Goofaroo

I was looking for a BMW 5 or 7 series or a Mercedes E320 when I came across a 1996 LS400 in beautiful condition so I just had to have it. I have always admired these cars so I'm very pleased to have found one in good shape. It is a one owner car with 129K, a complete printout from the Lexus deal of all service history since new, always garaged, never been wrecked, white with tan interior. He was asking $6,950 and we settled on $6,300. It was about half as much as I was willing to spend so the "tightwad" side of me was very happy with the purchase. I'll post some pics when I get a chance. I just got it tonight and put about a hundred miles on it getting it home. It is fantastic on the highway.

I have never been a fan of V engines so this is a departure from the norm for me. I generally drive inlines so I was looking for a GS300 when I found this. This is one of the few V8 engines that seem to get respect and obviously they are known for their longevity so I wasn't at all concerned about the 129K miles.

My question is about the gas mileage and performance. I have never tried a performance chip but I am curious if anyone here has tried one on their LS with any success. I would like to optimize the fuel mileage if possible and any power increase would be fine as well but I don't want to have to switch to premium fuel to accommodate an aggressive change in timing.

Here is an example of what I am curious about but I'm sure there are numerous chips on the market.

http://www.gfchips.com/lexusls400.aspx

Any input would be appreciated and I look forward to spending some time here in the forum.

Cheers,
Andrew

PureDrifter

iTrader: (10)

lol "chip"

that's a $69 IAT resistor (that costs ~$0.02-0.05 in parts, no labor) and will do nothing but richen your fuel mixture.

ie-utter load of $#17.

so you want more power, but on regular gas? yeah no. the LS was made for premium gas from the get go so by running regular you are already losing power and some small amount of mileage if you are driving it on anything but a flat surface.

you need to search.

Raddison

From your original post it sounds like you're running it on regular...

...I'm praying I just misread, or you just mistyped.

deanshark

Man, those things make me laugh. Up to 60 more HP, oh yeah. Surrrre. Welcome to CL, you can get all the info you need by reading past posts and searching, it's a big help. Change your ECT sensor and you'll get improved MPG and a much smoother running engine. And do a tune up if it needs one, you got the service records so you'll know when the last one was. Don't think about a "chip". Don't run on regular gas, you want it to run correct and smooth, use premium like you're supposed to. When did the previous owner change the timing belt last? Or did he ever? Again, welcome to CL.

TrAPsTaR87

On your dash it clearly states in big yellow letters PREMIUM GAS ONLY if you want to keep your lex running I suggest you follow the yellow brick road

steve2006

I don't know if this applies to later models but for earlier versions there was a modified ECU available (MINES) which upgraded the engine mapping.
They do appear occasionally on ebay and are plug and play.

PureDrifter

iTrader: (10)

total ECU replacements are available from japan only and for the 95-96 are quite rare. new price is ~$800-900usd plus shipping/freight from japan (and core return).

python

iTrader: (4)

i think pure drifter meant to say welcome to the forums...congrats on ur newly purchased car and we hope u fine the car as enjoyable as we do..sheesh

Brandicus

iTrader: (6)

lol yes indeed welcome to the forums! please use premium gas though, trust us it just isnt the same car without it.

RA40

iTrader: (6)

Welcome to CL.

The inline 6's were wonderfully smooth but even though this is a V engine, it is a very nicely designed motor. Plenty of YT vids with modded ones.

As others mentioned, regular gas is . Premium, the engine is happy and will respond accordingly. Simple mods will help the performance like exhaust and intake.

Post a pic up...always nice to see clean LS's on the roads.

PureDrifter

iTrader: (10)

also,

this.

RA40

iTrader: (6)

PD comes off like this but for those us us who know him...

Goofaroo

You guys seem to like your premium gas! As for the "chip", I was just trying to explain what I was interested in trying to accomplish. I would never expect a $60 chip to be worth a crap but I was hoping maybe someone who has owned one for longer than the 24 hours I have owned mine would know of something that is a worthwhile mod. This car is 16 years old so I figured there might be some sort of an upgrade to the mapping that is beneficial. I assume that someone has already checked with Lexus and they don't have any factory issued upgrades available.

As for the premium gas- every import car I have ever had has specifically stated in the manual that they need what appears to be premium fuel. However, the fuel ratings in other countries are different from here in the states and I have only owned one vehicle that required anything other than the lowest octane available and it only required the 89 octane to prevent preignition.

I have put a couple of hundred miles on mine with 87 octane and haven't had even a slight hint that it was going to ping. What makes you guys think that these cars need more octane? As far as I can tell so far I am only going to dirty up the combustion chambers and pollute more if I run higher octane fuel.

By the way, it's nice to find such an active forum for these cars and I appreciate all the responses. So far I have a feeling I am really going to enjoy this car.

Goofaroo

By the way, I am trying to post some pics but having a tough time getting them to work. Here is one as a test and I'll try to post some more. Anyway, it is all original paint and the inside is as nice as the outside. I was very pleased with it when I showed up in Tulsa to look at it.

Hilux22RE

The real reason why we should be using premium is because of the compression ratio, or CR, which is > 10:1, and the newer they get, the higher the compression ratio. The number that is reference on the pump is the octane rating, not news, I know. In leman's terms, octane is the resistance to detonation. So let's say you take a mid 90's 350 Chevy, it's going to be 9.0:1 compression ratio. It will squeeze the volume in the cylinder 9x smaller from where it starts at bottom dead center, or BDC to TDC. What is important about this is that this is where detonation come into play. The Chevy engine will call for 87 octane, because the more volatile gas, 87 octane will not effectively compress more than (IIRC) 10:1 CR. If you were to use premium in the Chevy engine, you wouldn't notice one bit because the extra resistance to detonation isn't required. Now, for the Lexus V8, which I believe are all at least 10:1 CR, and with VVT-i, it's even more important as the compression ratio will change per firing cycle. If you were to run 87 octane in a UZ V8, the electronics will take care of any real issues with spark timing and fuel trim, so you'll never notice the difference. However, what you don't see is that the 87 octane fuel is actually combusting before the piston reaches TDC, because the fuel to volatile to handle the added pressures of high compression ratios. Likewise, race cars often using ethanol based fuels because they have higher octane ratings, which give them the ability to make more power, while reducing detonation, knocking, and ultimately failure.

I Forgot who Posted this on another Thread but i still give many thanks to that person!!