rimpainter.com

Most of us here on Yotatech are familiar with Dr. Z’s ISR mod. I actually did this mod to my old 98 Tacoma Limited back in 2000 (so give me a little credit). I felt that I noticed a slight power difference, but removed the mod for 2 reasons:
1. My truck pinged on 87octane fuel.
2. The intake roar with the deckplate open rattled my girlfriends (now my wife’s) head.

Well, since I am in remorse over my recent $100 expenditure on the Helix Power Gazoo, I felt it was time to give things another go on my 96 4Runner. Here is the link on my data for the Helix Power Tower if you are interested.

What’s better than a free mod? My uncle had the perfect plumbing end cap lying around, and I had all the other supplies, so that’s all it took to install the ISR mod!

I had just filled up with 91octane in anticipation of the ISR mod install.

Surprisingly, the intake roar is not as loud as my 98 Tacoma. I followed my normal testing procedure after install; Reset the ECU, and drove around a while to allow for air/fuel mixture to adjust. I used the same technique: Set the cruise control to 30MPH in 3rd gear on the same road, in nearly the same conditions, and slammed the gas, taking it all the way to 70MPH while timing with a Speedvision digital stopwatch. This gives us a good indication of useable power, and any HP increase/decrease. The engine speed ranges from 2K RPM to 5K RPM during this test.

Here is the ISR mod installed on my 96Runner.

RTdawgs

nice

Dr. Zhivago

Good info! Thanks for the data.

Dr. Z

rimpainter.com

Your welcome. Those are great numbers for such an inexpensive mod!

Dr. Zhivago

I think the ISR mod is very worthwhile if you can handle your truck roaring a bit.

I've been considering doing something a bit different with the intake system to quiet it down while still maintaining the same performance level. No, I'm not ready to discuss details!

I don't know if the FPR mod will show such dramatic results as the ISR, but it's definitely noticeable way down low in the RPM range, so it might show up with your test scenario. I certainly wouldn't recommend S/C'd owners to cap off the FPR since Gadget has shown how effective the Free FMU is.

Peace!
Dr. Z

White SR5

Dr. Z: is the FPR hose mod the same as the thing described in your write-up for the ISR mod or is it something different? I didn't "cap" my FPR off, I attached it to the thing on the intake manifold. Oh yeah, for 2001 4Runner owners, all you have to do to reroute the FPR hose is attach it to the nipple on the intake manifold. There shouldn't be a hose already there, or at least there wasn't on mine.

Zach

loosehead

Good Job!

I have been very happy with this mod, and even happier once I capped off the FPR. It really help;s with that first inch you push on the gas pedal...

Dr. Zhivago

Hey Zach,

Capping the FPR connection means not having any hose attached to the brass FPR tube. The long and short of it is to just put a 7/32" vacuum cap on the Brass FPR tube and be done with it. I started a thread about this a while ago.

Hope this helps.
Dr. Z

98Tacoma

96,

What motor was in your taco? I have the 2.7 was gonna try this mod on sunday, along with the deckplate mod with the possibility of getting rid of my elbow.


I think i got enough courage to play with the intake system.

Hay off topic but does any one have a link to a header install for a 2.7 motor, or has anyone done it, i have to replace my exhaust manifold gonna do that sunday if it isn't to hard, i mean the directions show like 6 bolts on the motor with a few others for sensors and one U-bolt. Anyone know if a novice should attempt this???

John

rimpainter.com

John-

My taco had the 3.4L. Now I have a 96 4Runner, same motor.
Let us know how the ISR mod works on the 2.7.

White SR5

When I did the mod, I pulled off two such caps that you speak of -- one from the intake silencer, and one from the intake manifold. Maybe I'll put the intake manifold one back and cap the FPR to see what happens. I guess we're trying to trick the ECU? Could you shoot me that thread? I'd like to read it and see if there were any results, whether bad or good. As always, thanks.

Zach

midiwall

Hi Zach;

Dr. Z has a link to the thread in question in his email. You may not see the underline or the color change depending on how your browser is set up, but If you click on the word "thread", ("I started a thread...") you'll get there.

This is the "ugly" form of the URL:

https://www.yotatech.com/forums/show...&threadid=6786

rimpainter.com

I capped off the FPR line, and it seems to be the same. Hopefully this made the mixture a bit richer as Dr. Z has mentioned. I was unable to test the FPR line capped off because there was too much wind where I normally test. FYI.

I will let you guys know when I test it with the FPR line capped.