Potential Project Catalina

[SAmadei]

So... I have a broken '70 Catalina 4 door hardtop. I picked it up about 10 years ago as a parts car, for its drivetrain. It was hit pretty hard in the front... but I still drove it home. I was surprised by how nice the interior/body was, and didn't have the heart to part it out immediately. The engine/tranny is still coming out, though.

A little bit later I got a '70 Bonneville parts car... it was a rustbucket, and it was promptly disassembled.

While looking at the two cars, it was obvious I could fix at least one car from the two. The major problem with the Catalina is the front frame horns... so I saved the horns from the Bonneville, in case I was going to attempt a fix later.

'70 Full sizers are not my favorite, but considering that the Catalina weighs about 4000 and has a ton of space, I've considered putting an economical modern drivetrain in the Catalina. This Catalina actually got pretty good mileage from the 2 barrel 400... about 18 mpg on the freeway. I don't remember the rear ratio, but I'm sure its pretty low, numerically... as low as 2.29:1 was available... but I figure it has a 2.56:1 or so. No way it had higher than 3.08:1.

Now, as has been discussed in another thread, I realize that older cars do suffer from aerodynamic drag at speed, but considering this car already was getting decent mileage, I'm thinking of what mileage could be possible with modern technology... a lighter drivetrain... more gears... better fuel control, etc. Yet offer enough space for me to actually drive comfortably... unlike most of GM's present cars (Lucerne and DTS excepted).

So the question here... what would be the best ticket to hook up a modern longitudinal drivetrain and computer control into a car with either a 2.29:1 or 2:56:1 rear? I was looking at the CTS and second gen SRX drivetrains... but they both seem to be 3.73:1 ratio based. I was also looking at the Kappa drivetrains... but was disappointed by its standard mileage of the LNF. In this car, I'm not worried about acceleration, assuming its not crippled by it.

So what would be the best GM drivetrain to install that would be flexible to adapt the computer to use the most eco friendly gearing. You guys love to talk about how great the torque in the LNF and 3.0/3.6 are... this would be an opportunity to see if it would work here.

Again, being quick is not an issue. This would be a cruiser that gets decent mileage... 30 or 35 mpg would be a nice goal.

[ocnblu]

Aerodynamic aids, such as fender skirts, might help you reach your goal.

[§carlet §wordfish]

I can't offer any advice as far as the best drivetrain. Whatever you put in, I would recommend a device to monitor your fuel economy like a ScanGuage or a vacuum gauge if you wanna keep it classic.

It'd be a heck of a job to aero-mod. Fender skirts and full, smooth undercarriage covering would be the best compromise between discreet and effective.

[Drew Dowdell]

I don't think you're going to get 30-35mpg out of a '70 Catalina unless you get a Volt powertrain.

I could see you getting 25-27 mpg out of it from a Roadmaster LT-1.... it would also probably be the easiest and least costly swap.

Another one that might be interesting that I didn't see brought up is one of the Atlas motors. You have your choice of 4-cylinder, 5-cylinder, or 6-cylinder.

[SAmadei]

Aerodynamic aids, such as fender skirts, might help you reach your goal.

Well, I do happen to have a set of '70 fender skirts.

I can't offer any advice as far as the best drivetrain. Whatever you put in, I would recommend a device to monitor your fuel economy like a ScanGuage or a vacuum gauge if you wanna keep it classic.

Well, by swapping in a complete drivetrain and computer, I was hoping to be able to reprogram the computer for the rear gearing ratio and have the DIC report the average and instantaneous fuel economy. It would be cool to funnel that info into a old gauge... probably beyond my scope... unless I add a custom car computer that interfaces with the drivetrain computer automagically.

It'd be a heck of a job to aero-mod. Fender skirts and full, smooth undercarriage covering would be the best compromise between discreet and effective.

I wouldn't be doing any major aero modifications... besides fender skirts and maybe a smooth undercarriage.

I don't think you're going to get 30-35mpg out of a '70 Catalina unless you get a Volt powertrain.

If I went that route, it would have double the Volt battery pack and would never likely see a gas station again. Don't get me wrong, I look forward to the day everyone dreams of where the used batteries are still functional and so cheap used that retrofits are possible. But I fear the Volt will be a classic before that happens.

>>I could see you getting 25-27 mpg out of it from a Roadmaster LT-1.... it would also probably be the easiest and least costly swap.

Why would a LT-1 get better fuel economy than a 3.6 HFV6 or a LNF? Again, this does not have to be fast... my figuring is that if a 4 cyl is good enough for GM in a 3600lb Malibu, its not a stretch for a 4000lb Catalina that goes on a diet.

>>Another one that might be interesting that I didn't see brought up is one of the Atlas motors. You have your choice of 4-cylinder, 5-cylinder, or 6-cylinder.

Good point... I'll didn't look into those.

Of course, at this point, this is speculation. By the time I'm actually installing something, there may be a better donor drivetrain... maybe something with start-stop.

Edited May 14, 2011 by SAmadei

[balthazar]

My dad had a '70 Cat sedan. Pics, please- I have a weird affinity for these PMDs. Hardtop- sweet!

Skirts aren't going to do bupkis under 70 MPH. You are primarily dealing with square footage frontal area and lots of rough edges. I personally don't think they'd stylistically fit. Couldn't hurt, of course. Smoothing the underbelly is going to take some kind of time; she's a big girl.

-- -- -- -- --

I would agree that 2.56s are very likely.

I don't believe a 3.73 SRX powertrain would be a mileage liability with the ratio spread and double overdrive.

Edited May 14, 2011 by balthazar

[Cory Wolfe]

Another one that might be interesting that I didn't see brought up is one of the Atlas motors. You have your choice of 4-cylinder, 5-cylinder, or 6-cylinder.

It might just be the applications in which they were used, but the Atlas line of engines hasn't had a reputation for good fuel economy. They've also never been put into anything other than a truck or SUV, so who knows, it might suit an old Catalina pretty well. It might be too much of an unknown, though.

[loki]

i'd bet an lt1/6speed t56 (if a manual is possible)would be quite fair. ...unless you don't plan on driving more than ~65mph, ever. (down hills excluded)

[Camino LS6]

Another vote for the LT-1.

[Robert Hall]

To make it more aero, use flat '82 Firebird hubcaps and maybe replace the front end (fenders, hood, fascia, bumper) with the the sloping front from a 3rd or 4th gen Firebird...probably could be done w/ alot of bondo and duct tape.. And for an engine, maybe the 1.8 Turbo from the Solstice...

[ocnblu]

I was actually kidding about the fender skirts, in reference to the other thread discussing Pontiacs with them.

[Robert Hall]

I was actually kidding about the fender skirts, in reference to the other thread discussing Pontiacs with them.

Yeah, but they are a popular feature of the hypermiling set...along w/ other aero tricks..

[SAmadei]

I was actually kidding about the fender skirts, in reference to the other thread discussing Pontiacs with them.

I wasn't. The '70 Bonne parts car had fender skirts... of course I'd use them on this. I wouldn't use them on my '70 Tempest.

[Drew Dowdell]

>>I could see you getting 25-27 mpg out of it from a Roadmaster LT-1.... it would also probably be the easiest and least costly swap.

Why would a LT-1 get better fuel economy than a 3.6 HFV6 or a LNF? Again, this does not have to be fast... my figuring is that if a 4 cyl is good enough for GM in a 3600lb Malibu, its not a stretch for a 4000lb Catalina that goes on a diet.

Gearing... or would you lift the 6-speed into there as well?

The LT-1 just loafs along at 1600 RPM at 70 mph.

[SAmadei]

Gearing... or would you lift the 6-speed into there as well?

The LT-1 just loafs along at 1600 RPM at 70 mph.

Well, a 6-speed would be nice.

The trouble is... I already have a LT1 in my Caprice wagon. Its pretty good for mileage, but not as good as it could be. The LT1 is 18 year old technology. I want to see what modern technology can do.

Right now, I'd like to find a existing engine and tranny that are matched from a particular vehicle. That way the only thing that needs to be customized in the computer is the rear gear ratio... which will likely be low... like I mentioned, I think the existing gearing is 2.56:1.

I'm kind of bummed Dwight hasn't thrown in some food for thought.

[Camino LS6]

If not the LT-1, then an LSx of small displacement.

5.3 w/AFM?

And a 6spd.

I just think you'd be asking way too much of a 4-banger.

[balthazar]

Oooo- 5.3 with AFM/6-spd sounds great.

A buddy with that in a Silvie gets in the low 20s on the highway (He said 24 via the DIC, but not sure I find that credible, tho a 2nd guy with one confirmed the same).

You could also drill a LOT of holes in the Cat; 1 thing you can put in and make it lighter. I've done quite a bit of drilling on the B-59 so far (mostly in the front end, in a car about 250 lbs heavier than the P-70), but not sure how much weight I've saved (maybe 10 lbs; it takes a LOT of holes to add up to anything).

Edited May 15, 2011 by balthazar

[SAmadei]

I just think you'd be asking way too much of a 4-banger.

Normally, I'd agree. But lets look at the GMC Terrain. Its 3867 pounds... and is punching a bigger whole in the air than the Catalina. The Terrain is 72.8" wide 66.3" tall.. roughly 4826 sq inches... the Catalina is 54.7 high, 79.9 wide... roughly 4370 sq inches. Granted, the Terrain is smoother... but a 10% smaller hole has to count for something. GM is stuffing 182hp 2.4 LAF 4 cylinders in these Terrains... getting 32 mpg EPA highway and 9.2 seconds 0-60... probably faster than the Cat is with its 400/2bbl and 2.56:1(?) setup. The Catalina is 4000 pounds... and I'd say swapping in a modern drivetrain will easily take 300 pounds out of the equation.

Only problem... Terrain's setup is transverse. I need to find a similar setup that can be done longitudinally.

Oooo- 5.3 with AFM/6-spd sounds great.

A buddy with that in a Silvie gets in the low 20s on the highway (He said 24 via the DIC, but not sure I find that credible, tho a 2nd guy with one confirmed the same).

You could also drill a LOT of holes in the Cat; 1 thing you can put in and make it lighter. I've done quite a bit of drilling on the B-59 so far (mostly in the front end, in a car about 250 lbs heavier than the P-70), but not sure how much weight I've saved (maybe 10 lbs; it takes a LOT of holes to add up to anything).

I'm not too bent on weight... as it helps acceleration, but is not nearly as helpful for highway mileage. Best thing I could do there would be to go on a diet personally. I consider the Catalina is be a lightweight compared to vehicles its size today. Closest comparable car would be a smaller Grand Marquis at 4200 or S-class at 5000.

I suppose some lighter wheels would shed a bunch of weight.

[SAmadei]

Interesting... looking at the GMC Terrrain, I see that the tranny is "on-axis"... instead of being folded behind the engine... anyone have some details as to really helps the drivetrain layout? I imagine the output shaft still needs to be put behind the engine.

[ocnblu]

2.4L longitudinally mounted in RWD Kappa cars.

[balthazar]

Fully dressed PMD 400 is right around 675 lbs- so yes- you'll shed the most weight there.

C'mon- can we get a pic in here or what??

[SAmadei]

Fully dressed PMD 400 is right around 675 lbs- so yes- you'll shed the most weight there.

C'mon- can we get a pic in here or what??

LOL... I had pics but they were all from 10 years ago... and I can't find them. The poor thing is absolutely buried in the backyard... and last summer there was a something angry, flying and pointy nesting in under whats left of the hood... so I've been staying away.

There is this (awful) photo, posted by the past owner... Here at the top of the page. You can see that the paint is a bit faded in spots... and you can see the only rust the thing had at the time... a small hold in the rear quarter. You can also see the V-shaped rear window... a nice feature on these that to the best of my knowledge, the Bonneville coupe did not have. Not sure if the Bonneville hardtop had that or not.

Considering the '99 Bonneville needs a tranny, the '95 Caprice needs finishing, the '76 Blazer needs to start, the '89 Van needs to stop overheating... well... THEN the Catalina might be pulled out to get MIG "practice"... 8-0 ...to see if I can patch the frame horns up enough to put a front bumper and radiator support on it. 8-0

[Drew Dowdell]

If you do go with a 4-banger, it almost has to be a direct injection unit in order to get the low end torque you want. You probably want end up with an LNF from a solstice or something. Your final drive would be what gets you the mileage.

[67impss]

I like your full size Poncho idea and like Olds said the DI I4 late model sounds good to deliver as much torque as possible. Other than opting for a small diesel I don't have anything else to offer.

My plan is a Dakota EXT 2WD 5spd pull the engine add a Yanmar/Kubota 3cyl diesel with a Comet CVT between engine and tranny no need for a clutch. This way the CVT keeps the engine at max power(torque) and max governor speed while accelerating the car to speed. The power to weight is less than a fully loaded tractor/trailer so this will be a street worthy setup the only thing is to add a vacuum pump for the brake booster. The engines that I've looked into use 3/4 gal. per hr @ full load so I should achieve around 100mpg with any amount of highway miles. I plan to use a split fuel system diesel/SWVO. The inspiration comes from this but I want something that will be of use and that has a heater 10 HP GEO Metro

I talked to the Engineer that made this and the only thing he said was the heaver the car the slower the acceleration would be the 2 trannies make up for the lack of power. If I was working then I'd have the project in process, as for now I dream about it weekly.