphere, NA is giving:
190whp/14.696 = 12.93whp for every PSI.
While FI:
405whp/(14.696 + 14.3) = 405/28.996 = 13.97whp for each PSI.
Noticed something,
one atmosphere is 14.696PSI, being a bit accurate here just for fun. So relative to atmosphere, NA is giving:
190whp/14.696 = 12.93whp for every PSI.
While FI:
405whp/(14.696 + 14.3) = 405/28.996 = 13.97whp for each PSI.
Something is obviously done very good!
I think the losses from the drivetrain are a smaller % of the total as you make more power .
As a point of interest , I dynoed on that same dyno in the video in 2014 with my old Greddy 60-1 setup and made 360whp at 16psi (this time 424 at a shade over 15psi). That day the operator told me there was bad knock in the engine . This time he said engine noise was fine . You can actually see the readout from the knock sensor at the end of the video ..... green line to bottom right.
Very impressive Brett. I might not understand all the calculations you used to determine which turbine and impeller to use or how to set up the fuel mapping but I can appreciate that it takes a lot of time and study.. The amount of effort and persistence it took to get these results would have most people walking away a long time ago. Now you just need to make up some "Brettus turbo kits" and sell them to recoup some of your investment. LOL
Very impressive Brett. I might not understand all the calculations you used to determine which turbine and impeller to use or how to set up the fuel mapping but I can appreciate that it takes a lot of time and study.. The amount of effort and persistence it took to get these results would have most people walking away a long time ago. Now you just need to make up some "Brettus turbo kits" and sell them to recoup some of your investment. LOL
Thanks nz .... Making kits isn't on the agenda , but maybe I'll do something with an established supplier one day ....
Thanks nz .... Making kits isn't on the agenda , but maybe I'll do something with an established supplier one day ....
I think time is right for that. A conservative kit, that is. I think 300 - 350whp kit, that does keep engine life cycle as good as possible.
If its possible to shield from heat, one idea might be to 3D print some of the cold side piping. Thinking about the morons who has steering wheel on the wrong side and end up with way too little space
My knowledge is limited, but a friend who has some, said that there are plastic material that can handle well beyond 100°C. From this link 150°C seems to be obtainable: https://www.simplify3d.com/support/m...polycarbonate/
^As mentioned, if you can shield from radiated heat. I've lost track of Bretts layout.... And cold side will receive cooling from the air going through, i suspect the materials used in stock turbo setups rely on this quite heavily, it tends to be not too exotic materials....
I think time is right for that. A conservative kit, that is. I think 300 - 350whp kit, that does keep engine life cycle as good as possible.
If its possible to shield from heat, one idea might be to 3D print some of the cold side piping. Thinking about the morons who has steering wheel on the wrong side and end up with way too little space
You are not wrong .... that bloody steering column is right where you don't want it for a decent turbo kit!
Just for interest I plotted this chart as best I can for compressor flow. I'm using information gleaned from both matchbot and actual logs to get it as close as I can to reality. Intake vacuum has a big effect on Pr at higher flows but as the compressor is staying nicely in it's sweet spot this effect has been minimised by the high efficiency.
Looks like it's right up against the surge line on spoolup suggesting even if I could make it spool quicker it wouldn't be a good idea especially considering I don't have the antisurge housing!
Unfortunately the number of RX8 owners that will install a turbo kit at this point is pretty small and many of them will be on a budget looking for used kits where possible. Still there will be the occasional owner that wants the best performance an 8 can put out. The list of modifications Brett has made to his system is extensive and I have lost track of it.
Brett if you are willing to share please list out the main components used to produce the 400 HP, like exhaust dia. after cooler size, intake (2.5 with a 2.25 adaptor RH drive only) tuning modue etc.
Brettus, did you ever consider getting a compressor wheel with less blades, this should offer more air flow at low pressure ratio, don't shoot though I am trying to think out loud
Unfortunately the number of RX8 owners that will install a turbo kit at this point is pretty small and many of them will be on a budget looking for used kits where possible. Still there will be the occasional owner that wants the best performance an 8 can put out. The list of modifications Brett has made to his system is extensive and I have lost track of it.
Brett if you are willing to share please list out the main components used to produce the 400 HP, like exhaust dia. after cooler size, intake (2.5 with a 2.25 adaptor RH drive only) tuning modue etc.
Exhaust : twin system with separate pipe for WG ...Guess it's Equivalent to a 3.5" diameter single pipe.
Intake to turbo : 3"
Maf : extended stock maf range by about 15% using resistors
Intake manifold: stock , VDI wired shut.
Intercooler pipework : 21/4 straight off turbo to 21/2" rest of system
03-13-2018, 11:18 PM
It is what it is man, so long as you are having fun in the meantime that is all that matters.
