Safe max driving speed

[benbuff]

I am changing jobs and will have to drive 120 miles of freeway a couple times a week.  What is a safe speed I can drive for 2 or hours without hurting the engine?  Its a 88 dl wagon 5 speed efi.  Thanks

[Subasaurus]

my 89 wagon loved the highway more than the surface streets, i would go to mexico with the wagon (5hour drive) at 70-75mph the whole way, most comfortable vehicle i've ever had on the highway, or it could have just been the seats. although revolutions were pretty high, it never cared, never overheated, just the nature of the cars gearing and low HP. mine loved to cruise around 72mph.

[Nickoli]

I've driven both my 86 3 door 5 speed and my 85 wagon five speed fully loaded back and forth across the country--from colorado to florida--two times each with zero issues. I also don't rest much so it was like 2-3 12-18 hour days of straight highway. One time I had a partner and she went literally nonstop. They are well maintained with great tires. I usually cruise at 72 as well, for gas mileage maximization, but have no problem doing 80 if needed. I usually cruise at like 3500 rpms and run 10w40 in the summers. She seems to love it.

[benbuff]

Ok thanks.  I'll give it a try.  

[idosubaru]

what exactly are you worried about?   it's an EA82, it doesn't care what legal speed you run it at.  they're great engines and run all day long.

 

you'll be more of a problem than the engine.  have you maintained it at all - oil, leaks, plugs, wires, cap, rotor, timing pulleys, timing tensioners, timing belt, drive belts, fluids, battery and terminals?  that will be more indicative of it's performance than the engine itself. 

 

i had a 120 mile commute for years with my XT6 (same pistons/rings/valves/HLAs as EA82) with zero issues or concerns.  no big deal.

[Nickoli]

what exactly are you worried about? it's an EA82, it doesn't care what legal speed you run it at. they're great engines and run all day long.

 

you'll be more of a problem than the engine. have you maintained it at all - oil, leaks, plugs, wires, cap, rotor, timing pulleys, timing tensioners, timing belt, drive belts, fluids, battery and terminals? that will be more indicative of it's performance than the engine itself.

 

i had a 120 mile commute for years with my XT6 (same pistons/rings/valves/HLAs as EA82) with zero issues or concerns. no big deal.

++ this

Edited February 24, 2018 by Nickoli

[benbuff]

I was worried that when the car was made the speed limit was 55 and I didn't want to run it 75 for 2 hours if it was over revving.

[PA Grown]

The one thing I’d advise is to keep you emissions systems up to par. Especially the pcv and egr! It’ll save you an exhaust and burnt oil. I get great mileage on the highway with an 84 brat. Just got back from Salem 124 miles only had issues with the check engine light clicking on because it wanted to use the egr but I’d already removed it. Cooler exhaust temps save mpgs. Use a full exhaust all the way out the back and enjoy everything the ea81 has to offer, the mpg a cool Engine and no burnt oil! Once you start burning oil early check out that cat and your exhaust pipe for clogs or high heat. Honestly though they love the highway even stripped of emissions like mine.

[moosens]

Old guy advice says just run it under 4K rpm , and if no tachometer then just keep it under 85 for sure. Running constant as you will be you’ll be fine as mentioned previously 70-75mph that whole run and you’re treating it very fairly.

 

Don’t forget good tires are the real limit with old Subarus.

[benbuff]

I don't have a tach so I'll be sure and stay in the 70-75 zone.  

[jono]

It will be the whole package including driving conditions and the drivers abilities. New suspension and steering components are never a waste of money or time in these old girls. I used to run retreads which were horrid heavy things with shocking traction. Also ran used imported euro and japanese tyres. Then new Chinese made things that turned funny shade of blue in a year from fitting. Awful sideways traction, great in braking, dangerous sideways stability. Now run Bridgestone Potenza RE003 thaty look half track tyre but are awesome in all conditions

 

efi is that single port or dual port?

 

My dual port cruises so effortless at 70 mph makes me wonder if 140 mph is achievable

[subnz]

Agree keep engine between 3000 - 4000rpm for cruise   best for power / economy / longevity.

 

Most modern Japanese OHC 4 cylinders engines need a minimum of 3000rpm before they start to work properly  ie start developing reasonable  torque  / hp.  Have had two EA82s.

 

EA81  OHV  (old school tech  dating back to steam engine)   need less rpm to do the same thing ie   best  between 2500 - 3500rpm.

 

Have had 2  still have one of them  - bomb proof  simplicity / reliability  so long as don't over rev them.