Turbo minivan (planning 3.8L ford windstar project)

[js335]

Not talking about 10 second dodge caravans but turbo'ing for FE like discussed in a nearby thread. I am a long time lurker on this site and would now like you guy's input on this project. I have a 3.8L ford windstar kid hauler in the fleet that get amazingly horrible gas mileage, around 15-18mpg average, due to the fact that it is... well a ford windstar, and 90% of the time she drives it on very short trips around town(1-5 miles), a lot of times it doesn't get close to reaching operating temp.

I would really like to put an ac motor and half ton of lithium underneath of it but that's no where near in the budget. She wants me to put a diesel in it after seeing how I rarely I fill up my TDI, but a finding an affordable donor car is like finding gold.

I know a lot of people are on the fence about if turbocharging produces FE gains or not, but I think it might if done right, and it will be a fun project so I'm going ahead with it. For this reason I'm not looking to discuss that aspect too much, I'll just see if it works, the worst thing that could happen is I end up with a cool minivan that's fast and gets worse FE.

I'm a euro-car mechanic by trade and like many people on this board my hobbies include welding, fabbing, ecomodding, wiring, building, renewable energizing and (to most people) unnecessarily modifying everyday things. I have installed several turbo kits and built a few homemade turbo systems out of junkyard parts, but never a FE turbo build. One thing I have learned about installing a turbo on a NA engine is that it reaches operating temp much faster, a big benefit in the winter.

My plan is to use a single or dual turbo setup underneath the passenger compartment just rear of the subframe where the exhaust Y is, plenty of room under there, none in the engine compartment. An oil drain scavenge pump will obviously be needed and water injection(I'm a fan) will be used for intercooling.

The first thing I need to figure out is the turbocharger size, I am hoping to find a common unit used for cheap. I want to run 5-6 psi so I'm thinking a smallish turbo(s) with very fast spool. I may have access to a free pair of VW K03 turbos for a VW 1.8t, these small water cooled turbos spool very fast on the 1.8 and I figure the 3.8 is roughly twice the size of the VW engine. I would much rather use a single turbo though, because of the extra fab work involved with the twins.

So for starters, any thoughts on which turbo?

[MetroMPG]

Do you live in a house or apartment? I would start with adding a coolant heater, even if you're still planning to add a turbo. Your wife has the kind of usage (short trips) that will benefit most from pre-heating the engine. (The reason I asked house/apartment is whether you have the ability to plug in.)

Can't offer any turbo advice - I'm not even up on the theory of turbocharging vs. efficiency beyond my limited understanding that turbocharging's efficiency gains mostly come from downsizing the engine so that peak power demands are provided by the turbo, while light/moderate loads are handled off-boost by the otherwise smaller engine. (Similar to the approach of hybridization.)

Will be watching with interest.

[js335]

we live in a house and I have considered a coolant heater but the only catch would be that she comes and goes at random times except to make a very short trip every weekday morning and afternoon to take the kids to and from school. I could put it on a timer for those times but the rest of the day would either not get preheat or would be just running all day wasting electricity. And seeing how many times she pulled my extension cord down the driveway until it got yanked out when I was running a battery charger/desulfator on the van, I don't think this would be a very good idea.

One of the first ideas I had was a long tube in tube exhaust/coolant heat exchanger with maybe a coolant temp controlled exhaust diversion/bypass valve to help warm-up fast then bypass as to not overload the cooling system in the hot summer. This got me thinking about my first turbo build I did one winter, instead of freezing for a couple of miles I could give it one hard acceleration and have warm air almost immediately.

I get the whole small engine w/turbo better than big engine concept, and swapping in a small engine was something I considered, like maybe a 1.0 metro engine with a belt driven booster electric motor(think honda IMA), but I have done the whole "put a radically different engine in a car it doesnt belong" thing before a few times, and its time and money consuming not to mention a lot of work. maybe one day. If I were to do all that work I would just put an ALH TDI in it, injectors, tune and call it good.

I am thinking faster warm-up times, higher dynamic compression ratios under load, more go with less throttle = sooner/lower shifts and with little to no management it should run a little lean. I don't know, a lot of variables, I'm not a real engineer, just a backyard one. It will be something that will need to be monitored and tweaked and may or may not produce results. I need to do a full tune-up and establish a good baseline while I am gathering parts.

I'm holding out for a little bit for a single T3 or similar turbo but on the plus side I did talk to a friend today that has a pair of K03's for me for very cheap if I want them.

[RobertISaar]

Originally Posted by MetroMPG

turbocharging's efficiency gains mostly come from downsizing the engine so that peak power demands are provided by the turbo, while light/moderate loads are handled off-boost by the otherwise smaller engine. (Similar to the approach of hybridization.)

this is correct and where a large part of the gains come from.

another potential gain is that with an identical engine with a turbo, you can run along with a numerically lower FDR to drop cruise RPM and lower vacuum losses.

[MetroMPG]

That's true.

I wonder if the poster has the ability to swap gear ratios or change shift logic in his van's automatic though.

[js335]

Originally Posted by RobertISaar

this is correct and where a large part of the gains come from.

another potential gain is that with an identical engine with a turbo, you can run along with a numerically lower FDR to drop cruise RPM and lower vacuum losses.

Robert, could you explain what FDR is, I'm sort of a new to the technical aspects of FE, google seems to think it is flight data recorder.

Originally Posted by MetroMPG

That's true.

I wonder if the poster has the ability to swap gear ratios or change shift logic in his van's automatic though.

I just had that trans out to fix the torque convertor issue, I think I'm going to leave it in there for a while. I like your idea about the shift points and changing programming through flash tuning is something I'm interested in, as well may be necessary before I'm done. This is my first Ford since I was teenager, I'm really not familiar with their PCM's or how well they deal with boost. Know of any good diy programmers?

On another note, what do you guys think about asymmetrical turbo charging or using one turbo on one bank of cylinders that feeds the whole engine. saab did this for a few years on a v6 with not much boost or power increase but supposedly made the torque curve much larger. there are a few very interesting diy threads on this, I'll see if I can dig them up later.

[oil pan 4]

What elevation do you live at?
A few weeks ago we took the lincon town car up near 9000ft and it was hurting.
My suburban was suffering fairly bad power loss after moving from sea level to 4400ft, so I turboed it.

K03 turbo chargers are only good for around 180 horsepower.
I think that mini van motor puts out around 200 horses so a single K03 wont do you any good.

[RobertISaar]

FDR = final drive ratio.

having one bank feed a turbo..... wouldn't recommend it. it would place one half of the cylinders under different conditions, meaning the calibration would have to be compromised to keep both sets of cylinders safe. SAAB probably compensated for this in one way or another.

[js335]

Originally Posted by oil pan 4

What elevation do you live at?
A few weeks ago we took the lincon town car up near 9000ft and it was hurting.
My suburban was suffering fairly bad power loss after moving from sea level to 4400ft, so I turboed it.

K03 turbo chargers are only good for around 180 horsepower.
I think that mini van motor puts out around 200 horses so a single K03 wont do you any good.

I live in hampton roads, VA. sea level, flat as pancake, this van might see some elevation only a couple times in its life. I agree about the K03, it is tiny and would probably explode if I routed both exhaust banks to it, which is why I was going to use two, one per 3 cylinders/1.9L.

[js335]

Originally Posted by RobertISaar

FDR = final drive ratio.

having one bank feed a turbo..... wouldn't recommend it. it would place one half of the cylinders under different conditions, meaning the calibration would have to be compromised to keep both sets of cylinders safe. SAAB probably compensated for this in one way or another.

Ahh.. Final drive ratio, now that I am familiar with, lol. Trans parts are expensive and hard to get at, not to mention I believe the speedo could possibly need recalibrating. Since this van does mostly around town low speed driving, I think a shift schedule change to PCM would be much more cost effective.

I'm still researching and considering the asymmetric turbo setup, the single turbo would be pressurizing both banks intake valves, only difference would be one bank would have slightly higher back pressure due to the turbo, from what I have read so far, this is not a problem.