I list the sizes of the openings on Page 2 of my ISR Mod Article.

Hope this helps.
Dr. Z

Thanks Dr. Z- I think Lowe's was a bit too disorganized, I'm going to head down to a plumbing supplier warehouse and will probably have better luck finding what I need.

With my current set-up (2 out of 3 removed) NO pinging.

With all 3 removed and 87 octane there was pinging (in my 98).

I am pretty sure that the J-pipe is not a resonator, but a safegaurd for water ingestion. But, its a hamper to intake flow if you ask me, so out it goes! Just thought I would add that. :D

Actually, it is a resonator. Toyota named it thusly, not me. :)

My .02
Dr. Z

YW, and good luck!
Dr. Z

Hmmm. Doesnt it look like a little storage area for some water?

I know everything! What does Toyota know about Toyotas!
:laugh:

Yeah! The nerve of those guys not to consult you first! :laugh:

Dr. Z

I think both of you are wrong- its actually a hook to hang an air freshener to make sure your engine keeps that "fresh" feeling.:laugh:

LOL. We should start a thread on "What's that little J-pipe thing on your intake for?"

I think its for a factory installed NOS system that TRD decided "would not be profitable and might induce pinging."

Sort of related, here is something odd I noticed I'm hoping someone can explain:

When I did the deckplate a week or so ago, I reset the ECU (I actually pulled 2 ECU fuses from the inside and the EFI fuse from the engine bay, as I wasn't sure which one it actually was) as recommended. I *immediately* noticed an improvement - even to where starting the engine happened faster, like it was pumping more gas in for sea level or something (Denver has a lot less air to play with).

However, I've noticed a slight decline from the initial improvement. It's still better than it was, but it's like the ECU has gone backwards from what it reset itself to, probably resulting from the altitiude.

Is there anything I can do about this? I know it should be running better than it is (and can be), and if there's something simple I can do when I tune it all up I'd be all for it. I'm planning to do the ISR the same weekend but it really sounds like the ECU is holding back and could be made to haul ass, if it's inputs could be tricked into thinking there were more air than there really is perhaps......

Ideas? Comments? Am I just imagining things?

Check out:

https://www.yotatech.com/~corey/tech/dr_z_ect/dr_z.htm

Other than buying some type of control unit to manual tweak system settings, this seems like a pretty straight forward mod for "tricking" the engine, was developed by Dr. Z

Yeah I read that, I suppose it would accomplish the same thing really. The other way would be to change the output of the MAF somehow, but that's more trouble than it is probably worth.

I will try the ECT mod and see if it returns the rig to it's original peppy self, I mean it's just $5 in parts plus some wire I already have, no big deal. On the "to do after a tune-up" list...

thanks!

Dr. Z has done a good bit of playing with the MAF sensor, but his results have shown that Toyota's ECU programming clearly favors the ECT input over the MAF input when it comes to fuel flow.

As a sidebar... Dr. Z didn't develop this mod, but he should be credited to bringing it to this community. I bring this up only 'cause I know how he is about accepting and giving credit. :)

Check Home Depot as well - I had no problems in finding what I needed there. Sorry, I didn't note the part numbers. Like someone else suggested, pull the intake in the parking lot and bring it in. Or, just walk in with a tape measurer and Dr. Z's measurements.

One thing to remember is to check both sides of the caps. Ultimately you want to find caps where the flat side is the right size, but one of my caps I went with the "open" side. That will create a small vortex in the air path, but it's DRASTICALLY smaller than what was there.


Lowe's vs. Home Depot is a different thread :) but in general I think that while Lowe's has the upper hand in fasteners, and Home Depot has it in plumbing. There are of course a number of other differences... :)

Good luck!

Just to clarify, I didn't modify the MAF (VG) signal, but rather the IAT (Intake Air Temperature) signal that is part of the MAF. Modifying the IAT on these engines does not yield any performance improvement due to the way Toyota has the ECU set up.

Dr. Z

EDIT: Modifying the MAF (VG) Signal is what devices like the sAFC and SMT-6 piggyback devices do. They modify the signal by boosting or lowering the voltage to richen or lean out the mixture.

It's too bad that the Toyota IAC isn't like some of the GM ones. All you have to do is hook up a multi-meter, loosen the screws and move the IAC (it has slotted holes that can be made longer. :) ) until you get the desired voltage. I know nothing about the IAC on our cars.