Tuning Twins

Updated Turbo Tuning Spreed Sheet

Corrected issues are:

1) Percentages between chargers are now accurate. (A great thanks to: bush65 & me2)

2) Drive pressures readings are more accurate. (A great thanks to: AH64ID)
 

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ok guys i've read this whole thread from top to bottm and over and over. i have all the stuff listed in my signature... except i havent put in the 75%over nozzles yet because i dont have the mods for the CP3 to keep up just yet.

my boost numbers are 65psi total, and 25psi coming from the primary right now. if i put in these 150-170hp injectors(75% overs) this thing is going to want to make insane amounts of boost right?! all i have is a TiAL MV-S external with the boost source line coming from the secondary to the top of the gate. i dont have a manual boost controller on it yet... but something tells me i have too big of a spring in the external. i find it interesting that im seeing boost numbers that are equal to what others are running with similar setups BUT also with 150hp nozzles.

any help or advice would be much appreciated.
 
I could hit peak boost for my set on stock nozzles and a crap load of duration and it was California clean out the pipe. Monster injectors turn the same boost black at 1/2 the duration.

Short answer you can hit peak boost on a lot less fuel than what is required for max power.
 
yea i understand you, and thanks for replying. but shouldnt the boost jump up a fairly good amount when i actually add the fueling i need. cause my EGT's at 65psi are 1100degrees with the Smarty TNT software on level 9.


i was gonna try running level 7 and see if it works any better. but it doesnt spool that bad without nozzles. better than i thought actually. cant imagine with 75% overs.

and i know 75% overs arent that big of nozzles for my set of turbos. but this is still my dd
 
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Im sorry but i have read and still dont fully understand how exactly to tune both of the turbos.

I have a Boost gauge tapped to the intake horn ofcourse, and ill b attaching another to the s475 in a couple of days.

Wouldnt it b easier for me too just clamp of the wastegate on my 64/71/14 and leave it like that?

And if so how is it you guys divide the work load between both of them?

Also how do i tell if my s475 is internally gated?
 
luke7474 said:
Wouldnt it b easier for me too just clamp of the wastegate on my 64/71/14 and leave it like that?

And if so how is it you guys divide the work load between both of them?
Click to expand...

Adjusting the waste gate to open at an optimum psi is how you tune the two chargers to share the load.. Down load the Turbo Ratio Worksheet above and look at it, maybe that will help you understand it..
 
Thanks ill try and figure it out a bit better.

My last question is do you guys have 3 boost guages, Total, Top charger and bottom charger.

Or wich way is easiest.
 
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You need to watch the drive pressure to your secondary. (small turbo)
You need to watch the amount of boost from your primary. (Big turbo)
You want to see your overall boost, combined from both turbos...going into the engine.

Other options:
A gauge to watch the amount of drive pressure inside the hot pipe. (exhaust out of secondary, flowing into the primary.)
EGT gauge inside hot pipe to see how much heat is being used by your secondary, and lost before it gets to your primary. (only on ford and dmax twins, because of the long hot pipe.)
Turbo speed sensors on both turbos would tell you exactly where they are operating in their map...if you have the maps.
 
So three guages then
1 Intake Horn
2 Exhaust manifold
3 S475

Got it thanks

I also got a couple of exhaust leaks to work on.
 
i think the problem i am still having is that im using the biggest spring possible in my external( 24psi base). im thinking that if i drop the base spring pressure down a little bit more to say around 18-19psi. the gate can open sooner and let my primary do more of the work. i dont think my 65psi total boost... 25psi from the primary is doing me a lot of good right now. any ideas?
 
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