Brettus turbo 111 (the ultimate Renesis turbo ?)
#1553
Did a test to check boost pressure drop over the intercooler and pipework . Looks like around 2psi total at peak rpm (7500) and close to zero at 4000rpm .
Boost at manifold :
Boost at turbo:
From this and other previous tests I believe I have the following pressure losses (at 14.5psi) in the system at this point:
Intercooler pipework turbo to intake mani. : 2.5 psi
Muffler system : 2.5psi
Intake system : 1.5 psi
None of the above is huge but you can see they all add up and each has an effect on turbine back-pressure.The task to get turbine back-pressure down further from here is very difficult and expensive. I can now see how it would be a crap load easier to get the best WHP from a top mount system.
Boost at manifold :
Boost at turbo:
From this and other previous tests I believe I have the following pressure losses (at 14.5psi) in the system at this point:
Intercooler pipework turbo to intake mani. : 2.5 psi
Muffler system : 2.5psi
Intake system : 1.5 psi
None of the above is huge but you can see they all add up and each has an effect on turbine back-pressure.The task to get turbine back-pressure down further from here is very difficult and expensive. I can now see how it would be a crap load easier to get the best WHP from a top mount system.
Last edited by Brettus; 03-04-2018 at 03:00 PM.
#1555
Hybrid Greddy Boosted
From this and other previous tests I believe I have the following pressure losses (at 14.5psi) in the system at this point:
Intercooler pipework turbo to intake mani. : 2.5 psi
Muffler system : 2.5psi
Intake system : 1.5 psi
None of the above is huge but you can see they all add up and each has an effect on turbine back-pressure.The task to get turbine back-pressure down further from here is very difficult and expensive. I can now see how it would be a crap load easier to get the best WHP from a top mount system.
Intercooler pipework turbo to intake mani. : 2.5 psi
Muffler system : 2.5psi
Intake system : 1.5 psi
None of the above is huge but you can see they all add up and each has an effect on turbine back-pressure.The task to get turbine back-pressure down further from here is very difficult and expensive. I can now see how it would be a crap load easier to get the best WHP from a top mount system.
Edit: Would be good to compare this with losses on a Greddy setup, being the most common turbo setup. For those that want to tweak their Greddy setups for more efficiency.
Last edited by JimmyBlack; 03-05-2018 at 05:47 PM.
#1557
Hybrid Greddy Boosted
That's right, with my best Greddy setup at 7krpm and 10psi the exhaust manifold backpressure was 33psi, giving a BPR (back pressure ratio) of 3.3:1 - pretty inefficient and unhealthy for a turbo setup. I'm hoping my new setup with Greddy manifold and external wastegate will give a lower ratio (will update my thread after this weekend).
#1559
Hybrid Greddy Boosted
I haven't. My IAT sensor is located after IC before TB. Once I installed it I found that it was a bit laggy with the readings, not showing instantaneous temp. Would only produce useful results in a prolonged pull at fixed load/rpm/boost. Why are you asking, IC sizing?
#1560
SARX Legend
iTrader: (46)
I just know some high HP turbo drag guys use the temperature at the compressor outlet to determine if the backpressure is too high. But you need an IAT sensor that will read to like 400F or so.
#1563
Here is my latest dyno . Taking into consideration that this dyno reads conservatively (akin to a Mustang in the US) I think the results are pretty good . Best peak number I've made so far and far and away the best torque at 302lb/ft .
The difference between this and my earlier 411whp dyno is that the engine was comfortable at this power level . The dropoff of boost at the end of the run is due to where I set the wastegate to open.
For anyone that doubts the effectiveness of virtual dyno (when used properly) check this actual dyno vs the VD on the previous page . Within 1% on both power and torque !
The difference between this and my earlier 411whp dyno is that the engine was comfortable at this power level . The dropoff of boost at the end of the run is due to where I set the wastegate to open.
For anyone that doubts the effectiveness of virtual dyno (when used properly) check this actual dyno vs the VD on the previous page . Within 1% on both power and torque !
Last edited by Brettus; 03-10-2018 at 05:33 PM.
The following users liked this post:
jcbrx8 (03-13-2018)
#1565
Really didn't want to take it higher given the idicators .
#1567
Combustion pressure ....no idea ....
#1568
I suppose I'm getting back to your comments in this post https://www.rx8club.com/showpost.php?p=4826030&postcount=1339
where you think the exhaust ports are overwhelmed rasing combustion pressure.
I would like to know if you think you could run to 9k and higher boost without the backpressure of the turbine?
where you think the exhaust ports are overwhelmed rasing combustion pressure.
I would like to know if you think you could run to 9k and higher boost without the backpressure of the turbine?
#1569
I suppose I'm getting back to your comments in this post https://www.rx8club.com/showpost.php...postcount=1339
where you think the exhaust ports are overwhelmed rasing combustion pressure.
I would like to know if you think you could run to 9k and higher boost without the backpressure of the turbine?
where you think the exhaust ports are overwhelmed rasing combustion pressure.
I would like to know if you think you could run to 9k and higher boost without the backpressure of the turbine?
Short answer ...no . SC or turbo ...backpressure or not .
I've changed my thinking a little since then - I think past a certain engine flow /chamber pressure - it's the siamese port sleeve that becomes the overriding issue, not the exhaust ports themselves.
#1570
Ah got ya now .
Short answer ...no . SC or turbo ...backpressure or not .
I've changed my thinking a little since then - I think past a certain engine flow /chamber pressure - it's the siamese port sleeve that becomes the overriding issue, not the exhaust ports themselves.
Short answer ...no . SC or turbo ...backpressure or not .
I've changed my thinking a little since then - I think past a certain engine flow /chamber pressure - it's the siamese port sleeve that becomes the overriding issue, not the exhaust ports themselves.
#1571
As far as spotting it ... diminishing returns from boost , even though you think you have everything in place to minimise backpressure.
#1574
Congratulations Brett! 381hp at 13psi is a fantastic result, I'd say. It means that a boost that does not reduce life expectancy of engine drastically, can actually deliver very impressive numbers. On top of that torque is nice and flat, not just a big lump.
#1575
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
Last edited by Brettus; 03-13-2018 at 04:48 PM.
The following users liked this post:
jcbrx8 (03-15-2018)