1FZ external EGR cooler

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bjowett

bjowett

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Here's a few pictures of the external EGR cooler that is being installed on my 1FZ engine. IMO the internal cooler is part of the headgasket problem on this engine.

The stock through the back of the head passage will be blocked by a small freeze plug or ?. The manifold was milled flat on the outside just behind the number 6 runner, between the 2 rearmost studs. A hole was then drilled into the manifold to tap into the exhaust passage. I then cut a custom flange from some stainless steel.

The external cooler is from a Camry V6 3VZ-FE engine, you can see it resting on top of the valve cover in the second picture. It will receive coolant from the rear of the head, the throttle body coolant hose to be exact. Then stainless steel tube will be fabrcated to route the exhaust gasses through the cooler and to the EGR valve.

The perfect spot for a flange...

P1010528_0.JPG


modified...

P1010011_1.JPG


A little closer...
P1010012_0.JPG
 
I'll even go so far to say that this keeps the number 2 knock sensor happy. On warmer days this will mean less timing retard and better performance.
 
Very intresting. I would be curious to hear Robbie's impression on that. Keep up the great work man.
 
Please excuse my dumb question, but is there a reason why the EGR system couldn't be removed entirely? This is commonly done on Supra's with blockoff plates (as pictured below), and a 10 ohm, 1/2 watt resistor which is put into the harness plug to keep the ecu happy.
04-ws.jpg
 
Bruneti said:
Please excuse my dumb question, but is there a reason why the EGR system couldn't be removed entirely? This is commonly done on Supra's with blockoff plates (as pictured below), and a 10 ohm, 1/2 watt resistor which is put into the harness plug to keep the ecu happy.
04-ws.jpg
Click to expand...

The EGR system is for emissions as we know and it recirculates exhaust to your #6 cylinder which can superheat it and cause issues. Of course, due to restrictions the EGR system must not be tampered so with that being said the cooler seems like the way to go, although it is a modification which I doubt many inspectors would question if installed properly.

I removed the egr system on my Supra and the emissions were still fine!!! So far I haven't had issues with my cruiser (I am the second owner so I don't know if the HG has been replaced but with 170k miles either is has been replaced or I've been damn lucky...I'm guessing it has been replaced though)

For an engine...EGR is NOT a good thing... :-(
 
chriscruiser said:
Of course, due to restrictions the EGR system must not be tampered so with that being said the cooler seems like the way to go, although it is a modification which I doubt many inspectors would question if installed properly.

I removed the egr system on my Supra and the emissions were still fine!!!
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You say the EGR must not be tampered with, then you say you blocked it off on your Supra. :confused: Why have you not tried it on your LC?
 
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elmariachi said:
You say the EGR must not be tampered with, then you say you blocked it off on your Supra. :confused: Why have you not tried it on your LC?
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Honestly, my 80 is stock where the Supra was highly modified, when my Supra was stock I left the EGR alone and never had issues...once I upgraded the turbo to a Greddy T-78 I decided to block off the EGR since I wanted to play it as safe as possible.

I figure since my 80 is stock and I don't wheel or even drive it hard there was not sense in modifying it.

I am going to sell it this month so I don't want to tamper and cause any issues, if everyone finds this new mod to be helpful I'll point it out to whoever buys my 80.
 
One other note, if you put in the resistor, you need to disable the EGR or you will get the excessive flow code on your ECU. N/A cars if there are no issues or codes should still pass emissions.

So basically, if you do disable the EGR make sure you disconnect the vacum modulator from the EGR so the system is disabled. Then, add in the resistor (not sure exactly which one you'd need for the motor) and you should be fine.

It is illegal so before you mess with the EGR...make sure you are not going to do emissions (disconnected you could still pass BUT you may fail the visual)

Good luck!
 
chriscruiser said:
The EGR system is for emissions as we know and it recirculates exhaust to your #6 cylinder which can superheat it and cause issues.
Click to expand...

I guess this is why I asked my question. If we know it has a negative effect on #6 (and probably the head gasket), has anyone tried removing it entirely? I have not done this on my Supra or LX450, but I do live in a state that does not currently perform emissions testing or visual inspections. ;) I just found it odd that for Supra owners this is a really common thing, but in all the chatter on here about the EGR system I had never noticed that anyone had removed it.
 
The hot #6 issue is not solved by the alloy block off plates. They are a neat idea, but the EGR cooler passage remains exposed to the hot exhaust gasses. The number 2 manifold needs to be removed and a stainless steel freeze plug inserted to block the flow.
 
Bruneti said:
I guess this is why I asked my question. If we know it has a negative effect on #6 (and probably the head gasket), has anyone tried removing it entirely? I have not done this on my Supra or LX450, but I do live in a state that does not currently perform emissions testing or visual inspections. ;) I just found it odd that for Supra owners this is a really common thing, but in all the chatter on here about the EGR system I had never noticed that anyone had removed it.
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I actually passed emissions with the EGR disabled, I removed the hoses between the modulator and the EGR which basically still keeps the EGR inline so "some" gases will flow however, not operational.

It did pass emissions (actually best numbers I ever passed with) and I made it look "stock" to avoid any issues.

From what Bjowett said, even pulling the hoses to "deactivate" the EGR still will not do the trick nor will the block-off plates. From what he is doing, I would tend to think that he is correct about having to block the passage. Not sure exactly where this would need to be done (bjowett do you have a pic?)
 
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Hmm, I'll try and take some pics of my 1fz like I have for my avatar of my old 2F
 
trojan_knight said:
when i went through wyotech we were taught that if you run an engine designed for EGR with out it, it can cause detonation at highway speeds.
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That could be true depending on how the engine monitors fuel ratios. With it disabled on my Supra I never had issues and I monitored timing, fuel ratios, etc...etc...

So...I think that could be a yes or no answer, yes if the EGR disabled is not compensated by the difference in temps however, at high engine loads where detonation would occur, the EGR system is usually disabled!

I'll have to refer this to the experts, I'm not an EGR expert so I could be off but what I said is just in reference from what I've seen before on my Supra where I pulled the vacuum line from the modulator to the EGR essentially disabling it...but it was still connected so EGR gases could still flow.

Either way, I never had issues with my Supra and passed emissions cleaner which is interesting. As far as timing, I never monitored with the EGR on so I cannot say if numbers would have been different but I had no issues at all running the way I did.

I put down 594RWHP and 575ft/lbs of torque at 19psi on pump gas.
 
trojan_knight said:
when i went through wyotech we were taught that if you run an engine designed for EGR with out it, it can cause detonation at highway speeds.
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Definitely the case with carbed cars. I pulled the egr off my Bronco and it sounded like there were BB's in the cylinders at part throttle cruise until the bigger jets showed up to richen up the mix.

I know that the guys running the 5.0 mass air injection on the Broncos just pull the EGR off and let the thing ping like mad for a couple of drive cycles while the computer adjusts the fuel trim to compensate for the lack of EGR.

One would HOPE that the ECU in the cruiser would be smart enough to adjust the fuel trim to compensate for the lack of EGR by the lean reading on the upstream O2 sensor. I think this is all dependent on tricking the computer into believeing that the EGR is still operational however... easily done with a resistor in the temp sensor.

Another possibility to richen up the mix would be a resistor in parralel with the O2 sensor, with one leg on the sensor lead and one leg to ground. This would bleed off some voltage, and the voltage read across the sensor by the ECU would be slightly less (lean) and the ECU would richen up the mix to compensate.
 
ElJefe said:
Definitely the case with carbed cars. I pulled the egr off my Bronco and it sounded like there were BB's in the cylinders at part throttle cruise until the bigger jets showed up to richen up the mix.

I know that the guys running the 5.0 mass air injection on the Broncos just pull the EGR off and let the thing ping like mad for a couple of drive cycles while the computer adjusts the fuel trim to compensate for the lack of EGR.

One would HOPE that the ECU in the cruiser would be smart enough to adjust the fuel trim to compensate for the lack of EGR by the lean reading on the upstream O2 sensor. I think this is all dependent on tricking the computer into believeing that the EGR is still operational however... easily done with a resistor in the temp sensor.

Another possibility to richen up the mix would be a resistor in parralel with the O2 sensor, with one leg on the sensor lead and one leg to ground. This would bleed off some voltage, and the voltage read across the sensor by the ECU would be slightly less (lean) and the ECU would richen up the mix to compensate.
Click to expand...

From what I have seen both data logging and on the dyno, the computer will compensate for a lean condition.

As you said, a resistor and removal of the EGR should do the trick. However, as stated prior, the EGR will not be 100% removed until the passages are closed off.
 
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