Tuning Twins

5.9 Cummins Fan said:
Reporting back on some testing yesterday on a set s364 over s595. I remember seeing Big blue post that his interstage pressure was in the 50's or something along those lines. I encountered this yesterday tuning a set on a load dyno. First run the interstage pressure was 59 psi, made great power but was fairly slow to spool. The small charger was at a pretty low PR but I realized that the high interstage pressure may be due to not spinning the HP turbo fast enough. It makes sense to me the pressure goes up when there is resistance to flow, IE a slowly spinning charger. On the following runs we drove the HP turbo harder each time. The setting we left it on had a 450 degree drop in egts from the 1st run and we saw a significant hp increase with no fueling changes from run to run. I will see if the truck owner can send me the dyno graphs to give a definant hp increase number. Not saying all setups may be like this, as this may be a unique case with the primary being so large. But in the end the charger PR's were fairly close at WOT with drive to boost ratio being just a little over 1:1. Just trying to help this thread out some more.
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By driving the HP turbo harder you see power go up and Egt go down, were you going tighter on the w/g? I played with my w/g setting a little at the track but all 6 runs were 1800-2000 on the pyro and all trap speeds were close.
 
Okay on my twins I have a Hx40 over a s475 I'm new at twins could I just hook my waste gate to a tee in the primary boosted gauge because it wouldnt open to like 20-25lbs then I have a adjustable boosted elbow so I wouldn't have to run and external waste the mainfold and top turbo..
 
Quick question for you turbo specialist.

07 5.9 CR with a source auto kit 64/65/13 over S475 ( 74.6/96/1.32)
flux 3's (150hp range) (or 75-80% overs) and dual fuelers. EFI live.

Only the internal gate on the 64...64 has the stock dash pot.

Is this setup good for close to 800hp worth of air?
If not, where's it need to live?
Whats the possible flow on these?

Atl, Ga area... Close to sea level.


How bad is that 65 turbine gonna hurt things?
Swaping to the 71 be very beneficial?
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Yes it will move 800hp worth of air.

Loose those brass pop off valves ASAP, that is the easiest way to overspeed a charger and take it out. They were a poor idea in the late 90's and they are a poor idea now.
 
dvst8r said:
Yes it will move 800hp worth of air.

Loose those brass pop off valves ASAP, that is the easiest way to overspeed a charger and take it out. They were a poor idea in the late 90's and they are a poor idea now.
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x100000 plus they do not seal after 10 miles or so. you set them to 70psi and they will open at 20psi. best thing to do is loose them like mentioned.
 
inline6power said:
x100000 plus they do not seal after 10 miles or so. you set them to 70psi and they will open at 20psi. best thing to do is loose them like mentioned.
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Interesting....

I will be pulling the one off my twins tonight...

:thankyou2:
 
dvst8r said:
Yes it will move 800hp worth of air.

Loose those brass pop off valves ASAP, that is the easiest way to overspeed a charger and take it out. They were a poor idea in the late 90's and they are a poor idea now.
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inline6power said:
x100000 plus they do not seal after 10 miles or so. you set them to 70psi and they will open at 20psi. best thing to do is loose them like mentioned.
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Thanks!!

So just 86 the valves and let it ride as it sits huh..


It's not my truck YET..
So I assume they screw out and plugs can be screwed back in?
 
Torque Monkey said:
Interesting....

I will be pulling the one off my twins tonight...

:thankyou2:
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Big Swole said:
Thanks!!

So just 86 the valves and let it ride as it sits huh..


It's not my truck YET..
So I assume they screw out and plugs can be screwed back in?
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yup. when i put my kit on i had them set to 75psi on the dot. truck made 70psi out of the box and i was like ok they are close. after about 10 minutes of driving truck would only make around 60 psi. so i tightened the chit out of those valves and and still would only make 60psi. took them off thinking they were the problem and boost jumped up to 83psi. i have also seen a couple of them fail and drop the spring and valve parts into the intercooler. deff the best thing you can do is take them out and you can controll boost with the fuel or throttle if need be.
 
It's always interested me to read about all the gates and tuning and all on componds.
When mine were built Keating built my secondary, said run X primary and all will be well.
That was several years ago now and my 62/71/14 over a 1.32 S478 from ED makes ~65 psi, 25-26 from the primary, 1:1 drive pressure and there's not a gate to be found. the primary starts coming to life at about 20psi from the secondary and it's full song about a split second after that.
My question is why deal with them at all?
 
Yeah, I'll let Rich control the boost / power with EFI..

He's building a "Swole" tune.. Not gonna let me have all the torque down low and keeping max timing in check... LOL

I'll be kept on a short leash by He and Jeff.. lol
 
UNBROKEN said:
It's always interested me to read about all the gates and tuning and all on componds.
When mine were built Keating built my secondary, said run X primary and all will be well.
That was several years ago now and my 62/71/14 over a 1.32 S478 from ED makes ~65 psi, 25-26 from the primary, 1:1 drive pressure and there's not a gate to be found. the primary starts coming to life at about 20psi from the secondary and it's full song about a split second after that.
My question is why deal with them at all?
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is the 62 non gated? i am with you really, if they are sized right you do not need a gate but the only way to add more drive pressure to the primary is to bypass exhaust to it. i think a factory spring style gate on the top charger is all anyone ever really needs but if sized properly no gate is needed at all in my opinion. right now on my setup, my gate on my top charger is blocked completly off and i am making 83psi overall with 32 out of my primary and drive is at 1-1
 
I have no gates anywhere. I left the number crunching to Hellmann, Keating and Chris and couldn't be happier.
 
UNBROKEN said:
I have no gates anywhere. I left the number crunching to Hellmann, Keating and Chris and couldn't be happier.
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i have to agree with you. if everything is sized correct for your setup then no gate is needed really.
 
So his 64/65/13 ^ 475, Is this considered "properly sized"?

Sure seems to drive / spool great... Pretty dang quick too!

Hoping to get away with these for a while.. And go bigger later.
 
When I melted my motor, I was running the same 62/71/14 I am now with the internal gate disabled. I THINK the high DP at 100 PSI was PART of the reason the piston bowls are no longer round. I didn't have a DP gauge at the time so I don't know what it was running for a PSI/DP ratio. I do have one now and the gate running off a normal elbow (not an adjustable boost elbow) and it is 1:1 up to about 75-80 PSI then DP takes over really quick, spool is NOT the same as it used to be for obvious reasons.

I have yet to decide how to go about regulating the gate. Leaning toward using a cheap Turbo Smart boost controller.
 
SHughes said:
When I melted my motor, I was running the same 62/71/14 I am now with the internal gate disabled. I THINK the high DP at 100 PSI was PART of the reason the piston bowls are no longer round. I didn't have a DP gauge at the time so I don't know what it was running for a PSI/DP ratio. I do have one now and the gate running off a normal elbow (not an adjustable boost elbow) and it is 1:1 up to about 75-80 PSI then DP takes over really quick, spool is NOT the same as it used to be for obvious reasons.

I have yet to decide how to go about regulating the gate. Leaning toward using a cheap Turbo Smart boost controller.
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i am running one of their in cabin boost controller and love it. i set the gate on my top charger as loose as i could get it, about 2 threads in the coupler lol, then do all the adjustments with the incab unit. i had it set this way for a long time but drive pressure would open the gate because i had it set so low regardless of what my controller was at. i now have the gate set pretty tight and make sure the incab controller vents all the boost going to the gate so its basiccally gateless now and it runs strong this way.
 
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