Lexus IS Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter #1
There seem to be more than a few people with strong engineering backgrounds around here so let me throw out these questions re chip tuning...

1. How's it work?
2. What mechanical/electrical/other risks does it pose to an engine?
3. Is it worth it for a 10% hp / 10% torque improvement?
4. Anything else worth knowing about chip tuning?
5. On a car where you swap out the original chip but keep it, any obvious give away if you swap it back in later that the car was rechipped?

Since there also seem to be a few lawyers and a few wannabe lawyers floating around this board...

1. Does chip-tuning void warranties?
 

·
Registered
Joined
·
11,902 Posts
Good questions if you ask me...but I am a moron so I can't answer any of them...I'd be interested if doing a chip swap is more cost effective than Swift Racing's ECU and Intake Mod...in otherwords what is the ratio for X dollars you get y% increase...which would come out as a better overall value?
 

·
Registered
Joined
·
3,221 Posts
1. The main thing they do is modify the fuel maps, timing control, rev limits, wastegate control (boost control for turbos), throttle settings (for cars with eThrottle), etc.
Basically there is a PROM with computer source code that gets rewritten. In the most simple case they change a data table which tells the fuel injectors how much fuel to spray at given RPM and throttle settings.

2. The main risks is that they will change the air/fuel ratio and/or timing such that under certain circumstances you may have detonation (engine knock). The software from the manufacturer tends to be very conservative so that your car will run well even in 110 degree weather at 12,000 feet. The chip tuners may make a chip that gives you a little extra power under most circumstances, but may compromise the ability for your engine to run well at extreme temperatures or altitudes.

3. If you don't ever plan to drive your car at extremes (towing a trailer up a steep grade over a hot desert mountain pass) then a chip mod may be a cost effective way to boost performance with minimal downsides.

4. It is possible that the chip could effect your fuel mileage or emissions system performance.

5. Many newer cars have "telltale" histories in their ECUs. If you played with the engine control ECU, who knows what "history" the OBD-II computer might keep. I can't tell you for sure, but it is possible that it could get "logged" somewhere.
 

·
Registered
Joined
·
3,047 Posts
From a Veedub stand point I can tell you that the computer does have a "telltale" history within it. My friend works as a service mechanic at VW and plugged my ECU to their computers. It told them exactly how many times I redline my car per day, my average gas mileage, exact mileage of the car, and of course if any modifications had been made to the ECU with dates.
Definently grounds for voiding the warranty.
I'm not sure how chips work on automatic cars but on a manual tranny you can over rev in many cases causing crazy stress on the engine. However the good thing about chips is the timing control and fuel maps, sometimes bring horsepower and torque to lower levels in the RPM band and add additional horsepower by modifying maps and timing like TEG says.

Oh yeah and becareful if you do a chip install yourself. If you aren't properly grounded you WILL FRY YOUR ECU and if Lexus' ECU's are anything like VW's, they are not cheap.

Originally posted by TEG:
1. The main thing they do is modify the fuel maps, timing control, rev limits, wastegate control (boost control for turbos), throttle settings (for cars with eThrottle), etc.
Basically there is a PROM with computer source code that gets rewritten. In the most simple case they change a data table which tells the fuel injectors how much fuel to spray at given RPM and throttle settings.

2. The main risks is that they will change the air/fuel ratio and/or timing such that under certain circumstances you may have detonation (engine knock). The software from the manufacturer tends to be very conservative so that your car will run well even in 110 degree weather at 12,000 feet. The chip tuners may make a chip that gives you a little extra power under most circumstances, but may compromise the ability for your engine to run well at extreme temperatures or altitudes.

3. If you don't ever plan to drive your car at extremes (towing a trailer up a steep grade over a hot desert mountain pass) then a chip mod may be a cost effective way to boost performance with minimal downsides.

4. It is possible that the chip could effect your fuel mileage or emissions system performance.

5. Many newer cars have "telltale" histories in their ECUs. If you played with the engine control ECU, who knows what "history" the OBD-II computer might keep. I can't tell you for sure, but it is possible that it could get "logged" somewhere.
 

·
Registered
Joined
·
33 Posts
Most of the time chip upgrades don't do much for non-turbo cars unless your engine is seriously de-tuned by the factory. With turbos, you can alter boost pressure and really get a big difference from an upgrade. Take the Audi 1.8T and the TT roadster--150HP in the 1.8, 225 in the TT with the esact same engine, only different boost characteristics.

I also agree with an earlier post that ECUs can be very expensive--10 grand or more in many instances. And yes, messing with the ECU on most cars will make for hairy warantee claims if something goes wrong--try making Lexus give you a free 10K ECU b/c yours "failed".

------------------
 

·
Registered
Joined
·
11,902 Posts
QuickVR6, that was a good follow on post. I am glad to see you coming around. People around here respect knowledge not just trash talking...which is why I have not gained anyone's respect just yet.

The really frightening thing is just how much TEG knows...
 

·
Premium Member
Joined
·
15,322 Posts
please take a second to do a search in the "go fast" forum for chip and you will see there are no chips for the is300 that will do anything other than waste your money.
 
1 - 9 of 9 Posts
Top