Here is a stupid question(i know)

[024lover]

What exactly is a vnt what models were they on..or are they a looks package sorry for the stupid question just wondered.

[90DodgeVNT]

The VNT turbos can be found on:

1989 CSX-VNT
1990 Shadow VNT
1990 Daytona VNT
1990 Lebaron VNT

Check the www.theDodgegarage.com under the section * Turbo Database* for Specs and how it differs from the T-II, Etc.

[desertsnake1991]

Ya´ll forgot to add, that "VNT" means "Variable nozzle turbo". It was an engineering feat, that made the turbine vanes rotate on bearinged pivot points, that allowed the turbo to spool extra quick, and as air flow increased, to open. Much like the inlet guide-vanes and their actuator we had in the my Huey and Cobra helicopters. that I flew (I think all Helo turbines had that system). Just a bit of info...

[Mr. Stroker]

I'm not a diesel guy but i know that now the new trucks are using vnt and they make it sound like its such a big deal. dodge used it in the early 90's its only taken 10 years to catch on.

btw i thought that this might be interesting. my friend who is going to school with me said that the diesels can make 40psi at idle to overcome manifold pressure for egr

so dessertsnake slap one of these on to your daytona and go for a trip down the autoban. that would be fun

[turbovanman]

Quote:

Originally Posted by Mr. Stroker I'm not a diesel guy but i know that now the new trucks are using vnt and they make it sound like its such a big deal. dodge used it in the early 90's its only taken 10 years to catch on. btw i thought that this might be interesting. my friend who is going to school with me said that the diesels can make 40psi at idle to overcome manifold pressure for egr so dessertsnake slap one of these on to your daytona and go for a trip down the autoban. that would be fun

Yeah, Ford is using it on there newer Diesels but they do it an easier way, they alter the turbine a/r housing ratio, less moving parts and way cheaper than Dodges way of altering the turbine blades.

[jimredden]

The real question is, are VNT's actually any better than other intercooled engines? Are there any actual horsepower or torque improvement? My CSX is plenty fast, but there's still a little turbo lag and I know it'll cost me more to replace if I ever need to.

Jim
89 CSX #390
85 Dodge 600 SE T1
89 Dodge raider 3.0

[turbovanman]

Quote:

Originally Posted by jimredden The real question is, are VNT's actually any better than other intercooled engines? Are there any actual horsepower or torque improvement? My CSX is plenty fast, but there's still a little turbo lag and I know it'll cost me more to replace if I ever need to. Jim 89 CSX #390 85 Dodge 600 SE T1 89 Dodge raider 3.0

Thats up to you. There definatley a cork at higher HP and rpm's but they do spool faster than any stock Dodge turbo.

[sdac_guy]

Quote:

The real question is, are VNT's actually any better than other intercooled engines? Are there any actual horsepower or torque improvement?

It is mainly a driveability issue. The VNT has more torque at a lower rpm. Here is the difference on the street between my TII Shelby Lancer, and my VNT Daytona. In the Lancer, I take off from a traffic light normally and once I get rolling I mat the throttle, boost comes up after a bit of lag and then the boost builds and is all in by about 3K rpm. Car feels strong.

In the Daytona, I do the same thing. I take off from a traffic light normally and at about 5mph I mat the throttle. Boost builds immediately, is all in by about 2200 rpm and the right front tire goes up in smoke. It is fun to do.

At the drag strip a totally different driving style is required to launch the two cars. In my Lancer, if I launch below about 4K rpm, the engine bogs. In the Daytona, if I launch above 2K rpm the tires go up in smoke, and if I keep the throttle matted it continues through 2nd gear.

Yet stock, both cars were close on dynoed wheel horse power (both within about 5 of 150). And even with the mods now on both cars, they still dyno near each other (roughly 190+ hp, 230+ torque).

Barry

[024lover]

Thanks for all the help guys...nother question would all 91 shelby daytona's have vnt or not??? if it is stock that is.

[sdac_guy]

Other than the 1989 CSX-VNT, the VNT engine package was only available in 1990.

So there are no 91 VNT's from the factory.

Barry

[contraption22]

Quote:

Originally Posted by turbovanman Yeah, Ford is using it on there newer Diesels but they do it an easier way, they alter the turbine a/r housing ratio, less moving parts and way cheaper than Dodges way of altering the turbine blades.

Actually.. the new Powerstrokes work like this:


The most significant change to the PowerStroke in terms of performance is the variable geometry turbocharger (VGT). A valve on the turbo directs oil flow to vanes inside the turbine housing. The vanes adjust the width of the passages through which the exhaust gases pass into the turbine housing. By changing the passage widths the velocity of the gases increase or decrease. The smaller the passage, the higher the velocity and backpressure. At low engine speeds the vanes are narrow to allow for better acceleration and less lag. As engine speed increases under acceleration the vanes are opened to reduce backpressure while maintaining sufficient boost--up to 25 PSI--to meet the load demand on the engine. This is similar to the function of a wategate. The computer monitors the volume of air entering the turbo through a mass air flow sensor, boost pressure in the manifold with a manifold absolute pressure sensor, as well as intake air and manifold air temperatures and exhaust backpressure to determine how to adjust the turbine vanes.

.... which is exactly how the old Chrysler VNT's worked. The major exception being that the Ford's vanes are hydraulically operated, while the Chrysler vanes were pneumatically operated.

Nobody ever tried to put moving parts on a turbine wheel that is spinning at 170,000 rpm.

[DirectConnection]

I own a VNT Shadow with identical mods and boost as my friend's '89 T-II Daytona. If I'm in 2nd gear on a roll and mat it at 3,000 rpms, there is a second delay, then full boost swings in and of course, full torque starts burning both front tires like an on/off switch. THIS is real fun to do next to the ricer crowds. My friend's T-II Daytona... it will react at 3k, but boost will gradually climb and be full boost by 3,800-4k and starts chirping the fronts. Kinda buffers the "hit" as I call it.

To me... the lag feels exactly the same (at higher rpms). The difference is in the ability to build boost in the lower RPMs and how fast it hits full boost in those lower RPMs. Meaning, the T-II car.... anything over 4k and it will feel like my VNT as full boost will hit almost instantly. I can mat the VNT at 2,200 in 4th and hit full boost, but it makes *so* much torque down at that rpm for what it is (and overboosts a tad) that it frys the clutch.

[turbovanman]

Quote:

Originally Posted by contraption22 Actually.. the new Powerstrokes work like this: The most significant change to the PowerStroke in terms of performance is the variable geometry turbocharger (VGT). A valve on the turbo directs oil flow to vanes inside the turbine housing. The vanes adjust the width of the passages through which the exhaust gases pass into the turbine housing. By changing the passage widths the velocity of the gases increase or decrease. The smaller the passage, the higher the velocity and backpressure. At low engine speeds the vanes are narrow to allow for better acceleration and less lag. As engine speed increases under acceleration the vanes are opened to reduce backpressure while maintaining sufficient boost--up to 25 PSI--to meet the load demand on the engine. This is similar to the function of a wategate. The computer monitors the volume of air entering the turbo through a mass air flow sensor, boost pressure in the manifold with a manifold absolute pressure sensor, as well as intake air and manifold air temperatures and exhaust backpressure to determine how to adjust the turbine vanes. .... which is exactly how the old Chrysler VNT's worked. The major exception being that the Ford's vanes are hydraulically operated, while the Chrysler vanes were pneumatically operated. Nobody ever tried to put moving parts on a turbine wheel that is spinning at 170,000 rpm.

Ahh, thanks, I was a bit misunderstood on Dodges way, the way all the info read, it looks liked it said the turbine vanes, which baffled me, lol! I have seen VNT turbos but never taken one apart to have a look at.