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Series I Major Horsepower Upgrades This is the place to discuss Super Chargers and Turbos, Nitrous, Porting, etc
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Old 09-28-2018, 11:52 AM
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This is a thread for exchange of numbers when using MatchBot. Since our rotary is a bit different, itís a jungle to get the correct numbers.

Your opinion is not welcome unless you present your numbers, when you believe numbers presented by others are wrong, preferably with some simple explanation and math if possible.

If you have a question, please explain thoroughly, preferably with numbers/pictures. I can guarantee that other people are wondering the same questions, so donít be afraid of asking! Just put some effort into the question.

If you have numbers and charts for a good working setup, sharing is much appreciated!

And for the record, I'm not knowledgeable at this, I'm starting this thread to understand more. So do not expect good answers from me, but hopefully people will chime in, and together we'll get more knowledge.

Adding the initial picture of MatchBot for reference.

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Old 09-28-2018, 10:27 PM
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Here are numbers from my current setup that match very well to what I see in reality .




*I'm using 70mm 0.92 AR turbine match which seems to line up well with my Garrett 68mm 1.01

Last edited by Brettus; 09-28-2018 at 10:35 PM.
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Old 09-29-2018, 04:15 AM
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Turbo :
I have tried a few different combinations of turbine housing and compressor wheel in the GT3582r base turbo .
In the final analysis I saw only minor improvements going from the stock GT 35r wheel to a billet GTX3576r wheel .
I found the larger 1.01 AR twinscroll turbine housing to be superior to the 0.83 in all respects .
The slightly better spoolup of the 0.83 did not translate to more power at the wheels in lower rpm ranges as you might expect.
For a low mount turbo the GT3582r AR1.01 with a To4B compressor housing was a good choice for the 350-400whp level . Fitting a better turbo (eg BW EFR ) down low would require a lot of firewall modification .
One day we'll see some great results from a top mounted EFR that will better what this setup is doing ........ not holding my breath on that one though.
*I'm using 70mm 0.92 AR turbine match which seems to line up well with my Garrett 68mm 1.01
Honestly, and I've really tried, I'm not able to get the overview picture from this, there are too many numbers and figures running around in my head to get the overview. If you bother, some spoon- feeding would be great. Hopefully, I'm not the only one too stupid to follow you.
https://www.turbobygarrett.com/turbo...ing-AoverR.jpg
https://www.turbobygarrett.com/turbo...housing_sizing
Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.
So, since we are at relatively low boost, we would benefit from a relatively large A/R.

Back to MatchBot:
1. Why is your highest RPM set to 7600? When playing around, I've been at 8500 and even 9000, always thinking worst case.
2. When increasing max RPM to 8000, then do some guesstimations together with the numbers you represent, it looks like the EFR7163 that Team mentioned earlier is a good match, comments?:

3. Calculated Exhaust manifold pressure is 20.6PSI with a 70mm 0.92AR. This seems to be matching quite nice with your findings:
Originally Posted by Brettus View Post
I just replace my flexible intake with a solid one and seeing some good results for turbine backpressure
Backpressure at 14psi with solid intake:

Looks like a 1.5-2psi reduction at peak ...which is equivalent to going up almost 2 steps in turbine A/R
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Old 09-29-2018, 01:38 PM
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First thing that I have become acutely aware of through my project is a quote from Hartman : "everything effects everything else". The parameter that reflects this the best IMO is turbine backpressure. Any change you make that improves or restricts flow will be evident in what turbine backpressure (EMAP) you achieve so it is well worthwhile to be able to log this parameter. What isn't so obvious is how EMAP affects performance. The relevant parameter in Matchbot for this is BSFC. This is not something matchbot can calculate and you can only guesstimate the effect of EMAP on BSFC through trial and error.

1/ I set my highest rpm to 7600 because that is where I've found peak horsepower to be with my setup. At lower boost with a less than ideal setup it will be at a higher rpm. As I've improved my setup , the peak hp-rpm has gradually got lower and lower. I believe this is all about how well the engine ports flow.
2/You are doing yours at 10psi and mine was at 15psi . At 10 psi with a free flow setup , all the pressure losses will be lower than what you show there .
3/Not an apples for apples comparison - same issue as in (2)

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Old 09-29-2018, 03:20 PM
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Also : you need to choose a turbine that matches your chosen turbo .... The 70mm0.92 is wrong for the 7163. I think you will find that backpressures will be quite high once you rehash pressure losses , put the right turbine in and alter the compressor efficiencies to suit the correct pressure losses.
Edit:
I just did the exercise with a free flow system the 7163 and the 63mm0.83 and got 21psi backpressure @10psi and 8000rpm which would be acceptable . But raise the boost to 15psi and you end up with about 32 psi backpressure.

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Old 09-30-2018, 05:29 AM
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This is what i got for my setup.
Not sure about how accurate the figure is, but I''ve driven my friend's manual E46 M3, and I can feel that my car pulls much harder than his M3.
I also drove another friend's HKS supercharged manual 86. that one is also slow compared to my 8.







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Old 09-30-2018, 11:01 AM
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Originally Posted by Brettus View Post
Also : you need to choose a turbine that matches your chosen turbo .... The 70mm0.92 is wrong for the 7163. I think you will find that backpressures will be quite high once you rehash pressure losses , put the right turbine in and alter the compressor efficiencies to suit the correct pressure losses.
Edit:
I just did the exercise with a free flow system the 7163 and the 63mm0.83 and got 21psi backpressure @10psi and 8000rpm which would be acceptable . But raise the boost to 15psi and you end up with about 32 psi backpressure.
Why is 70mm 0.92A/R wrong for a EFR7163? Is it explainable, or is it just experience that is giving this answer? I can some recommendations to have a smaller turbine wheel than compressor wheel. I do not understand intuitively why a smaller turbine wheel is better. I get that there will be a gearing in tip velocity(tip of compressor vanes will go faster than tip of turbine vanes). I can also see that keeping turbine diameter within 15% of compressor is one recommendation. Are we looking for the same in our beloved rotarys, or do this change for us?

Example Application:
I want to make a 10PSI turbo system, because my engine is original and un- modded, and I want to run on normal pump gas.
Looking at MatchBot, EFR7163 looks like a decent compressor for the flow(see earlier post for picture). This compressor have a 71mm diameter. 71mm - 15% = 60.44mm minimum. Adjusting expansion ratio for 64mm 1.05AR, I end up with a maximum of 2.5(+exhaust back pressure).


Am I ready to order just by this? Sounds a bit to easy....
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Old 09-30-2018, 11:14 AM
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"everything effects everything else"
Word. In my previous post, I forgot to alter Volumetric efficiency. Below picture is more correct according to Brettus data set, makes a difference in Expansion ratio for turbine, pressure goes down from 2.5 to 2.35. So as :
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Old 09-30-2018, 02:20 PM
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Originally Posted by AAaF View Post
Why is 70mm 0.92A/R wrong for a EFR7163? ..
Because that turbo doesn't come with that turbine ...it comes with a 63mm turbine only. The number 71 stands for 71mm INducer compressor and 63 stands for 63mm INducer turbine. Other turbos use different naming methods:
Garret 3582 means : 35 series frame size with an 82mm EXducer compressor
Precision 6262 means : 62mm INducer compressor with a 62mm EXducer turbine
Very confusing

IMO the smaller turbine is a good reason not to use that particular turbo as the Renesis is very sensitive to backpressure . I would go with the 7670 all day everyday to do a 10psi setup. Becomes doubly important if you plan to run pump gas.

For your post above ..IMO :
you have way too much pressure drop on the air filter restriction . A top mount can be very free flowing so something around 0.6 at 8000 is more realistic.
You probably have too much for intercooler assuming all your pipes are correct diameter and it's a decent sized IC: somewhere around 1.5 at 8000
Muffler ... if you are using a store bought catback system that could be 3-4 at 8000 . If you make a free flowing one it could be down around 2

Last edited by Brettus; 09-30-2018 at 09:46 PM.
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