Hp limit

**kiltjim** · 07-05-2005, 01:53 AM

Originally Posted by lostreception

very interesting ida but unfortunatly unless your runing linux of some real stable os in there i wouldnt even venture to have my car computer control anything OEM related

No, no... All that is needed is that a computer being on, and maybe controlling the resistance across some O2 sensor or something, and only when the ignition is started. After its started, the ECU should go into automatic mode, and then the existence of the computer shouldn't matter, am I right (assuming the O2 sensor, or whatever it was controlling went back to normal)?

**0l33l** · 07-05-2005, 01:57 AM

Originally Posted by kiltjim

No, no... All that is needed is that a computer being on, and maybe controlling the resistance across some O2 sensor or something, and only when the ignition is started. After its started, the ECU should go into automatic mode, and then the existence of the computer shouldn't matter, am I right (assuming the O2 sensor, or whatever it was controlling went back to normal)?

Improper air to fuel ratio = bad for engine. You'd probably get a check engine light if you did that.

**wi77iam** · 07-05-2005, 06:55 AM

If you had a Subaru, you could get an ECU management tool like the AccessPort. It lets you upload new maps to the ECU. There are different maps for different modes - race, economy, valet, anti-theft. These basically vary the amount of turbo boost available, which changes the hp.

**DavidL** · 07-05-2005, 10:02 AM

Your not going to get this functionality with the base level tools and ECU access that is routinely available. You would need to change flash parameters to limit the amount of power available. You would NOT want to do that by altering anything with o2 as that will cause an engine problem (lean or rich related issues) and will cause a fault to be set.

There are lots of liability related issues that can be introduced here and less than proper execution can be hazardous to driver health.

Some less intrusive methods would be limit turbo boost max (if turbo) - like above poster mentions. Also, limiting Rev potential with a soft rev protection. Decreasing ignition advance in high rpm / load conditions. Etc. These are usually software controllable on a modern EFI vehicle, but not accessible via a common OBDII type scan tool.

**Moneyfink** · 07-05-2005, 10:08 AM

I'd give them full HP for acceleration, but a top speed limiter at 68 mph, but that goes down when high lateral g's are experienced. The G thang is about windy roads

**fantomas** · 07-05-2005, 10:35 AM

if you don't trust your kids and wife that much, don't let them drive your car

i've never gotten into an accident while accelerating with all my power, i have however, had to slam on my brakes and rear ended someone, had to slam on my brakes and hit a guard rail to avoid a drunk that slammed into said guard rail.. and i've been rear ended, which, unfortunately, i could do nothing about.

neat concept, though...i wouldn't exactly use it for the sheer nature of limiting the hp, but rather proof of concept. anyways, as mentioned before, us subaru owners can use the cobb access port

fortunately, volvos are safe cars.

the only thing you could do without constantly reflashing the ecu is log the information coming off the obd.

**Mechanic** · 07-05-2005, 11:51 AM

There is a very simple solution to this, its called a real time in-circuit eprom emulator(~$200). You can write code to it anytime you want to, even while you are driving. I have a system that employs one in my turbocharged 3100 Fiero Formula. It takes about 3 seconds to flash the entire PCM code, and I can change boost levels while I am driving via voice command (the emulator allows for individual code address changes that are close to instantaneous). There is also a security version of the code which is flashed when I park the car: will not even permit the engine to start. This is on a General Motors OBD-I platform, so I can change ANY aspect of the PCM code that I wish. It also has a pocket PC interface, which allows you to change the PCM code remotely via bluetooth or WiFi.

I am the only one who drives my car; single, no kids, pets do not have drivers license yet.. but I do have valet mode code in case I ever need to let an attendant move the vehicle.