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Finished mine yesterday. I spent $36 total. I got the silicone couplers and brass fittings from eBay, and the PVC pipe and two hose clamps from Ace Hardware.
The 90° elbow coupling has to be 3.5 inches internal diameter all the way through, and the straight coupling to go to the airbox has to be 3.5 inches on one end and 3 inches on the other. The pipe should be 3 inches internal diameter, and the one I got was black ABS and fit the couplers perfectly.
The brass fittings are 1/4, 3/8, and 1/2 inch barbs. Thread size doesn’t matter too much. I originally bought locknuts to hold them in place from the inside of the PVC pipe, but I discovered that I could hand-file the holes just smaller than the threads and they held in place just fine when screwing them directly into the pipe.
3/8 inch vacuum line works perfect for the PCV. Soak the one end in hot water and it’ll stretch over the largest fitting no problem. I used 1/4 inch vacuum line for everything else.
I don’t really notice a difference in power. Maybe it’s a tad more responsive down low. But at least I don’t have cracks and vacuum leaks anymore. This one will outlast OEM by at least 50 years.
Finished mine yesterday. I spent $36 total. I got the silicone couplers and brass fittings from eBay, and the PVC pipe and two hose clamps from Ace Hardware.
The 90° elbow coupling has to be 3.5 inches internal diameter all the way through, and the straight coupling to go to the airbox has to be 3.5 inches on one end and 3 inches on the other. The pipe should be 3 inches internal diameter, and the one I got was black ABS and fit the couplers perfectly.
The brass fittings are 1/4, 3/8, and 1/2 inch barbs. Thread size doesn’t matter too much. I originally bought locknuts to hold them in place from the inside of the PVC pipe, but I discovered that I could hand-file the holes just smaller than the threads and they held in place just fine when screwing them directly into the pipe.
3/8 inch vacuum line works perfect for the PCV. Soak the one end in hot water and it’ll stretch over the largest fitting no problem. I used 1/4 inch vacuum line for everything else.
I don’t really notice a difference in power. Maybe it’s a tad more responsive down low. But at least I don’t have cracks and vacuum leaks anymore. This one will outlast OEM by at least 50 years.
Nice work, I was thinking of doing the same to my 99 SC400.
Please provide feed back on your fuel consumption good or bad.
Nice work, I was thinking of ding the same to my 99 SC400.
Please provide feed back on your fuel consumption good or bad.
Lol my fuel consumption around town is always bad. I bought the V8 with the intent to use it On the highway though, I’ve regularly been able to get my car to do 28mpg, even before this mod.
Update: I didn't reset the computer after doing this mod, but it seems to have adjusted to the lack of vacuum leaks and it does feel like it has a little more response earlier in the throttle now.
I can't say how it would affect a system that wasn't leaking beforehand.
Got my new 99 GS400 a month ago with 92k miles on it and have been giving it some maintenance love here and there.... But this was the first mod the car needed. Usually, I'd just buy a K&n intake system kit for $300+ and call it a day. This time, I did not want to spend so much money so I started looking for other options. You guys have come up with some sweet ideas. I used 3inch internal diameter PVC pipe painted black with textured spray on bed liner. Also bought the two black silicone couplers on Amazon. I picked up the screw on barbs for the 3 air box hoses at Home Depot (I recommend going to AutoZone instead because I only found 2 in bronze and the 3rd in silver) at the same time I bought the PVC pipe. Also purchased red hoses on Amazon along with a k&n drop in filter for the stock air box. I cut out a large corner closest to the front right headlight to aid in the air flow into the intake. I cut part of the 3/8 inch red hose and split it down the middle to line the edges of the air box cut out, so it wouldn't look so rough along those edges. I drilled small holes at the top and bottom of the cuts to loop red zip ties to hold the edges on tight. Hope this helps ! Lmk if you have any questions
Stock infake Different color barbs 🙄 Stock vs new, as you can see the pipe is wider so it may require some adjusting during install. In the middle of it, decided to clean out the throttle body since it looked pretty dirty. Used extra hose to line edges of new opening on stock air box Replaced some stock hoses with red hoses, stock hoses may break considering many of these cars are pushing 20+ years old DONE!
In conclusion:
Gives you near the same if not better results than a name brand intake kit. Comes with extra cool factor cause YOU are the one that made it yourself. New enginee sound willwhave you giggling in no time. have fun!
What was done to the sensor on the back side of the top resonator?
No sensor attached to resonator box. The only sensor is attached to the top of the air box, right above the intake filter. That sensor does not need to be moved or changed. The hose that attaches to the resonator box needs to be replaced when you go through this process though. The stock hose is not long enough to reach the new air tube, that's why I replaced the stock hoses with the red hoses you see above.
Would anyone happen to know what the sensor on the back of the top resonator is? I have a 2003 GS 430, the top vacuum hose hooks up to it. And it also has wires and a plug connected to it......
That is a solenoid for the EVAP system, if you want to do this mod just extend the vacuum hoses and fab a bracket to hold the solenoid. I am working on this mod as we speak, however, I am using the original intake tube. I cut off the boxed section of the intake assembly, capped the opening and installed three vacuum barbed fittings.
I will post some pics when I get back from vacation next week.
That is a solenoid for the EVAP system, if you want to do this mod just extend the vacuum hoses and fab a bracket to hold the solenoid. I am working on this mod as we speak, however, I am using the original intake tube. I cut off the boxed section of the intake assembly, capped the opening and installed three vacuum barbed fittings.
I will post some pics when I get back from vacation next week.
I literally just got a check engine light yesterday and the car is throwing a EVAP code. I'm going to do some poking around now to see if maybe one of the hoses on the EVAP system came loose. Using the stock tube for the intake will definitely save time and money. I would just recommend checking the original tube sore signs of wear or cracks before reusing it
01-11-18, 08:30 AM
On the highway though, I’ve regularly been able to get my car to do 28mpg, even before this mod. 
