Tuning Twins

I have been kicking this around in my head for a while now. I was under the impression that a waste gate was needed. In some respects i believe it may still be needed. My thought is, if you know exactly where your power needs are then you can size the top and bottom accordingly. In my case I can't seem to leave anything alone and also on a pretty tight budget. This is the reason I am running an HX40/HT3B set up. I know I could do better with a more modern set up. Might as well play with this set a while and see what i can do with it.

What I would like to be able to do is regulate the pressure drop over the exhaust housing/ turbine. The way it is now @30 PSI of boost the wastegate is wide open. The HT3B is doing all the work (3.0 PR). My DP looks great though 1:1 for the most part.

I was thinking of just wiring the gate closed and see what happens.
 
Torque Monkey said:
I have been kicking this around in my head for a while now. I was under the impression that a waste gate was needed. In some respects i believe it may still be needed. My thought is, if you know exactly where your power needs are then you can size the top and bottom accordingly. In my case I can't seem to leave anything alone and also on a pretty tight budget. This is the reason I am running an HX40/HT3B set up. I know I could do better with a more modern set up. Might as well play with this set a while and see what i can do with it.

What I would like to be able to do is regulate the pressure drop over the exhaust housing/ turbine. The way it is now @30 PSI of boost the wastegate is wide open. The HT3B is doing all the work (3.0 PR). My DP looks great though 1:1 for the most part.

I was thinking of just wiring the gate closed and see what happens.
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this is basically what i did on my gate. my drive is at 1:1 also but my primary was dong alot of the work. so i made sure the gate was shut for sure and used the incabin turbosmart boost controller to bypass the boost going to the gate to make sure it didnt open and now boost is around 85ish psi from 75psi, egts are cooler since i am now driving the top turbo harder and drive is still at 1:1. like others have said in this thread, the harder you can drive the secondary turbo, the more power you will make, egts will go down, and total boost will go up.
 
inline6power said:
this is basically what i did on my gate. my drive is at 1:1 also but my primary was dong alot of the work. so i made sure the gate was shut for sure and used the incabin turbosmart boost controller to bypass the boost going to the gate to make sure it didnt open and now boost is around 85ish psi from 75psi, egts are cooler since i am now driving the top turbo harder and drive is still at 1:1. like others have said in this thread, the harder you can drive the secondary turbo, the more power you will make, egts will go down, and total boost will go up.
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Ok, so currently I have about 25 psi boost from the Primary and 50 psi boost total. I need to check these pressure relief valves to see if that is where the problem is with low boost numbers. Assuming there are no leaks for sake of conversation. According to this my PR on the Primary is somewhere around 3.0 and the Secondary is 1.0 +/_. I would like to be able to adjust this to make them more even. My first though was using the waste gate on the HX40 and relying on the spring tension to regulate the exahsut pressure through the Secondary turbine. I just don't think it is strong enough. I was thinking it would be nice to make sure you at least 20 psi more pressure in the exhaust manifold compared to the hot pipe. Not really sure, maybe it needs to be more. In this case I am almost positive that the spring isn't strong enough.

Any other ideas? Maybe I have to install an external waste gate with a reference from the mainfold and one from the hotpipe??? i just don't think it is going to last very long.

I don't race this truck or even compete for that matter. Just towing a travel trailer so this is just an expirement.
 
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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The issue we have found on the race truck is, even with an S476 secondary, the turbine isn't big enough to get out of the way at full go. However if we go any bigger on the turbine we can't get it to spool at the line without nitrous (we sled pull as well so this is a must). Once EFI live is available for the early cr's this will become a mute point as we will have the additional rpm range to work with when using a larger turbine / housing. I have a feeling we will still run one after just for the flexibility.
 
Torque Monkey said:
Ok, so currently I have about 25 psi boost from the Primary and 50 psi boost total. I need to check these pressure relief valves to see if that is where the problem is with low boost numbers. Assuming there are no leaks for sake of conversation. According to this my PR on the Primary is somewhere around 3.0 and the Secondary is 1.0 +/_. I would like to be able to adjust this to make them more even. My first though was using the waste gate on the HX40 and relying on the spring tension to regulate the exahsut pressure through the Secondary turbine. I just don't think it is strong enough. I was thinking it would be nice to make sure you at least 20 psi more pressure in the exhaust manifold compared to the hot pipe. Not really sure, maybe it needs to be more. In this case I am almost positive that the spring isn't strong enough.

Any other ideas? Maybe I have to install an external waste gate with a reference from the mainfold and one from the hotpipe??? i just don't think it is going to last very long.

I don't race this truck or even compete for that matter. Just towing a travel trailer so this is just an expirement.
Click to expand...
with the numbers you posted as far as boost this is what you got

total over all boost = 50 psi
primary boost = 25 psi
primary p/r = 2.7
primary charger % of load = 83%
secondary boost = 9 psi
secondary p/r = 1.63
secondary charger % of load = 33%
overall pressure ratio = 4.4

your primary is doing almost all the work on your setup. you deff need to spin your top charger harder. either you wastegate is open, or you have a boost leak somewhere. really seams like your wastegate is opening to make that much primary boost with only 50psi total boost or you have a boost leak.
 
inline6power said:
with the numbers you posted as far as boost this is what you got

total over all boost = 50 psi
primary boost = 25 psi
primary p/r = 2.7
primary charger % of load = 83%
secondary boost = 9 psi
secondary p/r = 1.63
secondary charger % of load = 33%
overall pressure ratio = 4.4

your primary is doing almost all the work on your setup. you deff need to spin your top charger harder. either you wastegate is open, or you have a boost leak somewhere. really seams like your wastegate is opening to make that much primary boost with only 50psi total boost or you have a boost leak.
Click to expand...


i will do some looking at this tonight and log some of the readings.
 
TorqueMonkey, my compound set-up is identical and I see almost the exact boost readings you are as well.
 
Torque Monkey said:
i will do some looking at this tonight and log some of the readings.
Click to expand...

Headcase98002 said:
TorqueMonkey, my compound set-up is identical and I see almost the exact boost readings you are as well.
Click to expand...

what mods do you guys have on your trucks? with just a plain jane sovo and 150hp sticks and no programming i can see 60psi overall and about 26psi out of my primary.


edit. never mind saw your sig. with that setup you should easily push 70psi plus if your wastegate is infact not opening up or no boost leaks. thats decent fuel for a vp setup granted non monster pump but still
 
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With the box off I see about 50psi total boost and 23psi out of my primary. I'm running a spring gate an trying different springs. Haven't really turned the box on to much with these new injectors, I just put them in Sunday. Im trying to get these things to light quicker, it's just slow spooling.
 
Big Swole said:
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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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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Driving it home yesterday... Did a few WOT runs on the hwy... 70-100...Only reaching 3000 rpms or so..lol.... I'm SO Shell Shocked and scared for life. I was expecting it to Blow up and window the block every time LOL
That's just how things go for me...lol

Something may be wrong or not adjusted properly... or those valves are leaking...

Total Boost was 55-59 psi (ISH)... Primary was creeping up on 35 psi... So based on what ya'll are saying the Secondary needs to worked a good bit harder...

Once I cap those valves off with plugs, IF it's still the same... How should I adjust this to make the secondary work more?
I was used to my MPI kit with the bolt and screw adjuster... With the stock dash pot on there, do I adjust the rod / bolt out or in ?

I just haven't really even had time to look at it closely...

I'll post a vid shortly of the runs and gauges....
 
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Just a slow roll the WOT on the hwy.. Only to 3k rpm's

Total is reaching 57-59 ish... Primary looked to go to 34-35 ish each time...


[ame="http://www.youtube.com/watch?v=AOgNg98Y4co"]http://www.youtube.com/watch?v=AOgNg98Y4co[/ame]

[ame="http://www.youtube.com/watch?v=vNutaqbEXP0"]http://www.youtube.com/watch?v=vNutaqbEXP0[/ame]

[ame="http://www.youtube.com/watch?v=mvKRlGQDez4"]http://www.youtube.com/watch?v=mvKRlGQDez4[/ame]
 
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Nice! What turbos are you running again? I just stepped up to a lot bigger spring on my wastegate today. I'm gonna see what I can do tomorrow. Still not using any fuel box though.
 
Headcase98002 said:
Nice! What turbos are you running again? I just stepped up to a lot bigger spring on my wastegate today. I'm gonna see what I can do tomorrow. Still not using any fuel box though.
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Just bought this truck yesterday.
Source Auto Kit. 64/65/13 over S475 (74.6/96/1.32)

Not really sure what this set / setup should be making really.
Once I get with Rich at Dog House Diesel and get this thing on the dyno.
He's going to really tune it perfectly. For now He'd just sent his nitrous tune file to the previous owner just so he'd have something to run. It's a big smokier that it should be ( extra fuel for the nos obviously) and lower timing I'm sure.

I would assume, tuned perfectly and those valves removed as well as the gate adjusted to make the secondary work harder, I'd think they'd make 60-70 psi for sure...
 
To adjust the wastgate you will either need to make the rod shorter, put in a boost elbow (or other mbc), or add a spring across the arm for more resistance.

I find springs from the hardware store are cheap and easy.
 
I wanna know more about those springs. You got a ballpark for how much tension? Like a throttle return spring but stiffer? I'm new to twins and cant keep the wastgate closed long enough. Whats y'all thoughts on those spring gates?

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I like my spring gate, but the spring it comes with is way too weak. I went to my local Fastenall and found a 38# spring, still a little weak but there's still more tension left in it. Easy to adjust.

Note: the s300 style spring gate may be stiffer than the Hx35 spring gate.
 
I like my spring gate, but the spring it comes with is way too weak. I went to my local Fastenall and found a 38# spring, still a little weak but there's still more tension left in it. Easy to adjust. <br />
<br />
Note: the s300 style spring gate may be stiffer than the Hx35 spring gate.
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I had the same problem with my s 300 spring gate. Stiffer spring from ace hardware and a jam nut seems to be working. I'm still tuning on it so I might have to go stiffer still.

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Dont think i made a sig yet. Got an s300g 62/65/12 over 475 1.10. Still need a primary gauge and dp. Im seeing 55ish total and its pretty laggy. Im thinking the gate is opening prematurely. Think it would hurt to wire the gate closed as a test?

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It Won't hurt for testing, just keep the boost down around 50-60lbs

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Cool im gunna try it. 55 - 60 huh? Whats the max boost a setup like mine would make? 150's, hrvp, and a quad for fueling.

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