mpavolka

Hey I read this page on this mod and I was wondering if anybody knew where the blue link can be found that talks about possible side affects of this mod (above halfway down the first post). It seems to me it is outdated/expired and does not work, but it might be my computer.

https://www.yotatech.com/forums/f130...-2000-a-75168/

I wanted to check it out because sometimes I have a hard time believing that thousands of engineers at Toyota are wrong.

k_southman

I have no idea what was on that link, but if you search you will find about 50 post on the ISR. I did mine about a year ago and have been happy with the result. I would say that the toyota folks were not wrong to put the silencer box on, it is a trade off. You get increased air flow but also increased noise. If you don't want a louder engine, leave it on.

Dublin

Link no worky. I'm not sure why you believe engineers are gods, when they engineer to meet the requirements they are told to. Optimal performance for them also requires boundaries (emissions, noise levels, costs {materials/labor}, deadlines, ect, ect.. They give us the best they can within set limits. Additional engineers, designers, mechanics, ect in not only company racing devisions but outside of the motor corporations expand on these designs. You find this true in almost everything. Don't get me wrong I believe the best place to start is with those involved in the concept//design/engineering, but almost everything can be improved upon. Is the ISR a good mod, for me yes, for others maybe no. Too many factors to make this an absolute (driving habits, weather, altitude, engine condition and more). The plus side of this mod is it can be reversed, it's cheap enough to try. We can't all be sheep, go on be an innovator. Thomas Edison " I have not failed 700 times. I have not failed once. I have
succeeded in proving that those 700 ways will not work. When I have
eliminated the ways that will not work, I will find the way that will
work".

Mic09dcsm

How could you hear the intake even with a metal one with the damn fan being as loud as it is on startup? At others times I realize it would be heard but god, its just a little noise, why are people so concerned with this?

infiltrator

Yeah, I really don't hear anything different or loud that you guys are talking about.

I feel some sort of throttle response, and know my engine can breathe better.

wizzells

I can definetly hear my True Flow intake. It's more of a roar of intake air now than when it was stock

mpavolka

Yea, I can understand better air flow, and I don't care how loud the car is, I have dynomax exhaust on mine.

I was just curious, it says in that link that it might be possible to loose low end torque, exhaust can be wierd like that. You could put a straight pipe on an exhaust, lose the back pressure and it will actually take torque away.

EDuke

Im also considering the ISR mod but have the same worries. I did the deckplate mod and was more than satisfied with it and want to do the isr. I want to know all the drawbacks first though and "more engine noise" just sounds too good to be true. surely there are some long term disadvantages..?

dsasteel

I just did mine yesterday. I have no clue if it did anything or not. These couplings were the only thing I could find at Lowes and Home Depot.

atistang

the only thing that concerns me is that fpr is hooked up to ported vacuum, a lot of people hook it up to manifold vacuum after they remove the silencer, which would make it work backwards.

This would be the correct way to do it

SnowRunner98

i happen to like mine, i can't believe that i waited sooo long to do mine. actually runs better.

97ltd4x4

You do not need to port the FPR(fuel pressure regulator hose) to the intake or manifold...Because its a spring pressure type,not a vacuum type...Hence its ported to the intake hose(no vacuum) vs. manifold port(vacuum)...Just take the hose off from the pipe that runs down under the center of the intake.........

If you don't believe me,port it to vacuum..fuel pressure will not change..leave it unhooked...fuel pressure will not change either...You can also see long fuel trim on the scan tool not change as well......I have no idea why toyota ported it to the intake....I think I know but its complicated and is a bad desighn,why its only on the 5VZ............

atistang

I was gonna hook a fuel pressure gauge up and unhook the vacuum line and see if the pressure went up or not. I've never seen one hooked up to ported vacuum before

fyi there is vacuum in the intake hose, it is just next to nothing when at idle and more when at WOT but still not much

there might only be a difference in the fuel pressure when it is hooked up when you are under WOT, it might somehow use vacuum to asist the spring in shutting the fpr somehow

seems like its a test i will have to do one day

JC_ez

The Engineers aren't wrong. It's not really a silencer; it's a Helmholtz resonator system. It's designed to reach resonance at the same frequency as the engine's intake at low rpms to increase low end torque. Engines don't take in a constant stream of air, it sucks air in pulses. When the frequency of the engine's intake pulses match the Helmholtz resonator box's resonant frequency, the box helps to force pulsed air into the the engine. The box should not really affect higher rpm function since it is not directly in the way of the air flow. I am actually on a Formula SAE team at my university and we are designing one for our car...because it WORKS.

As for replacing the flexible intake tube with a rigid metal pipe, consider that the engine is free to move around as it is held in place with rubber bushings. The Engineers were not wrong here either. The intake tube needs to be flexible to move with the engine.

If you still want to change your intake system, I'd advise you to keep these points in mind.

97ltd4x4

Here is the thing..If you take the FPR apart...there is no vacuum camber in the FPR to actuate anything...If you take it apart there is a screw that puts pressure through a spring which then acts on the diaphram,which does effect pressure..........But the thing is the hose going to it is above the screw..which does nothing.........I believe since the hose is on top of the screw..Toyota knew that the screw would move slightly up and down inside the FPR and instead of just capping the end with a filter..so it could expand and contract freely...They tapped into already filtered air(intake boot/box) and just ran a hose between the FPR and the intake...

To me this is just out of character for Toyota...Maybe they were going to at one point use a vacuum type FPR,but installed this at the last miniute........One other thing to add,If the hose does go bad,loose at some point its equivilant to having a tear in the intake boot... the engine will run lean,because of unmettered air..So for me the best solution is either to cap the ports and do away with the hoses or not port the ISR and leave the hoses off.....Its a lot smoother looking install,also a lot less work.

Next time you take your truck in ask them politely to see the long/short fuel trim #'s and pull the hose off.......The Data list is very accurate.

Maybe one day when I am bored I will hook up my pressure gauge and post some pics.......That is if I can find it buried at the bottom of my tool box..