Full Version: D-jet tune
I am turning my MPS in right now when I'm cruising I'm around 15 on the AF meter around 2500 RPM when I accelerate the drive drops to about 12.8 my question is some say 14.7 is the stoichiometric or prime level but with air cooled motors I've heard others say I don't see that discussed in the PB Anders information
This was just hashed over a couple weeks ago.... search is you friend.
http://www.914world.com/bbs2/index.php?showtopic=304320
http://www.914world.com/bbs2/index.php?showtopic=304320
QUOTE(Philip W. @ Feb 23 2017, 12:51 PM) 
...when I'm cruising I'm around 15 on the AF meter around 2500 RPM when I accelerate....
This is about the fastest way to fuck your engine.
Sorry if that is blunt but NEVER EVER LUG AN AIRCOOLED ENGINE!!!
Always cruise at or above 3000 rpm, fan speed is the main way this engine cools.
QUOTE(Mark Henry @ Feb 23 2017, 01:01 PM)
This was just hashed over a couple weeks ago.... search is you friend.
http://www.914world.com/bbs2/index.php?showtopic=304320
Great thread. Thanks!
Wow, this stuff has gotten technical over the past 25 years.
How the heck did we ever get by with just our ears, nose, and butt dyno?
QUOTE(Mark Henry @ Feb 23 2017, 01:10 PM)
QUOTE(Philip W. @ Feb 23 2017, 12:51 PM)
...when I'm cruising I'm around 15 on the AF meter around 2500 RPM when I accelerate....
This is about the fastest way to fuck your engine.
Sorry if that is blunt but NEVER EVER LUG AN AIRCOOLED ENGINE!!!
Always cruise at or above 3000 rpm, fan speed is the main way this engine cools.
no apology necessary.
thanks for the link, - and yes I usually am at about 3200rpm in 4th gear cruising around here , or my 5th on the interstate at about 75 is 3000rpm(5th gear was changed for lower rpm at 75-80 highway driving, - I was just using the 2500-2750 as an example because at that moment that is what my a/f meter was reading at that rpm while posting(yes I was posting this while driving- I had help)
QUOTE(Philip W. @ Feb 23 2017, 01:52 PM)
QUOTE(Mark Henry @ Feb 23 2017, 01:10 PM)
QUOTE(Philip W. @ Feb 23 2017, 12:51 PM)
...when I'm cruising I'm around 15 on the AF meter around 2500 RPM when I accelerate....
This is about the fastest way to fuck your engine.
Sorry if that is blunt but NEVER EVER LUG AN AIRCOOLED ENGINE!!!
Always cruise at or above 3000 rpm, fan speed is the main way this engine cools.
no apology necessary.
thanks for the link, - and yes I usually am at about 3200rpm in 4th gear cruising around here , or my 5th on the interstate at about 75 is 3000rpm(5th gear was changed for lower rpm at 75-80 highway driving, - I was just using the 2500-2750 as an example because at that moment that is what my a/f meter was reading at that rpm while posting(yes I was posting this while driving- I had help)
Follow that link, AFR down low as in 1st gear taking off should still be 12-13.5 :1, but lugging below 3000 will give you a high AFR. Really look at the AFR accelerating up to and over 3000 in this case.
I know peeps forget or higher rpm sucks in stop and go, but try to remember to gear down.
ok read back thru the other thread and this confirms what I thought-
fyi forgot to say this is a newly rebuilt MPS and it was so lean on first start car would not start, took 2 full rotations just for car to start( turns out to make more rich- it was that lean !)
so after driving a week this is where I was at, but I also discovered that the CHT was not the correct one- but I had one in my box that is a #12 ive had stashed away for some time, since back when you could by them from Autohauz for $30! and I just put this one in , and I will adjust the MPS to bring that WOT and cruising A/F reading closer to the 13.5 range and see how its doing(yes timing is set fyi,)
fyi forgot to say this is a newly rebuilt MPS and it was so lean on first start car would not start, took 2 full rotations just for car to start( turns out to make more rich- it was that lean !)
so after driving a week this is where I was at, but I also discovered that the CHT was not the correct one- but I had one in my box that is a #12 ive had stashed away for some time, since back when you could by them from Autohauz for $30! and I just put this one in , and I will adjust the MPS to bring that WOT and cruising A/F reading closer to the 13.5 range and see how its doing(yes timing is set fyi,)
QUOTE(Philip W. @ Feb 23 2017, 02:41 PM)
ok read back thru the other thread and this confirms what I thought-
fyi forgot to say this is a newly rebuilt MPS and it was so lean on first start car would not start, took 2 full rotations just for car to start( turns out to make more rich- it was that lean !)
so after driving a week this is where I was at, but I also discovered that the CHT was not the correct one- but I had one in my box that is a #12 ive had stashed away for some time, since back when you could by them from Autohauz for $30! and I just put this one in , and I will adjust the MPS to bring that WOT and cruising A/F reading closer to the 13.5 range and see how its doing(yes timing is set fyi,)
Ok so now after slight adjustment and drive home- a1/4 turn out and the a/f @3200rpm was 13.2-13.5 , 12.5 or so on wot.
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