4runrjunkie

Hey guys,

Figured I would show off my new ISR intake that I built, and new exhaust that got welded up yesterday.

New intake:




I have a filter thats coming in for the crackcase vent. I also have a fitting coming in for the other vacuum line that is currently left open because I have been told I will have issues if i just vent it to atmosphere but so far havent had any issues.

Exhaust: (dont mind the rust )








The exhaust sounds great. Its just 2.25 piping to an 18" magnaflow muffler, and then out the back. Aside from the fact that they welded it solid instead of leaving me a flange somewhere, I think the shop did a great job and am very happy with it

The one thing I have noticed is that when I'm driving and I take my foot off the gas, there is often some popping and crackling that's happening. I did some reading up on it and some people say it's completely normal and some people say it usually indicates an exhaust leak higher up, or leaking valves. Any one got input into this from a Yota 4runner perspective?

Edit: Im not sure why all the photos are different sizes, but w.e, it works

catfish21

iTrader: (1)

It could be that you need more back pressure that is a problem slot of times

stanprophet

The popping and cracking means the muffler may be defective, I would be happy to dispose of it for you!

It is perfectly normal for that to happen on a high flow exhaust system. That is a sound that is engineered to not be there in a factory exhaust system on most cars. Jump in a HP car and it will pop and crackle on throttle lift. This is because a performance enthusiast wants that kind of sound.

You changed all exhaust, and the intake, eliminating the Helmholtz resonators in the intake. Thus allowing more engine noise to be heard through the intake and exhaust.

4runrjunkie

Perfect. That is what i figured but i just wanted to make sure. Thanks for the info.

stanprophet

Back pressure is not really a desirable thing. The engine is just a big air pump, and the less restrictions on intake and exhaust the better. With a cast iron manifold and a full length exhaust there should be little to no measurable back pressure at idle if the system is working correctly.

When the exhaust is shortened and a header added it will cause a loss of low end torque, and gains in high end horsepower. Many people relate heavy exhaust modification and loss in low end torque as a back pressure loss. It has more to do with scavenging effects and less to do with back pressure. Burnt valves can happen on a car running strait headers, since there can be a large lapse between exhaust pulses allowing fresh air to enter the exhaust port of the cylinder head. This caused rapid heating a cooling of the valve, causing a failure. This will not happen on a full length exhaust system unless there is a large exhaust leak. Even with factory exhaust there is little to no back pressure until the engine is on a significant load or RPM.

The design aspects of an exhaust system that make them quiet, is the same thing that causes them to be more restrictive. Most OEM mufflers have a larger inlet than outlet, as the exhaust enters the chamber it hits the perforated tubes and chambers. This causes the exhaust pulses to be smoothed out, and also causes the air to cool and condense. Condensed exhaust takes up less space than hot exhaust. This allows the exhaust to exit the pipe in a much steadier stream, and the smaller outlet is used to help smooth out the cylinder pulses.

On an aftermarket high flow muffler, air can and will enter the exhaust system because of non smooth exhaust pulses. It will never reach the valve, but can reach the muffler. The collision of hot and cold air can make some popping and cracking sounds.

OP: Looks good!

Roark

What did you use for your ISR, material wise?

4runrjunkie

I just picked up a peice of walker exhaust piping (3" with a 45 degree bend and 4" straight sections on each side of the bend) and two 3" sections of silicon tubing ... It fit perfectly.

4runrjunkie

Thanks!

Roark

What did that run you, like $30-40? Looks great btw!

4runrjunkie

Pipe was $40 but things in this city always cost more than they should haha. Silicon tube was like $6. With all that and the clamps and paint it was about $50.

Thanks btw, im quite happy how it turned out.

imhousing

man that looks awesome! i'm tapping my foot waiting for my current set of pipes to start leaking so I can follow suit!

also regarding the popping and crackling: i'd inspect the upper end of your exhaust closest to the motor for leaks. i usually just dip my hand in water and then follow the pipe with it when i'm close to the motor. hate for u to burn out that shiny motor

ps man i do not envy the hands that have to wrench on that motor. every time i see one my knuckles start bleeding

4runrjunkie

yeah that's what I was concerned about ... mostly whether it could indicate the crossover was leaking, so maybe I will check it out even if there is a good chance its fine lol

imhousing

if you could delete your cat without any inspection worries how would you fab the new pipes. are aftermarket headers a must or really that worth it?

4runrjunkie

Im not 100% i know what your asking, but ill try and answer haha. I dont have to worry about inspections so i deleted my cat and just ran a straight section of pipe between the o2 sensor and the new muffler.

As for headers, i have looked at them and decided its not worth the price ... Yet. I may look seriously at them one day but not right now. Deleting the stock crossover is definitely looking like a possibility in the near future though.

Shoua

I have always wanted to do the intake pipe mod, but have always been unsure because of one thing: what do you guys do with all the hoses that are all interconnected within the whole intake system???

hockey88fan

Wondering the same?

4runrjunkie

In my case (i think its the same for everyone) there are only two hoses that you have to worry about. One of them connects to the top of the driver side valve cover, and the other to a tube that passes under the intake plenum. Currently I have left both of those open to the atmosphere, but am in the process on correcting that. I am putting the crankcase vent filter in place of the tube that runs to the valve cover, and am getting a 7/16" fitting to screw into the intake pipe to fit to the other tube.

Im not sure if that makes sense haha, but go here and it will make better sense: https://www.yotatech.com/forums/f130...4runner-75167/

Shoua

I was looking into doing this, but decided that I'd just get the upper intake boot instead because there was a huge crack developing. Well, I said "Hell no!!!" after I was quoted $70 for this little part alone (and that's with my employee discount)!

So I went to the hot rod store, and the only steel pipe I found (which wasn't even 3-inches) was retailing for $75! Instead, I came home and ordered a 3-inch, 45-degree bent aluminum "intercooler" pipe from Amazon for $15, and 2 3-inch-to2.75-inch silicone connectors (the stock throttle body inlet and air meter outlets are 2.75-inches in diameter) for $13 each. Grand total of parts was about $60 after shipping. I know, they charged a load for shipping.....

Anyway, my before and after pics:

Shoua

Here's the parts:



Old parts versus new parts:



I didn't have a pipe cutter available, which would have made much cleaner parts, so I used a cutoff wheel instead:



I didn't have time to incorporate the fittings for the 2 lines that go into that part of the intake tube, but will later on.

One little problem that I did run into was that the pipe is now hitting my brake master cylinder (as you can see in the "after" pictures in my previous post), and will rub against it. My remedy? Well, for now, I stuck a little square piece of velcro on the intake pipe right where it rests against the master cylinder. I may or may not choose to fix this later.

Overall, I built this intake pipe for less than just the upper rubber piece from the dealership.

4runrjunkie

Yup ... this is also why I ended up going this route. Really no big power difference and I havent really noticed a sound difference in throttle, it was just cheaper than staying oem haha