Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jun 2005
Location: Colorado
Posts: 680
Quote:
Originally Posted by gumba View Post
What fuel head/wur adjustments would you make to compensate for the elevation change? My motor was built and tuned at sea level (Bay Area). At 7,000 ft my a/f's at wot seem to be the same as sea level, 11.5 wot. I recently had a full rebuild on the K27 and was checking the a/f's. I did crank up the boost knob slightly to get up to 1.1.
Here's what I've seen traveling between altitudes. Idle AFR varied quite bit, but once you cracked the throttle and got some airflow throw the metering plate the AFR's were close to the same, just the curve was offset a little.

This makes sense when you think CIS is just measuring air density by the amount of flow past the metering plate. At idle, it's just a stop screw without much measurable air flow, but once the air flow increases to move the plate it's measuring density. Less dense air, less fuel flow.

I was getting the same WOT AFR's at various altitudes when I adjusted the boost pressure up to compensate for the higher altitudes.

Your 11.5 AFR was at 1.1 bar at 7000 ft? 11.5 AFR at 1 bar sea level? Sounds about the same as my results.
__________________
1986 911 Turbo
3.3L, K27HFS, Tial 46mm, TurboKraft Intercooler, 964 Cams, Monty Muffler, MS3 w/MS3X, M&W Ignition, Zietronix WBO2 Data Logger, Wevo shifter, coupler and motor mounts.
Old 06-02-2014, 09:59 AM
  Pelican Parts Technical Article Directory    Reply With Quote #21 (permalink)
Registered User
 
gumba's Avatar
 
Join Date: Dec 2001
Posts: 3,585
.9 bar 11.5 a/f at sea level on engine dyno. 1.1 bar 11.5 a/f at 7,000. Next time I'm out I can check it at .9 bar. Just trying to figure out if I need to do something.
__________________
Harold
'79 930/DP935
Old 06-02-2014, 10:53 AM
  Pelican Parts Technical Article Directory    Reply With Quote #22 (permalink)
Registered User
 
Alan L's Avatar
 
Join Date: Apr 2006
Location: New Zealand
Posts: 2,904
Quote:
Originally Posted by T77911S View Post
here is something that is REALLY far fetched.

if you were to run a tube from earth to outer space, would it suck all the oxygen out?
LOL.
A. NO.
You already have the same pressure gradient between outer space and atmospheric pressure - without your straw. A bit OT, but the explanation is................................................ .................................................. ..............
Gravity. Thank heaven for gravity - so we still have the O2 to breathe, and the other gasses - nitrogen CO2, Argon etc. The lighter Big Bang gasses - helium/Hydrogen escaped the gravitational field before you and I wore diapers.
Alan
__________________
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 06-02-2014, 10:31 PM
  Pelican Parts Technical Article Directory    Reply With Quote #23 (permalink)
Registered User
 
T77911S's Avatar
 
Join Date: Oct 2006
Location: MYR S.C.
Posts: 9,096
good to hear from you alan. i think the last time i really talked to you you had done some bodywork on your 930, non-intensional. i picked up an 86 930 since then.
__________________
86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ [__] RUNNING: [__] NOT RUNNING:
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[] RUNNING:[_] NOT RUNNING:__2000 MER E320 WAGON [_] WRECKED:[]RUNNING:
Old 06-05-2014, 07:23 AM
  Pelican Parts Technical Article Directory    Reply With Quote #24 (permalink)
Registered User
 
Alan L's Avatar
 
Join Date: Apr 2006
Location: New Zealand
Posts: 2,904
Ha, yes. Car all re arranged back to normal. Painful process. Off to track this w/end.
My greatest fear is always about damaging the car. Just waiting for Chris @ Turbokraft to assemble some more go-fast bits.
Regards
Alan
__________________
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)
Old 06-05-2014, 12:06 PM
  Pelican Parts Technical Article Directory    Reply With Quote #25 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 12:38 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2017 Pelican Parts LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.