It turns out its not a good choice for a 20B semi PP. All out of compressor at a bit over 700hp at the hubs (Mainline hub dyno). It might go another 50hp or so on a mild port 20B, and more on a 13B.
1.30 Tialsport turbine housing, E85 fuel.
MGP = manifold gauge pressure

 

thanks for the post and info on your situation. BTW, it is great to see you are on my favorite ecu.

think Link.

you are pretty smart guy logging backpressure, especially as it is the prime suspect as you are approx 100 short of where you should be given the compressor map. of course some of this could be the dyno but the big thing that jumps out is your backpressure.

19 psi boost, 34.7 back pressure, 76% more than boost and 15 PSI net force back into your intake charge air. this creates misfires and moves you closer to knock and pre-ignition. do you have a zero smoothed dyno graph?

here's my most recent run for comparison:



G40-1150 T4 divided 1.06. 22 psi, 30.2 backpressure. 37% to boost.

i believe we have the same (really good) turbine tech. my average hotside diameter is 6.58 square inches and yours is 8.9, 35% larger. the area comparison is valid as we have the same tech on our wheels. it would seem your turbo manifold is a primary culprit. you are making the equivalent of 466 on a 2 rotor. of course there could be a significant number of other factors but given what you have posted back pressure is certainly a prime suspect.

i also note you are having to close the WG quite a bit near the end of the run to maintain fairly modest boost. something, probably backpressure, is holding your setup back. note the WG is paralleling backpressure.

what rpm is the crossover point boost/backpressure

 

For my own personal curiosity, can you post a photo of the manifold/turbo area?

 

I am curious as well.

What diameter is your down pipe / exhaust?
What diameter are the turbo manifold runners?

 

2in ID turbo mani runners. 4in downpipe/exhaust - one straight thru muffler. Tial 60mm gate in turbine housing.

 

20Bs seem to swallow a huge amount of air, especially semi PP and hi flowing intake mani.

 

Timing is true?

Leading and trailing leads not swapped.

Conventional maths says it should do ~800hp, especially on a hub dyno.

 

by virtue of the fact that you have a 3 rotor you have a large amount of 1500 F tubing very close to your aluminum intake runners.

the entire challenge of making safe power is to get lots of oxygen molecules into your motor. (i know you know that)

efficient compressors, efficient intercoolers, efficient fuels, efficient low drag systems. all to get lots of oxygen into the motor.

working directly against this efficiency is the 1500 degree heat from the exhaust/manifolding. you have lots of it and it is close to your aluminum lower intake runners.

one of aluminum's distinct qualities is heat transfer. there are only 3 metals (copper, gold, silver) that transfer heat more efficiently. that's a bad thing as to the LIM.

i see you have recognized this and have a heat barrier between the LIM and the manifolding. the problem is that it is ineffective.

according to The Engineering Toolbox:

aluminum heat transfer coefficient is 240
titanium is 24
stainless steel is 14
MICA is .71
fiberglass (your barrier's primary working component is) .04

wow, fiberglass looks even better than MICA. the problem is there is very very little of it compared to the mass of a solid 1/4 inch of MICA. it is a bunch of strands. strip the fiberglass out of your panel and weigh it. then compare it to the weight of a sheet of mica.

how important is it to have effective heat shielding? Cam Worth was dynoing an FD that seemed to be ******* it a bit. he noticed the turbine was close to the LIM and didn't have heat shielding. he picked up a piece of stainless steel and placed it between the the turbine housing and LIM. during the next run the AFR improved one whole point. since the heat was primarily effecting the front runners that would mean the front rotor moved 2 full points.

i suggest you replace the ineffective heat shield with a 1/4 inch sheet of MICA. please see my section on system setup: anywhere you can put mica shielding, do it.

SYSTEM DESIGN

Mica P/N 85165K82 @ McMaster Carr (1/4 inch) this P/N is perfect size for a 2 rotor, you may need additional

the second thing would be to add a thermocouple to the front LIM runner. you have a high dollar investment in your engine bay and you are currently blind to one of the most important metrics. (this is assuming you don't have an air thermocouple.... maybe you have and just haven't mentioned it... )

https://thesensorconnection.com/prod...rcharger?v=567

a thermocouple type IAT sensor should be standard equipment on all single turbo rotaries. simply put, if you don't have one you have no idea as to your IATs.

at 600+ in the above run my IAT was 71 F degrees. if you measure IAT w a "fast" acting thermistor you will find it is approx the same temp as before boost. this is because a thermistor is glacial as to rate of change.

we have ultra efficient turbos. the Garrett "G" technology is awesome. at 83 pounds per minute the temp out of my compressor was 241.9 F. this is 60 degrees less than my EFR9180. typical temp out of the compressor of other turbos would be around 400. do the math re IC and AI heat reduction and you will see your actual IATs (from a non G turbo) are around 200.

my efficient intercooler removed 65% of the compressor generated heat uptick (137) and the 600 cc of W/M removed the other 66.

you have a couple of other things working against you on your setup. your air intake/filter is not partitioned off against the 125 underhood engine bay temp when the hood is closed.

more importantly, your air intake is positioned directly in the exhaust from the intercooler. when you consider that the IC is removing 130 F from the charge air and much of it goes out the back end of the IC.... and that's where your intake is.

all of the above making it important to know your IATs

suggest before turning the key:

wrap your manifold runners
MICA heat shield
thermocouple IAT sensor
relocate your air filter out of the IC exhaust
600 cc W/M

not making the changes may result in more than just being down power.

i would reorient the output from the compressor to the bottom and enter the IC endtank at the bottom for a direct shot to the endtank and diagonal flow thru the IC. this would allow a 4 inch tube from your compressor to pass by the IC to get cooler air.

 

I have done that exact setup with that exact intake. Made 820HP @ 18PSI (mailing hub dyno on literally the same setup(projay, semipro 20b, g45-1350 , 1.44 vband)

 

840HP with the 1450 comp wheel fitted (essentially a G45 1475 for all intents and purposes). Much better. Engine is a lot happier too. At max engine rpm the compressor is very close to its published flow limit however, so there is no point driving turbine back pressure up in search of boost it'll never make. Being a drift car with all of the associated airflow problems that lead to excessively high temps, the tune is purposely kept ultra conservative.

If the engine was a secondary bridgeport instead of a semi PP I think the compressor could be pushed to 900hp @ around 2.6 pressure ratio.

 

Whats the driving impression?

It looks like the original G45-1350 the boost came on very nearly linear and full boost at 4,500rpm.

The G45-1450 the boost ramps exponentially with full boost at 5,000rpm.

Now, I know the hub dynos have a very hard time simulating actual vehicle dynamic load and the spool characteristics can be different on the road.

Jusy based on dyno results the 700hp g45-1350 looks like a VERY different turbo to drive over the 840hp g45-1450.