A&Q about 350Z
Q:
Just a general question about turbos. Up until now I was always under the impression that turbo cars weren't really affected by higher elevation when it came to track times. Something to do with since turbos compacted air into the engine that the higher up you went it just compressed more air, or something like that. Well since I got my WRX and my friend got his SRT-4 both car groups, no matter how many different forum websites you go to, insist that the higher the elevation the worse times you'll run just like with non turbos. Now I always knew that non turbos got hit pretty good on their track times the higher the elevation but like I said, I thought turbos didn't (maybe .1 at the most at really high elevations). Since I trust my Z family the most I thought I would ask here. Do turbos get affected by elevation and if so is it as bad as non turbos? Thanks
1977 280z: Intake, exhaust, high flow cat, header, euro damper, cam, MSD, adj. FPR, 3.7 lsd, F+R sway+strut bars, 2580lbs
1984 300zx: intake, exhuast, high flow cat, headers, JWT ECU, F+R sway bars, F strut bar
06 WRX TR
A:
Yes they are affected.
Even though they compact air, the air is still thinner the higher you are in altitude.
They are not affected as much as non-turbos because NAs are also affected in their volumetric efficiency due to a less restrictive exhaust flow as the altitude increases.
Turbos aren't affected as much because they have almost always the same back pressure due to the turbine.
Mario
1976 280Z - Dad's Z (turbo swap?)
1978 280Z - Stock Rebuild | 5 Speed | Twice Pipes | Gutted
1982 280ZX - Turbo | MSnS-E | 5 Speed | Large NPR IC
BROKE: Will build computers, webpages, networks, MS units, troubleshoot computers for money
A:
Living at 5300 feet I can tell you they are definately affected by altitude, its pretty amazing to see the difference, and yes turbo cars are affected less.
Currently own:
1990 2+2(For sale soon)
1991 TT(parts for sale)
1993 NA(parts for sale)
1993 Convertible(Converted TT)
1996 TT(with 9,124 miles on it)
"When you do things right people cant really tell that you've done anything at all."
l
A:
air pressure is 14.7 psi at sea level, for every half mile or so you go up it drops 1psi. 0 on the boost gauge is what ever atmospheric pressure is, then boost is counted on top of that. 10psi at sea level isnt the same as 10psi at 5280ft, 24.7psi vs 22.7psi.
I dont know how big of a role it plays if any, but it's somethign to think about.
---
Justin T
72 240Z L28, 5-speed
77 280Z 5-speed (t-boned 8-25-04)
80 280ZX automatic(retired)
A:
Okay, thanks guys. It was something I read on a Z32 forum years ago on a message board that is no longer up. I knew I could count on my zcar.com members.
1977 280z: Intake, exhaust, high flow cat, header, euro damper, cam, MSD, adj. FPR, 3.7 lsd, F+R sway+strut bars, 2580lbs
1984 300zx: intake, exhuast, high flow cat, headers, JWT ECU, F+R sway bars, F strut bar
06 WRX TR
A:
the difference of how altitudes affect turbocars and naturally aspirated cars is astounding. I too a naturally aspirated Z32 to Denver and the car lugged down in 5th gear. I had to drive the car in 4th gear just to be able to run the speed limit (75 MPH).
I took a Z32 that had forced induction to Denver and it ran fine. there was a power loss, but it was hardly noticeable...even to 13000 ft.
If all were equal, none would be strong.
Ballistic,Ruler of Interstates
Stage XX+ 1993 Z32 NA
"SoulTaker"
A:
put that turbo car on a conveyor belt, and man will it move at 10000 ft Ha!
82 zxt 5-spd, oil cooler!
96 240sxes
78/81 jeep j-20
A:
You can correct for elevation with a turbo by increasing your boost, up to a certain point. The issue you run into is that as density decreases with elevation your choke and surge limit will shift to the left ( to less airflow). So not only are you pumping lower density air and getting less HP but when you try and crank the boost the compressor can physically not flow the same airflow as it would at sea level.
06 Lemanz Sunset Track Z
Best car I ever bought.
IHI Turbos comming soon.
A:
Well I'm not too high up. I recently moved to Henderson, NV (near Vegas) and the track that is 45 min away is supposed to be at 2200-2300 ft above sea level. Even back in Ca where I lived for years the track was only at 3000ft above sea level. I mean my Z's don't feel any different here than back home and neither does my wifes 73 maverick. So would it be safe to say that at the elevation I'm at there is probably only about .1 sec difference?
1977 280z: Intake, exhaust, high flow cat, header, euro damper, cam, MSD, adj. FPR, 3.7 lsd, F+R sway+strut bars, 2580lbs
1984 300zx: intake, exhuast, high flow cat, headers, JWT ECU, F+R sway bars, F strut bar
06 WRX TR
A:
On a normally aspirated car you will run at least .10 of a sec slower in the 1/4 mile for every 1000 ft increase in track elevation.Your engine will lose 3% HP for every 1000 ft of elevation increase.
-----------------------------------------
12.804 @ 107.26 mph on crappy street tires with Dual SU Powered 2.9L Stroker!
ZCAR.COM member since Aug 1998
Post Edited (Nov 13, 8:20pm)