Why Enrich at High RPM - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members

MEGAsquirt A place to collectively sort out this megasquirt gizmo

LinkBack Thread Tools
Old 11-22-2013, 11:11 AM   #1
Elite Member
Thread Starter
DNMakinson's Avatar
Join Date: Jan 2013
Location: Seneca, SC
Posts: 2,701
Total Cats: 268
Default Why Enrich at High RPM

I am trying to understand the logic of running richer AFR in the RPM ranges above 5500, when at 50-100kPA.

I ponder this because most posted maps show this, as well as most base maps.

However, Y8S and Westfield do not enrich this area, but leave it at 14.7, or whatever they were running for that kPA at about 5000 RPM.

So, again, I'm not talking about enrichment due to boost, or high kPA, but rather due to higher RPM.

Any thoughts?
DNMakinson is offline   Reply With Quote
Old 11-22-2013, 01:54 PM   #2
Elite Member
iTrader: (8)
Ryan_G's Avatar
Join Date: Jan 2012
Location: Tampa, Florida
Posts: 2,578
Total Cats: 155

From what I understand this has more to do with the fact that you make more power when you run 13:1 AFRs and when you are at higher rpm's gas mileage is obviously not your priority. I do not believe there is any underlying reliability reason for it.
Ryan_G is offline   Reply With Quote
Old 11-22-2013, 02:38 PM   #3
Destroyer of Inconel
iTrader: (37)
EO2K's Avatar
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,642
Total Cats: 954

Good jorb on doing some of the research, but fuel is only part of the story. Check spark maps for those same regions on those guys tunes. While you are looking at all these maps, try to figure out who is just using a map, and who is actually tuned on a load bearing dyno.
EO2K is offline   Reply With Quote
Old 11-22-2013, 03:01 PM   #4
Elite Member
Thread Starter
DNMakinson's Avatar
Join Date: Jan 2013
Location: Seneca, SC
Posts: 2,701
Total Cats: 268

E02K. Correct.

Those with 14.7 at 7000 RPM have aggressive timing maps to go along with the slower burn. To me that makes sense. I am presently trying maps close to Y8S and have seen no issues (Air temps are cool these days).

Just wanted to make sure I wasn't missing something that would eat a piston.

One could also look at the converse. Perez was looking into advancing his timing, but with that, he may want to keep the high RPM area stochiometric (again, 100 kPA and under).

Another thing about Y8S AFR's. Notice he does not go rich (13.0-13.5) at 100kPA with a turbo. Makes sense. On a NA, as I understand it, you go rich at WOT (100kPA) go gain power, not for protection. BUT if you have a turbo, then you have power above 100kPA.

DNMakinson is offline   Reply With Quote
Old 11-22-2013, 05:23 PM   #5
Join Date: Nov 2013
Location: France, Paris
Posts: 18
Total Cats: 0


On turbo engine lot of cars run rich (13) to very rich (10) to cool down the turbine and/or cool down catalytic converters.

On NA as it was said, you don't really bother about fuel economy @ high rpm, but power, and thus your goal is to use all the oxygen in the cylinder, burn it fast and in the vincinity (centred) of the TDC. So you run with a AFR around 12.7

Last edited by Regis_92N; 11-22-2013 at 05:23 PM. Reason: orthographic flaws
Regis_92N is offline   Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
01-05 Fab9 PNP COPs (used) FrankB Miata parts for sale/trade 6 09-30-2015 12:48 PM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -4. The time now is 09:40 AM.