The 3.4L TRD Supercharger Thread

[4Reak Show]

so I've been tossing the idea around of an electric exhaust cutout, basically i would want to do it before the cats, which in return would make it even better then a high flow cat and exhaust, also it would probably sound mean as hell. does anyone think this would be a bad idea ? also would it throw any trouble codes. haven't really looked a ton into this but i wanted to ask just to see what you guys thought about it

After my conversion install I drove the rig to the exhaust shop sans muffler/cat and I promise the 3.4's exhaustless sound very mean. However, you will set a code for cat efficiency and probably even 02/AFR performance codes as well. Simple enough solution: clear the codes, keep your exhaust cut out closed, and drive it for a couple days IF your area requires a smog test.

 

[shootmymime]

But does the sensors still read if it cat is working properly when it's in open loop?

 

[4Reak Show]

But does the sensors still read if it cat is working properly when it's in open loop?

To answer the question I would say no. However open loop normally only occurs while the engine is cold, or when you give it WOT. After its warmed up and driven normally around town and such it's in closed loop almost always. (Otherwise it would set a code for "delayed closed loop operation". Perhaps he wants the cut off valve to run only in open loop during WOT. Then of course the ECU won't care.

Essentially how check engine lights and codes work is a series of "monitors" which individually are really just a set of tests the ECU runs during specific driving events while observing the behavior of certain sensors. For the truck to set a P0420 (cat efficiency below threshold) you normally have to drive at 50-55 MPH for 3 minutes, decel without the brake down to below 25, and then do that again. (Something like that normally works for me in the shop for confirming CEL repairs.) it needs to see SOME activity on the rear sensor to prove it is actually watching a real post cat 02. If it were to only see it staying at .8 volts or so being that it's constantly lean due to being removed from the system, then it may think the 02 is dead and set a code for it. Also, the front 02 is used extensively for fuel control feedback, and if the cut out is BEFORE the front 02, the ECU will never be able to accurately compensate and set a code for THAT sensor's performance.

Basically what I'm saying is that if you take the cat/02's out of the system via a cut out and drive it as you normally would, I promise it will set a code or codes. However, if you only activate the cut out during WOT (open loop) the ECU won't be running its "tests" and won't care for that short period of time.

 

[awpsome]

When in that 2-3k range what boost levels are you at? Remember the piggy back works off map and rpm so you could have been bellow boost pressure but been at 2-3k.

My AFR at wot should be 11.5-11.7 those are the golden numbers. And 12.5-13 at part throttle boost.

Don't take this the wrong way. But have you owned a URD 7th? Installed it? And tried to tune it?
Only curious because I want to understand your strong opinion against them.
The URD 7th piggy tuning displays boost on the Y axis and RPM on the X axis, if my memory serves me correctly. I know for sure the variables are boost pressure aka PSI and RPM.
Which is why while i was tuning I was able to tune the RPM at each level of boost so that as more or less boost is induced at a specific RPM I was able to add more fuel if needed at that point.

So not sure what you mean by what boost level was I at. Unless you mean what PSI was I leaning at?

At 2-3k rpm range I was leaning with 1-2PSI boost. Ish.

Which leads me to believe there must be a confusion somewhere cause you don't seem to be understanding how to tune the URD 7th. Don't take this the wrong way just trying to understand why the URD 7th isn't working for you.

 

[MTD]

Don't take this the wrong way. But have you owned a URD 7th? Installed it? And tried to tune it?
Only curious because I want to understand your strong opinion against them.
The URD 7th piggy tuning displays boost on the Y axis and RPM on the X axis, if my memory serves me correctly. I know for sure the variables are boost pressure aka PSI and RPM.
Which is why while i was tuning I was able to tune the RPM at each level of boost so that as more or less boost is induced at a specific RPM I was able to add more fuel if needed at that point.

So not sure what you mean by what boost level was I at. Unless you mean what PSI was I leaning at?

At 2-3k rpm range I was leaning with 1-2PSI boost. Ish.

Which leads me to believe there must be a confusion somewhere cause you don't seem to be understanding how to tune the URD 7th. Don't take this the wrong way just trying to understand why the URD 7th isn't working for you.

Oh trust me I know how to tune a car, this isn't my first rodeo. I base everything on fact, and I know from my research it won't work for the models I have listed. I appreciate your concern, but everything I have said about the 7th I can back up, I am not one to just spout off shit I have done my research

Also I only referenced the 2-3k levels, because that is what you had said... Like I said I have quite a bit of tuning experience and every tunner format is the same pretty much. Load on the y and rpm on the x.....

 

[foxrider56]

To answer the question I would say no. However open loop normally only occurs while the engine is cold, or when you give it WOT. After its warmed up and driven normally around town and such it's in closed loop almost always. (Otherwise it would set a code for "delayed closed loop operation". Perhaps he wants the cut off valve to run only in open loop during WOT. Then of course the ECU won't care.

Essentially how check engine lights and codes work is a series of "monitors" which individually are really just a set of tests the ECU runs during specific driving events while observing the behavior of certain sensors. For the truck to set a P0420 (cat efficiency below threshold) you normally have to drive at 50-55 MPH for 3 minutes, decel without the brake down to below 25, and then do that again. (Something like that normally works for me in the shop for confirming CEL repairs.) it needs to see SOME activity on the rear sensor to prove it is actually watching a real post cat 02. If it were to only see it staying at .8 volts or so being that it's constantly lean due to being removed from the system, then it may think the 02 is dead and set a code for it. Also, the front 02 is used extensively for fuel control feedback, and if the cut out is BEFORE the front 02, the ECU will never be able to accurately compensate and set a code for THAT sensor's performance.

Basically what I'm saying is that if you take the cat/02's out of the system via a cut out and drive it as you normally would, I promise it will set a code or codes. However, if you only activate the cut out during WOT (open loop) the ECU won't be running its "tests" and won't care for that short period of time.

so the exhaust cutout would only be good in wot? if thats the case then it should make more power then correct? since the cats and muffler are not restricting it?

 

[awpsome]

Oh trust me I know how to tune a car, this isn't my first rodeo. I base everything on fact, and I know from my research it won't work for the models I have listed. I appreciate your concern, but everything I have said about the 7th I can back up, I am not one to just spout off shit I have done my research

Also I only referenced the 2-3k levels, because that is what you had said... Like I said I have quite a bit of tuning experience and every tunner format is the same pretty much. Load on the y and rpm on the x.....

That's great and good to hear.

Did you install and tune your own URD 7th? It's boost and RPM as its variables. Not map and RPM.
What issues are you having that the URD 7th isn't doing for you?
What have you done to conclude you can't tune your truck in closed loop?

 

[4Reak Show]

so the exhaust cutout would only be good in wot? if thats the case then it should make more power then correct? since the cats and muffler are not restricting it?

The cutout would be good all the time really for power gains. A more freely flowing exhaust is going to generate more power. What I was getting at was trying to set it up in a manner to not set a check engine light/code. That's something that would be a bit tricky. Not sure if you need smog in your area, but if you do you'll have to put it back to normal and make sure the codes are cleared. If I were to set one up, I would have it in a manner that it opens the exhaust AFTER the FIRST 02. This way the ECU can still use that sensor for fuel control during normal driving. But be warned: taking the cat out of the system is just about guaranteed to set a code. It will not cause any damage in my belief but it will keep the check engine light shining bright if you drive with it bypassed all the time.

In all reality, you probably won't feel that much of a difference in overall power but I could be wrong. Hell, be a pioneer and set it up man. It'll be loud and roar like a monster if nothing else. See what the experience is. Just do it the day after it gets smogged if you're required to.

 

[MTD]

That's great and good to hear.

Did you install and tune your own URD 7th? It's boost and RPM as its variables. Not map and RPM.
What issues are you having that the URD 7th isn't doing for you?
What have you done to conclude you can't tune your truck in closed loop?

I don't have a URD, bud....... I said I did my research, and thus the reason I am doing write up on the AEM......

As for the boost and rpm comment, that should be an indication right there NOT TO GET A URD. The industry term for pressure they call boost is MAP (manifold absolute pressure). Boost is a relative reading, as in psig (gauge pressure), which varies due to elevation, opposed to psia (absolute) which is what we use for tuning.

I don't understand why you are defending the URD stuff anyway. Yeah you may be running it, but it doesn't make sense... I have said before that they do make a good product, especially if you have the 96-98 models, but it isn't the only option. It may be what you and others feel safe with, and that is why there is so much push back, but that is no reason to not explore other options. Like I have said before if the URD 7th works for you great you are set, but for some it won't work and doesn't without spending more money that some, myself included, don't have.

 

[MTD]

That's great and good to hear.

Did you install and tune your own URD 7th? It's boost and RPM as its variables. Not map and RPM.
What issues are you having that the URD 7th isn't doing for you?
What have you done to conclude you can't tune your truck in closed loop?

And about the closed loop thing that came right from the horses mouth (gadget).....

Only from the 00-02 period of course...

 

[shootmymime]

Did you install and tune your own URD 7th? It's boost and RPM as its variables. Not map and RPM.

so let me go over this with you and me. (my problems)



i am at 4,500 ft elevation, my boost gauge (on my a pillar ) reads 6 psi (maxed out) where when i plug my computer in and read the settings from the URD programmer and it only reads a max of 3. that's because URD reads it in map and not straight boost pressure like my gauge.



I called gadget and he said that the urd reads manifold absolute pressure not boost pressure so thats why my numbers are not matching up from the computer and my gauge.

As you can see my map is not stock. I'm getting 13.4 at part throttle and 12.0 full throttle. (I messed it up recently so need to fix it). But it works properly at this map.

I only reach 4psi and 4,500 rpm so that's where I really kinda end at my tuning. I did add up to 5 psi as you can see.

 

[MTD]

so let me go over this with you and me. (my problems)



i am at 4,500 ft elevation, my boost gauge (on my a pillar ) reads 6 psi (maxed out) where when i plug my computer in and read the settings from the URD programmer and it only reads a max of 3. that's because URD reads it in map and not straight boost pressure like my gauge.



I called gadget and he said that the urd reads manifold absolute pressure not boost pressure so thats why my numbers are not matching up from the computer and my gauge.

As you can see my map is not stock. I'm getting 13.4 at part throttle and 12.0 full throttle. (I messed it up recently so need to fix it). But it works properly at this map.

I only reach 4psi and 4,500 rpm so that's where I really kinda end at my tuning. I did add up to 5 psi as you can see.

Either your boost gauge or the map sensor in the URD box is bad. At your elevation 6psig would equal aprox 17 psia. Who makes your boost gauge, obviously that would be what you want to fail since its cheaper.

 

[shootmymime]

Either your boost gauge or the map sensor in the URD box is bad. At your elevation 6psig would equal aprox 17 psia. Who makes your boost gauge, obviously that would be what you want to fail since its cheaper.

It's a cheep sun pro one.
BUT! I've checked it with my motorcycle gauges that are super accurate for tuning carburetors. And the gauge was matching.


So are you telling me my URD map sensor is Effed up? You can't really just unplug the urd and plug a new one in super simple. Damn!

 

[MTD]

It's a cheep sun pro one.
BUT! I've checked it with my motorcycle gauges that are super accurate for tuning carburetors. And the gauge was matching.


So are you telling me my URD map sensor is Effed up? You can't really just unplug the urd and plug a new one in super simple. Damn!

They don't have a bypass for the URD system?

 

[shootmymime]

They don't have a bypass for the URD system?

Bypass?

 

[MTD]

Bypass?

Basically a plug I plug into the AEM side of the wiring that makes it completely bypass the piggy back and the ECU runs like it was never there then.

 

[shootmymime]

Basically a plug I plug into the AEM side of the wiring that makes it completely bypass the piggy back and the ECU runs like it was never there then.

Not that I know of.

No one has a spare urd gauge I could play with.
Rewiring would suck plus. I got this used so I'm not sure what it's supposed to be at. FML

 

[MTD]

This thing, it connects the ends of the 2 FIC side wires together

 

[MTD]

Not that I know of.

No one has a spare urd gauge I could play with.
Rewiring would suck plus. I got this used so I'm not sure what it's supposed to be at. FML

Sorry dude, it still might not be the problem. If it is a high quality sensor in the box it probably isn't that. A map sensor is one of those parts that should last the lifetime of a vehicle...

 

[shootmymime]

Sorry dude, it still might not be the problem. If it is a high quality sensor in the box it probably isn't that. A map sensor is one of those parts that should last the lifetime of a vehicle...

Yeah exactly what I'm hoping.


Ok so another general question.


I go part throttle and my AFR drop to 13 ish. Then (month ago I go wot it would drop to 12) now I go wot and it downshifts and my injector stops and afr jump up to like 15 still wot and still high boost.


So I look at my computer and what the urd settings is reading and the boost drops off at that point to where it's not programmed to be turning on (like 1 psi).

So I'm wondering if I have a hose that expands and let's boost bleed off or my MAP sensor is not working. Idk....