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Old 10-07-2015, 12:43 PM   #1
tmontague's Avatar
Drives: '08 2zr swapped Vios M/T
Join Date: Oct 2012
Location: Caledonia Ont.
Posts: 2,931
JB Weld stock intake manifold port w/ 1ZZ Throttle Body

I figured I'd post this under a new topic for ease of anyone searching for it in the future. All in all this mod went very well with a few minor hiccups that I did so you readers don't have to.

I was happy with the 1ZZ TB mod but couldn't help but be disappointed with the air flow being restricted by the stock intake manifold. I have an after market header which works great, a short ram intake and a better flowing TB but it is all restricted with the intake manifold.

I found a thread from 2010 about someone doing this mod and how he enjoyed the results but no one since then has posted about it or stated that they did this mod. The price for an aftermarket intake (as nice as they are) is beyond my budget right now as I'd rather put that cash elsewhere on my car.

I took a day off school and decided to just go for it without buying a new manifold. If I messed up then I was screwed until I found a new one.

I removed the intake, throttle body and then the manifold from the car. I then removed the oem gasket from the manifold and then removed the 3 studs on the intake for mounting the TB. With the opening of the manifold now flush/flat I got to work.

I used the tan colored JB Weld which sets in 15 mins and can be sanded in 30 mins (realistically 1 hour depending on how thick) It has a higher strength than the grey JB Weld and it cured much quicker. I then filled all of the holes on the mounting surface as well as the gap that was left from removing the rubber gasket.

I couldn't get rid of the air pockets in the holes so I needed to buy a second syringe to fill the holes created from the air after the first batch cured ( a more liquid JB weld would work better, the tan if fairly thick). I basically filled the holes, then used a dremmel to sand down (definitely use a dremel it will save you so much time and effort!) everything and started shaping/porting the manifold the way I wanted. Once the JB hardened (about 1-2 hours) I then picked off any pieces that were not attached/secure because of air pockets below them.

I then used my second syringe of JB to try my best to fill the air pocket under and around the already hardened first set of JB I had applied. I waited for it to cure and then again sanded everything down.

I also sanded the lip inside of the manifold to help improve the air flow.

Some mistakes I made:
-I did not make the mating surface on the manifold as flat as I possibly could (needed more time)
-Made the opening a little too large on the manifold (makes it more difficult to get a good seal on TB
-Did not make a paper gasket to use with RTV (made getting a proper seal harder
-Did not wait a few hours for RTV to semi cure and started the car too early which ruined the RTV seal I made.

When I had everything installed back on the car it turned over fine but my ultra gauge was showing fuel trim values indicative of a vacuum leak. I never heard the tell tale hiss but the engine was idling very rough and at around 1100rpm and sounded like it might stall.

I used a stick of incense to find a vacuum leak (works awesome)

I removed the TB and re applied the RTV but in a larger bead this time. I waited 1 hour until it became very tacky and then finger tightened the TB. I then waited 2 hours and fully tightened the TB down.

**I then opened the butterfly valve and used my finger to remove any of the oozed RTV that was now inside so that it never got sucked into the engine (or obstruct the airflow) when it hardens

**make sure the electrical connector is unattached from the TB when you are manually opening the butterfly valve to reduce issues down the road**

I then started the car up the next morning (today) and the idle is now down to about 600-680 rpm and is no longer erratic. The fuel trim is showing the short and long term within about 7-8% of one another. This is not perfect but much better and would only be this way if there is a super tiny vacuum leak and no leak at all. It may improve once the ECU fully resets so I'll keep an eye on the fuel trims.

The next time I remove the TB (when ever that is) I will be making a paper gasket and letting the RTV sit even longer before installing. If that isn't perfect then I can also just apply some JB weld and build the mounting surface up so that the hole is a little smaller (more flush with the 1zz TB opening)


The car wants to go!!! With light pressure on the throttle the RPM's go up much higher than stock, they also go up much quicker due to quicker acceleration. Definitely more tq, and I'm not sure about HP or top end, I've yet to do any highway pulls, may get around to those tonight.

The engine bay noise is a nice growl and is louder at lower rpm's than before. It definitely feels like the 1NZ can breath better. Before you had to stomp the pedal down to get the rpm to climb and even then it felt like I was waiting for it to climb. Now the rpm's climb much quicker.

This cost me a total of about $30 as I also bought 400 grit sand paper (I would recommend 200-300 next time) to do a finish sanding once I was finished with the dremel. Make sure you have a dremel, I cannot stress this enough it makes the job more enjoyable, don't think I could have down this without.

This is a very inexpensive mod for a great performance increase and it is fairly easy to do for those that like DIY's. It take some patience, time and your own skill as it is not a simple bolt on from a product you buy. I knew I took a risk by using the only intake manifold I had but if I shaved off too much I could always just build it back up with JB weld.

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Old 10-07-2015, 09:04 PM   #2
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Drives: Vitz RS
Join Date: Feb 2009
Location: Trinidad and Tobago
Posts: 272
nice mod and diy.
I will definitely try this soon.
My valve cover is that same blue but I don't have those trd coils they were discontinued when I was ready to purchase.
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Old 10-07-2015, 10:31 PM   #3
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Drives: '08 2zr swapped Vios M/T
Join Date: Oct 2012
Location: Caledonia Ont.
Posts: 2,931
Thanks, yes it is by far a worthy mod right up there w/ the TRD sway bar, except a little longer obviously do.

The coils are stock coils painted with engine block paint. Cleans the look up a bit
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