Tuning Twins

Lots of stuff happening now...
Everything is pulled off to be ceramic coated. (Loosing over 400*F from manifold to primary turbo on easy acceleration.)
-I have port matched the new .80A/R housing for the 68mm turbine wheel, and opened up the wastegate ports to 5/8")
-I have port matched the .80A/R housing for the 73mm turbine wheel...left the gates as-is...they are already oversized from Industrial Injection.
-I have port matched the .70A/R housing to the bigger T3 manifold gasket I have. The .70 housing was port matched already, but the new gaskets I found are bigger yet. The waste gate ports are opened up from before.
-Primary housing is being coated in high lustre, and all three T3 housings are being ceramic coated with the "Titanium" coating (Rated at 2000+*F). (Inside and out)
-Hotpipe is being ceramic coated in high lustre. (inside and out)
-Primary turbo mounting bracket is being ceramic coated in high lustre, as it has the elbow and v-band connection on it.
-Ordered turbo blankets from Levi for the T3 and T6 housings.
-Drilled and tapped another 1/8" female npt port into the elbow just before the primaries inlet flange so I can watch the temperature and the pressure at the same time, and not just one or the other.
-Purchased a new 40mm JGS wastegate from a fellow member here.
-During the winter, I will fab up the gate to my system, and have it set to open around the 45psi rising mark, and dump into the hotpipe.
-Heres a couple pictures of the bigger T3 gasket.
 

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Ghostman said:
Extended Power, have you thought about trying a larger turbine housing on the secondary with a smaller wheel? Less velocity at lower rpms but the turbine wheel wont require as much to reach is map, and then less restriction from the secondary at higher RPMs and more DP to the primary? Just thinking out loud?
Click to expand...

I have thought about alot of things.lol

I was wondering how a 63/73/80 or 63/73/70 would work for a secondary...but I want to try everything again with the coatings on them...and without the BD Divider valve on the Silver Bullet.

Going to a smaller turbine wheel would just push my drive pressure up even more without adding a gate.
 
Keeping the heat in has the greatest potential of getting the most spool available. Alot of guys are missing this with their chargers, whether as singles or compounds, & would be amazed at the difference it does make.
Port matching & porting in general also helps with flow which means less DP. Of course there is a fine line when porting. Big is not always best, specially with smaller chargers.

liteweight
 
Well thats what I'm figuring it is....as my last setup was using a 66/71/80 with a smaller 2.880" ID hotpipe that was ceramic coated and wrapped...and it spooled the primary, S480/96/1.32 harder then this setup...(I got 35psi out of the last primary, and have got this 82mm up to only 30psi so far.)

But I haven't pushed the truck really hard since I replaced the flex joint section either...short blips of acceleration....just enough for the wife to slap me...nothing serious though.

Have been watching the temperature on the primary inlet instead of the drive pressure to it. (But like mentioned before, I now have 2 1/8" ports in the piping now, so I can watch the drive and the temperature to the primary.)
 
rlawless said:
...
photobucket-16969-1339496309978.jpg
Click to expand...
I have found this thread very useful, particularly your idea to video the gauges and entering the pressures into a spreadsheet.

I re-created your spreadsheet but have come across some issues with how the load sharing percentages are calculated.

If I simply assume load based upon PR, then with my limited knowledge I would calculate the percentage load for each charger as follows:

for primary charger = [primary PR / (primary PR + secondary PR)] x 100%

for secondary charger = [secondary PR / (primary PR + secondary PR)] x 100%

My issue is that I can't get results corresponding to those in your pic, and also can't understand how either charger can have a percentage greater than 100%, nor why the sum of the primary plus secondary percentages don't total exactly 100% (ignoring rounding of decimals).

Can you please explain this process for me?
 
I never could get the percentages to work exactly.. What you are is the closest I could get it.. I believe its because of the compounding from the primary.. Send me your email address and I'll be glad to send you a copy of the spreadsheet and maybe you can figure it out.. I've been waiting for someone to bring that up, lol. I'm constantly changing things on it..
 
for primary charger = [primary PR / (primary PR + secondary PR)] x 100%

for secondary charger = [secondary PR / (primary PR + secondary PR)] x 100%
Click to expand...

The total PR for the system is primary PR x secondary PR

Thus the ratio of work each is doing is calculated as follows.

for primary charger = [primary PR / (primary PR x secondary PR)] x 100%

for secondary charger = [secondary PR / (primary PR x secondary PR)] x 100%
 
liteweight said:
One other thing
Atmospheric pressure should be added into the pressure on the primary also, yes?

liteweight
Click to expand...
Because pressure gauges read pressure relative to atmospheric pressure, it is necessary to add the local atmospheric pressure to gauge readings. This converts gauge pressure (psig) to absolute pressure (psia) needed for calculations.

Pressure at the primary inlet is local atmospheric minus losses in the air filter system.
 
rlawless said:
I never could get the percentages to work exactly.. What you are is the closest I could get it.. I believe its because of the compounding from the primary.. Send me your email address and I'll be glad to send you a copy of the spreadsheet and maybe you can figure it out.. I've been waiting for someone to bring that up, lol. I'm constantly changing things on it..
Click to expand...
Thanks. I've been lurking here in order to learn, but haven't posted enough to use pm's.

If you could send a copy to my email jdobbyns@gmail.com that would be great.
 
me2 said:
The total PR for the system is primary PR x secondary PR

Thus the ratio of work each is doing is calculated as follows.

for primary charger = [primary PR / (primary PR x secondary PR)] x 100%

for secondary charger = [secondary PR / (primary PR x secondary PR)] x 100%
Click to expand...
I knew how total PR was calculated and understand where you are coming from.

The problem I have with the method you suggest for calculating the ratio of work is that IMHO it doesn't work mathematically. Though maybe I'm missing something, which is the reason for my earlier post.

For the maths issue, take one example when both chargers are operating at a PR of 3.

Since both are working with the same PR, I would assume same work i.e. each one is 50%.

If we use [3/(3 x 3)] x 100% we get 33.3% for both. The total is 66.7% so where is the missing 33.3% work coming from?

If we use [3/(3 + 3)] x 100% we get 50%. This makes more sense to me.

Just trying to understand, and not wanting to be a dickhead.
 
bush65 said:
I knew how total PR was calculated and understand where you are coming from.

The problem I have with the method you suggest for calculating the ratio of work is that IMHO it doesn't work mathematically. Though maybe I'm missing something, which is the reason for my earlier post.

For the maths issue, take one example when both chargers are operating at a PR of 3.

Since both are working with the same PR, I would assume same work i.e. each one is 50%.

If we use [3/(3 x 3)] x 100% we get 33.3% for both. The total is 66.7% so where is the missing 33.3% work coming from?

If we use [3/(3 + 3)] x 100% we get 50%. This makes more sense to me.

Just trying to understand, and not wanting to be a dickhead.
Click to expand...

Good point. I have to think about this for a bit. I'll post back tomorrow.
 
To find the percentage of the total of a product, we'll have to use natural logs.

In this case, ln(3) / (ln(3) + ln(3)) = 50%. Or ln(3) / ln(9) = 50%.
 
me2 said:
To find the percentage of the total of a product, we'll have to use natural logs.

In this case, ln(3) / (ln(3) + ln(3)) = 50%. Or ln(3) / ln(9) = 50%.
Click to expand...

bush65 said:
Thanks for that, I'll give it a try.
Click to expand...
Thanks again me2 for posting that. I gave it a try and the method gives results that I am now comfortable with.

For the primary percentage load = ln(primary PR)/ln(total PR) x 100%

For the secondary percentage load = ln(secondary PR)/ln(total PR) x 100%

Note formatting spreadsheet cells for percentage automatically does the last bit ( x 100%) so don't put that part in the formula.
 
nice spreadsheet.

if it were mine i'd like to have the drive pressure differential (ie drive pressure - boost pressure) as both a number and a percentage.
 
Last edited:
me2 said:
nice spreadsheet.

if it were mine i'd like to have the drive pressure differential (ie drive pressure - boost pressure) as both a number and a percentage.
Click to expand...
In the spreadsheet kindly supplied by rlawless, the column that calculates [drive pressure / boost pressure] can (when the ratio is greater than 1.0), provide the percentage (drive pressure - boost pressure) of boost pressure with fairly trivial mental arithmetic.

[(drive pressure - boost pressure) / boost pressure] x 100%

is identical to [(drive pressure / boost pressure) - 1] x 100%

so read the value from the column for (drive pressure / boost pressure) subtract 1, then move the decimal sign 2 place to the right, in your head and that is your percentage.

If DP/BP was 1.15 then the percentage is 15%
If DP/BP was 1.25 then the percentage is 25%
If DP/BP was 2.15 then the percentage is 115%

The same applies if DP/BP is less than one but the mental arithmetic is a little more difficult

If DP/BP was 0.85, when we subtract 1 we get -0.15 then the percentage is -15% (15% less).

Just pointing this out for those who have the spreadsheet and might be interested.
 
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