i have been tuning my evo for 91oct all my 3erd gear logs have 0 knock sums and no timing being pulled but my question is the following when i pull my car WOT starting from 1st gear all the way to 4th gear i do get knock on 3erd and 4th gear my knock sums go up to 5 and it pulls like 2degress this only happens by redline 7000rpms plus so what could it be? iam confused
thanks
the only difference i see i my logs is that my coolant temp raises to 200 deg as compared to the 3er gear logs whick at most hits 182 deg could this be the problem?
do i leave my map alone or do i take out more timing?
thanks

 

did you check the load area.... every gear is going to be a bit different..

 

yeah the load area is a bit different but it always stays on the same colum which is the 160 it never passes 180 load stays between 160 and 178

 

It is a good possibility that your intercooler is getting heat soaked. The coolant temp raise is normal, and I have seen many FMIC's heat soak to the point that the ecu pulls timing/sees knock from a 1st - 4th gear pull if ambient temperature is hot enough.

Kyle Deiwert

 

Are you sure about that load value? It seems a little bit low. How much boost are you running? Also, what is your AFR? Maybe you are running leaner in the higher gears. AFRs do change slightly between gears.

l8r)

 

its the smae load and the afrs in 3er are 11.0 and on 4th gear they go to 10.7

 

heat soak doesn't happen that fast... and the fact the higher the gear the richer it gets to compensate a little

 

It's pretty simple, if you're doing a 1st-4th gear pull, you're above 4.5k rpms the whole time putting a lot of load (heat soak, etc) on the engine over an extended period of time.

One third gear pull isn't really going to heat up the motor much. It's like doing a 100m sprint versus 400m sprint.

 

so where do you tune cause i see that in the night i dont get knock my intake air temps drop to 83 while at noon i see intake air temps at 95 also coolant temps are lower at night
so what would any of you guys do cause the way i see things is that if someone is being tuned at a very cold day and then a couple weeks you run the car again on a dyno but that day is hotter the tune will be off? i know the ecu has to compensate for the changes but mine isnt doing it

 

Well.... you can tune for whatever the current weather conditions are, or you can tune for worst case (hot weather, road course work), and it should never knock in better conditions. Tuning for current weather conditions means... well, you'll be tuning all the time.

A drag racing tune can be a lot more aggressive than a road course track car tune. A drag race only lasts for a fraction of a minute. Tracking your car involves full throttle for many many minutes. Things get very hot after 20 minutes of full throttle. In a drag race, your coolant temps might be 170, oil temp somewhere around there.

In a road race, your coolants temps can be 220 with oil temps hitting 300. So basically, your motor is going to be LOT hotter which makes detonation much more likely to occur.

So think 100m sprint versus a marathon. Sprinter = really strong, fast, goes over 20mph. Marathon runner = lean, lightweight, 13mph average speed. Sprinter tries to maintain 20+mph for a half mile and they blow up

There's a few hills/mountains near me that I can go and really push the car uphill for somewhat extended periods of time. Not as good as using a real road course race track... but it's not too bad.

If you can only tune in 'good' weather, you can back off the boost and/or timing a little bit for warmer weather

 

You absolutly can get heat soak, or at least significantly increased temp, during a single 1-4 gear pull.

From David Bushur's EBAY IC test (only 4th gear pull, not even 1-4)

"Air temp after the intercooler at the start of the pull, 62.60 degrees.
Air temp after the intercooler at the end of the pull, 122 degrees!!
That is an increase in air temp of 59.4 degrees in a single gear pull!"

And this is with an Ebay IC, which may or may not be better than stock.

This increased heat can make the car more likely to knock. Of course the knock could be caused by other factors but you can not rule out heat soak.

 

few things. You can be knock free with a 3rd gear pull, but see knock in 4th. There is more load on the engine in 4th grear also the pull takes longer as well. This will make the engine more knock prone and more heatsoaked.

Your AFR's will get richer the higher the gear you are in. Make sure you are tuning you AFR's in 3rd gear. This will make sure you don't run too lean 1-2nd, and not too rich 4th-5th. for instance, if you are tuning for 11.1:1 in 3rd, 1st gear will read into the high 11's, second will be in the mid 11's. 3rd will read 11.1:1, 4th will be in the 10.9-11.0:1, 5th will be in the high 10's.

Even if you don't have knock in 3rd, and you do a standing start race, 1-2-3-4th. You will notice, 1st gear might not have any knock, but it's very possible knock will occur in 2nd, maybe a few counts. once the knock gets going, it's hard to stop it, even when the ECU is pulling timing especially during a hard run through the gears. Once you get into 3rd/4th, the engine/intercooler will be extremly heatsoaked. This exaserbates the knock issue. This is why it's very important to tune ignition timing while extremly heatsoaked. THis is easy to do on the dyno, especially on a summer day in a shop with only a fan blowing into the intercooler/hood. This insures that most cooler conditions will be knock free.

This also shows why intercooler effeciency is so important. There is very little we can do(within reason) to keep coolant and oil temps down. But intercooler effeciency is easy. I don't have any hard numbers on the stock intercooler, but i do believe it heatsoaks fast and stays hot for a good while. A switch to a good IC would be a good move, especially if you live in very hot climates, where there are very high ambient temps. This will help keep knock under control and will actually allow you to run a little more ignition timing safely. Also, more boost safely as well.

CJ

 

i think thats the way to go get a better intercooler and maybe a ralliart thermostat should help things cool down cause where i live is a very hot climate

 

i get close to the same thing. except when i datalog in 3rd i will get no knocks at all, but when i go into 4th i will start knocking but it tapers off. like its a boost spike or something,