https://www.evolutionm.net/forums/sh...ing+knock+tune

Reminder of a useful previous thread on here.

 

Hhahaha 6th gear man you must be bookin lol

 

I did a 5th gear pull the other day.. the car is filthy stinkin rich.. the car is still untuned on stock injectors with a GT35r turbo running 11psi of boost with lame timing.. And the car is STILL faster than the car was with the stock turbo and variants I tested.. DLL reported around 380whp/370lbft torque which is up 30whp at this lame boost and tune.. Not very impressive for a GT35r at all, but impressive as hell considering I am running low boost with around 5-8 degrees of timing HIGHEST..

 

105 lbft/bar/liter if that is a 2.0. If you calculate out the VE with basic assumptions that is quite incredible... too incredible IMHO.

A few comparisons:
S54 3.2 269 lbft = 84 lbft/bar/liter
Stock Evo 289 lbft (IIRC) at about 1.3 bar = 63 lbft/bar/liter

 

Not sure if that was directed at me.. But my car is pretty highly modified, and these are the numbers reported by DLL which are roughly what a dynojet would report but generally a little higher.. Thats actually not an unusual number to get, but it was unusual for my level of tune in the state its in..

 

I don't disagree with the possible torque figure or higher, but at that boost level it seems extraordinary. Based on 2.0 liters and 1.75 pressure ratio, what volumetric efficiency do you estimate?

 

Not sure, but you were correct, I had my settings incorrect.. but it still produced close to the same output as my Evo did before the swap.. I am also going from a reading from a GM Map sensor, the Autometer gage in the car reported 15psi where the GM sensor reported 11psi.. FWIW the car is faster than it was before even at this level..

 

I reckoned depending on the assumption of BSFC as good as the best NA race engines that you had about 130% VE, which is considerably better than the best race engines. For reference, a Formula 1 engine is also about 85 lbft/liter/bar. It tends to be a limit of present (even race) internal combustion engine technology. Making power through revs is another matter. Big Garrett turbos can feel really nice at low boost as long as they spool up. So little exhaust back pressure, and the torque stays nice and flat. Sounds like a nice ride

 

Its a fun car, always has been, and I really didn't feel I sacrificed much, even at this low level of boost with the new turbo the car feels much nicer at higher speeds, and at lower speeds, the car isn't "Twitchy" plus my gas mileage went up dramatically (the one advantage of a few hundred RPM of lag) I'm almost always on call, so I didn't get the chance to install the few parts I needed to tune the car (bigger injectors and an upgraded fuel pump) so I have to go another week with the boost as low as it goes..

 

In comparing the levels of timing on a 8 to a IX, it is also important to access the effect of the MIVEC which works in direct relationship with the ign timing in adjusting the cyl pressure in the low and mid range tq curve

One of the reasons why I try and tune on the rich side is to attempt to minimize any knock that results from variation from tank of gas to tank of gas

When tuning, zero knock sums are desired and also a margin of saftey underneath the threshold when the "stock ecu thinks it sees knock" (knock count) for tank to tank variance

Remember often real knock is undetected by the stock ecu and also non knock noise is interpreted as knock - it aint perfect but the stock ecu does a great job with knock control

In the case of the car which is the subject of the thread, it would seem that your present tank of gas is a little lower octane that what ever you were tuned on.

If possible try some alternative fuels in your area and see if you can find a brand which can hold the timing without knock sum counts

If not, then simply lower the timing a degree in the areas where you see knock which should do the trick

One of the reasons which makes the stock ecu so great is the really amazing knock retard system which constantly monitors the tune and can pull back timing as needed to avoid detonation. When driving on varying tanks of fuel you should expect to pick up some knock counts when you get a weaker tank full.

If all cars were tuned so that they did not get any knock count ever they would be about 20 - 30 whp lower in whp than what most modified evos produce on dynos.

 

I did some logging on my VIII, stock boost and no knock....goota love evoscan

 

Factory have done a good job for when a boost hose comes off then

My JDM ROM is the same, the only det I could get was lift off between 3000-4500 RPM from high boost (heard with det cans and seen with knocklink), and I think one loud knock audible in the cabin at the top of 5th gear - just the once.

 

Haha you think that is extraordinary, hondas do it all the time. I see 2.0 liter hondas making 400hp on 11psi. I know it aint awd but still. I myself made 351 on 9psi 60-1 in a 1.8 gsr. comp 9:1. I mean his numbers maybe be slightly inflated but it is definetly possible.

 

I can definetly agree with what AL is saying, and even though stock ecu is good at detecting knock it sucks is that the stock ecu is so sensitive it seems that your car feels faster at times and slower at other times because of the knock sensor filter, which makes it to inconsitent. And it seems the only way around it is to eventually adjust the knock sensor filter. I have seen this because I loaded one map on my car made a pull and showed 0 knock sum. Stopped to eat 30 min later made another pull using same map all of a sudden I see some 1's on the log for about 4000-5000 rpm, so timing gets pulled. I always make sure I am at operating temp too before I ever lay into my car. That is why I am hittin dyno next week to play with knock sensor filter and tune my timing curve. My tuner always checks plugs after runs so he can see if any detonation. Hopefully all goes well.

 

I got knock today on my bone stock IX running 93