how does one go about to check this? Is it easy, simple hand tools or do I need special tools?

 

Drive pressure traditionally on a single turbo isnt really that important. All it is is the pressure coming out of your exhaust manifold. So if you tapped the exhaust manifold and ran it to a pressure gauge that would be your drive pressure. It is a little more complex than that, but that is it in a nutshell. Like I said drive pressure really only matters on a twin turbo setup.

 

so when I set up twins, should I tap an other hole by the pyro and install a boost gauge to read the drive pressure?

 

yes, if you would like to know. use copper tubing on the manifold.

 

and any boost gauge will work right, would a 0-60psi cover it. What kind of number would one see with hx35 and a s400 twin setup

 

any psi gauge, even oil. here is a hx35 over a S400 with mach 6.5's.


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I'm running an HX35 over a 400 right now... I have a 14cm housing on the 35 and a slightly massaged wastegate.

My drive pressures are 1:1 up to 55psi and at 65psi my drive pressures are 68-70psi...

Oh and I never have EGT issues at my HP level..
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so is 1:1 good? What is bad and what would be perfect. I take that what ever the final boost psi I end up with the drive pressure gauge should exceed that number

 

yes 1:1 is good meaning at 45psi dp is 45psi.

on a stock turbo when you overboost it at 42psi or whatever the dp is like 70psi something. that is bad, all hot air. thats when the HG goes pop.

 

oh I see so is it possible to get the dp under the boost pressure?

 

i think so, before the boost get high, the dp is lower.

 

i talked to a guy that did a hx35 over a ht3b with a 40cm internal wastegate and had 45psi dp with 55psi boost. the main thing is to get the turbo is its "comfort" range with minimal restriction.

 

You could also just watch the pyro and you're boost gauge. Usually is around the 1:1 area. If you start seeing more than just a haze, you peak on boost and you're pyro is going to moon, you're over the 1:1 ratio

The drive pressure is always important measurement. It tell if you have more power available in the exhaust. Single turbo will peak and then just restrict the exhaust flow. Its up to the wastegate at the point, if its big enough to dump enough exhaust.

 

You could also just watch the pyro and you're boost gauge. Usually is around the 1:1 area. If you start seeing more than just a haze, you peak on boost and you're pyro is going to moon, you're over the 1:1 ratio

The drive pressure is always important measurement. It tell if you have more power available in the exhaust. Single turbo will peak and then just restrict the exhaust flow. Its up to the wastegate at that point, if its big enough to dump enough exhaust, egt's and drive pressure will be at 1:1. If the truck wants more boost (tons of fuel) and there no boost left (hot air), you get more than 1:1

 

You can also control your DP with a wastegate. I have a 60mm JGS wastegate that is tapped into the exhaust manifold. Its preset at certain psi to release and then dumps into the hot pipe going into the bottom turbo so that energy is not wasted and will help to spool up the bottom turbo and still keep DP in check. Works very well.