How about a 75hp shot to help on those hills?
Towing Dilemma & In Need of Good Advice
- Thread starter tenmile
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- Thread starter
- #42
Nay, whats your daily driver?
- Thread starter
- #43
I like it, are 80 owners using nitrous? Maybe that is the HG problem.
Here's some numbers I pulled out of thin air, with some highschool math.
at sea level:
normally aspirated fzj80 ~220hp
supercharged fzj80 ~300hp (guess?)
at 3000ft (-10% performance)
n/a 220-10% = 198hp
s/c 300-10% = 270hp
at 6000ft (-20% performance)
n/a 220-20%=176hp
s/c 300-20%=240hp
So at 6000' and supercharged you barely have more than a stocker at sea level.
Add 50hp shot:
n/a 176+50=226
s/c 240+50=290
Add a 75shot:
n/a 176+75=251
s/c 240+75=315
Now 315hp would be just a bit more than a regular supercharged fzj80 at sea level. If the nitrous is tuned properly, I don't see any issues with heat for the 10-15 seconds you're going to have it switched on. Now if you leave it on for a full five minutes, that would be a different set of math.
Or if you use the nitrous at sea level, you'd be cranking out 375hp which could be detrimental to some stuff.
Any engineering types want to fix my math?
at sea level:
normally aspirated fzj80 ~220hp
supercharged fzj80 ~300hp (guess?)
at 3000ft (-10% performance)
n/a 220-10% = 198hp
s/c 300-10% = 270hp
at 6000ft (-20% performance)
n/a 220-20%=176hp
s/c 300-20%=240hp
So at 6000' and supercharged you barely have more than a stocker at sea level.
Add 50hp shot:
n/a 176+50=226
s/c 240+50=290
Add a 75shot:
n/a 176+75=251
s/c 240+75=315
Now 315hp would be just a bit more than a regular supercharged fzj80 at sea level. If the nitrous is tuned properly, I don't see any issues with heat for the 10-15 seconds you're going to have it switched on. Now if you leave it on for a full five minutes, that would be a different set of math.
Or if you use the nitrous at sea level, you'd be cranking out 375hp which could be detrimental to some stuff.
Any engineering types want to fix my math?
I think what you're missing is that it takes 5 - 10 minutes to climb these passes.
egads. at 8800ft the air pressure is 10.6 psi
at 12000ft the air pressure is 9.3 psi
that's 28% loss of performance at 8800'
and a staggering 36% loss at 12000'
re-doing the math for the above,
8800' s/c: 300*.72=215hp
12000' s/c 300*.63=190hp
so a 75shot would REALLY help. The trick would be to find a shop that thinks it's worthwhile, and has experience with nitrous install and tuning.
lol. I don't think a nitrous bottle will last that long.
But I'd imagine a quick BOOT to get more speed at the bottom portion will carry the speed for longer up the hill?Ah, I thought my bench-racing days were over. My next thougths are of a turbo, because the boost pressure isn't proportional to atmospheric pressure, it's in addition to atm pressure.
But since tenmile already has the supercharger, if it were my car, I'd turn the boost up a bit with a smaller pulley, and try to lower charge temps (intercooler) to make the best of the present investment.
Or simply put up with the extra time needed to go up the pass, since almost everyone else is going the same slowness
That said, I have zero experience with tuning for altitude. I usually play with street and track cars at sea level.
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- #48
You guys are funny. Are we seriously talking about "nitrous boosting" my poor cruiser! What does this setup run$$$?
Maybe I should look closer at the pulley/intercooler thing- what does that setup run?
Maybe I should look closer at the pulley/intercooler thing- what does that setup run?
The pulley is like $80 (not sure, it's been a while). the intercooler runs $200-$300 in parts and then your time to install (or money to pay someone to do it). good luck on your dilemma
crawdad, on this forum has a stock cruiser and has been in mine many times, you could PM him for his opinion on the performance difference.
good luck Bret
crawdad, on this forum has a stock cruiser and has been in mine many times, you could PM him for his opinion on the performance difference.
good luck Bret
Last time I went up Vail pass I passed a guy (driving my corolla) in a extended cab 2500 dodge cummins towing a 5th wheel horse trailer with 3 horses in it. He was probably towing 8k-10k lbs but he wasn't going over 55 mph. Granted he might have been ABLE to go faster, but he wasn't towing. I think you should have no problem keeping up with the semi's and others towing trailers when going over those passes.
Leni
Leni
i'm not sure about sc but turbos loss of HP with respect to elevations is MUCH less than that of a NA motor, in fact some people will argue that is the turbo is sized a certain way there is no effect on elevation. i would guess a SC is similar so comparing a sc at elevation to a NA motor would be ...well...... no comparison
I think that has already been covered.
I'll add my two cents...
I have never been over vail pass, but coming up the Lewiston Grade in Northern Idaho with a load of Costco stuff (750ft-2800ft over 6 miles) I was doing good to stay above 60 and out of 2nd gear. This was in my 93 and my 94 with no SC. If you can run 70+ up I-70, you don't have anything to worry about. Hook up the trailer and roll with it. You may have a few slow sections, but the vast majority of the time you will be walking all over expeditions and suburbans that are towing the same load....
Not quite true.
s/c boost is not regulated, boost is dependant on s/c rpm which is proportional to pulley size and engine rpm, along with available air (barometric pressure).
Turbo boost is regulated, and most turbos can put out much more than required. Turbo speed is not regulated, it will spin as fast as required.
So yes, turbos are altitude compensating devices and superchargers are not. A s/c engine will have more output at higher barometric pressures.
