Drive pressure

[Big Chris]

What are people seeing for drive pressure on the 4094avnt. I'm considering one but won't if it has high drive pressures and doesn't drop egt's very well

 

[07dirty]

i wanna know what drive pressure is and how you determine it? as for my boost pressure, i tapped into my driver intercooler pipe and ran my vacuum hose for the gauge to that. idk if that the correct way to do it or not. lol

 

[JMK777]

i wanna know what drive pressure is and how you determine it? as for my boost pressure, i tapped into my driver intercooler pipe and ran my vacuum hose for the gauge to that. idk if that the correct way to do it or not. lol

Its the pressure of the exhaust pree turbo that drives the turbo

 

[crazycrew]

Its the pressure of the exhaust pree turbo that drives the turbo

So like from the up pipe? Would that be the place to tap?


Sent from My iPhone

 

[fctry286]

yes. but your best bet would be getting the readings from the manifolds

 

[07dirty]

so if i want to run a bov, i need to run drive pressure of the exhaust manifold

 

[eric.davis]

So like from the up pipe? Would that be the place to tap?

I would tap as close to the turbo pedestal in either one of your up-pipes

yes. but your best bet would be getting the readings from the manifolds

I would say this to be true if you wanted to read EGT's due to the fact you want to read as close to where the turbine is to get the most accurate reading. Granted the pressure difference won't be great.

so if i want to run a bov, i need to run drive pressure of the exhaust manifold

Your BOV will be determined from your throttle input and will vary depending on the percentage you let off when you want it to open.

 

[07dirty]

but bov require some sort of vacuum, so since the lbz doesn't have vacuum ports, doesn't that mean drive pressure will do the job to regulate the bov spring?

 

[Odyssey25013]

You plumb drive pressure into the vacuum port to apply pressure to the valve to keep it shut. Have a weak spring in it and when you let up and the drive pressure goes down that weak spring will open

 

[eric.davis]

you can either run drive pressure or boost pressure either one will work. And like Odyssey said you will have to play with the spring rates in it. Depending on how you want it to work since no 2 people are going to want the same thing.

 

[LBZrcks]

60 psi of drive pressure and ~48 psi of boost with the .9 housing

 

[BUST'EM 504]

Off topic. What drive pressure gauges are you guys using?

I use a auto meter 100 psi boost gauge. You will probaly need a needle valve to keep the gauge from pulsating but some don't need it

 

[whitetrash21]

Is this prior to your converter locking up or after. Your drive pressure (exhaust back pressure) should be close to a 1:1 once your converter locks. But since it's a VGT it'll change based on what your VGT duty cycle is. Either way your at a 2:1 which could lead to issues. I know you said your waiting for it to pop but I would rather gate that or lower your tune till you can get a different charger put on

That was peak. When I saw it, it would hit 70+in first and second. Past that, it was getting to 50-55...... Unless he's seeing different now, it was a little less than 2:1. From what i've heard and seen, vgt's are a lot worse on drive pressure that wastegated turbos. I believe it was Pat that said the stock tune LLY could see 3:1 at times.

 

[bigbird]

Highest I've ever seen on th recall is 170 psi. That before convertor locks. After lock between 90-100. 90 lbs boost.

 

[RoboF16]

4094va
Drive pressure on this thing is all about tuning. Stabilized pressures are 1.5:1 above 35 PSI and closer to 1:1 around 30 PSI of boost. DP spikes in transition can be up to 2:1.
The SDP intake on mine made a huge difference, unexpected but nice.

 

[Harbin_22]

My drive is around 70ish and boost is around 58. The other thing to keep in mind is rpm is gonna run your drive up more with the stocker.

 

[Harbin_22]

My 68 cheeta was making 75# drive and about 43-45# boost and not near as much power

 

[Dudgy]

I'm gonna be putting one in the racetruck too, have one in the towtruck and i see 1:1 most of the time unless i pin it on the Hot setting on the Black Maxx it might go up to 1.5:1, never see over 50 on that one.

I'm really scared to see my racetruck's dp though, probably thru the roof running those low 12's on stock everything. Something's bound to go boom in my motor but it has to last a couple more events before i'm upgrading the turbo.

 

[GeneralTJI]

When I rev 4th out high DP goes crazy... 24-25psi of boost and 50-55psi drive pressure... and that's with the vanes opened way up lol

In the 3000-3300 rpm area it's more of a 1.5:1 ratio....

There is a place however where the truck will make 12-13psi of boost and only 10psi of drive pressure... that type of ratio doesn't last long though when you really start putting any fuel to it