S13 Slide said:
hook up a timing light to your motor and rev it up, even at a certaint rpm the timing is jumping around to find the best degree, now unhook your knock sensor and see what happens....the ECU goes into safe mode and runs the timing retarded so theres no chance of knock, also loss of power, that was one of my ECu codes that came up along with my TPS and CTS i fixed all 3 of them and wow the differeance is HUGE.
Trust me the ECU dose detect Knock. how else do you think the S2000 2.0 Liter produces somewhere around 240hp?
Wow you seriously didn't read what I said did you.
LIKE I SAID a ECU has predetermined parameters. If you look at a map in the ecu you'll see the timing table it specifies what amount of timing will be at that parameter for example at idle you might get 1000rpms x 34kpa will have like 39* advance timing.
As for the timing jumping thats called Interpolation. The reason it jumps is because youd have to a have a big ASS map in order to have it in one location. If you ever looked at a tuning software while tuning you'll see the point on the map where it'll specify where the motor is at, it fluctuates because the ecu determines other factors like engine temp, air temp etc etc. The motor will never stay at for example 2354rpm it always bounces so the ecu usually changes every 250rpms or less depending on how good the code is, so thats why it changes, not because the ecu is continuing to advance for best performance.
But the predetermined parameters the ecu will not go over that, unless you have a shitty code than your motor will go bye bye.
ok what does removing the knock sensor have to do with anything. I told you ususally after 3000rpms the ecu doesnt listen to the knock sensor because after 3000rpms the motor produces so much noise that it would constantly retard timing. And if your under 3000rpms and remove the knock sensor ofcourse it will retard timing. So your point is invalid.
Again reading comprehension is king.
Here are some links to disprove you guys and back me up.
http://www.state.mn.us/mn/externalDocs/Commerce/Gasoline_Octane_Facts_102902052227_OctaneFacts.pdf
http://auto.howstuffworks.com/question90.htm
http://www.co.suffolk.ny.us/webtemp3.cfm?dept=3&id=2049
http://advanceautoparts.com/english/youcan/html/ccr/ccr20030201fs.html
David A said:
Exactly the reason most cars which run 93 will yield bigger MPG compared to a lower grade.
Also, running a higher octane will allow for more HP...why else do you think high HP turbo cars run race gas?
Anyway, Nick, I didnt' read all of the thread but if I had to take a guess at why you are having problems at idle I'd say check your MAF and see if that is the problem. All you need to do to check is disconnect it, cover the port and see if the car will run better at idle...this is the only method that I really know of other than visually inspecting it...
Let me know if you want some help...I'm free all weekend.
I'd also say run that injector cleaner through anyway...
if you look at the links I provided you'll see that higher MPG with higher grade gas is a Myth. Fuel Economy is based several factors not just the gas.
The reason why High HP turbo cars and regular high hp N/A cars need high octane is because Turbo: compress air and pack air in the combustion chamber so if your compressing air into that chamber, and the motor compresses that air more on the compression stroke your heating the air up more which will cause detonation so you run a higher octane to battle detonation. N/A cars use a higher compression ratio for the pistons thus compressing a lot of air on the compression stroke which creates a tremendous amount of heat. Have you ever seen how a diesel engine works, it creates power power by igniting the diesel fuel with compression, and diesel engines have a high compression ratio usualy 17.7:1.
So no High Octane does not give power, it just allows you to run higher compression and advance timing which is where the power comes from. The higher octane only allows you to achieve that because it doesnt detonate.
I'm not trying to come off as an asshole I'm just trying to educate you guys.