Under Plenum Job SUCCESSFULLY Running With Removed Equipment

[j.hardstyle]

I just completed my under plenum job, timing chain guide replacement, valve cover gasket, fuel rails/injectors. It was a 2 week long process and I am glad that I did not rush anything.

I replaced all hoses and lines under the plenum, replaced the chain guides, new valve cover gaskets, cleaned everything, new 94 style fuel rails, new 94 style fuel injectors, etc etc etc.

Now, I did remove some clutter out of the engine bay and I am SUCCESSFULLY running without it. Now, I am not RECOMMENDING that anyone do this to their car, and it is not legal to do, but I am sharing my experience.

Under the plenum, there is a pipe that is capped off at the end...the IACV connects to this pipe via a Y-shaped hose. One side of the hose plugs into a pipe connected to the plenum, one side plugs into the bottom of the IACV and the other side plugs into this capped off pipe that trails along the knock sensors and ends at the back of the thermostat housing. This pipe was referred to me as a "vacuum arrestor" or "vibration arrestor"....it seemed to serve no purpose in my mind, so I eliminated the clutter....now the IACV is plugged directly into the pipe connected to the plenum itself and I am successfully running this way.

I have also successfully removed the EVAP canister and all the lines associated with it. The vent line from the gas tank was left OTA and routed into the drivers side fender well. The two solenoids were left plugged in with no vacuum hoses running to it....this has to be left so the ECU does not throw a code. Again, I am successfully running with this removed.

Lastly, the EGR....yes, it is "illegal" to remove, not encouraging anyone to do it. The tube at the manifold....the nut was removed from the pipe itself, a nickel placed into the hole on the manifold and the nut put back in on top of the nickel. The EGR was removed from the manifold and a block off plate was put in its place. NOW, I could not get a Nissan block off plate (you would use a 240sx or 300zx plate) but I had access to a DSM plate from my DSM days. The bolt holes lined up almost perfectly...a bit of drilling to elongate the holes and it was a perfect match. I placed an 82k resistor in the connector for the EGT (EGR Temp Sensor) and havent gotten any codes at all. I am again, successfully running with this removed.

I dont want to hear about the legality issues of why you should leave the emissions stuff in the car....I am simply wanting to state that the Q isnt some Godly spaceship so complex that it needs all of these systems in it. Even though it is a complex machine, ahead of its time, we forget that it is still an OBD1 Nissan, it is still a combustion motor, and it is just like a lot of motors out there when it comes to being able to remove these systems.

[Q451990]

Sounds interesting... congrats on a DIY guide job!

My one concern with the EGR delete, is that part of it's function is to slow combustion - so you may find that you have more spark knock in hot ambient temperatures. Your ECU will correct by enriching the fuel mixture and may cause a greater loss of power vs. the correction it would do with the EGR functioning properly.

Heath

[j.hardstyle]

The chain guides werent as hard as everyone makes them out to be....time consuming, YES....along with all the under plenum stuff. Not hard, just very time consuming and many back aches. I tackled everything at once, had my motor pretty much naked....parts all over the garage, bolts everywhere. Very fun, very frustrating, but makes me have a lot more respect for the beast...and it gave me an accomplished feeling doing it all by myself. Not one person helped, i even tightened that crank pulley bolt alone, lol.

As for the EGR....I was reading the FSM when I was trying to decide what to do with the temp sensor. The EGR only opens when you are under certain conditions, such as coolant at a certain temperature, certain speed, certain throttle, etc. Pretty much when cruising at part throttle....when you are over a certain throttle, under a certain coolant temp, under a certain speed, idling, in park, etc....then the EGR remains closed.

The possible effects, in my eyes, are trivial. I have done the EGR delete on my 240, my DSM's, a few Hondas, etc. and have never had any issues. As I said, the Q may be ahead of its time....and what may sound like a lot on paper, maybe isnt that much at all.

For example....do you REALLY know what the "vacuum arrestor" does, aside from whats on paper? Its a long pipe that is capped at the end for crying out loud. I know Nissan engineers made a purpose for these things when building the motor, but this is where the fun of modification comes in to play. Take a look at all the other Nissans out there, the 240sx, 300zx, 350z, the hardbodies, etc....what makes the Q any different? I am not afraid to test new ideas and see how far we can go with these cars. Where is the fun and originality?

[BadQ45t]

I guess no smog tests in Seattle, here in CA you would have pay someone 2 grand to get a get out of jail free card from a smog guy.....otherwise lack of an EGR is a sure fail...Arizona too, surprise the tree huggers in WA haven't caught on with smog testing.

[j.hardstyle]

I will be 100% honest with you....Washington could give a s*** less about emissions. Its all a farse for more $$$.

Lets say you go in to get tested....you fail the test. You dont even have to fix the issue. As long as you go to an "approved repair shop" on THEIR list that they give you...and you spend $150 toward "fixing" the issue, you automatically pass.

You dont get any visual test, they dont check if your emissions equipment is in the car or anything.

OH AND get this...some people are COMPLETELY EXEMPT depending on which county they live in, which city they live in, if they are in the outskirts, etc. So some people have to get tested and some dont.

So dont come barking up my alley without your facts straight....what little bit the emissions recirculates into your motor is trivial.

[Q451990]

So what is the advantage of not recirculating exhaust gases into the intake?

Heath

[j.hardstyle]

You act like this isnt commonly done on vehicles...just because it is done to a Q and its "virtually unheard of" doesnt make it wrong/bad/etc. My car will not blow up over removing the EGR system.

And to prove that, take a look at any JDM motor and tell me where you see the EGR valve. You wont see it, because the EGR is PURELY a USDM emissions control system. If removing a system that was only put in place to regulate even a TRIVIAL amount of NOx emission is going to make my car explode, then I guess I am prepared for it. The Japanese dont have it on their motors....but let me guess, their motors have a little bit different specs so it throws the equation off and makes up for not having the EGR system, right?

I am not trying to argue here, especially over the internet. The Q forum is so close-minded here. It is either do it "by the book" or GTFO. Thats absolutely ridiculous. Just because I thought outside the box and went against the grain, that is wrong? No way....

[qship96]

So what is the advantage of not recirculating exhaust gases into the intake?

Heath

BINGO....we have a winner. Removing all the stuff he did has little to zero advantages, but plenty of disadvantages,many of which he is obviously unaware of.

[j.hardstyle]

Lol...alright, keep thinking what you want and I will keep thinking what I want.

I posted this to shed some light on the unknown and my experiences. Apparently just because I am the first to do it, everyone wants to cause a ruckus about it. Please tell me all of the disadvantages since there are so many of them.

You guys have helped me out a lot, but seriously wow....its sad when new ideas cant be brought to the table. No wonder everyone just lurks around the board and never posts.

[darktalon2gnt]

I'll for one, agree with you j. I've been a DSMer since I could legally drive and not had one that DIDN'T have an EGR delete... it's useless and has no real performance affect, in fact, the amount of vacuum lines it gets rid of in a turbo car causes less headaches since there's less to leak!

I'd also like to hear these 'expert' opinions on the negatives, and I'm betting they're read out of a manual rather than real live experiences. I'm gonna be doing an EGR delete on my VH45 when I swap it into my 240sx... Want to keep the q45, but there's so little support for it, it's becoming not worth the effort...

[BCC93QT]

There are individual(s) on this site that are literally walking living manuals. It is a bible to them and the Q45 itself is not a car. It is some sort of mythical beast or an ark of some sort.

[j.hardstyle]

Darktalon, both of my DSM's (90 and 91 TSi AWD) had no EGR...that was one of the first things I got rid of, along with the charcoal canister and the solenoids on the drivers side strut tower. I reached 480AWHP on my 1990 and it didnt skip a beat due to a blocked off EGR port. It is still running to this day, sold it to my friend.

My Q is still running like a champ...no CEL's, no knock, no pinging, the motor hasnt fallen out from underneath the car, hasnt blown up....I drove the s*** out of it and still not a single miss or stall.

Steve, I agree...it seems the Q is some religious shrine that must not be tampered with in any way, shape or form.

[Q451990]

Still asking what advantage there is to the EGR delete... I'm not being critical, I really would like to know what you're accomplishing by not having it?

Heath

[j.hardstyle]

well for one, theres not going to be a .5mm layer of carbon build up in my intake. The engine bay looks a lot nicer and less cluttered (this is only an appearance thing obviously). I will never have to worry about vacuum leaks, diagnosing and replacing a faulty EGR or related components, etc.

For ME, it was worth deleting. To YOU maybe not...

[qship96]

well for one, theres not going to be a .5mm layer of carbon build up in my intake. The engine bay looks a lot nicer and less cluttered (this is only an appearance thing obviously). I will never have to worry about vacuum leaks, diagnosing and replacing a faulty EGR or related components, etc.

For ME, it was worth deleting. To YOU maybe not...

FYI, I have never had any vacuum leaks,faulty EGR, or related components.......and I have over 285,000 miles on my Q,but then again,my Q has not been subject to hacking by multiple previous owners,especially young un-educated,inexperienced ones who think they are smarter than the professional engineers who designed it and randomly delete and modify the car thinking they are "improving" it . I guess those who purchase an old,ragged out, multiple owner vehicle for about the cost of a good bicycle have a different mindset.

[superuber]

Ouch!

[j.hardstyle]

LMAO, wow....go take the professional engineering and shove it up your a** dude. JDM motor doesnt even have a f*** EGR valve. I will do whatever the f*** I want to my f*** car. Go ahead and leave your 285,000 mile car all stock, do I give a s***? No, not really. Thanks and goodbye.

[BCC93QT]

qship.... what kind of education does it take to run a car from 0-285,000 miles? You abuse the fact that you had the opportunity to buy this car when it was new? I took my car which didnt even run @ 94k miles, rehabbed it as well as reversed all butchered "repairs" that previous owners have done as well as beat the living piss out of it and am at 260,000 miles. Runs like a champ. I'm not even half as old as your worthless egotistical wrinkly behind. So then again, YOU are the one that must be uneducated because you think your some sort of genius that has maintained a gasoline engine longer than us twenty something year olds.

But yet all of us non original owners (younger) are uneducated aren't we?
Better to learn ourselves than to have you worthless elderly folk tell us "do it this way, do it that way"

[qship96]

LMAO, wow....go take the professional engineering and shove it up your a** dude. JDM motor doesnt even have a motherf***ing EGR valve. I will do whatever the f*** I want to my f**king car. Go ahead and leave your 285,000 mile car all stock, do I give a s***? No, not really. Thanks and goodbye.

Wow,that kinda sums it all up ........about you. Maybe you and BCC should get a room?

[OwnerCS]

Unfortunately the Q has a small market segment -- so there aren't many options for aftermarket performance parts. Members have different areas of specialty and expertise. I know some club members have made the following enhancements:

1) Two members have converted their Qs to 5-speeds.
2) Two members have converted to a turbo system.
3) Two members are running fully enhanced LevelTen transmissions -- far different from stock
4) A member developed a method for reprogramming the ECU that I believe now offers 4 stages. Many club members have purchased these reprogrammed ECUs.
5) A member developed a fix and sells corrected climate control units.
6) Many members are running Z32 sub frame spacers with rear sway bars.

I experimented with nickel plated fuel lines where the plating covers the inner surface that was done using an electroless process to provide exTreme corrosion protection with ethanol fuels. So far it has been a good experiment as it performs as good as it looks.

[j.hardstyle]

^^^^
If I would have known about this, I would have sent off my fuel rails to you. I ended up just painting them with Duplicolor "Stainless Steel" to give them a fresh look. And then ended up painting my valve covers and plenum gloss black, leaving the chrome on the emblem....and then freshening up all the black plastic trim with Krylon Fusion gloss black. Turned out better than I was hoping as well.





But to venture further out into the "oh noes, my Q will blow upzzzzz", I am planning a Zex 75 shot wet nitrous setup....along with z32 suspension coming up in a week or two.

[Lokim]

Nice looking engine bay ya got there!

[OwnerCS]

Cool!

[ThatsMyQ2Go]

Looks nice man...how bad is the E10 anyways? I've been curious but haven't worked up the nerve to just check

[j.hardstyle]

You talking about the ethanol in the gas? They say up to 10%

[j.hardstyle]

Thanks for the compliments....heres another just because, but I did not have the radiator cover installed at the time.





And the blockoff plate over the EGR port, with stanless allen bolts.

[ThatsMyQ2Go]

@J I understand its up to 10% I was really trying to inquire how bad the E10 is on the older fuel lines and injectors. Sorry if there was confusion

[j.hardstyle]

@J I understand its up to 10% I was really trying to inquire how bad the E10 is on the older fuel lines and injectors. Sorry if there was confusion

Ohhh....well, to start off, almost all of my under plenum lines were dry rotted except for the coolant lines. The fuel lines still had a LITTLE pliability but where they plugged into the metal lines, they were hard as a rock and I had a hell of a time getting them off.

But they did not leak, there was no cracking, there was no deterioration on the inside, etc. The fuel injectors, I did not take out of the fuel rails, but I did have to pull the injectors out of my 94 fuel rails, so I would assume they were about the same. The 94 injectors didnt show any signs of deterioration or anything like that. My stock injectors didnt leak, they didnt misfire, they were all in working order.

I know that the plenum has never been off, these were the original fuel lines, vacuum lines, injectors, etc. Honestly, I dont think the E10 does as much damage as everyone claims. Then again, this Q was originally bought in Oregon then made its way to Washington....so maybe the gas isnt as harsh up this way. But from my experience, the E10 is all hyped up to a degree.

[OwnerCS]

For E10 the stock fuel system should be fine.. I setup mine to be able to handle E85 in the event the level increased to like an E50 or beyond. There was some legislation proposed to increase it from E10 to E15 around the time I got into researching it.
So I used E85 dispensing guidelines and information from Brazil where nickel plating is used to prevent corrosion from high ethanol based fuels. The electroless plating process coats the inner rail surface with Nickel so I felt it might add a layer of protection from any type of seam breakdown 20 years from now.. It was a fun project at the time -- though I think the money would have been better spent upgrading the sound system..

[Infinitiguy19]

I mean no disrespect but getting rid of a EGR system that's been used for 30+ years (If my homework was done right) is an act of laziness. I say laziness because you don't want to spend a couple of hours cleaning the EGR valve and plenum every couple of years or less...

Other than making the intake tract slightly more dirty it has no other negative effect.

If it were my car I would find a way to coat the inside of the plenum and top of the runners (Before the injectors) so the soot wont stick to it. I think Ford went down that road so look there.