View Full Version : Anyone driven a VNT/Auto car??
Im thinking about building one (already have the parts), but curious if anyone else has done so and if so, what their opinion on it was.
Any info appreciated.:nod:
ShadowFromHell
11-09-2010, 09:16 PM
It would be interesting. It has been a while since I drove a VNT car, but my dads rampage with a 2.5/mitsu spools so fast I can not imagine It being any faster!
GLHNSLHT2
11-09-2010, 09:45 PM
I don't know, I've only driven a VNT once. And while the boost was instant there still wasn't any power. No flow through the rest of the motor. I plan on having VNT like boost on my automatic, with a ported head, my big plenum intake, and a S60 turbo. Probably just end up blowing the tranny :)
Well, at least half the reason i want to use the VNT stuff at all is just for the fact that its unique. I am not SO much interested in real power, although i am pretty much set on upgrading the compressor side to some extent. Depends on what parts donor turbo i can get for cheap. Regular 60 trim t3 wheel from a merkur seems likely.
It would be mostly stock to start though.. 86-87 t1 2.2 bottom end, stock g-head, stock 1pc (to start), stock tIV intercooler, etc. I AM considering putting it on a tbi header with an external wastegate, though. I think the EWG is the biggest thing the VNT setup needs other than a bigger compressor.
Im thinking of putting this in the executive sedan with a 2.6FD lockup trans, so weight + gearing is going to kill the speed in any case.. i just want it to be nice to drive (i think a 2.2 at 15psi would count, even with the weight, but itll NEED instant/constant boost) and get good highway mpg (limo should be a road-trip car, right?).
Thanks for the thoughts so far... anyone else?
sdac guy
11-09-2010, 10:53 PM
With 2.5 cat back exhaust and a chip that allows 14 psi boost, my VNT Daytona makes 174 hp at the wheel, with full boost by 2100 rpm. Very similar to, or better than, a fairly stock T2 setup. It does fall on it's face at 5000-5200 rpm though as it just can't breathe through that restrictive exhaust turbine housing.
As it is, if I take off easily from a stop light and once I am doing about 10 mph floor the gas, the tires just break loose and burn through 1st, sometimes into 2nd.
IMO, if it was an automatic, the torque multiplication at launch would just make it worse. Very little traction in 1st and maybe 2nd also.
It would certainly be a fun drive, and would impress folks on the street, being able to roast the tires almost at will. But it only adds to the low end the car already has which to me is not good for overall performance.
Barry
Oddly enough, i seem to have a different opinion than most people about the 2.2's torque (keeping in mind this will be a 2.2).
To be clear, all my personal experience has been with cars built with stock parts.. i.e. no big turbos, major porting, etc.
I have never for half a second thought that any 2.2/auto car, either log or with a basic t2 setup, was remotely torquey without boost, and even with boost the ones i have driven are underwhelming. I have never experienced a 2.2/auto burning through first gear. In fact, i have had a 2.5/auto t2 setup up to 14psi and only occasionally would that break loose in 1st, and only after the boost kicked in (15 mph or so?). In comparison, my 2.5/5spd aries will often burn through 2nd at 7psi. My 2.2/5spd spirit doesnt have traction problems in 2nd until something like 14 or 15psi, and thats with worse tires.
Having driven comparable low-power, stockish setups in both 2.2 and 2.5, manual and auto, its been my experience that the auto ALWAYS makes tire spin less likely than with a 5spd, and makes the car a LOT slower. I have not paid close attention to spool but they seem to make transient spool-up slower as well, although they do allow you to build boost before rolling if you want to.
Anyway, I think that perhaps putting an external wastegate on a tbi header will help with the high rpm restriction of the vnt turbine housing.. Wont know for sure until i try. It's definitely never going to make power above 5k unless i put something better than a stock 1pc intake on it.
Thanks for the input.
ShadowFromHell
11-10-2010, 02:46 AM
My experiences, with the 2.2/auto have been the same as yours. That said, My dads 2.5/auto rampage with a mitsu makes 1st gear useless. Tire smoke on demand. But, it has a 90 motor and tranny. I THINK that the later cars, 89+ have a higher stall then the 88 and older cars. My Ny has a T2 swap, and with a 300rpm higher stall I think it would respond very similar to the rampage. With the lower stall, all the older cars 2.2 cars I have drove seem to have the converter engage a few hundred RPMs before the car spools. The rampage does not have that problem, BUT the 2.5/mitsu vs a 2.2/t3 is apples to oranges on spool time. One thing I did to my NY that seemed to REALLY help the low end was swapping to a 88 T1 roller cam. I swapped one into my 2.2/carb rampage and it seemed help it too.
I think the key here, is in the converter. But, from what it sounds like what you want to do, why not go for a 3.0/3.3/3.8 swap?
Mostly because i think the vnt thing will be more unique and get better mileage. AND, i already have all the parts and its an easy swap.
Big_P
11-10-2010, 08:59 AM
This is going to be cool. Where did you get the VNT stuff?
clocktowersniper
11-10-2010, 09:09 AM
I have driven one. It wasnt the fastest but it was unique. Thats what I liked about it.
blk86trbo
11-10-2010, 10:27 AM
Hey man this is kinda ironic, as I was contemplating the same exact thing when reassembling the 85 Lancer ES last month! In the end I chose a mitsu, because I figured that the difference in spool would be minimal. Also, since the Lancer has a non-lock-up auto tranny, and is going to see lots of highway use, there's a chance it may occasionally see some higher RPM's...in which case, the VNT's negative aspect of choking up could possibly become an issue.
A friend of mine mentioned that most people wouldn't be able to identify a VNT turbo while it's tucked back behind the engine anyhow, and that if I wanted to make people think twice, I should merely install some "VNT INTERCOOLED" decals on the hood, and then use what ever turbo is best for the application LOL!
But it's definitely a neat idea! If you have the parts available and that's what you want, go for it! :thumb:
sdac guy
11-10-2010, 11:06 AM
Oddly enough, i seem to have a different opinion than most people about the 2.2's torque (keecar ping in mind this will be a 2.2).
To be clear, all my personal experience has been with cars built with stock parts.. i.e. no big turbos, major porting, etc.
I have never for half a second thought that any 2.2/auto car, either log or with a basic t2 setup, was remotely torquey without boost, and even with boost the ones i have driven are underwhelming. I have never experienced a 2.2/auto burning through first gear. In fact, i have had a 2.5/auto t2 setup up to 14psi and only occasionally would that break loose in 1st, and only after the boost kicked in (15 mph or so?). In comparison, my 2.5/5spd aries will often burn through 2nd at 7psi. My 2.2/5spd spirit doesnt have traction problems in 2nd until something like 14 or 15psi, and thats with worse tires.
Having driven comparable low-power, stockish setups in both 2.2 and 2.5, manual and auto, its been my experience that the auto ALWAYS makes tire spin less likely than with a 5spd, and makes the car a LOT slower. I have not paid close attention to spool but they seem to make transient spool-up slower as well, although they do allow you to build boost before rolling if you want to.
Anyway, I think that perhaps putting an external wastegate on a tbi header will help with the high rpm restriction of the vnt turbine housing.. Wont know for sure until i try. It's definitely never going to make power above 5k unless i put something better than a stock 1pc intake on it.
Thanks for the input.From your comments it seems you don't have much experience driving a VNT. It is unlike any T1 or T2 car. It builds its boost down low, making it a VERY torquey response.
My VNT Daytona has been my summer daily driver for over 10 years now. On the street, I can break the front tires loose at nearly any speed in first gear (without revving the motor up first). With full boost coming in at 2100 rpm it darts through traffic unlike any other turbo mopar. There is NO turbo lag.
Here's the difference I've seen at the drag strip. My Omni (T1) and my Lancer (T2) both need to be launched above 3500 to keep the engine from bogging in the first 60'.
My VNT Daytona, if I launch above 2000 rpms, the tires just go up in smoke and 2nd gear is nearly as bad. That is how ALL correctly running VNT's should run.
The only mods from stock on my car are the 2.5" cat back exhaust and a chip that allows 14 lps boost. The car runs a mid 16 quarter mile, but the speed (about 90) shows it should be a mid 15 or quicker car. But without slicks it is nearly impossible to launch it without massive tire spin, ruining the 60' times.
If you only have the VNT engine and not the correct wiring harness with the 3 VNT solenoids and the correct engine controller, you may as well swap the turbo and make it a T2. You cannot properly control the VNT turbo without these items.
Barry
This is going to be cool. Where did you get the VNT stuff?
Off a VNT daytona that Strax22 and i parted out for his van a few months back. Other parts of it are on my other cars.
A friend of mine mentioned that most people wouldn't be able to identify a VNT turbo while it's tucked back behind the engine anyhow, and that if I wanted to make people think twice, I should merely install some "VNT INTERCOOLED" decals on the hood, and then use what ever turbo is best for the application LOL!
Lol, that would be mean! Get everybody all worked up for nothing.. :p
From your comments it seems you don't have much experience driving a VNT.
That's true, i have none. Never driven a VNT car. It's probably going to go down just like several of my other 'firsts'.. first 5spd car i owned was the one i built. First running/boosting turbo car i owned was the one i built,and now the first VNT car i ever drive will probably be the one i build.
I do have the correct harness and everything else from the VNT daytona, for the record.
What you said has me thinking now that if the turbo spools up BEFORE the converter stalls.. then yes, there might be some crazy torque multiplication going on. I admit that before i didnt really consider that possibility after your first post.. it didnt sink in. Now i am VERY curious. Limo Burnouts ought to get some looks.
sdac guy
11-10-2010, 03:43 PM
What you said has me thinking now that if the turbo spools up BEFORE the converter stalls.. then yes, there might be some crazy torque multiplication going on. I admit that before i didnt really consider that possibility after your first post.. it didnt sink in. Now i am VERY curious. Limo Burnouts ought to get some looks.
Yep, definitely a possibility!
Best of luck with your build.
Barry
Dusty_Duster
11-10-2010, 04:02 PM
What you said has me thinking now that if the turbo spools up BEFORE the converter stalls.. then yes, there might be some crazy torque multiplication going on. I admit that before i didnt really consider that possibility after your first post.. it didnt sink in. Now i am VERY curious. Limo Burnouts ought to get some looks.
What if you put a less restrictive manifold and some bigger cams on it to shift the power band up a little higher?
Well, since im putting the car together i can decide before hand how i want the converter to be. Although realistically id be choosing between like a 3.0/670 converter and a neon 2.0 converter. ive had both and they are pretty different stall, both cheap too. I think i will probably just err on side of torque and go with the neon converter.
As far as moving the powerband up.. well, making it spool at a higher rpm is one thing, i can probably do that just by messing with the factory dual port can on the turbo. I doubt i will try to make it spool up slower, though. As far as making it make power at a higher rpm.. That comes down to 2 basic things.. the 1pc intake, and the turbine side of the VNT. Those are the things that would hold it back the most at high rpm. I am building a modded 1pc for the aries right now. If it works well i can build another one for the limo. As far as the turbine housing, i dont know that i would modify it before trying it the way it is (i havent driven a vnt, i want to know what im trying to fix before i try to fix it), but the turndown piece that hooks to the downpipe looks like a big POS and looks easy to build a better one. I probably WILL do that.
Even with the stock crazy spool, hooking it up to a tall gear auto is going to make it pretty easy to modulate, i think. Even if i never rev it past 5000 rpm either, 5000 rpm is over 50mph in 1st gear with a 2.6 fd and tall tires.
Reaper1
11-10-2010, 06:27 PM
I've driven a couple of VNT cars...they are a lot like driving a V6 actually! It's effortless. As Barry mentioned...launching them is tricky, to say the least.
I'd imagine if you wanted to get a feel for how it would drive, go test drive a newer VW 1.8T, or TDI. It's gonna be pretty darn close!
I really like TDIs. If they didnt hold value so darn well i'd own one.
I assume putting a heavier compressor wheel on is going to slow things down a LITTLE bit, but probably not much.
sdac guy
11-10-2010, 08:53 PM
I've driven a couple of VNT cars...they are a lot like driving a V6 actually! It's effortless. As Barry mentioned...launching them is tricky, to say the least.You know what is just about hardest thing to do in a VNT? Leave a light quickly without squealing the tires. Next to impossible. Lots of clutch slippage needed to pull it off.
Barry
Tony Fields
11-10-2010, 10:52 PM
From your comments it seems you don't have much experience driving a VNT. It is unlike any T1 or T2 car. It builds its boost down low, making it a VERY torquey response.
My VNT Daytona has been my summer daily driver for over 10 years now. On the street, I can break the front tires loose at nearly any speed in first gear (without revving the motor up first). With full boost coming in at 2100 rpm it darts through traffic unlike any other turbo mopar. There is NO turbo lag.
Here's the difference I've seen at the drag strip. My Omni (T1) and my Lancer (T2) both need to be launched above 3500 to keep the engine from bogging in the first 60'.
My VNT Daytona, if I launch above 2000 rpms, the tires just go up in smoke and 2nd gear is nearly as bad. That is how ALL correctly running VNT's should run.
The only mods from stock on my car are the 2.5" cat back exhaust and a chip that allows 14 lps boost. The car runs a mid 16 quarter mile, but the speed (about 90) shows it should be a mid 15 or quicker car. But without slicks it is nearly impossible to launch it without massive tire spin, ruining the 60' times.
If you only have the VNT engine and not the correct wiring harness with the 3 VNT solenoids and the correct engine controller, you may as well swap the turbo and make it a T2. You cannot properly control the VNT turbo without these items.
Barry
Sounds like you are driving my GTC VNT Barry. It too, reacts like your Daytona. Lots and lots of fun to drive. I love the performance.
GLHNSLHT2
11-11-2010, 12:26 AM
hehe 2100rpms is where my S60 had full boost on my 2.5.
Reaper1
11-11-2010, 01:23 AM
You know what is just about hardest thing to do in a VNT? Leave a light quickly without squealing the tires. Next to impossible. Lots of clutch slippage needed to pull it off.
Barry
Sounds like you need stickier tires! LOL.
JK
This thing will NOT have sticky tires, most likely.
Im starting to think converter choice will be really important here.. I think im going to stick a stock 3.02 trans in it with a v6 converter to start, and then when the 2.6 trans is ready i will decide whether that converter was right or whether to do the looser one. I think i need the transfer gears to do a 2.6 trans anyway.. used to have em but i think thats one of the many 413s i gave away to clear up space..
decided on a v6 converter, slowly putting together the motor right now.. future updates will be in the thread about the car:
http://www.turbo-mopar.com/forums/showthread.php?35377-Dragged-home-another-one-part-two/page3&highlight=dragged+home+another
Thanks again for all the input in this thread.
vipernbox
02-11-2011, 12:30 AM
From what little I have driven around that VNT car I have... My experience is the same as everyone else that has posted here.. makes boost at idle.. and instant.. love it...
A couple quick blips of the throttle..to build boost with no load on the engine.. love that... and it has them squealing from a light half hearted clutch slip at 40 mph in second...
Then of course seems to run out of breath... but that feels normal to me, just like a heavy daytona..... :lol: or like a stock 2.5 with a stock garrett..
What sorta calibration ya going to manage a VNT auto combo with? sounds fun to me... a great way to beat around town...
Well, im going to use the stock computer to start with. I'll have to do some interesting work to merge the vnt SBEC harness to the 84 40pin k-car harness.
When i get to the point that i need bigger injectors and real tuning changes.. i guess i'll cross that bridge when i come to it.
22shelby
02-11-2011, 01:21 AM
YES vigo, i just read thru the thread for the first time, and u just answered my thoughts... u need a diff convertor...the lower the stall tha better in this instance... not sure what kind of range the v6 convertors, but it would make sense since the 3.0 make a ton of power down low....
get r done and report back STAT!!! :)
---------- Post added at 01:21 AM ---------- Previous post was at 01:21 AM ----------
thinking of a fun lil DD omni!!!
RoadWarrior222
02-11-2011, 08:14 AM
On mine stall seems to be not far above 2000.
BadAssPerformance
03-26-2011, 10:21 AM
Moved to VNT section :thumb:
shackwrrr
03-26-2011, 11:02 AM
Are you going to run a 44mm or larger wastegate. I think that will put you where you need to be, it will only open when you start to outflow the turbo
The Omni has an 89 CSX engine in it and is an auto, so I guess I've driven one!
However, it was pretty poochy, but to be fair, I'm all but certain that I didn't have the actuator hooked up correctly after we got the engine/trans in, and never did any tuning as the heater core went out shortly thereafter and has been in hibernation since... So when I get back to it, I'm hoping I just have to adjust things.
BTW, anyone know if the stock TII (GLHS TII) boost control will run the VNT? I know that normally there would be another solenoid/driver to control both sides of the can, but it seems like it should be possible...
Mike
Are you going to run a 44mm or larger wastegate. I think that will put you where you need to be, it will only open when you start to outflow the turbo
If i use the stock manifold im not sure there's really anywhere i can put a 44mm hole in it.. ill have to measure before i decide what to buy.
440dart
03-30-2011, 09:01 PM
i just picked up my first vnt car, it spools so fast, i really like it its so nice for daily driveing but iam also use to driveing around my TIII with a sc61s turbo, it reminds me of my v6 5speed shadow i had but with a little more power
Well, with the majorly upgraded compressor side on mine it should be able to make a lot more than 200hp. Whether its going to be fast or not, i dunno. I figure it'd take almost 300hp with this weight and gearing to make it feel 'fast'. The turbo im doing will easily blow that much air but id need bigger injectors, intercooler, and tuning to get there. I still need to buy some gaskets, fix some broken bolts, buy and install a wastegate, get the turbo machined and balanced, clean up and repair the trans, build the harness..
I dont know why it feels close when i list it like that but i FEEL like its getting close! lol
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