Why Is It So Hard To Get More Power?

[Sc400 Tuner]

I recently purchased a 93 Sc400, and have been reading alot, and it seems near impossible to get any real power increases without the use of forced induction, Why is this? Ive been a mustang owner all my life, so I am somewhat spoiled by the plethora of aftermarket performance parts available. With mustangs you can get a fairly decent power increase from just intake, filter and exhaust (~30-40 hp), along with a dozen other free horsepower mods. Is it just that these 1uz's breathe THAT well from the factory? I dont see ANY way that could be true by the looks of the microscopic breather to the air intake, OR the labrynth of exhaust parts in these cars. (I screamed :o when I saw BOTH headers fed into a single 2.5" cat!!!!). Is there even a performance intake available for these cars? It seems there must be a way to get a 30-40 hp increase without massive high dollar work(radical cams, forced induction, raised compression, or anything that requires new internals, etc..). Are they just cammed ultra conservative? Any explanation or direction would be greaty apriciated. Im in a state where I can cheat on emisions, and considered scrapping all 3 of the cats, but from what ive read I loose low end power by doing that!?!?! Is that correct? Any direction/comments/suggestions are greatly appriciated. Thanks! :D

p.s. Awesome forum guys!!!

[AWJ]

The exhaust system has been opened up in the past by others. In addition to Peter Scott's page, please look at the Lextreme website. If you only want 40 hp then get a custom exhaust along the lines they mention - you discuss a true cold air type set-up for intake in your other thread wich may or may not help. I don't believe they do much after having used them in the past in various cars. It has been proven that the accord piping defeats the engineered design of the oem piping losing low end torque for a slight gain in top end hp. With a modified computer and torque converter - this may improve performance a little. For the money spent on that stuff - I'd rather just put it in a turbo or liquid plasma tv. There is no such thing as free power. A 50 shot will do the trick for the cheapest price. Toyota motors (at least the 1uz and 2jz) are extremely well designed pieces. Porting or upsized throttle bodies are not going to do much if anything. The 1uz throttle body is huge already in it's oem form. Honestly - boosting is the way to go for the money. They have been stroked in the past with Tundra cranks and custom rods and all that jazz. Still at the cost of doing that - the gains are below that of boost.

For your questions on the exhaust, I don't see why removing the cats will lose low end. Backpressure is bad. See Lextreme's page. The cams are decent - but I don't know the duration. Perhaps some more timing can be added - I beleive that is what the SRT ecu's and stuff will do. I would suggest following up on the info on that page there. Starting simply with the exhaust, torque converter and bfi. Then either consider n2o or a turbo system. But you will have to pay to play. Good luck - please share with the forum any proven findings. I think dyno charts are the best way to document improvements.

[jzz30]

the reason why you loose bottom end when you blow off your cats is that back pressure in you r exhaust creates more bottom end torque. when you modify an engine most of the time you have to loose to gain. in any case you have to remember that this engine was originaly made for the LS 400.....a luxury car made for confort and reliability. not a race car right? have you ever heard the story that toyota, when revealing the first production LS400 to the press built a champagne glass pyramid on the hood of the car and started the engine.......what happened? not one fell showing everyone how smooth the engine was.

[Lextreme]

I agree with AWJ. You have to pay to play. However, it will cost a lot more to pay to in order to play with Lexus. Here are my answers to your questions:

1. Demand and Supply: Lexus owners are into luxuries and smoothness of the ride. Not loud, rude horse power like the mustangs. Its just not a muslce car. The demand for performance is just too low for any medium to large company to invest time and money in.

2. The V8s are so well design and made, space for Forced Induction is very difficult.

3. Money is the last factors. Now the older lexus are affortable to younger buyers. However, young buyers are into looks. Therefore, most of their money are allocated to Rims, Body Kits, HID lights and Audio system. If the above is priority, go fast money would be gone.

The above three factors are what i have been seeing. People want go fast stuffs, but not willing to pay for it. However power is expensive. You have to willing to pay to obtain HP.

[Sc400 Tuner]

Thanks for all the replys guys, shorty after posting I ran across Lextreme's site, WOW! awesome site!

[AWJ]

Lextreme is right.

About exhaust. Backpressure is always bad. Backpressure causes reversion wich translates directly into poor efficiency, detonation, and a failure. No system is without backpressure but an adequately designed system will produce as much vacuum as possible to get to a conditon referred to as scavenging.

Click here please

[Throbblethorpe400]

Approximately how much horsepower do cat back exhaust systems add?

What about with the cat(s?) removed?

[AWJ]

Not much. If anything. They look good though. :D

[Sc400 Tuner]

Exhaust is my next move, and my plan was to scrap everything from the front cats back, ( I hear they actually flow pretty well, so ill let the stock cats live for now), and have an Xpipe at the junction where they connect into one pipe on the stock exhaust (why the hell they do that?!?!?!). Then just piping all the way out to 2 can mufflers at the end. How loud would something like that be? could anyone suggest a type of muffler with good flow, that wont be deafening loud, but still have good tone? Thanks for all the advice guys.

[jzz30]

one person i know has flow masters on his and it looks stock if you dont look carefully and its not loud at all but you get that nice 6 cylinder growel you wont hear it coming but if your close you can tell its not stock