wideband testing with mods and stock ECU
11-27-01, 11:39 AM
#1
wideband testing with mods and stock ECU
This is a copy of my post to the RX7 list. Mod your car at your own risk.
I put a wideband on my 93 R1 last night with the stock original ECU.
Relevant mods and condition are:
DP
RB dual tip CB
Efini y-pipe
Stock air filter is about 8K miles old (and only really driven on clean
highways)
Stock fuel filter is about 20K miles old
Plugs are about 2-3K miles old
Original motor and turbos, 56K miles
It was cold last night, about 38F and dry so I figured it was a perfect opportunity to test. Results are simple, WOT at anything above ~2500rpm gave a reading of 10.0, the limit of the wideband, completely rich. This might explain the 10% fuel dilution I get in my oil, and I change it every 1500-2000 miles, tested at Southwest Spectro Chemical.
One piece of advise I would give is to not go WOT below 2000rpms, I had a little detonation a couple weeks ago at WOT in 5th gear, 1800-2000rpms. The wideband told me why, at WOT under 2000rpm the a/f ratio was in the 12's and 13's, above 2000rpm it would turn to 11's after about 2500rpm it read 10.0
all the way to redline, 1st, 2nd and 3rd gear, I didn't test WOT to redline in 4th or 5th but I expect similar results.
Think the car isn't running right? It ran a 13.598@ 102.85 this summer, in October I beat my own record at an annual auto-x event. Also I raced a friend with a 93 Touring and the exact same mods from 50-120mph, it was like racing a mirror, neither one of us pulled more than a foot or two on each other.
Bring on the comments!
Jeff
I put a wideband on my 93 R1 last night with the stock original ECU.
Relevant mods and condition are:
DP
RB dual tip CB
Efini y-pipe
Stock air filter is about 8K miles old (and only really driven on clean
highways)
Stock fuel filter is about 20K miles old
Plugs are about 2-3K miles old
Original motor and turbos, 56K miles
It was cold last night, about 38F and dry so I figured it was a perfect opportunity to test. Results are simple, WOT at anything above ~2500rpm gave a reading of 10.0, the limit of the wideband, completely rich. This might explain the 10% fuel dilution I get in my oil, and I change it every 1500-2000 miles, tested at Southwest Spectro Chemical.
One piece of advise I would give is to not go WOT below 2000rpms, I had a little detonation a couple weeks ago at WOT in 5th gear, 1800-2000rpms. The wideband told me why, at WOT under 2000rpm the a/f ratio was in the 12's and 13's, above 2000rpm it would turn to 11's after about 2500rpm it read 10.0
all the way to redline, 1st, 2nd and 3rd gear, I didn't test WOT to redline in 4th or 5th but I expect similar results.
Think the car isn't running right? It ran a 13.598@ 102.85 this summer, in October I beat my own record at an annual auto-x event. Also I raced a friend with a 93 Touring and the exact same mods from 50-120mph, it was like racing a mirror, neither one of us pulled more than a foot or two on each other.
Bring on the comments!
Jeff
11-27-01, 02:59 PM
#2
Rotary Enthusiast
I am suprised to see that at WOT at low rpm the car being lean. I will have to see what happens when I get my wideband o2 sensor going. Thanks for the post, how bad was the detonation? Could you hear it? Do you have a J&S sensor/monitor?
What wideband o2 sensor were you using?
Mike
What wideband o2 sensor were you using?
Mike
11-27-01, 03:17 PM
#3
I borrowed the wideband, I think the brand is FJO? Not sure.
The detonation only happened once, the sound was distintive, I heard it, clear as day, stereo wasn't on and neither was the interior fan. No J+S, I just heard it and lifted immediately. My mods have been on since Feb 2000, so I've driven it many times in cold weather before and never had a problem.
My TII tends to be lean under 3800rpm also, only after the secondaries come on at 3800rpm does it richen up. The FD seemed to be pretty rich after 2000-2200rpm or so, after 2500rpm it definetly wasn't a problem.
Jeff
The detonation only happened once, the sound was distintive, I heard it, clear as day, stereo wasn't on and neither was the interior fan. No J+S, I just heard it and lifted immediately. My mods have been on since Feb 2000, so I've driven it many times in cold weather before and never had a problem.
My TII tends to be lean under 3800rpm also, only after the secondaries come on at 3800rpm does it richen up. The FD seemed to be pretty rich after 2000-2200rpm or so, after 2500rpm it definetly wasn't a problem.
Jeff
11-27-01, 03:28 PM
#4
Rotary Enthusiast
FJO is a company in my town. The guy makes his own ECU for (EFI). By the specs it is an excellent stand alone computer, but I don't know if anyone has one an a rotary motor. Lots of guys run them on piston engine with great success.
I am anxious to see how much my car leans out below 2500 at WOT.
Thanx for the reply.
Mike
I am anxious to see how much my car leans out below 2500 at WOT.
Thanx for the reply.
Mike
11-27-01, 05:55 PM
#7
I didn't have the wideband installed when the car detonated, so no readings for that specific time. The readings I'm giving are all rough figures, I don't have a data logger and even in 5th gear rpms climb quickly so not much time is spent below 2500rpm.
The 10.0 a/f ratio is not a rough number it is the limit of the wideband and it reads 10.0 from roughly 3000rpm on to redline without any waviering, not even a 10.1.
Jeff
The 10.0 a/f ratio is not a rough number it is the limit of the wideband and it reads 10.0 from roughly 3000rpm on to redline without any waviering, not even a 10.1.
Jeff
