A/F ratio on the dyno vs. A/F ratio on the streets
Thread Starter
Honda-Tech Member
Joined: Feb 2002
Posts: 4,444
Likes: 5
From: Basin, WY
A/F ratio on the dyno vs. A/F ratio on the streets
I think I read your A/F ratio will increase by like 0.5 when you take it off the dyno because of the increased airflow... ? Is this true?
i.e. You have your car tuned to 12.5:1 on the dyno, but when running on the streets, it will run a 13:1 A/F ratio
i.e. You have your car tuned to 12.5:1 on the dyno, but when running on the streets, it will run a 13:1 A/F ratio
Honda-Tech Member
Joined: May 2001
Posts: 2,523
Likes: 0
From: 604 whp NorCaL
Re: A/F ratio on the dyno vs. A/F ratio on the streets (xThexHeadx)
i don't know about increased airflow, but its safe to say that a dynojet dyno cannot take in account of aerodynamic load which does have effect on the motor. more specifically, that means in real operating conditions the motor can reach cells on the map which aren't tuned.
[Modified by SEFI8LOxCivic, 8:40 AM 11/7/2002]
[Modified by SEFI8LOxCivic, 8:40 AM 11/7/2002]
Honda-Tech Member
Joined: Sep 2001
Posts: 4,116
Likes: 2
Re: A/F ratio on the dyno vs. A/F ratio on the streets (xThexHeadx)
Also, tuning by say a 3rd gear pull on the dyno will give you leaner values for 4th and 5th gear. If you do dyno pulls in 4th gear, or run lower air/fuel values in 3rd (say 11:1, if you are shooting for 12:1 in upper gears) than you are guranteed to cover yourself for good air/fuel in the upper gears. This is the reason that everyone says no 5th gear boosting, your air/fuel values get to low. This is due to the load that 5th gear places on an engine, commanding the most amount of fuel.
Smarter than you
iTrader: (1)
Joined: Apr 2001
Posts: 8,240
Likes: 2
From: Third Coast, united states
Re: A/F ratio on the dyno vs. A/F ratio on the streets (boosted hybrid)
ive always heard your a/f will be .5 leaner on the streets then on the dyno. 5th gear boosting is the leanest of all gears like boosted hybrid said, if u choose to boost in 5th I just hope u have an EGT guage so u can tell when the temp changes and u need to let off. ony my FMU set up the car would read 750degrees in 3rd/4th then by the top of 5th it would read 780.
Trending Topics
Joined: Mar 2002
Posts: 915
Likes: 0
From: Somewhere, NJ, USA
Re: A/F ratio on the dyno vs. A/F ratio on the streets (gsx4R1)
I wonder how "off" the wideband is at the dyno, it being in your tailpipe and all.... I have my own wideband now in right before the cat and wondered if anyone did a tailpipe wideband -> before cat wideband comparison...
I had originally tuned at 12.1-12.5 A/F at the dyno it wasn't HOT out but a little warm, my guess is 70F in the dyno.... when I went to the track and race the A/F ratio was 11.1 at the highest during boost even in 3rd gear (what I tuned at)... then again it was about 35F out :D
I had originally tuned at 12.1-12.5 A/F at the dyno it wasn't HOT out but a little warm, my guess is 70F in the dyno.... when I went to the track and race the A/F ratio was 11.1 at the highest during boost even in 3rd gear (what I tuned at)... then again it was about 35F out :D
still want my question answered if anyone has experience...
Thread
Thread Starter
Forum
Replies
Last Post
92 civic VX B18c
All Motor / Naturally Aspirated
1
Apr 20, 2004 02:23 AM