liazon

iTrader: (1)

the srt website, shown below, quotes a 30 horsepower gain for adding thier intake/ecu combo!? who can you really trust ya know? also, does the ecu require additional installation and if so, is it about as easy as installing the air intake?
http://www.swiftracing.com/index2.html

RacingAristo

yes, you need to solder SRT's ECU. There is no plug n play ECU available for 2nd GS.

gs400tx

I think I would be more inclined to pay 300 bucks for 10hp and no wiring harness work than 550bucks for 20 hp and something that could affect longterm operation.

Specifically, the part number is
http://www.martelbros.com/

KNN 57-9011
FIPK; LEXUS GS400 V8-4.0L, 1998-2000

You Pay: $ 309.99

///MDex

Obvioulsy, there are several different takes on it. The idea of doing an intake without an ECU seems half-*** to me; JMHO

Like mentioned above by manaray, the stock ECU is already at the ceiling at ideal OEM parameters, so you're throwing $ away if you don't get an ECU matched to your aftermarket intake....

gs400tx

Camaros and most other vehicles tend to get 10 to 15hp with just a intake. Sounds like its a good initial mod to me regardless of platform. OBD2 and current emission regs prevent any significant HP increases even with an ECM mod. Most cars are very close to emission limits at wide open throttle.

Plus, modifying the ECU/M on a car that does not use the ECM for every aspect of the car is one thing. If you get it wrong it probably won't be to much a problem to replace (or prevent the operation of the car)

I don't really look forward to the idea of having to replace a $2,000 ecu if something went wrong in the soldering process (or after).

An extra 12hp is not work the risk to me personally. When I think about how many times I needed an extra 12hp, I can count them on the fingers of one hand.

///MDex

I don' think you can compare the Lexus engine mgt with a camaro . Thats why mods are so expensive for these cars - depth of complexity. ie. no chips, or piggy back ECUs readily available like for the ODB2 or 1 systems, like BMWs right?

The ECU under the hood doesn't control everything. The tranny is controlled seperately, but I know what you are saying. The install: that's why I had a professional do it (SRT, who can do it with their eyes closed); even though its a breeze to do yourself.

But yes, I will agree that an intake is a good initial mod. My purely spreculative guess would be that cars like the camaro and similar builds have a larger buffer for bolt on HP availability.

Only one hand? Can you not count any higher? J/K guy We all drive differently for sure. I just like having it. Its really a subjective level of comfort and confidence in a mod - I don't consider an intake highly volatile.

I just passed this along originally because I know we all find different mods appealing - and because I saw it on a GS4 on TV

I can agree to disagree

gs400tx

I don't think it comes down to what mods cost what on which car. Its just as simple as can the engine take advantage of extra airflow without some type of other optimization (timine or fuel changes). In just about all cases, the answer is yes. Noise reduction will often require the factory air-intake to be much more restrictive than it need be.

Quote:

The ECU under the hood doesn't control everything. The tranny is controlled seperately, but I know what you are saying. The install: that's why I had a professional do it (SRT, who can do it with their eyes closed); even though its a breeze to do yourself.

To my knowledege, the security system, traction control, probably the audio system , all have some interface to the ECM in the glove box. I think the trans is also controlled that way. Put it this way, when I got the ECM upgrade for the improved downshifts, they changed the box in the glovebox.

As you indicated, the install went with out a hitch.

What happens 3 years from now when the car has a fault and the dealership can't find out why? They could very well say that they will not be able to fix the problem without a replacement-unmodified ECM being installed and that would be the end of it. It might be something as simple as the doors not unlocking or something as complex as it not starting.

My luck is such that I can't afford to take the chance.

JBrady

Manaray, glad to see that you are looking for answers rather than just posting your opinion. Never-the-less, I must respectfully disagree with your source. It would be a HUGE design error for ANY car to be delivered with NO allowance for additional air flow. I would be SHOCKED if Lexus didn't have a safety factor (this is why it is critical).

Now, how MUCH more air MASS can the factory ECU account for? I can not say but would guess 15-20hp. This is ONLY around a 5% of the engines rated power.

A GREAT site for learning about real world changes and power increases for the 1UZ engine is http://www.users.bigpond.com/pgscott/

Also, people get caught up in PEAK power increases. You can add say 25hp to an engine at say 4800rpm but end up with the SAME peak power at 5600rpm. This engine would have MORE power through the USED RPM range when accelerating and therefore be FASTER than the other one. BOTH would have the same PEAK power but would perform differently! Think about a torque converter upgrade. It does not improve peak power but allows MORE power during acceleration and therefore makes the car FASTER. That is the goal... right?

///MDex

I had the same TSB done - that is the tranny ECU. The 'other' ECU is under the hood, which controls all the funtions you named above.

When diagnosing an issue, there is a plug under the hood, similar to an ODB port the techs use; they don't hook it up directly to the ECU.

I think you're missing the point on the mods / cost relationship. I'm not going to begin an economics lecture.

I've grown tired of bickering about this. I will enjoy my car; I imagine you will enjoy yours.

Happy Holidays.

RacingAristo

Even KNN's intake is expansive compared with RMM, RS Akimoto and Weapon R. Weapon R is around $210ish.

gs400tx

with the exception of RMM (and it does not appear to provide much improvement at all depending on who you talk to).

All the tests I have seen quoted or referenced here have not provided any real conclusive results.

I think K&N does have somewhat of a repeatable and known track history on making bolton air-intakes that provide a slight performance increase.

RacingAristo

granted, RMM's intake may actually reduce the hp. There is a dyno on WR's site regarding their intake on GS400.

Manaray

JBrady - Well I just finished talking to him on the phone and here's what he said...

He said from experience (he has experimented with various intakes modifacations), the ECU's will not give the car more power simply because you have more air intake. While the ECU does protect against the car running too lean, it won't give you anywhere near 5%...he said the difference wouldn't even be noticable.

If the ECU detects too much air intake, the engine will simply die. And resetting the ECU will set the "curves" at "baseline". Nothing more. It will not "learn" to pump in more fuel...it will only pump in the preset MAXIMUMS in the ECU.

Mo? Leo? Anyone who has first hand fiddling with the ECU should be able to give us more info as they should know what the stock ECU maps are...anyone? anyone? Bueller? Bueller?

If anyone is going to do a "before" and "after" dyno with an air filter (with no ECU), please do the "before" test with a BRAND NEW clean stock air filter...the numbers are skewed if you do it with a dirty air filter....

DevilDog

Tranny ECU???

The engine ecu under the hood controls the trans also. What ecu did you have changed???????????

///MDex

Apparently the same one as gs400tx - is there one in the golve compartment or that region?

Are the ECU locations and control setups the same for the GS & IS?

My dealership told me that they replaced another 'board', if my memory serves me correctly, but not the full ECU uder the hood. If it was the full ECU under the hood, I imagine I'd have to do a little more convinving that what I did since an ECU swap can't be cheap for the dealership.

I could care less where it lives, but the TSB they performed worked on alleviating my hesitaton at mash throttle - before my SRT goodies.

Maybe this is a technicality - maybe its not called an ECU/M - what is it called? Do you know?

Cm'on Master Tech - hook us laymen up with the 411 on the procedure .