blow off valve...
- Thread starter DavidT
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Chris Benvie
Every so often
Exhaust Gas Temp
Chris Benvie
Every so often
Autozone? 
AIR/fuel is almost a must on a Supercharged SHO
AIR/fuel is almost a must on a Supercharged SHO
twr
whoohoo
Chris Benvie said:Autozone?
AIR/fuel is almost a must on a Supercharged SHO
An acurate a/f is a must on a supercharged SHO. Those little autometer gauges are useless. What you need is a Wideband O2 sensor with a controller. http://www.plxdevices.com/ has a reasonably priced Wideband O2 sensor packages.
Mike Kopstain
New Member
Skip the wideband and use an EGT instead. The two aren't used together. It's typically one or the other. An EGT is going to tell you the temperature of your exhaust gas. The higher the temperature the richer the mixture and visa versa.
The Autometer A/F gauge, or any other A/F gague not using a wideband sensor, is really just a light show. The gauges sweep is too narrow, especially for a supercharged car, to get an accurate reading.
Dave, what you need is a laptop mount and a TwEECer R/T. Every gauge you'll ever want will be on the display of your laptop without the worry of innacurate gauges.
The Autometer A/F gauge, or any other A/F gague not using a wideband sensor, is really just a light show. The gauges sweep is too narrow, especially for a supercharged car, to get an accurate reading.
Dave, what you need is a laptop mount and a TwEECer R/T. Every gauge you'll ever want will be on the display of your laptop without the worry of innacurate gauges.
Mike Kopstain
New Member
$550 to your door. 
Laptop and stand not included.
Batteries not included either.
Laptop and stand not included.Batteries not included either.
gmorrell
Never been a noob...
EGT's are the other way around, higher temps mean leaner, lower temps mean richer. On a normally aspirated engine, we typically (depending on a lot of other things...) tune for 1250 to 1300F EGT for a hard, WOT pull. Water and alcohol injection (used with some boosted applications) can affect EGT's, making them read higher then the actual air/fuel mix would indicate.Mike Kopstain said:
WBO2 is really a better way to measure A/F, EGT is subject to environmental variables that often can't be controlled or are unknown. If the cost of a WBO2 unit is a problem, I suggest contemplating the cost of rebuilding a melted-down motor.
twr
whoohoo
Try more like $339 for a Wideband O2 with control and digital display. The WBO2 is going to be alot more accurate at reading A/F. The problem with EGT's, and I've seen it first hand and had discussions with both Pat and Gary is just what Gary stated above, they are effected by alot of variables and interperating the output is almost an art.
Mike Kopstain
New Member
Understood.
Gary's post
If the cost of a WBO2 unit is a problem, I suggest contemplating the cost of rebuilding a melted-down motor\
Wouldn't it be wiser to get a
"laptop mount and a TwEECer R/T. Every gauge you'll ever want will be on the display of your laptop without the worry of innacurate gauges."
for $40 more???
Also, are the $30 Autometer air/fuel guages THAT inaccurate that they are USELESS?
If the cost of a WBO2 unit is a problem, I suggest contemplating the cost of rebuilding a melted-down motor\
Wouldn't it be wiser to get a
"laptop mount and a TwEECer R/T. Every gauge you'll ever want will be on the display of your laptop without the worry of innacurate gauges."
for $40 more???
Also, are the $30 Autometer air/fuel guages THAT inaccurate that they are USELESS?
AutoSHO
No SHO = Mo $$$
"Also, are the $30 Autometer air/fuel guages THAT inaccurate that they are USELESS?"
Yup.
A Tweecer will not give you "all the gauges you could ever need" because it only reports on what the stock sensors are seeing. Optimally you ought to have a wideband sensor and a Tweecer so that you can view and record actual A/F ratios and be able to correct them in the computer's programming.
Also, the Tweecer R/T is $550, not $370.
Yup.
A Tweecer will not give you "all the gauges you could ever need" because it only reports on what the stock sensors are seeing. Optimally you ought to have a wideband sensor and a Tweecer so that you can view and record actual A/F ratios and be able to correct them in the computer's programming.
Also, the Tweecer R/T is $550, not $370.
twr
whoohoo
Here's my plan for my car. I'm not saying that this is the best way to do it, but I know I will feel alot better about what my engine is doing under WOT and full boost.
1)Tweecer RT
2) WBO2 Sensor with controller and digital display (also the a coverter that steps the 5v WB sensor signal back to 1 volt and feed that to my exisiting autometer a/f for quick ref or the data logger)
3) Boost Guage
4) Fuel Pressure Gauge (relative if I can find/make one)
5) Additional knock sensor with monitor
6) APEXI for on the fly a/f adjustments
My thinking is if I have good A/F and no detonation (knock) than I should be safe.. Atleast that's the idea anyway.
This is in addition to my existing Oil pressure and H20 gauge.
The autometer A/F gauge by itself running off a stock (narrow band) 02 sensor is no way accurate enough to give good feed back of the real A/F ratio
1)Tweecer RT
2) WBO2 Sensor with controller and digital display (also the a coverter that steps the 5v WB sensor signal back to 1 volt and feed that to my exisiting autometer a/f for quick ref or the data logger)
3) Boost Guage
4) Fuel Pressure Gauge (relative if I can find/make one)
5) Additional knock sensor with monitor
6) APEXI for on the fly a/f adjustments
My thinking is if I have good A/F and no detonation (knock) than I should be safe.. Atleast that's the idea anyway.
This is in addition to my existing Oil pressure and H20 gauge.
The autometer A/F gauge by itself running off a stock (narrow band) 02 sensor is no way accurate enough to give good feed back of the real A/F ratio
Axianator
I am a banana!
Although I hate to disagree with Mikey (gasp, lol), I'm going to have to side with Gary on the WB HEGO vs. EGT gauge issue. A good wideband O2 setup (with controller and display) is essential to obtaining quick and accurate measurements of your true air/fuel mixture, especially when running a boosted application. As Terry has stated, the stock HEGO sensors are "narrowband" sensors that only have a typical effective range of about 13:1 - 17:1 at most. A true wideband HEGO setup will usually afford you an A/F range of about 10:1 all the way up to 20:1, depending on the sensor used.
Assuming you don't want to construct your own wideband setup (like the guys at DIY-WB have done), then your best bet is probably with one of the previously mentioned PLX wideband setups. The less expensive model M-300 uses a more common "consumer grade" Bosch wideband sensor and sells for $339 from the PLX website. The more expensive M-200 uses a less common "lab grade" NTK sensor and sells for $485 shipped from Josh's website. Both models share the same controller and display form factor, with the only real difference being the sensors themselves. Either one would probably be your best bet for a completely pre-built and good-quality wideband setup.
As for the APEXI, Terry, you won't need one if you go with a TwEECer R/T. Combined with the wideband O2 setup and other gauges you have planned, you'll be able to modify your A/F on-the-fly and in real-time via the TwEECer thanks to the Stabilized Fuel and other tables we have access to. What's more is that you don't want to be "working around" the EEC all the time (like you might with the APEXI) as this could eventually lead to some major problems, especially in a boosted application. IMO, it's better to control the EEC directly (which controls everything else) and work from there. Fortunately, we have a tool like the TwEECer that will let us directly manipulate the EEC in to doing what we want it to do, rather than fudging with things externally like the APEXI have us do.
As far as a relative fuel pressure gauge goes, check out Josh's post on that subject here.
Assuming you don't want to construct your own wideband setup (like the guys at DIY-WB have done), then your best bet is probably with one of the previously mentioned PLX wideband setups. The less expensive model M-300 uses a more common "consumer grade" Bosch wideband sensor and sells for $339 from the PLX website. The more expensive M-200 uses a less common "lab grade" NTK sensor and sells for $485 shipped from Josh's website. Both models share the same controller and display form factor, with the only real difference being the sensors themselves. Either one would probably be your best bet for a completely pre-built and good-quality wideband setup.
As for the APEXI, Terry, you won't need one if you go with a TwEECer R/T. Combined with the wideband O2 setup and other gauges you have planned, you'll be able to modify your A/F on-the-fly and in real-time via the TwEECer thanks to the Stabilized Fuel and other tables we have access to. What's more is that you don't want to be "working around" the EEC all the time (like you might with the APEXI) as this could eventually lead to some major problems, especially in a boosted application. IMO, it's better to control the EEC directly (which controls everything else) and work from there. Fortunately, we have a tool like the TwEECer that will let us directly manipulate the EEC in to doing what we want it to do, rather than fudging with things externally like the APEXI have us do.
As far as a relative fuel pressure gauge goes, check out Josh's post on that subject here.
twr
whoohoo
Adam,
Very good post. The only reason I ever considered an APEXi is because of Pat McGrath. He has one, and with a couple pushes of a button can dial a little more fuel in or out. I planned only to buy one if I felt I needed the additional adjustablility. In all honesty, I almost put it down as an optional item.
Very good post. The only reason I ever considered an APEXi is because of Pat McGrath. He has one, and with a couple pushes of a button can dial a little more fuel in or out. I planned only to buy one if I felt I needed the additional adjustablility. In all honesty, I almost put it down as an optional item.
Axianator
I am a banana!
Gotcha.twr said:
While I'm sure that there is more than one way to duplicate Josh's setup and get a "relative" pressure reading going, I'm not sure what it is yet (I still need to research this subject more). Assuming Josh doesn't chime in here, I'll get with him here soon and see what he recommends as an alternative to the obsolete sending unit.DavidT said:
Axianator said:As for the APEXI, Terry, you won't need one if you go with a TwEECer R/T. Combined with the wideband O2 setup and other gauges you have planned, you'll be able to modify your A/F on-the-fly and in real-time via the TwEECer thanks to the Stabilized Fuel and other tables we have access to. What's more is that you don't want to be "working around" the EEC all the time (like you might with the APEXI) as this could eventually lead to some major problems, especially in a boosted application. IMO, it's better to control the EEC directly (which controls everything else) and work from there. Fortunately, we have a tool like the TwEECer that will let us directly manipulate the EEC in to doing what we want it to do, rather than fudging with things externally like the APEXI have us do.
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Your right in that you don't NEED an Apexi if you have the tweecer R/T or the SC-Tuner. As you point out, your far better off making the adjustments within the EEC directly than to make the adjustment from the outside through a "workaround".
I had been using my Apexi SC-Tuner for A/F tuning before I had access to the SC-Tuner and now the Tweecer and and liked the ability to make quick adjustments to the WOT fuel settings on the fly. No pc, no boot up, no re-starting the car, etc. You just tap a few buttons to add fuel at any RPM range you want - on the fly.
My intent is to perform the base A/F tune with the Tweecer and have the Apexi by default not making any a/f adjustments for normal day to day driving. But, should the SHO need a bit of extra fuel richness because of knocking (say a hot day or a bad load of fuel), I can easily add a bit or richness for WOT with the Apexi with the push of a few buttons at the desired RPM ranges. Its mostly convenience that I'm after.
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