From post 632 of RedSpencers build thread, I posted the notion of the 2UR intake but have since learned the UR heads are significantly lower profile than our GR heads. They did it by changing the combustion chamber design and moving the valve angles. All of that said, with its extra displacement, why doesn't it make more power?

Follow this and read up on some of the differences and similarities the 2UR and 2GR share.

This intake is no go for us. And with our intake ports high up like they are, I'm guessing the only way you make a functional intake will lead to a bump in your modified hood as there is no room to fix the runners until you leap and do the dual TB as Ultra has been suggesting. Even then it would be super close! FWIW the link has the other half of the manifold.


Edit: does anyone know if for example Solidworks can model the flow of a running engine or is it limited to static user set values? I'm curious as the log runner above has feeds for 8 cylinders. If we split the into two separate plenum placed over the valve covers, would this hinder the flow vs being combined like the UR?

 

In short, no. The UR has an additional cylinder pushing on the crank per rotation, thus develops power sooner in the RPM range, thus the disruption of each cylinders' intake gulp is a lower percentage of the overall plenum volume, thus why the intake design doesn't need to be as streamlined. Also why the UR's firing order is 1-8-7-3-6-5-4-2. Also also packaging; they'd give it a F430 intake, if they could.

Look at what all the hypercars do with their naturally aspirated intakes. The Pagani Zonda is my favorite, because Pagani just took a lowly SL600 engine, ground down the cams, made custom valves and appropriate springs, a custom intake and headers, and bingo-bango-bongo: the best sounding engine on the planet.

Edit:

 

I'm definitely not going to post this over in their forum, but after spending this whole week completely immersed in LFA and 1LR-GUE data/literature looking for engineering parallels with the rest of the *R engine and -F badge families, I have come to what I think is a very unpopular conclusion:

The LFA is just a fat, disfigured C5 Corvette with a better sounding, less useful engine. And way more stuff to break. The only reason to own an LFA over a C5.R clone is status. You can fix the C5.R in an AutoZone parking lot...good luck getting an LFA oil change.

...I really was a LFAnboy until this week.

 

^Yeah, but the sound that exhaust makes!!!! LOL!

 

Absolutely zero arguments there.

The LR is still on my list of favorite car sounds with the M120, Ferrari 131 and 136 V8s, Alfa's Busso V6, and solid-roller high-CR 2nd gen Hemis.
If I continued that list, the GR family would be coming up awful soon, and I'd add the UR is nowhere near my top-20. V8's have just been done better on both sides of the refinement scale.
And we're still on topic here, because a byproduct of straightening the airflow between intake valve and throttle body is increased induction noise. Get rid of the plastic fun limiter to replace it with something more aerodynamically flowy and less acoustically lossy, and I suspect you'll have one of the best sounding V6s on the planet. Definitely the highest-HP N/A RWD 2GR...
The 4GR's gonna be a crap shoot with the ACIS flap.

 

I am currently in the works of doing this . I have a 2006 lexus is350 with ppe headers , invidia catback, and the RR racing 7200rpms tune, megan racing strut tower brace, fsport lower intake box, K&N filter, fsport sway bars, RR racing USRS(Ultimate Steering Response System), seibon carbon fiber hood. I am also porting and polishing my lower intake manifold. I also ordered valve springs, retainers and will be ordering the camshafts really soon. I will be creating a build thread on the process of the build!

 

I'm interested in the results of the port/polish of the intake manifold and valvetrain upgrades.

 

For best results one needs to continue into the heads blending the runners and bowls keeping in mind that bigger is not always better as it drops port velocity. Think, smooth transitions. So with cams and N/A, it should be a winner...

 

I have I have been toying with the idea of picking up an intake manifold and cylinder heads from a salvage yard and sending them out to be ported and matched. I bet with a very mild port of the intake manifold and intake/exhaust ports along with some combustion chamber work there could be some decent gains to be found.


What I find strange is that a slightly larger throttle body and port matched upper intake manifold is not a common mod. It has worked well on many other engines I have modded. Does anybody have any experience with this?

 

Seconded. I have been seriously interested in these mods, especially when I learned that Monkey Wrench developed cams for our platform. Subscribed to this thread and watching it like a hawk to see if anyone finds any real gains with either cams, port/polish, or both!

 

The good and bad is these are so reliable it's hard to open a good engine just tinker. There is a 250 owner @Ultra4 who bought heads and ported them at home (like myself has prior experience), but IIRC it's the wife's DD, so downing it for head swap comes at a cost.
He also opened up the upper plenum. No gains to be had there without going from scratch which I feel applies to the 350 also. That said, the upper may have the most to gain but it takes the most effort to create from new. To maintain a low profile one may have to opt for twin TB's, but with TBW, this could be an issue unless you go mechanical and link them that way.


Where is our Solidworks genius and 3D printer????!

 

I've already ordered cams from MWR and got an extra lower intake manifold that I will be porting . I'm just waiting for the cams to arrive so the project can be started. If you would like to see the outcome here is my thread. https://www.clublexus.com/forums/is-...w-heights.html

 

The plenum of the plastic intake manifold splits into two right before the #5 and #6 cylinders, separating the left and right banks from each other. The smallest crossectional area of the entire common air tract is right there, and there really isn't much to do to fix it, which is borne out through larger throttle bodies not yielding measurable gains. You gotta cut and reshape the plastic at that pinch point.

I cut that intake even further apart, as well as my junk head. I'll eventually share with the class, I suppose...

 

I would love to see the results ! Please share !

 

Do any of you performance guys have easy access to a dyno?