Update - So I purchased a Stock TB for my 2013 Lexus GS350.

I sent out for this service. Should be back to me next week and I'll post the pics. No enlargement, just these to go with the Flow Benched port/polish upper/lower intake manifold.

• Knife edge of front lip
• Port in a velocity stack
• Removal of casting marks
• Port and taper of factory steps before butterfly
• Increase diameter of the TB before and after the throttle blade

 

I've got to ask.... any updates? Curiosity is killin' me.

 

^^ Good question!

@jgscott How is the weather treating you? Anything to share on the GS?

 

Hey yes sorry. Been in the 4th Gen GS Nothing works performance wise forum.

I forgot about the forum that does like to do engine mods. lol! I'll post up the TB and Intake tonight later. The upper and Lower Intake were Flow Bench Ported and ended up with a 28% gain. I asked that it Not be Chrome look polished as I read some pros and cons about very shinny finishes. Sorry so late to get back.

 

Ya, rough leaves some boundry air making less drag. Great for the exhaust as carbon may not stick for a while, but not as good for the intake.

Looking forward to it. TIA

 

So here is what I ended up with. A few things......

Some of the surfaces don't look so smooth as they actually really are because of the pics light. The Intake lower and upper I got used and it has not been finished for install cleaned yet. The plastic Black upper internals also look rough still. Run a finger across and they are only slight rougher than glass. They are very smooth. I gave the U&L intake to a Head port shop. He made a template for the ports to put on a flow bench. I was kinda surprised at the improvement being almost 30%. Its not the looks but the improved shape and not just flow either.

The TB was sent out for just polish and a Venturi funnel enhancement. It is just ever so slightly bigger due to metal removed for the polishing. I thought they were going to knife edge the front TB flap but looks like they did not? I may do myself before I install. The casting roughness, seams, and the injector bosses were all flowed better on the U&L intake. I used the flow bench port shop to also make sure all 6 ports were as evenly matched as could be.

Now just got to install them. Oh yea, there was also some over hang of the air way, of the Intake Gasket was was cut out of the flow path and gasket flow matched. Well at at any rate I now have what I have done.

Lower ITM

 

Inside you see a few seam lines. Its looks like a obstruction. Its not. When you run your finger along it you feel nothing but straight smooth plastic. Its does not look that way but you can't feel a transition or gap valley at all. The Upper to lower is also matched up very well. No lips, no over hang and the same transition shape.

Plastic Upper ITM

 

TB




I thought I had some before pics of all 3 the TB, Upper nad lower Intake. I'll see if I can find them. There is a big different in Before and now After. Sorry I took so long to get back, I did not realize anyone was that interested at all. lol! I always love see engine mods others do here!

If there are any question let me know. I have appreciated all the help the IS guys have given me here. Thanks!!!!

 

TB Before Stock

 

But is any of it installed??
What's your opinion on routing hot water through the TB? I see no purpose. I think its only to prevent icing under 1 in a million conditions as by the time the engine needs heat there its too late from a cold start.

 

A few of my thoughts. Frist about the mirror or semi mirror finish port walls? On that intake lower, mirror would have been ok because there really is no fuel sprayed on it that would need help atomizing instead of dripping on the walls. But my objective on ports, is always flow/velocity, and shape. Not a shinny wall.

I plan to do away with the coolant going into the TB. I'm just going to put a bypass fitting in. Where I am and the fact that my GS is mostly garaged, I don't think I will see to many sub fuel freezing days low enough and long enough to freeze the fuel. I will get a few bottles of gas antifreeze just in case if to run through. The purpose of the bypass is to allow the TB to run cooler and deter Knock with the cooler intake charge air.

No I have gotten around to install as I had many things to do and prep before I could. I should have them all just about done by next week some time, to go to thee Dyno and get some ECU fine tuning on the Dyno dialed in to my Mods. I plan to get some Dyno runs in and some track time run numbers in when I get done. I have also sourced a set of heads that I plan to do on Stage II with very mild cams, maybe. But thats later down the road. I've run Nitrous safely on most of my Lexus builds, this one is a maybe, or not sure if at this point. But normally once I start? Who knows?

 

Just popping in here to comment about port wall finishes: regular ol' unladen air that's not carrying a fuel travels fastest down a polished pipe because the boundary layer shrinks and the tube effectively gets larger. When the air charge is trying to carry fuel, the smoothest you want to go is 80 grit on the port walls so as to maintain that boundary layer of turbulence that keeps fuel in suspension, instead of puddling against the walls.

Throttle body mods aren't going to provide much return until the chokepoint right before the transition into the #5 and #6 cylinder intake runners is opened up. Coolant through the throttle body will keep you from getting stuck at WOT while driving through severe winter weather that the car itself would not make it through. I don't think there's much to gain from bypassing that coolant line, but you technically are reducing the amount of heat that could get absorbed by the intake air...it just tends to move faster than it needs to rise in temperature. Polishing does, however, reduce the amount of surface area that can act as a radiator, though, so that's why my TB got attacked with the jeweler's rouge.

 

Yes its exactly what I already said about polished pipe, and fuel puddling.

TB Polish Mods can provide return with other matched mods. There are a million before and after dyno's and track time test of this of just the TB polished and lips and air flow cliffs impeding air flow removed that back up the gain with measures. A reduction of air intake temperature can also allow the ECU to see cooler temperature reading thus allowing advance and/or decreasing retarding. In fact the the 1st statement you made which is" travels fastest down a polished pipe" would in fact apply to the surface of the TB also. With that I plan to measure the before and after results.

Have you done a measure that validated no improvement? If you have please share. I would like to ask you some questions about the results that had nothing to gain that you stated? Thanks.

 

Just to recap, icing has little to do with cold ambient temps. Icing can occur on a 90° F day if the conditions are right. More often than not it's a factor of carburetors dispensing fuel that induces enough extra cooling on a warm humid day when the air can hold more moisture, thus leading to icing. The combination of low throttle blade positions creates a bigger pressure drop (more cooling capacity) than WOT. So it's partial throttle settings that are of greater concern. Adding fuel as with a carb, lowers the temperature èven more and before you know it, throttle plates stick. Warm coastal areas with high humidity are more prone.

As for the actual heat added to the air moving through the TB, it really has to be low to none, but every degree matters.

All piping, filters, air ducts ahead of the MAF likely induce more heat (from ambient and heat soak) than coolant passing through the TB housing.

 

I already understand why the coolant is run to the TB. If you research the Technical design objective and purpose you will find that there is lots of misinformation on the purpose. There is really only one reason it's done. In order to not derail a good thread that was started and degrade to TB and coolant, let stay on track. lol!

There was a request to see my work done on the TB and Manifolds. So I posted it up and explained why mine were done like they were. A head guy who has been doing heads on a flow bench for 36 + years, and does any Head from a Honda Civic to NASCAR Heads measuring flow air molecule with the latest high tech computer models along the way, was good enough for me. I have ported a few heads and other myself in the Garage, but I always send them off to a bench shop to finish. It's interesting to see your garage port job improved and matched if you haven't messed it up too much. Various porting of pieces canlead to some impressive power gains if performed properly. I gave up on probably won't do much things long ago, for having what does work, done correctly.