Horsepower?

[BillH2]

I have an 01 GS430. (3uzfe engine) In reading these posts, I assume that this car is one of the very few that can actually benifit from a K&N air filter. So often these things are purchased with the idea of gaining HP, when in fact there isn't a restriction in the intake tract.

What would be the issues if any, (besides noise) in removing the entire exhaust system, cats, mufflers, etc and replacing the whole thing with true dual exhaust system with turbo mufflers and crossover, retaining the oxygen sensors. (Assuming you lived in a place where there is no emission testing)
Thanks
Bill

 

[BillH2]

Anyone, or did I post this to the wrong forum?

 

[Lextreme II]

I think the exhaust opening wil help alot on hp gain, but slightly more noise....

 

[400ZED]

i would agree guite a lot of noise.
the HP gain would most likley be in the headers. that is just my opinion.

 

[BillH2]

It wouldn't be raspy, like a V6? Seems like if you used a couple of good quality turbo mufflers and a properly designed crossover, you could keep it managable. I wouldn't mind a little noise. If I want a LOT of noise, I will just crank up the Shelby. (the sound insulation consists of a little jute padding under the carpet)

Did anyone actually notice a gain by installing a K&N filter?
Thanks
Bill

 

[Peewee]

I doubt the K+N will give any HP.
You will probably loose HP unless you stop it from breathing air in the engine bay, ie, it needs its own cold air feed.

Toyota filters are very good themselves.

As for the exhaust, it depends on what headers are on the car.
If you have the extremely restrictive headers, you will maybe see 5-10hp gain.
If you have the nicer flowing headers, it may be more like 10-15hp.

 

[Lambo]

Exhaust gains

hi billh2, have a look at this site it may give a hint to what you could expect to gain http://www.clublexus.com/forums/showthread.php?t=102726
Regards
Lambo

 

[JBrady]

Bill,

If you have followed the power evolution of first the 4.0 liter 1UZFE and then your 4.3 liter 3UZFE you will notice that the 1998-2000 GS400 4.0 liter makes 300hp and the 2001+ GS430 4.3 liter also makes 300hp. A big reason for no power increase is a change in exhaust manifolds. While the 1998-2000 are not pretty and need help they are better than the 2001+ manifolds that went back to a single tube log manifold. Until the headers are complete I cannot say exactly what you will gain but it could easily be over 20hp. With a proper exhaust and headers I would not be surprised to see 40hp.

I would recommend reading up in the exhaust forum as there is a ton of good info there.

 

[BillH2]

Bill,

If you have followed the power evolution of first the 4.0 liter 1UZFE and then your 4.3 liter 3UZFE you will notice that the 1998-2000 GS400 4.0 liter makes 300hp and the 2001+ GS430 4.3 liter also makes 300hp. A big reason for no power increase is a change in exhaust manifolds. While the 1998-2000 are not pretty and need help they are better than the 2001+ manifolds that went back to a single tube log manifold. Until the headers are complete I cannot say exactly what you will gain but it could easily be over 20hp. With a proper exhaust and headers I would not be surprised to see 40hp.

I would recommend reading up in the exhaust forum as there is a ton of good info there.

I always wondered about the difference in displacement with no increase in horsepower rating. The exhaust system pretty much explains it. Headers will be a great improvement, when and if they are ever available.
An LS400 that goes 14.2's? I have to wonder about all of your victims, guys who are still scratching their heads wondering what the hell happened! "Did I really just get my doors blown off by an LS Lexus?"

 

[Peewee]

I'd say the tuning on the 3uz-fe is more conservative too.

Take a 3uz-fe, put on a nice custom set of extractors, tune it with an aftermarket ecu, and you'll have one very powerful machine.

This is of course, my own opinion, I haven't had the oppurtunity to test it.