Any feedback on a 518 in a Fusey?

feets, are you going to put your rebuilt engine on a dyno so you have an idea for your torque curve? I'm interested to know how to figure out the best torque converter for a modified engine based on the final torque curve from a dyno session - at least I think that's the better way?

I know there's ways to make the 518 live behind a torquey motor - I know it's already been done. I think that's a grand idea and I look forward to learning more about what you find out.

The best of luck!!!!!
 
70bigblockdodge said:
The 518 is a piece of crap trans, not a fan of super tall OD and half-breed heritage, but since you went that way it will be okay. I am going to assume you got a non electronic govenor, earlier one. Just make sure you ultimately have manual control over shift points and converter lock up to make it not hunt for gears on a grade.

Yeah I'm "that" guy
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I agree with 70BB: I'm not too happy with the way the 518 uses the OD rather than a true fourth gearset. That's what makes the weird switching necessary. However, the PATC kit seems to be work and be pretty cost effective. I also think the OD is pretty steep.

However, this too is probably going to be outside the budget, and I'll probably just rebuild what I've got.

feets said:
I have the same transmission in my 92 D250 diesel. Those things use the TPS to control the OD and nothing else. They also have a habit of eating expensive TPS sensors. I put the truck on a hydraulic switch using governor pressure (with a manual override) over 100,000 miles ago.

I know how to make these transmissions work.

This thread was all about fitment issues in a 72 Imperial.
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Doesn't that mean you have a 618 in your truck? My understanding is that they have beefier internals.

Since you seem to know about them, can you tell me if you can use a 618 and the valve body from a 518 (gas) trans? Or, generally, what else can you tell us about how to make them work and live?

I thought the OD was 0.69, by the way. I built my spreadsheet with that ratio. Not that it matters much. Anyway, here's the revs at speeds for 3.23 and 3.55. I updated the tire size to the one you listed. Note that it assumes 5% trans slippage when the TC isn't locked and assumes a rolling radius 5% smaller than the calculated tire height. I also included 2.94s with 235/75-15 which is what most guys run here. For a stock 727, look at the 3rd direct column as that's the 1:1 3rd with no lockup.

3.23.jpg


3.55.jpg


2.94.jpg
 
The thing I'd be concerned with is the sub-2300rpm power. On many current vehicles, that's where things are in OD at 70mph cruise. Then how easily it would be to get a kickdown into direct for hills and such. AND how the manifold vacuum levels were at these rpms and such. At which degree of "grade" would it be best to downshift into direct to keep the manifold vac up so the fuel system did not go into the enrichment phase of things.

To me, IF the governors and pressure switches are correctly matched/calibrated, then manual over-ride would be minimal. Keeping it locked in OD might result in lower vac levels and then get into the fuel enrichment situation, which is not the best for fuel economy. Not that the engine would not pull OD in those situations, but at what level of intake manifold vacuum?

It's going to take some "on the road" testing and recalibration, I suspect, to get things dialed-in.

As for dyno curves, Comp Cams has a neat program for predicting those.

Enjoy!
CBODY67
 
Pretty slick way to modulate things! Any further economy checks? Just curious.

CBODY67
 
CBODY67 said:
Pretty slick way to modulate things! Any further economy checks? Just curious.

CBODY67
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Not my videos, not rich enough to own B-body, so had to buy C-body :) But im doing A518/A618 swap also. Not because economy, because then i can swap 3.9-4.1 rear end... :)
 
I have no plans to dyno the engine prior to installation. The car will get strapped down after it's running to see how things look.
The build will have EFI so vacuum signal is not going to be a issue.
If all else fails I can go as high as a 3.91 gear to gain some around town grunt and still drop highway rpm.

As for the 618 variant, it uses the same number of clutches and pinions as the later gas transmissions. The biggest change is in the increased weight of the governor used to make WOT shifts below 2400 rpm.
 
Thanks for the info. I'd wondered about that.

You and I are coming from different perspectives. You want to drop significantly from 3.23. I want to get more acceleration around town than offered by a 2.94. So I look at things as just a small decrease in RPM from my stock.

Having said that, if you want relaxed high-speed cruising, you might consider either the revs you get at 2.94 or 2.76 (is that right? Is that the other standard "tall" rear end?). For reference,
3.23 is 2700 RPM at 65
2.94 is 2450 at 65
2.76 is 2300 at 65


With a 518,
3.55 puts 65mph at 1950 rpm
3.73 is 2050
3.91 is 2150

So 3.91s would be lower on the freeway than you have now, or any of the previous Imperial ratios. The thing I've been thinking about is what happens during kick-down to third direct then to second gear. That's what the other columns are. It looks like at any reasonable speed, the kick down to 3rd direct gets right into the meat of the power/torque even with 3.73 gears. If really needed, you could even get into second for a big pass on a secondary road (55 or 60 mph). The stock Imperial engine is (in '67 where I'm familiar) has a torque peak at 2800 rpm and a hp peak at 4500.

I know this was a question about fitment, but hey... it's a discussion forum!

Food for thought.
 
Going by the power estimation software I have it looks like my 440 should be north of 400 lb/ft from 2,000 rpm to 5,000. Knowing that is a rough estimation (pretty accurate on past engines) I should have plenty of cruising power at part throttle. If more rpm is needed to get it happy I can easily arrange it through rear gears.

In Texas we have plenty of 70, 75, and even 85 mph limits. The car sure rides nicely at those speeds (it IS an Imperial) but I have grown so accustomed to newer vehicles that I really don't like the engine buzzing along at a constant 3,000 rpm. It just bothers me.
 
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Texas highways are a different use case! You'll be well over stall speed on those roads.

Can you tell me your engine specs and simulation software? I'm using Engine Analyzer and the numbers (including for the factory 440 specs) seem to come out low (if consistent).
 
FWIW, years ago, I always wondered the "Why?" of the 2.94 ratio in the Imperials, but 2.76 in Chryslers. THEN it hit me, the Imperials have a taller tire under them. That taller tire effectively changes the rear axle ratio downward (numerically). Therefore, approximately the SAME mph/1000rpm between the two cars. At that time, most Chryslers had 8.55x14 tires and the Imperials had 9.00x15 tires.

In those earlier times, I calculated our '66 Newport (383-2bbl w/2.76 rear axle ration and 8.55x14 tires to be 28.66mph/1000rpm (ideally). Now that I have much more accurate tire revs/mile information, I probably need to re-check my numbers.

CBODY67
 
bajajoaquin said:
Texas highways are a different use case! You'll be well over stall speed on those roads.

Can you tell me your engine specs and simulation software? I'm using Engine Analyzer and the numbers (including for the factory 440 specs) seem to come out low (if consistent).
Click to expand...

I use an old version of Desktop Dyno.
The engine parts are set up to have right at 10:1 compression (had to use specific Cometic gaskets to get it to work), Edelbrock heads (entered flow values by hand), a mild little 261/261 463/463 114+4 cam, shorty headers, 2-1/2" duals, and a FiTech EFI system.
 
What can is that? I’m guessing that 114 is the LSA? Most aftermarket cams in that duration range I’ve seen are 112.
 
It is a Comp cam that I had them tweak for my needs.

I don't believe in buying off the shelf grinds. Instead, I call them with my EXACT application and have a cam customized for what I'm doing. Unless you get silly it comes out to be the same price as shelf grinds but is targeted for the data you gave them.
This one was tweaked for the Eddy heads, and log manifolds. Add in the weight of a crew cab Imp, the desired low/mid rpm range, and other factors and you end up with this cam.

I decided on shorty headers but they flow a lot like logs so it should be okay.
 
I also it would be awesome if you'd either expand this thread to talk more about your car and rebuild in general, or put up another thread dedicated to it.
 
feets said:
I use an old version of Desktop Dyno.
The engine parts are set up to have right at 10:1 compression (had to use specific Cometic gaskets to get it to work), Edelbrock heads (entered flow values by hand), a mild little 261/261 463/463 114+4 cam, shorty headers, 2-1/2" duals, and a FiTech EFI system.
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How do you like the EFI system? I’ve been thinking about doing that to my 383.
 
I haven't picked one up yet. That's on the to-do list.
The company has a pretty good reputation and I helped a friend drop one on his 75 Dart.

My hot rod (fuel injected twin turbo 440 65 Belvedere) ran an Electromotive TEC II system with distributorless ignition and I liked it.
 
feets said:
I haven't picked one up yet. That's on the to-do list.
The company has a pretty good reputation and I helped a friend drop one on his 75 Dart.

My hot rod (fuel injected twin turbo 440 65 Belvedere) ran an Electromotive TEC II system with distributorless ignition and I liked it.
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That Belvedere sounds very interesting!
 
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