View Poll Results: Is your SC400 faster without the MAF?
Yes
17
32.08%
No
5
9.43%
I think this is a stupid post
20
37.74%
Its impossible so I will not even accept it as a possibility
11
20.75%
Voters: 53. You may not vote on this poll
Unplugged MAF = More torque, gas, fun 92-94
09-16-10, 10:43 AM
#19
We are gonna go to the strip in Bradenton within a couple of weeks and I might do separate runs with and without maf to provide more irrefutable evidence, and hopefully I can get the two others here in Tampa to do the same. It may be hard for me to force myself to be slower for a run, though, lol. I'll see if I can bite the bullet.
09-16-10, 12:19 PM
#20
ok, you guys really want to know whats happening?
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
09-16-10, 12:57 PM
#21
ok, you guys really want to know whats happening?
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
There must be a problem with the aged electronics/wiring in these cars which is preventing proper monitoring, and so the car is not fueling/timing the engine correctly. Nobody knows exactly, or they are holding out on us. In this case, it is not necessarily just the added fuel in the mixture causing the increased output, but the general fact that the safe mode is removing those erroneous variables from the equation.
Last edited by BartleDoo; 09-16-10 at 01:06 PM.
09-16-10, 01:02 PM
#22
Lexus Test Driver
iTrader: (7)
Join Date: Oct 2006
Location: SoCal & SLOcal
Posts: 927
Likes: 0
Received 0 Likes
on
0 Posts
ok, you guys really want to know whats happening?
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
when you unplug the maf the car goes into safe mode and the engine runs a safe tune (rich air/fuel mixture) to make sure you don't run lean and blow anything up, cause it has no idea how much air is entering the engine, it only knows what rpm you are at now, and the range of fuel for the different amounts of air that could possibly be coming in for that rpm. with me so far?
so if you know a little about tuning, one of the obvious side affects of running a little rich is increased torque and increased HP, depending on how rich you are running (there are 2 different A/F ratios for max HP, and max torque, both of which are way richer than what the factory runs). So now you guys know why the safe tune gives you a little more umph and why your gas needle is falling faster than you could ever imagine.
I have an air-fuel controller and have experimented by dumping a $h!t load of fuel at low and high rpms, the outcome the car always feel faster. But it's fine tuning this air fuel ratio so that you can get maximum power or maximum fuel economy.
Last edited by sc-driver; 09-16-10 at 02:52 PM.
09-16-10, 01:26 PM
#24
I remember dyno'ing my SC awhile ago, the AFRs dipped below 11-12 area... I cannot imagine any richer allowing to make more power...
I found this bit of info, ill quote it.
It seems that pulling the MAF allows higher rpm/wot to add less fuel than stock....but cruising speeds dumps more fuel, hence the bad gas mileage.
Becuase there is NO way, that my car dyno (at best) 12afr, and pulling the maf allows more fuel (10? afr) and make more power, it should make less since that way below the optimal afr (14.7, which you dont want to run obviously at WOT for safety reasons.)
And obviously we are overlooking the root of the issue, why does this happen when the car warms up? My car has new o2 sensors (3 sets now in different locations along the exhaust), multiple ecus, mafs, tps, coolant temp sensors were tried..... and the only way to make the car run better is to pull anything that relates to the maf out of the equation.
Mr. Doo just tried a new Maf, coolant temp.. and the other guy who tried this is completely stock.
I found this bit of info, ill quote it.
The ideal AFR varies depending on where in the engines operation you are, plus about 273945798457 other variables. But for a typical medium to low compression NA engine:
Idle AFR doesn't much matter. I would try to lean it out until idle RPM starts dropping, then richen it back up a little. 11:1 sounds too rich, but anything close to 13:1 or leaner is just fine.
Under cruising, engines are factory tuned to 14.7:1 to keep the catalytic converter happy and minimize emissions. If you can run leaner at cruise then you can save some fuel. You might not be able to go much leaner at cruise though without also advancing the timing in those areas. Leaner mixtures burn slower so they require more timing advance. I find that 15.5:1 works ok. Any leaner and it starts getting wheezy and kind of nervous feeling due to lean misfires.
At WOT, leaner will tend to burn hotter and produce more power but only up to a point. Go leaner than stoich and power starts going down (as does temperature) because you aren't burning as much fuel as you could be. Unless you have high compression (or really low octane fuel) you aren't going to burn any valves or run into detonation. 13.5:1 is a good target for WOT.
Under hard deceleration I wouldn't bother trying to change the AFR. The engine is using so little fuel it's not worth worrying about.
C|
Idle AFR doesn't much matter. I would try to lean it out until idle RPM starts dropping, then richen it back up a little. 11:1 sounds too rich, but anything close to 13:1 or leaner is just fine.
Under cruising, engines are factory tuned to 14.7:1 to keep the catalytic converter happy and minimize emissions. If you can run leaner at cruise then you can save some fuel. You might not be able to go much leaner at cruise though without also advancing the timing in those areas. Leaner mixtures burn slower so they require more timing advance. I find that 15.5:1 works ok. Any leaner and it starts getting wheezy and kind of nervous feeling due to lean misfires.
At WOT, leaner will tend to burn hotter and produce more power but only up to a point. Go leaner than stoich and power starts going down (as does temperature) because you aren't burning as much fuel as you could be. Unless you have high compression (or really low octane fuel) you aren't going to burn any valves or run into detonation. 13.5:1 is a good target for WOT.
Under hard deceleration I wouldn't bother trying to change the AFR. The engine is using so little fuel it's not worth worrying about.
C|
It seems that pulling the MAF allows higher rpm/wot to add less fuel than stock....but cruising speeds dumps more fuel, hence the bad gas mileage.
Becuase there is NO way, that my car dyno (at best) 12afr, and pulling the maf allows more fuel (10? afr) and make more power, it should make less since that way below the optimal afr (14.7, which you dont want to run obviously at WOT for safety reasons.)
And obviously we are overlooking the root of the issue, why does this happen when the car warms up? My car has new o2 sensors (3 sets now in different locations along the exhaust), multiple ecus, mafs, tps, coolant temp sensors were tried..... and the only way to make the car run better is to pull anything that relates to the maf out of the equation.
Mr. Doo just tried a new Maf, coolant temp.. and the other guy who tried this is completely stock.
Last edited by RedPhoenix; 09-16-10 at 01:30 PM.
09-16-10, 02:52 PM
#27
Lexus Test Driver
iTrader: (7)
Join Date: Oct 2006
Location: SoCal & SLOcal
Posts: 927
Likes: 0
Received 0 Likes
on
0 Posts
My 1UZ is different then your 1UZ since 96 is when they changed up a lot of stuff. I have a different maf sensor then you guys (hotwire vs karman), different compression, different intake valve timing, I have sequential multi-port fuel injection, my power curve is different then your guys', my exhaust manifold is semi-dual type vs single type, you guys have 4 group type injectors that feed into 2 cylinders each...and so on.
You want max power, get a standalone and get it professionally tuned. A safe max power output is in the richer side on full throttle while if you're looking for fuel consumption, you need to lean it out a bit.
I'm not saying dumping a tank load of fuel will get you across the world in a couple seconds, I'm saying a slightly richer mixture than stock will get you going faster.
