What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Can you cruise at 80+mph in your truck?

I have got my mostly stock 1990 blazer,350 tbi and 700r,I have taken many road trips with this rig,and seems very happy cruising 75-80,and will go much faster,but it starts to feel like it is working to hard at higher speeds,and the fuel economy drops way off
 
Interesting thread. My '83 would go 80 without too much trouble when I had the original axles and sway bar, 4" lift and 35's. It droned a bit from something, but that's it. Now that I have the soft springs, crossover, 1-tons and no sway bar, I'm hesitant to hit the interstate. Biggest question mark is the brake situation since I really don't know what would happen in a panic. My recent accident was kind of an eye opener about how easy it is to have your head up your ass for one second and have something bad happen... I may stick to back road and keep it under 60 or so.
 
80 in the jimmy isn't a problem unless you hit a hill. The 4.10's, 37's and stock 350 TBI leave a lot to be desired for power. But speed on the flats is not an issue.

I have replaced suspension, body mounts, shocks, steering components, have 4 wheel disk so it is comfortable at speed.

The old 4 wheel drum brakes and worn mounts, suspension and steering components, over 60 was kinda scary.
 
My 84 will cruise at 85 for as long as I can stand to watch the fuel gauge slide towards empty. That 305 is definitely not happy about doing those kinds of speeds at this elevation, and it gets very thirsty. Single digit thirsty.

Wind noise and NVH isn't much of an issue even; the door and window seals are in good condition, and the sound deadening is at least adequate. Its obviously noisier at 85 then it is a 70 (which is generally where I prefer to cruise, best time vs mpg for me), but most of the noise is tire roar.

It tracks straight and true also, no wandering or weaving except in heavy crosswinds.

Mechanically, it's entirely stock, and for the first 65000 miles of it's life it mostly just went to the corner shop and back. I just rolled over the 100k mark a few weeks ago.
 
y5mgisi said:
So I'm wondering if I'm spinning my wheels trying to get something to do a job that it simply can't do, and if I need to be looking in a different direction. Particularly an ifs direction.
Click to expand...

The bottom line is that these trucks would not be as comfortable...period. Back when your Suburban was new, people were making these same trips all the time and didn't know any better....now that we have ridden in newer technology there is no way it can compete....
so...enjoy your old rigs around town and drive a newer vehicle on the long trip.
 
I cruise my 89 dually at 70 regularly and have had it at at 80 and above multiple times. As Chris mentioned though, the fuel economy of the cummins starts to drop waaaaaaaay off above 75. At 70 mph I average 18 mpg or so. At 75 and over it drops to about 13 mpg.

The solid axle isn't a hindrance IMO. Dodge and Ford still use them.
My suspension and steering is tight, and my truck handles really well at any speed.
If you try to drive anything that's 30 years old down the road with worn out suspension, sloppy steering, and square tires, then you're going to have your hands full at any speed
 
My 6.2/400/37's is happy at 65 on longer trips. It will go faster but gets tiring listening to the diesel wrapped up especially with bare cab floor and firewall and really starts to drink fuel. It is a lower mile CUCV and most everything suspension-wise has been gone through and it rides and tracks down the road great.
 
I made an 800+ mile run up and back to Northern Oklahoma last week. I cruised all the way up and back at 80 mph, sometimes faster when conditions were right. The Burb has 2 inch EZ Rides, a rear shackle flip, Bilstien 5100's and Dura Trac 33's. With the stone stock 5.7 TBI, 700R4 and 4.10 gears it takes forever to get to 75-80mph but once you are there the truck seems to be in its sweet spot power wise and pulled every grade on the trip without kicking out of overdrive. The truck recorded 12.6 MPG on the way up and 13.4 MPG on the way home. It sucked down almost a quart of oil but has no valve seals left I'm sure. It was very comfy for me and beyond the expected tire and wind noise was not fatiguing.
 
But as far as actually holding on to the wheel and easily dictating what direction you were going, you were good there?

Side bar, How do you like the ride with ez rides and the bilstines? I have been told that the ez rides are too soft for burbs.
 
y5mgisi said:
But as far as actually holding on to the wheel and easily dictating what direction you were going, you were good there?

Side bar, How do you like the ride with ez rides and the bilstines? I have been told that the ez rides are too soft for burbs.
Click to expand...

My truck has 70K original miles, the front end and steering box are reasonably tight for this vehicle type. The steering wheel does not shimmy but the console lid has a noticeable tremor to it at highway speeds. I am still using a stock rag joint. This is no slot car, that is for certain, steering inputs are slow to respond but predictable. Emergency lane changes would be scary with the trucks center of gravity, but I did swerve a few months ago to avoid a dog about 65mph and was surprised the truck took the line as well as it did.

I love the ride with the springs and shocks, it is still abrupt on some holes and harsh pavement, but wallows down the road like an Detroit Land Yacht of yesteryear. Most people familiar with this kind of vehicle comment how nice it rides when they are in it. If I balled it up tomorrow I would build another just like it.
 
Just to clarify,my blazer has 247000 on it ,with all new ball joints ,tie rod ends,shocks ,and it runs down the road just fine ,straight ,and true ,with no wandering
 
Hydro assist and crossover steering and a new steering shaft without a rag joint made a huge difference on how it steers and tracks straight down the road.
Rear disc brake was also a nice improvement. I do know there are much better aftermarket brake components available.
A good set of radial tires on good wheels with the correct load rating and higher speed rate goes along way in how a vehicle drives at hi speeds.

The LS motor and 4L65E makes driving this K5 at 70/80 mph much easier.
Power(HP), proper transmission and axle gearing also go along wain how it drives.

With this all being said you can upgrade and improve these truck to drive so much more like a newer model truck.
 
I've gone the opposite way, but I feel my input is similar. Newer truck, leaf springs and solid axle. Tires make the biggest difference. It'll run all day at 80+ with the 37" military BFG's. On an interco it doesnt like 75. It will do it, but mileage suffers. 52" front springs, 5100 bilsteins, 6.0/4l80e with 4.56 gears.


38377k5 said:
Really? :rolleyes:

Not that I doubt you've passed a diesel truck before, but that mentality is asinine. 25 details on both trucks are more important than diesel vs. gas.

Wind and speed friction will pretty much affect any truck equally and it's exponential. New trucks are better in wind tunnels etc. but higher speed in a truck pretty much equals lower MPG.

I can run my K30 at 80+ easily but it's not worth the MPG loss to me (12V Cummins and 5 speed, 4.10's and 37's). If $$$ for fuel doesn't matter to you, do what you want. If it does, do the math. You lose a LOT of efficiency at higher speeds in a full size truck.
Click to expand...

He's got 90's dodge diesel torque numbers, you know he's king of the road. Nevermind that I can easily run 80 pulling a 32' trailer with a 6k truck and quads on it getting similar mileage (9-12) while never having to watch the pyro. Sure envy that big block.
 
My K10 will do 85+mph all day long. I did 2000 miles round trip to Michigan last summer averaging about 75-80mph. I was also pulling down 15mpgs to boot! Now I did wear ear plugs only because it was hot and I had to have the windows down. Add in the mud tires, the exhaust, and the stereo, I figured plugs were better than being deaf after the 14hrs.

Before that I did some testing and hit 125mph and it was still pulling, but the truck started to wander quite a bit so I let off.

I found the key is properly balanced tires, all newer front end components, good weatherstripping and window seals, quality shocks, decent springs, overdrive, tight u joints, lots of insulation, and a decent seat.

Before I redid my truck 2 years ago it was rather uncomfortable at highway speeds. Any trip over an hour would be very tiresome. Bad shocks, worn out seat, no insulation, and no overdrive made for a very loud and painful ride.
 
THats what i'm finding as an overall theme. I have never really been too happy with the tires i have on the burb. I would be pretty curious to try a different set on it and see if that helps it out at all.
 
A good set of tires will make all the difference in how a truck drives.
There is a huge difference in just a new set of Nitto tires verses old ones on my 2500HD.
I know the SSR radials aren't the best tire for cruising the highway at higher speed, but it isn't all that bad. If it had a good set of 4" springs, shocks and some good all terrian tires on it. I believe it would not be any problem to drive it on long road trips.
 
I don't think we've heard from many people with 1-ton conversions, crossover, etc. Have we? I remember one.
 
Mastiff said:
I don't think we've heard from many people with 1-ton conversions, crossover, etc. Have we? I remember one.
Click to expand...

Mine's not a 1 ton swap per se because it's a K30, but just for grins I ran 80-85 on a 60 mile trip today instead of my usual 70. Runs just as good as anything.
 
38377k5 said:
Mine's not a 1 ton swap per se because it's a K30, but just for grins I ran 80-85 on a 60 mile trip today instead of my usual 70. Runs just as good as anything.
Click to expand...

Can I just ship my K5 up to you guys and have you iron out all the remaining issues? :D I need a general contractor to finish this thing off. Only been pissing around with it for 20 years. I'd like to enjoy it while I'm still able to get in and out... :doah:
 
You must log in or register to reply here.

Latest Posts

Top Bottom