I am thinking of going small four for fuel ecomomy...thinking of early gti cis for fuel
but have no ideas for internals etc
and have to sell a few homes before this project gets a move on
but wanted to open up dialogue on the subject

slap some 96's on it to get it up to 1911!

Build a turbo system for this motor! Then drive it till it smokes or makes a loud bang.

That's what I'm doing.

I'm going to do the same for the original motor in my car which is an EA case, 49 state. The motor from my roller is a 1.7 EB California which is lower compression, going to get it rollng with that one. From what I've read you need to start with higher compression to get good fuel economy. Of course you'll be buying Premium, but it'll last longer.

Also I'm thinking about 165 series tires. I believe that's an original 914 tire that was the spare of my parts car. I think those are 185's next to it.
Click to view attachment

depends on the budget.
cheap: 96mm pistons, 8.5 comp, find some 1.8 heads, better exh like ssi with bursch 4-2-2-1, L-Jet, port match intake and exh, 911 valve adj, chr-mo push rods, valve geo corrections

About the heads, the journals would be larger. Would larger valves help economy even?

The 1.7/1.8 ssi's are slightly larger diameter than stock, but I wonder if horsepower is what you need. The restrictive stock exhaust is for torque, and it's getting going that takes the gas. We are talking about economy here right? A turbo is false economy from what I've read, btw.

Oh, I see the "what would you do" part. carry on then.

You'd have to check with Joe Sharp but I think Linda had a 1.7 with single throat carbs and got over 40 mpg. Joe?

What thoughts are there for pepping up the motor? heads? etc

http://forums.aircooledtechnology.com/showthread.php?t=2328

Steve, give us some parameters...

Budget upgrades?
Remaining 1.7?

Otherwise, it becomes a simple, "Build it into a 2270."

Fuel economy comes up here a lot less than h.p. Sounds like an interesting project . 40 mpg would be amazing... In which case you might want to go with lighter wheels,f/g parts, lexan rear window etc.

Ive got 2 sets of 1.8l heads for ya Steven.

Jake great read!!
McMark, trying to keep the displacement to 1.7 and making it as much fun as i can, and hoping to get around 40mpg, hoping the rabbit cis helps a bit...for use as a summer driver

The 1.7 heads have nice small ports that are good for low rpm velocity and keeping the mixture nice. I wouldn't go bigger on any of that for MPG. If you wanted to spend some money on heads, you could use stock 1.7 heads with the 2.0 spark plug location for a better burn.

Long intake runners is also a good idea. The longer the tube, the more air-in-motion and that can help push extra air/fuel into the chamber at some RPM.

A tunable injection system would help more than CIS. You with a tunable injection system you can pull out extra fuel on overrun and keep the cruise RPM fuel ratio as lean as is safe to get extra MPG.

And, as mentioned, upping the compression ratio.

I wonder if there is anything as far a piston coatings or ring designs that would help reduce piston to cylinder friction. Lowering that will free up a little power and keep the engine cooler. And since it's not a race car, you have a whole different set of design considerations that may make a different piston setup work well.

I once had a '71 1.7 that routinely got 40+ MPG on the freeway, bone stock. Not impossible.

The Cap'n

I have a 1.7 with 180k on it.
I can still get 35-37 mpg...never broke 40 yet.

If the motor was redone, 40 would be certainly atainable...mine has old rings, old valves etc....its all stock.

the FI system of the stock car will get you there.
I suspect a modern EFI system would get you higher than 40 if it was built correctly...

I have been reading about direct injection lately....makes me wonder....

Rich

It all comes down to budget. As soon as you open the case on a type 4 engine the money starts pouring out of your pockets. Scouring Craigs List and eBay can result in picking up some good deals on parts, but the more you buy the more you want to tweek it, resulting in more $.

For fuel economy, a lot depends on the cam you select, and the cam you select is largely determined by the fueling option you select.

The CIS parts are likely available pretty cheap, but you will be largely on your own in making it work as there are not a lot of people who have gone down this route. It may be difficult determining if this solution will result in better fuel economy than stock until you try it.

McMark is correct, that tunable EFI is likely to give you more mileage benefit than CIS. I hear Megasquirt can be made to work with stock throttle body and runners. The Megasquirt brain is fairly cheap and there is a large community of users to help support it. By the time you get all the parts together, however, even a simple EFI system can add up to $1,000.

If cost is an issue, stock FI may be the best option.

wow , thats exactly the info i've been looking for 2 , jake provides great info on this

and after reading : I think if i ever have the dough .

i'm so sold on , bone stock 1.7. to 2.0 . all the points he made have this as my ideal engine .


yeh

I 2nd all that , I have plenty of everything w/ my 1.7 djet .

but if I was going to do anything , i'd go modern e.f.i before I went displacement or at least in that order . reverse order from most other's i'm guessing .

?

Nuttin ...

I drove the snot out of my bone stock 1.7L FI and still got over 30mpg.

It took some time to get some of the bugs dialed out, but after than, it ran like a champ.
One big thing with FI, you really need to check and double check the engine harness. They're 40 years old by now and they all have cracks. Unfortunately, a lot of times the cracks are *under* the thick insulation and not visible.

It took 3 used engine harnesses and one long Saturday afternoon to build myself a good harness.

agreed , sounds crazy but stock f.i. is kinda like

John o' sullivan

old as hell but can whip any sob in the place .

an

20+ yr old carb engine , forget about it .

20 yr old djet , may be it fires up ,

I meant John L Sullivan

If interested in CIS I have the majority of the set up ready to go... One of my employees pulled it off a performance T1 engine and its all there. Just add CIS injector bungs to a TIV intake and rock on.. I LOVE CIS

Jake I am going to take it , it will be a lot easier than figgering and fandangling it all by myself!! Thanks

I am removing some 2.0 heads that are on a fresh rebuild, only issue I know of is a snapped exhaust bolt and so you will need to fix that. I am upgrading to a set of Jake's heads.

PM me if you are interested.

Larouex

2.0 heads aren't compatible with 1.7 cylinders. The bore in the heads is different. But if you're gonna build a 1911, those heads would be perfect.

my thoughts are- if/when i am upgrading any parts and ripping into the motor ...I will be getting heads from Jake, I have a "bit" of stuff kicking around...