Swede

I was bored at work last night, so I popped the hood on my '98 4Runner and started thinking about the ISR mod. So this morning I began reading up on the ISR mod and was wondering if a single piece of 3" (id) rubber hose would work, running from the MAF to the TB? One would just have to figure out how to attach the two vaccuum hoses to it right?

wimpywade94

i bet if you did do what you said, and just drilled pretty small holes in the rubber you could get a barbed hose end type thing, (like you would repair an air hose with) into the holes and attach the other lines!
mabey it would work
wade

Swede

Never thought of that. My concern would be that, over time, it would wiggle loose.

wimpywade94

mabey some flexible gasket maker would hold it in place,
the only thing i saw wrong with the idea is the hose may suck close if you didnt have a sturdy one, if you get what im saying

later
wade

rimpainter.com

Only problem is you lose the ability of going back to stock. I like having that option so I can run regular unleaded, or if I ever have to sell it, etc.

Your idea should work though, as long as you dont mind "destroying" the stock tube.

The barbed fittings in my write-up should work.

Swede

"Your idea should work though, as long as you dont mind "destroying" the stock tube."

That's just it, I won't touch the stock tube, I just replace the whole thing from the MAF to the TB, and add a couple fittings and I should be good to go I think.

As for the hose, I was thinking along the lines of a large rad hose.

ravencr

Where do you get tubing like that?

Chris

Swede

I went to a local heavy duty diesel shop and got a little chunk of 3" rubber hose to see if it would fit on the MAF. It did, perfectly, but I went to try it on the inlet of the TB, it didn't. The TB inlet is 2 3/4" diameter. So now what? I was thinking about getting 2 3/4" hose and try stretching it to fit over the MAF outlet but that may prove to be very difficult (the wall of the hose is about 1/4" thick with fiber strands in it), or stick with the 3" and then build up around the TB inlet (perhaps with a couple dozen wraps of electrical tape?). Maybe I could grind out the inside of the MAF end of a 2 3/4" hose to fit it? Any suggestions?
I'm just wondering if it is even worth it because the stock tube is straight through anyways without any restrictions (that I can see). Maybe I'm missing something?

rimpainter.com

How about doing the ISR mod like the rest of us?

MTL_4runner

I wouldn't do anything that is not easliy reversible.
If the car starts pinging or is too loud for your taste you want to be able to go stock pretty easily.

Just plug the silencer holes with PVC caps like the writeup says....very easy and cheap.

Swede

"How about doing the ISR mod like the rest of us?"

That would make sense.... but I'm not that smart.

I figured that a new hose would be better being completely smooth inside without any restrictions whatsoever.

rimpainter.com

Not trying to slam your idea, because your thinking is good. But, how much trouble is this going to be? It seems like the .01HP gain of a smooth pipe vs. plumbing end caps wouldn't be worth it.

That is the only reason I said what I said. I just seems like you are hitting some dead ends.

ravencr

I love your idea, and the easiest way I can think of is get a reduction coupler from Lowes. That's what I used, and if your's works out real well, I'm going to get rid of my pvc tubing and go your route. Let us know!

Chris

Swede

Well I did the mod the other day and ran into a snag. The hose I used was a marine exhaust hose which turned out to be alot stiffer than I had anticipated. It kinked when I tried to bend it and there was no way to get it out. So back to the drawing board. Then yesterday, I happened to come across a piece of 3" mandrel bent tubing in the shop where I work and cut it to the desired length so that its angles line up with the MAF & TB and used the hose I had to connect the ends and, wouldn't you know it, it worked! I gotta say though, that it is bloody loud at WOT. I'm not sure if I can live with it like that. I'll give it a week or so and decide from there. Oh, and no I don't have a digital camera yet so I don't have any pics.

I also took off my TB and cleaned it and trimmed out the "D" gasket to an "O".

ravencr

I would wrap the metal with thermo tec wrap, which should quite it down a tad.

Chris

P.S. We want pics!

MTL_4runner

Can you reuse the old gasket when you trim the "D" or do you need to buy a new one?
I would really like to do this on mine.

Swede

I just trimmed out the excess metal by tracing a line on the gasket. You can see a distinct arc and discoloration on the gasket from what was exposed in the plenum and what was sandwiched between the TB and intake. Then I took a set of "tin snips", actually they were pruning shears I think, in any case, just make sure they are in good shape or all you do is bend the gasket. I cut into the gasket going from the middle of the opening to the traced line I drew, about every 1/16th of an inch or so, then cut along the traced line. I just made sure I didn't get too close to the ridged part of the gasket, which I believe, is the part that actually seals it. That's it.