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-   -   High altitude performance (http://www.risingsun4x4club.org/forum2/showthread.php?t=77)

rgsiii 08-27-2005 10:26 AM

High altitude performance
 
I am normally driving at an altitude of about 200 feet and when I went to Colorado earlier this month there was a marked reduction in performance of my Land Cruiser. I was driving a 1994 FZJ 80 with 285 tires, weighing 6,250 pounds empty and not regeared. It was tuned up recently and the timing and compression tests are OK. I first noticed the problem in Denver and when I had some work done at Christo’s they commented on it on it being sluggish. I put some Toyota BG44 in the gas and it made a slight improvement. Driving on the Interstate to Grand Junction, there were spots when it was unable to go faster than about 30 mph. It was a heavily loaded vehicle likely well above 7,000 pounds. Off road it did OK except in one spot. What sort of speeds are normal on the Interstate for a FZJ 80 at high altitudes?

When I got back home, it appeared that the throttle positioning sensor was acting up and I replaced it. I got rebuilt fuel injectors from Man-a-Fre and the vehicle is doing better than I remember it doing in the past. Does anybody have other ideas on getting the vehicle ready for another trip? I will likely be hauling less stuff in the vehicle in the future—I brought a lot of camping and what I later realized was unnecessary recovery equipment.

Thanks,

Richard

wesintl 08-27-2005 10:44 AM

30 mph is still faster than me... :eek:

Romer 08-27-2005 01:49 PM

Maybe what you did alreday fixed it. I don't have any issues like those you talked about. Although it does get a bit sluggish on the steep mtn. passes.

Ken

Uncle Ben 08-27-2005 02:07 PM

Quote:

Originally Posted by rgsiii
I am normally driving at an altitude of about 200 feet and when I went to Colorado earlier this month there was a marked reduction in performance of my Land Cruiser. I was driving a 1994 FZJ 80 with 285 tires, weighing 6,250 pounds empty and not regeared. It was tuned up recently and the timing and compression tests are OK. I first noticed the problem in Denver and when I had some work done at Christo’s they commented on it on it being sluggish. I put some Toyota BG44 in the gas and it made a slight improvement. Driving on the Interstate to Grand Junction, there were spots when it was unable to go faster than about 30 mph. It was a heavily loaded vehicle likely well above 7,000 pounds. Off road it did OK except in one spot. What sort of speeds are normal on the Interstate for a FZJ 80 at high altitudes?

When I got back home, it appeared that the throttle positioning sensor was acting up and I replaced it. I got rebuilt fuel injectors from Man-a-Fre and the vehicle is doing better than I remember it doing in the past. Does anybody have other ideas on getting the vehicle ready for another trip? I will likely be hauling less stuff in the vehicle in the future—I brought a lot of camping and what I later realized was unnecessary recovery equipment.

Thanks,

Richard

You don't want to hear it but forced induction is the key to high altitude blues! I can do 65 on most any pass in my supercharged FZJ-80. Its all about how much your willing to spend for drivability!

rgsiii 08-27-2005 07:24 PM

Quote:

Originally Posted by wesintl
30 mph is still faster than me... :eek:

No wonder, you don’t even have spark plugs! I have a BJ42 that is turbo’d. I really think it would have done better at altitude. It would have killed me going across Oklahoma, Kansas and Arkansas. Maybe with the remedies, it will make the 80 more altitude friendly. I never noticed any real problem at sea level.

Quote:

Originally Posted by Romer
Maybe what you did alreday fixed it. I don't have any issues like those you talked about. Although it does get a bit sluggish on the steep mtn. passes.

Ken

Ken, what sort of speeds can you get up to in the area of the Eisenhower Tunnel? I really was getting pretty nervous with 18 wheelers passing me up.

I really enjoyed meeting you in Denver. We didn’t make it to Moab, but had a great time around Ouray. Maybe Moab in the spring.

Quote:

Originally Posted by Uncle Ben
You don't want to hear it but forced induction is the key to high altitude blues! I can do 65 on most any pass in my supercharged FZJ-80. Its all about how much your willing to spend for drivability!

I am toying with the idea of a TC or Supercharger. I am thinking about going to Mexico and will have to figure out how available premium fuel is south of the border. I would hate to be stuck using a low octane fuel and get into trouble in a country with only a small Toyota presence.

Richard

Romer 08-27-2005 07:52 PM

I can do 50-55 getting up close no problem, 60 if I push it. The 40 would probably be doing . . . . 40.

bh4rnnr 08-27-2005 09:29 PM

I can usualy keep the runner around 50mph going up the tunnel/vail pass.... New gears helped on that part alot... Befor it was around 40. Kinda get used to getting passed by truckers. It gets me home, thats good enough for me.

Rzeppa 08-28-2005 03:11 PM

You're on the right track, concentrating on fixing things that may not already be working optimally, but with fuel injection your mixture should be already properly compensated. As Kevin mentioned, the only remedy is forcing more air in there. You have a heavy vehicle, and the laws of physics aren't on your side. Gears will only compensate for tires, but can't make more power.

Welcome to Colorado!

farnhamstj 08-31-2005 07:15 AM

uzj 100
 
I decided I wanted to do 75 over the passes. So I went for the v8. No comparison to the 80. Putting a header on my 40 maybe gained 5 mph up the pass. When I first arrived in the mountains I would get pissed at how slow I drove. You quickly decide that Land cruisers were just not made to go fast. Oh except the 100 :D


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