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So my ACIS solenoid died, and the intake manifold had to come off... So I figured, why not buy the plastic 2UZ intake from badblackgs and see what happens when I install it? From his experiments with it, he noticed a decent increase in torque. Plus the plastic keeps the air temperature down and is way lighter to lift off the engine when doing the starter. He sold it to me with a full set of fresh injectors, which was (initially) more cost-effective than having my injectors cleaned and balanced. The injectors from the 2UZ up to 2002 are plug and play in the GS400 harness and fit the 05+ intake manifold perfectly.
Big thanks to badblackgs for all the parts and some technical insight.
In order to keep the surgery minimally invasive, I tried my hand at making an adaptor to bolt the throttle body on to the intake using some eBay aluminum plates and some bolts from Ace Hardware. The cost started climbing from there, since I needed a 3-inch hole saw to cut the throttle body bore, and the metric bolts were pricey.
The adaptor worked though, so I test fitted everything. I planned on just using the 2UZ fuel rail, but the GS400 fuel line has the part that goes across the manifold integrated into the feed line. So I had to use the driver's side rail from the 2UZ, plug the hole at the other end, and use the passenger side rail from the GS400.
At this point, the two mistakes I made were not putting new upper seals on the fuel injectors and stretching the smaller of the two coolant lines to the TB because the whole TB was moved forward. The injectors leaked gas everywhere the next morning when I tried to go to work, and the coolant line popped later that night after I replaced the injector seals. #rookiemistakes
At this point though, everything is fine. The manifold bolted right to the engine, the vacuum lines all hooked up, and I was able to adapt the bracket for the throttle cable, even though the 2UZ manifold doesn't have a place to mount a throttle cable because the 03 and up are all 100% drive by wire. I relocated the vacuum canister and solenoid for the ACIS so I could access them without removing the manifold. Also installed a new solenoid, and the ACIS is working properly.
How does it drive? It definitely pulls harder through the mid RPMs, and the top end feels like it breathes easier. This car really moves.
I haven't had much time to really get familiar with it, but so far I'm thinking it's not a big enough gain to justify the pain of the install. Fabbing the adaptor took a lot of time, and as always when taking stuff apart there's the risk of breaking other stuff. At the very least, I know all those parts are fresh and working properly now.
UPDATE: I’m feeling better about it all after driving on the highway today. The car just feels healthier. It moves easier. It’s subtle but pleasant.
At this point though, everything is fine. The manifold bolted right to the engine, the vacuum lines all hooked up, and I was able to adapt the bracket for the throttle cable, even though the 2UZ manifold doesn't have a place to mount a throttle cable because the 03 and up are all 100% drive by wire. I relocated the vacuum canister and solenoid for the ACIS so I could access them without removing the manifold. Also installed a new solenoid, and the ACIS is working properly.
just a heads up 2001+ are all drive by wire or atleast ALL GS430's are drive by wire
did you by any chance weigh the old manifold and the new one? probably would have been a good time to rebuild the starter since you had everything already off. can you bolt your engine cover back on or is that gone now?
just a heads up 2001+ are all drive by wire or atleast ALL GS430's are drive by wire
did you by any chance weigh the old manifold and the new one? probably would have been a good time to rebuild the starter since you had everything already off. can you bolt your engine cover back on or is that gone now?
you are correct, the GS430 is DBW from 01+. The 2UZ kept the hybrid throttle thing until around 03.
The new manifold is probably 15lbs lighter. I was going to do the starter but discovered that it had already been done, probably within the last 40k miles. So, I’ll wait until it goes again and then do the starter and knock sensors in one shot.
The engine cover brackets didn’t transfer over, but that’s no big deal. The hood probably wouldn’t close with it on anyway.
good job. theres something bothering me though looking at the pics of the install complete. just after the throttle body there is two 90 degree plastic pieces that two hoses attach to. the one on the left you have running from the intake to the intake pipe. the problem is thats not hooked up correctly. whats happening is the engine vacuum instead of being controlled from the throttle body is pulling on that hose that runs to the intake pipe. so id imagine that its probably idling high or idles high before the ecu shut the throttle down as much as possible to stop the idle concern. that hose from the intake should run down to the power steering vacuum switch. its designed to increase the idle whenever the wheel is turned to help with instant assist. so i recommend resolving that than let the engine computer relearn it once its reconfigured. or just plug it or put a cap in that port.
good job. theres something bothering me though looking at the pics of the install complete. just after the throttle body there is two 90 degree plastic pieces that two hoses attach to. the one on the left you have running from the intake to the intake pipe. the problem is thats not hooked up correctly. whats happening is the engine vacuum instead of being controlled from the throttle body is pulling on that hose that runs to the intake pipe. so id imagine that its probably idling high or idles high before the ecu shut the throttle down as much as possible to stop the idle concern. that hose from the intake should run down to the power steering vacuum switch. its designed to increase the idle whenever the wheel is turned to help with instant assist. so i recommend resolving that than let the engine computer relearn it once its reconfigured. or just plug it or put a cap in that port.
its already plugged it’s just like that because I didn’t have any caps. And my power steering air valve leaked fluid so I plugged with a fat bolt.
Interesting thread, wish there was a dyno before and after, curious how it moved the power band, but it sounds like you just needed to knock this out. Looks like ill be on the hunt for a manifold lol
Turns out the vacuum hose I used on the PCV when doing the swap was not rated for oil and it basically melted. So since this was installed I've had a decently fat vacuum leak that I didn't know about until just a few days ago when I hooked up my scan tool.
So I replaced that hose and that fixed a number of issues...
Then tonight I goosed it to get through a yellow light and HOLY FRIJOLES I've never felt that car move so fast.
So @badblackgs was right when he hyped this mod, after all! Sucks for me for screwing up the install with one lousy hose.
So my ACIS solenoid died, and the intake manifold had to come off... So I figured, why not buy the plastic 2UZ intake from badblackgs and see what happens when I install it? From his experiments with it, he noticed a decent increase in torque. Plus the plastic keeps the air temperature down and is way lighter to lift off the engine when doing the starter. He sold it to me with a full set of fresh injectors, which was (initially) more cost-effective than having my injectors cleaned and balanced. The injectors from the 2UZ up to 2002 are plug and play in the GS400 harness and fit the 05+ intake manifold perfectly.
Big thanks to badblackgs for all the parts and some technical insight.
In order to keep the surgery minimally invasive, I tried my hand at making an adaptor to bolt the throttle body on to the intake using some eBay aluminum plates and some bolts from Ace Hardware. The cost started climbing from there, since I needed a 3-inch hole saw to cut the throttle body bore, and the metric bolts were pricey.
The adaptor worked though, so I test fitted everything. I planned on just using the 2UZ fuel rail, but the GS400 fuel line has the part that goes across the manifold integrated into the feed line. So I had to use the driver's side rail from the 2UZ, plug the hole at the other end, and use the passenger side rail from the GS400.
At this point, the two mistakes I made were not putting new upper seals on the fuel injectors and stretching the smaller of the two coolant lines to the TB because the whole TB was moved forward. The injectors leaked gas everywhere the next morning when I tried to go to work, and the coolant line popped later that night after I replaced the injector seals. #rookiemistakes
At this point though, everything is fine. The manifold bolted right to the engine, the vacuum lines all hooked up, and I was able to adapt the bracket for the throttle cable, even though the 2UZ manifold doesn't have a place to mount a throttle cable because the 03 and up are all 100% drive by wire. I relocated the vacuum canister and solenoid for the ACIS so I could access them without removing the manifold. Also installed a new solenoid, and the ACIS is working properly.
How does it drive? It definitely pulls harder through the mid RPMs, and the top end feels like it breathes easier. This car really moves.
I haven't had much time to really get familiar with it, but so far I'm thinking it's not a big enough gain to justify the pain of the install. Fabbing the adaptor took a lot of time, and as always when taking stuff apart there's the risk of breaking other stuff. At the very least, I know all those parts are fresh and working properly now.
UPDATE: I’m feeling better about it all after driving on the highway today. The car just feels healthier. It moves easier. It’s subtle but pleasant.
The 1UZ VVTi came with the Pink Denso injectors and they carried over to the first 2 years of the 3UZ, but they get replaced about halfway thru the 3UZ’s life with a newer design with higher pressure and I think they’re made by Bosch. I think they are gray, and have a different wire harness plug
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2UZ intake installed on GS400
it’s just like that because I didn’t have any caps. And my power steering air valve leaked fluid so I plugged with a fat bolt. 
