My MV Modifying a Dodge Caravan

[malibuguy]

Originally Posted by Christ

I rather like the 3 speed, honestly. The 41TE is electronically controlled, whereas my transmission still has bands in it, that I can freely adjust and play with to my heart's content. All in all, the swap over to a 41TE might get me a few MPG's, but chances are, it will cost me way more than it's worth.

Also, the swap would be counter-intuitive for me, since the 41TE is mated to the 3.3 and 3.8 engines, and the sensors that they use. I'd be going for 1/2 again the engine I already have.

In sticking w/ the 2.4 engine, I have several more economical options to switch up with. I could swap down to the 2.0 (420a) engine, I could step up and mate a SRT-4 drivetrain to the van, I could do an auto-manual swap, I can rebuild the transmission to several other gear ranges and final drive ratios, I can install LSD in the transmission, I can utilize the auto transmission and a manual valve body setup, employ TC lockup in every gear, etc. (earlier caravans had options for Turbo/intercooling AND manual transmissions.)

First things first, I have to get a decent baseline set down for the kind of mileage I get driving like I would drive anything else...

the 41te is also in 4cylinder stratus' & i think a few neons got them too, they have a shorter final drive gearing to better match the torque output of the 4cyl...i popular mod for the v6 guys is to run the 4cyl final drive to get shorter gearing...i don't care for it, my van did 35 in first, 65ish in 2nd...& the fastest i ever went was 120...in 3rd @ 5200rpm...i never got it to go in fourth @ WOT...the torque converter locks up at around 80mph/4200rpm in 3rd @ WOT

if i ever get another van, i plan to swap in the 5-speed from the 2.7stratus GTC & have awesomness

[micondie]

Have been looking at my 03 and thinking that a blocked off grille with air intake below ahead of the small air dam might work (I have been looking at my 93 Trans Am which has no grille opening and gets all it's air from below) Maybe the air dam would need to be enlarged.

[Christ]

My biggest problem with going to a 4 speed is the electronic controls... That transmission won't operate w/o the computer, and the computer won't communicate w/ my Engine computer or body control module, so I'd have to swap a bunch of wiring, and add some in, etc.. it's way beyond anything I'd want to do with the van for just a few % gain.

Instead, I'm going to bulid a manual valve body 3 speed with manual lockup control in all gears, *hopefully* LSD. I'm also going to build a turbo 2.0 (420A) DOHC engine to swap in place of the 2.4 that I have now. Turbo + .4 liters less should get me a nice power curve with great mileage, considering the 28mpg I just got on the last tank with no effort at all.

I gotta get my Garage setup for the van on here... I just wanted to wait until I had a few tanks and a solid baseline so it didn't seem so weird that I got over EPA right away w/o trying. (25.66 I think it was)

So what else is OP doing to improve the van? I'd love to see some more on this, since I too have a Caravan and plan on modding it for better mileage.

[micondie]

I have installed an aftermarket (flea market $5) cone air cleaner on my 3.3 Caravan (2003) and have some interesting results (not scientific) Since there was no place to put the air temp sensor I just tied it to the wiring harness at the firewall. I took a trip and my SG which usually gives me low to mid 20's at highway speeds was giving me mid to high 20's with occasional low 30's. I think the combination of the cone air cleaner, the warmer air intake and the probably even warmer temp reading that the computer was getting combined to give me these numbers. Any comments?

[Shawn D.]

Maybe I missed mention of it, but covering those fog light holes in the bumper with a flush piece of plexiglass will be beneficial.

[89shelby]

Just thought I'd chime in here as I have a 1997 Chrysler T&C that I've been working on.

Started at an average of 18.6mpgUS (on the trip computer- have verified a few tanks and it seems to be quite close)- seems the 3.8L engine isn't the best for economy.

However, by removing the roof rack and putting a smooth undertray as far back as the gas tank the average over 1000km went up to 21.5 mpgUS.

Last thing I did was put a cover over the windshield wipers and now the average is up to 22.0mpgUS. I don't know if the newer vans are the same as the old ones, but when driving before there always used to be a bit of a whistling sound that seemed to be just at the top corner of the windshield. This cover got rid of that sound so that was a positive as well. Was also fairly simple, built out of a single piece of coroplast and held in by shutting the hood on it.

I'd like to try a Kammback as well - could you post some pictures of your new kammback when you get a chance. Thanks.

[micondie]

How about some photos of your undertray and wiper cover? I think your wipers are more exposed than my '03. Are you concerned with transmission cooling with the full tray? Does your 97 have a transmission cooler?

[89shelby]

Here are the pictures of the wiper cover. It is just one piece of coroplast cut to the shape of the wipers and shut in the hood. The top of the coroplast just barely comes to the parked wiper position.

[89shelby]

And the underbody. The underbody is zip tied into the front bumper and then tied with wire onto the engine/transmission subframe and lastly into the body seam that runs along the sides. This version only goes back as far as the gas tank. To keep the exhaust from melting the coroplast I stitched it together again with heavy wire over that area as you can sort of see in the second picture.

[89shelby]

I haven't done any A-B-A coastdown tests on the wiper cover or the underbody. I will try to do some when I do the next version of the underbody. I would like to do it out of metal as the coroplast flexes too much. I have had this version on for about 3000km and I will be changing it out in 2000km when I do my next oil change. I also plan to put a door in the next one for changing oil.

Also, regarding the question of transmission heating. I haven't been too concerned because of the open area near the wheel. Also, any air that comes in the radiator now has to travel past the engine/transmission to exit at the wheel wells or the rear of the undertray. And this van does not have a transmission cooler- I think that only came with the tow package in '97.