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Discussion Starter · #1 ·
Any of you guys running Twin Turbos and considering running with a Motec M800 ECU I now have my car tuned so if you want a copy of the loaded tune you are very welcome.
 

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What kind of HP you making? :z:
 

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Discussion Starter · #3 ·
Dyno'd on a "Mustang 1500" Dyno at 498 BHP at only 7lbs boost.
I am going to get the wastegates opened up to allow for about 20lbs boost and will then see what sort of numbers it produces :)
 

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Whew, according to my calcs, 20 psi should give you about 802 rwhp!

What static compression ratio are you running, and what are the specs on your cam at 0.050" lift?

Have you beefed up the drivetrain too?
 

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Discussion Starter · #5 ·
I'd be very happy with 802 :)

I have an Exedy twin plate clutch but apart from that the tranny and drivetrain is stock.
The engine has a 383 Lunati stroker kit fitted as part of the turbo install. This included the dished pistons which gives the car a compression ration of about 8.4:1
I had the heads ported and spoke to a guy I know Lingenfelter about cams and he recommended the stock one as there is not much better out there on the market.....unless you know better :)
 

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vetteheadracer said:
I'd be very happy with 802 :)
Well, based upon what you did at 7 psi, I broke it down and built it back up using 20 psi. Alright, here's what I did:

Finding crank hp (..CHP) first, using .85 for manual trans:
CHP = RWHP / .85
CHP = 498rwhp / .85 = 586 CHP

Now we need to find what your engine does normally aspirated (..NA), or without the blower. First we need to find the Pressure Ratio (..PR) which is the number of atmospheres above normal the engine 'sees'; normal is 14.7.

PR = (14.7 + psi) / (14.7)
PR = (14.7 + 7psi) / (14.7) = 1.476 PR
(..this means your engine 'sees' nearly an extra half an atmosphere)

The calculation to find NA CHP on a forced induction (..FI) engine:
NA CHP = (FI CHP) / PR
NA CHP = (586 FI CHP) / (1.476 PR) = 397 CHP
(..so your motor is putting out approx. 397hp at the crank without the turbo's)

Now we have everything to project how much HP will be generated at 20psi; here's the calc, it should look somewhat familiar:

Starting with the same calc above, we solve for FI CHP:
NA CHP = (FI CHP) / PR
(NA CHP) x PR = (FI CHP)

And just rearranging we have:
FI CHP = (NA CHP) x PR

First we need to find the PR at 20 psi:
PR = (14.7 + psi) / (14.7)
PR = (14.7 + 20psi) / (14.7) = 2.361 PR

Finally, we have everything to find the HP produced at 20 psi:

FI CHP = (NA CHP) x PR
FI CHP = (397 CHP) x (2.361 PR) = 937 CHP

RWHP = CHP x .85 (..manual tranny)
RWHP = 937 x .85 = 797 RWHP!

For simplicity's sake, I omitted thermal losses, etc.

You will without a doubt need hardened output shafts, etc, with that setup. Also, spend whatever it takes to get a good tune!

This included the dished pistons which gives the car a compression ration of about 8.4:1..
With that low of compression ratio using an 85% efficient intercooler with a proper tune, the calcs say that you can safely run 30 psi.

...and spoke to a guy I know Lingenfelter about cams and he recommended the stock one as there is not much better out there on the market.....unless you know better :)
I'm a centrifugal supercharger guy, so I would stick to what Lingenfelter says regarding cams and turbos since they are the experts in turbocharging.
 
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