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AMC 258 w/4.0 head & EFI

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC 6 Cylinder Engine Repair and Modifications
Forum Description: AMC-made I-6 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=31069
Printed Date: Mar/28/2024 at 9:08am
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Topic: AMC 258 w/4.0 head & EFI
Posted By: cjthenoisemaker
Subject: AMC 258 w/4.0 head & EFI
Date Posted: Jul/15/2011 at 3:15am
I wanted to take my 258 and rebuild it in the near future. While this happened, I wanted to use the 4.0 head and its fuel injection system for more power and supposedly better fuel economy over using the Carter 2BBL or MC2100. I've gone and read writeups on swapping a 4.0 head onto a 258, but most people use the 258 intake manifold and MC2100 which was my original idea until I had to change the plan.

So has anyone used the MPFI system from a 4.0 with the head?


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Setsuna - 1985 AMC Grand Wagoneer (R.I.P.)

Failure - WAS a 1984 Ford F150

Nodoka - 1987 AMC Grand Wagoneer: 360/727/NP208/Dana 44s



Replies:
Posted By: poormansMACHINE
Date Posted: Jul/15/2011 at 5:40am
Fuel mileage and horsepower between the injection and a well tuned stock carb is negligible.



Posted By: 7Xpacemaker
Date Posted: Jul/15/2011 at 5:59am
I am working on a project that is a little bit like this. I am putting a supercharged 4.0 in my '77 Hornet and am currently working on a megasquirt system for it. My Megasqirt system is using the hall effect sensor in the distributor from a '87 Ford 300 six cylinder. This will create the pulses to fuel injection. Also, I am using a fuel pump from an '87 Ford 300 six also. This requires a regulator, which I am unsure as which avenue I am going to pursue. Some Jeeps have a fuel filter with a built in regulator. Using this would prevent me from having two individual pieces in the system. My megasquirt requires an IAT sensor (already on jeep manifold), temp sensor (on 4.0 thermostat housing-ms uses a GM sensor), an injector harness, the IAC plug off of the throttle body, a high idle plug (optional), a MAP sensor, and a few other things. I am running an MSD system through the (fairly) stock 96 distributor. I mounted the Megasquirt controller inside the car and made a two piece harness with an aircraft (cannon) plug that can be disconnected at the firewall. This way I could disconnect the engine compartment harness after I am done building it, as the car is basically stock now. When I do the installation, I don't want a lot of down time when I make the switch. My time is limited in the garage because of my kids right now.Unhappy

-------------
C.J.

1981 AMC Concord
1977 AMC Hornet AMX
2001 Firebird Convertible LS1
1978 AMC Concord
1982 AMC Spirit GT
1974 AMC Hornet



Posted By: farna
Date Posted: Jul/15/2011 at 8:13pm
Well, I agree with PMM... mostly. The deal is the EFI system keeps the engine in tune for conditions pretty darned good, whereas the carb is tuned for ideal conditions and is just fair in all others. Tune it in the summer for warm weather and it runs, but not the best, in winter. As far as all out power there is really no difference -- for the conditions the carb was tuned in. So on a dyno there is no difference, day to day the EFI engine should average better power, if only 1-5 hp depending on how different conditions are from when the carb engine was tuned. That's the main reason there is a 2-3 mpg advantage to EFI -- tuning better matches conditions. The smarter the computer (some learn driving habits) the better the mileage difference.

So overall an EFI engine runs better longer, but doesn't really produce a noticeable power increase. Where you gain power when switching a carb engine to EFI is that the tuning is more efficient, closer to the most you can get from the engine. There isn't much to gain from simple, inexpensive bolt-ons on modern engines because they are already pretty finely tuned. You might be able to get 10-15 more hp from a 4.0L with bolt-ons (no cam change or going into the engine proper), but that's it. Not much more to gain from even a cam change and keep it EFI friendly. You can take a 74 360 that produces around 200 hp and make a carb/intake/exhaust change and gain a good deal of power... 20-30, and another 20 from a cam change (not a "lopey" cam, but still street/power brake friendly) -- easy to get 50 hp, not real hard to get 100. Of course part of it is size, but you get the idea. Even an old six can easily gain 20-25 hp without too much work. This is why super chargers and turbos are becoming the norm for hopping up a modern engine. It's expensive though -- $5K+ for a kit to add 50+ hp ("how fast can you afford to go" takes on more significant meaning today!).

EFI increases driveability (just crank and go no matter what the weather, no warm-up really necessary) and a little fuel mileage, but driveability is the most noticeable benefit. The 4.0L head breathes better than the old 258 head. It won't add a noticeable power increase by itself (may 5-7 hp, but only in the higher rpm range, nothing noticeable from a standing start). Adding a better exhaust, intake, and bigger carb (or EFI) wakes the 4.0L head up -- now you're doing something to take advantage of the higher flow. The increase in efficiency can also increase fuel mileage -- as long as you take it easy. Most tend to take advantage of the extra power potential so end up with about the same mileage as before or a couple mpg drop. But about the same mpg with more power is a win-win to me!


-------------
Frank Swygert


Posted By: poormansMACHINE
Date Posted: Jul/15/2011 at 9:49pm
Best example of how well both the antique and new tech systems compare.
Some of you may remember John E from Arizona. He has the carbed 258. drove from Az to Cordova and raced it. Next year he had the Chrysler EFI system and did the same. All data (fuel mileage and 1/4 times) were so close, you'd be really hard pressed to make an honest call.


Posted By: Wrambler
Date Posted: Jul/15/2011 at 10:56pm
I agree and remember well his disappointment with his efi result.
The true key is if you are a John E. You have to tune to perfection.
Everyone has a thing and if tuning a carb is yours then leave efi off your budget and tune.

My 69 Rambler, 4.0L, 82 AMC T5 gets 22-24 city and 28+ highway with 91 Wrangler efi.
I like the no tune ,  hit the key and go



-------------
Wrambler
69 AMC Rambler
4.0L, 5 speed
2015 Grand Cherokee Limited
2019 Chrysler 300


Posted By: nali
Date Posted: Jul/16/2011 at 12:48am
Originally posted by 7Xpacemaker 7Xpacemaker wrote:

I am working on a project that is a little bit like this. I am putting a supercharged 4.0 in my '77 Hornet and am currently working on a megasquirt system for it. My Megasqirt system is using the hall effect sensor in the distributor from a '87 Ford 300 six cylinder. This will create the pulses to fuel injection. Also, I am using a fuel pump from an '87 Ford 300 six also. This requires a regulator, which I am unsure as which avenue I am going to pursue. Some Jeeps have a fuel filter with a built in regulator. Using this would prevent me from having two individual pieces in the system. My megasquirt requires an IAT sensor (already on jeep manifold), temp sensor (on 4.0 thermostat housing-ms uses a GM sensor), an injector harness, the IAC plug off of the throttle body, a high idle plug (optional), a MAP sensor, and a few other things. I am running an MSD system through the (fairly) stock 96 distributor. I mounted the Megasquirt controller inside the car and made a two piece harness with an aircraft (cannon) plug that can be disconnected at the firewall. This way I could disconnect the engine compartment harness after I am done building it, as the car is basically stock now. When I do the installation, I don't want a lot of down time when I make the switch. My time is limited in the garage because of my kids right now.Unhappy


I m slowly (kids , money , etc ... )  building the same for a 232 :) Supercharger ( I have a M62 Eaton ), 4.0 head , dual exhaust and Megasquirt . Do you have pictures ?


-------------
No more car :)
Maybe a 1965 Ambassador Coupé someday .. If I can find a cheap one.


Posted By: 7Xpacemaker
Date Posted: Jul/18/2011 at 5:52am
I will post a few so far. I am getting ready to start on the 4.0 in the next month or two...

-------------
C.J.

1981 AMC Concord
1977 AMC Hornet AMX
2001 Firebird Convertible LS1
1978 AMC Concord
1982 AMC Spirit GT
1974 AMC Hornet



Posted By: Thikstik
Date Posted: Jul/19/2011 at 4:00am
EFI is better at raising volumetric effeiciency because a dry manifold that isnt full of gas droplets charges the cylinder with more air.  IIRC ,7% more. That's like a pound of boost. Of course, the I6 intake, by design is pretty bad for fuel puddling and uneven mixture, so efi wins there too.  Also, a computer is always getting feed back of engines parameters and building tables (block learn/integrater) to give the perfect mixture/timing to the engine under all conditions/demands.  I do agree with others that a well tuned carb/dizzy can nearly match efi. At WOT, the advantage of EFI IS negligable.  As far as hiway cruising... I would say OD would easily trump efi for ultimate mpg.  The I6's really can tolerate being clamped down with a deep OD ..whereas in the city they shine well with only 3 speeds. I sure hope you do this project nevertheless.

-------------
75 gremlin x, jeep 4.0 headed 258,
264H Cliff cam, intake,header. 390 holley. I want a 282 VAM motor!

AC/PS/PDB.

72 AMX , 304 2bbl, 3speed, now disks...probably will sell, want an automatic /AC.



Posted By: nali
Date Posted: Jul/19/2011 at 4:29am
Whatever the efficiency, I thing it s funny to convert an old engine to EFI and Megasquirt .
Will the millage better ? Not sure .
Will this be reliable ? Not sure

Will anyone learn while swirtching to EFI  ? Yes for sure .

Our 40 years cars are toys . :P


-------------
No more car :)
Maybe a 1965 Ambassador Coupé someday .. If I can find a cheap one.


Posted By: 7Xpacemaker
Date Posted: Jul/19/2011 at 6:16am
I have learned a lot about fuel injection by doing this Megasquirt system but I am sure that I have a lot more to learn. I agree with Wrambler that I will like the "no tune" that you get with fuel injection. If I want to tune it, I'll use my laptop. Personally, I am tired of the various amounts of ethanol that different stations can have. With that being said, it is next to imposssible to keep a carb tuned when the mixture of gas varies. I have been having trouble for the past couple of years with the Carter WA1 carbs on my Hudson. (yes, it has two carbs- "Twin H power") the carbs tend to seize up if the linkage is not exercised periodically. This never happened until ethanol. If I can get everything operating correctly with the AMC, I will be making the switch on the Hudson too. Some may think that the gas can not contain more than 10% ethanol. They couldn't be more wrong. They vary up to as much as 21%. I stopped at one chain gas station on my way to Florida in May and within 25 miles of getting the gas, my mileage went from 21.3 to 15.8 mpg. After I ran that tank out I got gas in Florida and my mileage went back to 21.3 mpg. My point to the story is this- With today's fuels it is impossible to keep all of your carbs set correctly. Just my .02 cents worth.... 

-------------
C.J.

1981 AMC Concord
1977 AMC Hornet AMX
2001 Firebird Convertible LS1
1978 AMC Concord
1982 AMC Spirit GT
1974 AMC Hornet



Posted By: billd
Date Posted: Jul/19/2011 at 6:30am
Originally posted by Wrambler Wrambler wrote:

I agree and remember well his disappointment with his efi result.
The true key is if you are a John E. You have to tune to perfection.
Everyone has a thing and if tuning a carb is yours then leave efi off your budget and tune.

My 69 Rambler, 4.0L, 82 AMC T5 gets 22-24 city and 28+ highway with 91 Wrangler efi.
I like the no tune ,  hit the key and go



Remember Doug from the Nest?
Try upper 20s @ 55mph with a 258, CARB and automatic
Mid-20s at 65
Top that with EFI.

I've not checked my Eagle 4.0 with T5 yet, but I know it's doing pretty well from as slow as the gas gauge moves down. I checked the speedometer against my GPS device and they agree at all speeds so checking mileage should be fairly accurate after 3 or so tanks.


-------------


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Posted By: billd
Date Posted: Jul/19/2011 at 6:35am
Originally posted by 7Xpacemaker 7Xpacemaker wrote:

Some may think that the gas can not contain more than 10% ethanol. They couldn't be more wrong. They vary up to as much as 21%. I stopped at one chain gas station on my way to Florida in May and within 25 miles of getting the gas, my mileage went from 21.3 to 15.8 mpg.  


PROVE IT.
Prove it was 20% - federal law says 10% - besides, did you know that it's actually expensive to blend ethanol (unless you are in Iowa where there is a tax advantage)
At least around here the dept of ag drives around with test equipment checking pump outputs and ethanol levels. You mess up, you are fined and/or closed down.

I'd love for those claiming 20% ethanol to run a test and prove it beyond this "my mileage dropped so it MUST be more" bunk.

So far all anyone has is hearsay, speculation and conjecture often based on "well a friend of my cousin's second wife's half brother said.......".

If anyone can prove it, then do so - and we'll finally see some facts and I might believe it.



-------------


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Posted By: farna
Date Posted: Jul/19/2011 at 6:53am
I don't think there's that much variance Bill, but there can be +/- 1-2% in some states. SC allows distributors to blend the ethanol and gas themselves. We've had problems in my brother's Ford truck (98 F-250 w/351) with that fuel. After a couple tanks he has to run a good cleaner through it, so he just switched brands. We know for sure that particular distributor blends fuel himself (has several stores in the area). I'm not sure if it's alcohol content (seems to be a bit better when gas prices are down though!), the stores have water in the storage tanks (they are all fairly old), or what, but there is something about that gas! Most vehicles run fine, just a few are a bit sensitive. I can tell a slight difference in my motorcycle -- it runs okay with that gas but obviously runs a bit better with almost anything else. Not sure if FL allows distributors to do the blending or not, but when ethanol is cheaper than gasoline there is the temptation to put a little more in. As you stated, that's not often the case though. Since ethanol absorbs water there could just be more moisture in the fuel through the tanks... or on purpose.

I don't think you can compare an EFI car with a carb for fuel efficiency. An EFI car will get more mpg consistently. A carb depends a lot more on conditions, an EFI system makes running adjustments. So yes, you can get good average numbers with a carb, but check it during the worst conditions and the EFI will get better. Averaged out over a one or two year period EFI will win for power and mileage, though I don't think it will be more than 2-3 mpg. The big win for EFI is that it will put out fewer pollutants over that time period too. EFI is the main reason oil change intervals went from an average of 3K to an average of 5K (from the manufacturer) -- carbs tend to run a little rich in most conditions. A little rich is better than a little lean when you can't precisely control the fuel mixture, and running a little rich will contaminate the oil faster than the correct mixture. So there is more of an economy gain than just mpg. Of course many have the 3K oil change interval so ingrained (and the oil change stores still "recommend" it!) that the extended interval is ignored.

Once an EFI system is set up it's as reliable as a carb, or more so. An owner installed system is only as reliable as the installation, and there are more things that can go wrong (wiring connections and sensors), but in general I've had no more engine control related issues with my car with EFI than I did when I was running a carb, or compared to my J-10 (with carb). It's true that if something does go wrong you can't fix it on the road as easily -- no just keeping an extra set of points/condenser in the glove box -- but then it rarely quits.


-------------
Frank Swygert


Posted By: purple72Gremlin
Date Posted: Jul/19/2011 at 9:08am
Originally posted by billd billd wrote:

Originally posted by 7Xpacemaker 7Xpacemaker wrote:

Some may think that the gas can not contain more than 10% ethanol. They couldn't be more wrong. They vary up to as much as 21%. I stopped at one chain gas station on my way to Florida in May and within 25 miles of getting the gas, my mileage went from 21.3 to 15.8 mpg.  


PROVE IT.
Prove it was 20% - federal law says 10% - besides, did you know that it's actually expensive to blend ethanol (unless you are in Iowa where there is a tax advantage)
At least around here the dept of ag drives around with test equipment checking pump outputs and ethanol levels. You mess up, you are fined and/or closed down.

I'd love for those claiming 20% ethanol to run a test and prove it beyond this "my mileage dropped so it MUST be more" bunk.

So far all anyone has is hearsay, speculation and conjecture often based on "well a friend of my cousin's second wife's half brother said.......".

If anyone can prove it, then do so - and we'll finally see some facts and I might believe it.

I agree.    there are so many variables.....................temperature, humidity........I could go on....


Posted By: purple72Gremlin
Date Posted: Jul/19/2011 at 9:13am
And EFI is more maintenance free.....is it more efficient than a well tuned carburator? No.  a well tuned carburator will work just as well as fuel injection.......but I know people will not agree with me.  I used to fool with the carburators on my cars so they would start with one pump of the gas pedal......yeah, I worked on the choke and the choke pull off too....


Posted By: farna
Date Posted: Jul/19/2011 at 10:02am
The carb is only good for a comparatively narrow range of conditions though. Within those conditions I agree with you -- a carb is as efficient as EFI. Outside that range the carb starts to fall off -- more so as the conditions get further from the tuned range. That doesn't happen with EFI. That's why the guys at the track have portable weather stations and tune carbs all day long, to keep as close to an ideal mixture (for power) as possible. A street car is tuned to operate in a wider range, but still falls off efficiency as conditions change. Most people buy a carbed car and leave it alone. If you're a real carb guru you could probably tune it 3-4 times a year and stay closer to the most efficient range, but most simply won't or can't do that. So a carb is at it's most efficient range MAYBE 20-25% of the time at best, depending on how much the weather changes in a particular location. Down south here 20-25% is probably about right, the further north you get where there are wider extremes in temperature the more that percentage of time when the carb is "right" is going to fall off. 

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Frank Swygert


Posted By: Thikstik
Date Posted: Jul/19/2011 at 11:14am
Re carb efficiency...I agree that efi AND computer control win out.  Consider that carbs run super rich when choke is on...and most dont have perfect adjustment.  I love getting a near perfect driv-off on a cold day with 1 half throttle pedal tap , then one more tap to calm down the hi idle step.  But sure, its not as perfect as efi.  Alot of carbs in the past had aneroids for barometric pressure adjustment and they had hot idle compensators for , well, hot idle conditions.  Thats neat stuff, but most carbs dont have such things.
Re fuel. Maybe some of the problem is octane varience.  Maybe some of it is moisture.  I personally experienced some gas from a Shell that would not even light off if poured on the ground. This was on a 4 wheeler single cyl engine that a buddy said just quit when he used their gas.  It never even sputtered despite hot ignition.  Pulled plug and cleaned/dried and it woudnt spark AT ALL.  Thats when we poured gas on ground , and it wouldnt light!  The carb had to come off and be totally purged and spark plug tossed, and new gas b4 it ran.  I couldnt believe it.  Station was getting all kinds of complaints and new cars were stalling , but mostly just running rough with CEL on.  My theory on that gas was that the nitrogen and water was forming some strange brew .  (they have that nitrogen cleaner).  It was just at that 1 station.


-------------
75 gremlin x, jeep 4.0 headed 258,
264H Cliff cam, intake,header. 390 holley. I want a 282 VAM motor!

AC/PS/PDB.

72 AMX , 304 2bbl, 3speed, now disks...probably will sell, want an automatic /AC.



Posted By: billd
Date Posted: Jul/19/2011 at 12:02pm
>>Since ethanol absorbs water there could just be more moisture in the fuel through the tanks... or on purpose.<<

LOL - one has to wonder what ELSE is in there...........

EFI is richer when cold, too..... thus the temp sensors all over the place. It simply takes a richer mixture on a cold engine.

Maybe some folks just don't like setting up carbs properly, or the thinking and measuring involved. But a good carb with proper settings will start, go, and not have issues like so many describe.

Wonder why all drag racers running classic or older cars aren't converting over to efi?


-------------


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Posted By: 7Xpacemaker
Date Posted: Jul/19/2011 at 1:58pm

TWO new cars were taken to my friends Chevrolet dealership in northwestern Pennsylvania because one would barely run and the other would not run at all. Long story short- the gas was drained out and a sample was sent out from each vehicle. It turned out that there was 21% ethanol in the gasoline. You can take or leave my information or call it "hearsay", it matters not to me. No matter what I say it is all hearsay to anyone else. I have also gotten good mileage from carb'd vehicles as well. My daily driver (84 miles per day) was an '81 Concord/ auto with a two bbl carter. The best I could get out of it was 22 mpg at 70 mph. I had the car tweaked as close to stoich as I could without detonation. I am an aircraft mechanic by trade and definately have the skills to properly set up a carb. My intention when adding to this thread was not to stir up other people's emotions. I apologize if I have. I sometimes come across wrong, I guess.Disapprove



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C.J.

1981 AMC Concord
1977 AMC Hornet AMX
2001 Firebird Convertible LS1
1978 AMC Concord
1982 AMC Spirit GT
1974 AMC Hornet



Posted By: farna
Date Posted: Jul/19/2011 at 1:59pm
EFI is expensive for drag racing. The guys with big bucks ARE running EFI with computers. Instead of breaking out the jets and screw drivers they pop open a laptop. For an easily adjustable EFI system you have to start with at least $800 (Megasquirt), but that only gets you a controller and wiring. You have to come up with sensors and half the wiring harness. Figure more like $1200. I'm not sure the MS system is all that great for racing, but then I don't see why not. Carbs are way cheaper and easier to learn than an EFI system for most.

Most people (self included!) simply don't know HOW to set carbs up right. But I say even then they are only "right" within a certain set of parameters. They simply can't adjust for as great a driving condition range as EFI.

I think we are all describing our "worst scenario" conditions. My truck didn't act up all the time, only on the colder days. Most other times it ran fine... except when the secondary float stuck, TWICE... mainly because the poor old thing hardly ever pulled in the secondaries. I don't think it was creating enough vacuum due to worn rings. I had a screw in the slot so at 3/4 throttle it would crack open the secondaries anyway.


-------------
Frank Swygert


Posted By: nali
Date Posted: Jul/19/2011 at 2:14pm
Farna , a Megasquirt doesn t cost 800 $ ... The controller is about 260 $ .
For this price , assembly is required , of course :P
http://www.diyautotune.com/catalog/megasquirt-ii-kits-c-30.html?osCsid=a9b390422824ef8a7fdf45beff572c4c


-------------
No more car :)
Maybe a 1965 Ambassador Coupé someday .. If I can find a cheap one.


Posted By: billd
Date Posted: Jul/19/2011 at 3:09pm
70 mph ain't gonna get you MPG in any case........... you drop off seriously above about 60 or so, no matter how much you tweak, EFI or carb.
The smaller the engine, the bigger the drop in many cases.


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Posted By: poormansMACHINE
Date Posted: Jul/19/2011 at 3:35pm
Double the speed and resistance goes up by a factor of 4. 


Posted By: farna
Date Posted: Jul/20/2011 at 8:07am
I've heard 60-65 is about the limit for most cars and more modern light trucks that are a little more aerodynamic than in the 70s. Most of out AMC cars are about the same aerodynamically as 90s-00s light trucks. Just a bit better than pushing a brick through the air (I'm NOT including an XJ Cherokee as a bit more aero...).  The more frontal area the lower that speed. Some of the more streamlined cars don't hit that wall until 70-75 though. Seems like more people are complaining about gas prices, but many of the loudest complainers are also driving big vehicles at 75-80 and won't slow down.

Nali, I was referring more to a ready built system that a racer could use. You can assemble and piece together a Mega Squirt system for under $800.  The MSIII assembled with daughterboard for sequential injection and wiring harness (which still doesn't have connectors) is just over $700. Then you need a laptop. I should have specified when I mentioned MS though -- I was considering the premium system, not the basic. An assembled MS1 unit with everything you need still runs around $500. The Micro Squirt would be the base level of EFI, and can be used on cars though it was designed for smaller engines. You're still looking at $400 (+connectors). The Micro and MSI are both batch injection with two injector drivers.


-------------
Frank Swygert


Posted By: billd
Date Posted: Jul/20/2011 at 8:53am
>>Seems like more people are complaining about gas prices, but many of the loudest complainers are also driving big vehicles at 75-80 and won't slow down.<<

Ain't it the truth!

I have done tests with my new truck.
55-60 I can do 22 mpg highway.
60-65, she drops 2 to 4 mpg with no other changes.
65-70, forget it, might as well be driving through KC during rush hour as far as mpg.
But if you can stand to be 2 minutes later when driving from here to Ankeny, keep it at 60-65 and you'll do very well.

OK, so that's a truck, right - brick through the wind........ but I've found it to be similar for many vehicles i've owned, including the javelin. When I can keep it under 80, it's a lot better for mpg.
The Javelin is hardly brick-shaped.

I do have to admit - if I could afford it, I'd be putting some form of fi on the 258 in the '80 Eagle wagon for my wife. She's been so long away from carb'd cars - it would just make sense.
She's not mechanical and gets frustrated if something doesn't start quickly and allow her to simply drive off. (frustrated is a nice word for the effect)


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Posted By: farna
Date Posted: Jul/20/2011 at 9:02am
Are there any pull-a-part type yards in the are? Plenty of XJs in them now! If you find a Renix powered one the wiring is even pretty easy as the ECU/engine wiring is totally separate from the body wiring. The wiring is similar to the later H.O. engine, main changes are some of the sensor types. Shouldn't be too hard to convert a Renix harness to an H.O. ECU, but I haven't looked into that in detail.


-------------
Frank Swygert


Posted By: tyrodtom
Date Posted: Jul/20/2011 at 9:18am
  Air resistance squares with speed.  Go twice as fast, resistance increases 4 times, 3 times as fast 9 times more resistance.
 
  Ever notice in the late 80 when NASCAR was still running somewhat stock appearing cars , with some aerodynamic improvements.   The cars had about 4 times the hp of the stock car but wasn't quite twice as fast, even at Taladega and Daytona.


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66 American SW, 66 American 2dr, 82 J10, 70 Hornet, Pound, Va.


Posted By: amcguru
Date Posted: Jul/22/2011 at 8:58pm
Originally posted by farna farna wrote:

Some of the more streamlined cars don't hit that wall until 70-75 though. 
Very true.  My Benz has a .25 Cd and ambient temp/humidity plays a greater role in fuel economy than cruising speed.   The truck on the other hand is a whole different story...20.5mpg @ 65 and 17mpg @ 75.


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NAMDRA #3646

"I believe the best social program is a job" ~ Ronald Reagan



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