High Gear, Low Rpm Ping In My Car

[winstonusmc]

Anyone expriencing this? My head is shaved about .4mm and it has about 190psi in all cylinders, so I am guessing 9.5/1 compression ratio. Does good on the upper RPM range, but at initial take off or going up a hill at low RPMs, it pings a little when hot. Other background is thie injectors were just changed, happened before. Also, I have a wideband O2 sensor and it stays pretty steady at 14.7 during the pinging. It has been timed a few time since I noticed this. I am thinking two things, bad TPS or too much timing at low RPMs. I have tried to remove timing from the ignition map at low RPM but I am tuning blind as I dont have access to a map tracer. The stock advance is around 45 degrees at low load. Should be less with higher compression. I use 93 octane fuel BTW.

[Pattygtst]

Get the tune checked and you should only use 98 octane.

[TiTAN]

if he is using 93 i assume that he is in the USA? if so that's equivalent to our 98.

[Beer Baron]

dude, change down a gear! labouring your GTR up a hill in 5th at 60km/h and 2100rpm witb 100% throttle and high load is always going to be bad for it and make it ping. you could probably tune around it but these high load conditions are always bad news. the easy solution is drop down a gear or two. it is a sports car after all and quite a peaky one at that. GTRs aren't giving you their best at anything under about 4500rpm. sure cruising is one thing, but labouring it up a hill is just bad all round.

[SKiT_R31]

Check your ignition timing, you might need to wind it back a couple degree's to counter the extra compression, but as said before, use a lower gear, its much better for your engine.

Edited November 20, 2009 by SKiT_R31

[winstonusmc]

The thing that I really worry about is the normal take off like from a stop sign. I always drop it down a gear to keep it above 2500rpms going up a hill, but my wife likes to drive it like a V8, 1200rpms chugging up a long hill. She gets mad at me when I correct her. If I drop back timing it will be in the ignition map, not on the CAS.

[blind_elk]

but my wife likes to drive it like a V8, 1200rpms chugging up a long hill. She gets mad at me when I correct her

If she won't drive it like it should be driven, don't give her the keys

My experience is that RBs like fuel to get rid of ping.

[MBS206]

If she won't drive it like it should be driven, don't give her the keys

My experience is that RBs like fuel to get rid of ping.

Damn straight... I'd rather an argument with the missus not being allowed to drive it then a 10G rebuild fee...

[JonnoHR31]

what ecu are you using?

[WizardBlack]

if he is using 93 i assume that he is in the USA? if so that's equivalent to our 98.

Actually, some parts of the USA only get 91 octane or less (particularly People's Republic of Kalifornia). Likewise, during winter months, the additives can get a bit heavy; further reducing the octane of the fuel.

[Cjmartz2k]

He's in Okinawa (japan) and running japanese high octane. That's a little silly saying "just shift gears". It shouldn't do that if it's properly tuned, which is what he's trying to do. He's using a rom tune that he's doing himself. What he's asking (I'm guessing) is what else could make it knock. I still think it's just timing and more needs to be pulled out, but I understand that's hard to do with out a map tracer.

Winston, what's it knocking? Also, isn't it kicking itself down into the "knock maps"?

[winstonusmc]

Yes, Chris is correct in saying that I am running Rom tuned R32 GTR ECU. The fuel that I use is the equivelant to US grade 93 Octane. I am not sure if they use a winter grade here in Okinawa, but it has been pinging for a while, maybe August.

I am going to borrow a Map tracer from Casey sometime to use for other tuning purposes. I will just log the area of the map at that time that pings. Funny thing about the knock map is it looks the same as the normal map. Datascan should also tell me if it goes into the knock map anyway. I am going to just pull a bit of timing off the bottom of both Maps and see what it does.

[winstonusmc]

An update on this topic. I always hate an unanswered problem when it falls by the wayside. The problem is all but gone now. I have cut almost 6 degrees out of the first 3000rpm of the timing map. I get a ping every once in a while, but its about 99% gone. Now the base timing is 15 degrees. This was adjusted in the map, not by turning the CAS. Now it spools a little better too, extra bonus. I think in the mid range, spool can be had at the sacrifice of power by retarding the timing. The trick is to find the proper medium in between spool and power. I am posting up the map to show how much timing I had to remove. Geen is stock RB26, red is my map.

[JonnoHR31]

more timing will bring the boost on sooner. retarded timing will make it come on at a lower rpm but the car will be much slower.