How much HP to expect??

I think you'll hit in the 525rwhp range, maybe a bit more depending
on how hot and humid it is when they make the pulls.

Typical 5.0 mustang with 347ci motor and a T-76 will brush 600rwhp at 10psi.
Seen it several times. So 525rwhp is my safe bet guess. And more would not surprise me.


ho hum, I really hate it when you get a bunch "butt facts" on the internet.
(butt fact: fact someone pulls out of their a$$)

Lets crunch some numbers.

(346ci X .85 X 6,000rpm X .5) / 1728 = 510cfm
(10+14.7)/14.7 = 1.7 PR

510cfm X 1.7PR = 867cfm boosted

867 / 13 = 67 lbs/min


A single T-70 will provide enough flow but will be getting inefficient at the top
end as goes out of the efficiency envelope.
http://i74.photobucket.com/albums/i2...1234/70map.jpg


A single T-76 is better, but again gets inefficient on the top end
http://i74.photobucket.com/albums/i2...1234/76map.jpg


Twin 70's stay in heart of envelope like you want but ride the
the surge limit line as they spool up off idle.
http://i74.photobucket.com/albums/i2.../70maptwin.jpg


Twin 62-1's would be the bomb. Can't ask for a better engine plot out
on a compressor map. Plenty of room to crank the boost up and stay right in center
of envelope too.
http://i74.photobucket.com/albums/i2.../62maptwin.jpg

Quote:

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Originally Posted by r.barn

Lets crunch some numbers.

(346ci X .85 X 6,000rpm X .5) / 1728 = 510cfm
(10+14.7)/14.7 = 1.7 PR

510cfm X 1.7PR = 867cfm boosted

867 / 13 = 67 lbs/min

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What do these represent? (.85, .5)?

Quote:

---

Originally Posted by r.barn

Twin 70's stay in heart of envelope like you want but ride the
the surge limit line as they spool up off idle.
http://i74.photobucket.com/albums/i2.../70maptwin.jpg

---

What is the surge limit and what does it mean?

ya, and you cant run twin 76s on a 6.0 either.....lol.... another butt fact for you im sure

Quote:

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Originally Posted by ramair2002

What do these represent? (.85, .5)?

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.85 is the volumetric efficiency for the engine.
This number is fudged cause you never really know what your engine Ve is.
but .85 is for 85% Ve, which should be somewhat close.

.5 is cause 4 stroke engine. Pulled formula out of turbo engineering book I have.

Quote:

---

Originally Posted by ramair2002

What is the surge limit and what does it mean?

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http://www.rbracing-rsr.com/turbo/Tu...pressormap.gif

Operating characteristics: The compressor operating behaviour is generally defined by maps showing the relationship between pressure ratio and volume or mass flow rate. The useable section of the map relating to centrifugal compressors is limited by the surge and choke lines and the maximum permissible compressor speed.

Surge line: The map width is limited on the left by the surge line. This is basically "stalling" of the air flow at the compressor inlet. With too small a volume flow and too high a pressure ratio, the flow can no longer adhere to the suction side of the blades, with the result that the discharge process is interrupted. The air flow through the compressor is reversed until a stable pressure ratio with positive volume flow rate is reached, the pressure builds up again and the cycle repeats. This flow instability continues at a fixed frequency and the resultant noise is known as "surging".

Choke line: The maximum centrifugal compressor volume flow rate is normally limited by the cross-section at the compressor inlet. When the flow at the wheel inlet reaches sonic velocity, no further flow rate increase is possible. The choke line can be recognised by the steeply descending speed lines at the right on the compressor map.

Quote:

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Originally Posted by TurboMic

ya, and you cant run twin 76s on a 6.0 either.....lol.... another butt fact for you im sure

---

Sure you can, depends on what rpm you're running and boost levels.
None of them are wrong, but sometimes with a little research you can find better for your particular wants and needs........

Also comes down to whether you want big top end power with some low end lag
or less low end lag but limited on top end. ...... We've all been thru this before.

Plotting out on a compressor map isnt some end all be all answer either
but it will tell if you're in the ball park and how different turbos compare
for same given theoretical engine flow numbers.

And if I remember correctly, twin 76s is the limitation that many catagories have in the LSX shootout.

Quote:

---

Originally Posted by r.barn

.85 is the volumetric efficiency for the engine.
This number is fudged cause you never really know what your engine Ve is.
but .85 is for 85% Ve, which should be somewhat close.

.5 is cause 4 stroke engine. Pulled formula out of turbo engineering book I have.

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Thanks! I think... :confused:

I'm surprised the T-70 is maxing out already! I thought it was good (and efficient) for at least another 100hp! I may have to re-think my set up...

I'd sell the T-70 and put a single Master Power GT-45 or GT-42 with like 1.0 a/r on.
They run about $800.

Should bolt up ok, maybe have to put different V-band connector on downpipe.

Quote:

---

Originally Posted by r.barn

I'd sell the T-70 and put a single Master Power GT-45 or GT-42 with like 1.0 a/r on.
They run about $800.

Should bolt up ok, maybe have to put different V-band connector on downpipe.

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Even with the rear mount? It seems like it might be a little laggy with that exhaust side...

lol, a single turbonetic T-106!

Quote:

---

Originally Posted by ramair2002

Even with the rear mount? It seems like it might be a little laggy with that exhaust side...

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Those extra cubes and those heads especially are going to
move a lot more air. Intake upgrade to match them wouldnt be bad idea either.

Those 243/317 heads flow MUCH better than the LS1 or truck heads.