LB Lex

Have you ever looked inside your intake manifold and noticed a tube going across the center? It is for the egr, but if it was not there, it could free up some hp especially at high rpms. Has anyone removed or modified this pipe yet keep the egr working? I tried grinding it down, but brass (or whatever it is) is really tough.

On another note, there is a vacuum module that opens the secondary intake runners under full throttle. I modified it so that the secondaries are partially opened all the time and this increased low range torque (noticably more low rpm pull).

blue wax

yo 93 lexo,

how did you do that ???

thx

LB Lex

On the lever that attaches to the intake (on the plenum that connects to the "V" shaped top portion) there is a stop which the lever rests on when the secondaries are not opened. I drilled a hole and inserted a screw so I could adjust how much it is open.

What I mean by "noticeable" is that the difference could be noticed but the increase in torque is not significant. Maybe a 5hp increase, but that is better than nothing.

marcus

93Lexo... last night I tried what you did with forcing open the secondary throttle ???? and I cannot believe the difference it makes off of the line !!!! It is an incredible difference... How much have you opened your throttle? I opened mine about a quarter of an inch and I am now watching the gas needle (nothing accurate) for now. I am assuming that more air means more gas to maintain the correct air-fuel mixture. I see that this modification might answer why our engines are not that fast off of the line... until now. I think you are too modest.

2Lexos

anybody got pic of this mod? lets see what everyone is talking aobut please.....

marcus

I have an inexpensive digital camera and I will attempt to take a picture after work. If I cannot obtain a closeup, I can at least point out where this vacuum operated throttle plate is located. I have always wondered what this was for.. I do not have a shop manual.

blue wax

I think that the ETC does more or less the same,
so just put it on..... and VROOooarrrrrRRR....... of you go

lol

yezzzzzzzz

Pianoman72

I don't notice any difference at all with ETC on. I think the car shifts a little harder but that's it. I leave it on all the time.

LB Lex

Marcus, just like you, I opened it up a quarter inch. I experimented with a larger opening but it did not good.

I am glad to share this mod because I am sick of hearing stories about lesser cars beating our cars up a freeway ramp or from stoplights.

Also, try replacing the air intake resonator (that black plastic box thing between the airflow meter and the throttle) with a three inch diameter pipe...it increases the top end power.

SoCalSC4

Sounds like the GS has something like the T-Vis on the normally aspirated 1600cc 4-AGE powered MR2s and Corolla GT-Ss... The MKII MR2 Turbos had it as well.

You guys must know something Toyota doesn't... I am VERY surpised that this mod frees up any power. In fact, I suspect it hurts torque at lower RPMs. Guys have tinkered with changing the opening RPM 'trigger' point on the 4-cylinder Toyotas, but from what I've heard, torque is always decreased...

-but more power to ya!

marcus

Here's my picture showing the location of the throttle arm, for lack of a better term. You can see I mickey-moused this as I did it late one night. I used a piece of wire to hold a 1/4 inch nut between the arm and the "stop". This effectively holds some secondary throttle open 24/7. I am still amazed what an improvement this has made off the line. As far as a change in gas mileage, I am not sure if it affects it negatively enought that I will remove it. I LIKE THE EXTRA POWER.

Pianoman72

Looks like a cool mod. I am going to try it. Forgive my ignorance, what exactly are we doing here? What is SoCal talking about? Sorry, I'm lost.

SoCalSC4

Okay, I'll have to go out & look at my brother's GS3, this is not really like the 4 cylinder set-up at all.

The 4-AGE Toyota engine (and a few others) use TWO intake runners per cylinder. Below 4400 rpm, one of each cylinder "runners" is closed to increase gas velocity on the other runner and promote swirl in the combustion chambers.

Depending on load and rpm, the secondary runners open at 4400 rpm, increasing high-end power. Works like a double-barrel carburetor. With minor intake mods (drilled airbox) you can really hear the difference when they open, but the power increase comes mostly from the secondaries opening, not the modified intake.

Looks like the Lexus has something similar, but it is perhaps a single plate in the intake manifold upper plenum, whereas the Toyota engines I spoke of have the plates at the bottom of the manifold, right near the fuel injectors.

LB Lex

Marcus, thanks for the pictures. It is hard to explain this without pictures, but I don't have a digital camera.

Another tip. Sometimes the throttle body gasket supplied by Lexus is too large and should be grinded down so it doesn't block the flow of air. I also matched the throttle body with the intake by grinding it. Now the whole intake path is smooth.

marcus

93Lexo.... Thanks again for this mod.... It does not appear that there is a significant lowering of mileage since I did this mod. How about you ??? You mentioned earlier about removing the black box... days after I bought my 93 GS300 I drilled several holes in the box-shaped part to let more air in.. I have done something similar to all of my past cars. I drilled too many holes and the engine kept stalling. I then began covering holes until I found a balance where the engine did not stall or drop in idle RPM... Maybe this is similar to what you did. I realize this fools the air flow sensor, but mileage has never been compromised. I am going to disassemble the intake manifold sometime and check out the gasket situation. I have a Dremel tool and grinding stones...THANKS AGAIN.. This mod is incredible. Marcus