Timing and EGTs
 

hello all. ive got a question i have a t2 with walbro/safc/720cc secs/ at 11 lbs. i get an occassional ping at 4200 now that i have upgraded my injectors. i am running the same map as i had with stock injectors(a very rich map). why am i getting this at this range now.. i know the car is running really rich at 5lbs and 6000rpm 2nd gear the car will bog from too much gas.. i dont have a dyno around my current location so i would like to get an EGT gauge.. would this help on my "on the road tuning" also i was wondering should i retard the timing and if so how many degrees should i start out with?

Let me give you some advice from my observations of a friend's car:

Run stock boost untill you have a better intercooler OR water injection.

Do not boost from low speeds(like off a light) because that is when the intercooler is most heat soaked try to keep boosted runs out on the highway(where the intercooler is getting lots of air thrown at it)

Pick up a good intercooler replacement(meaning an upgrade) for the stock one and/or get a water injection setup.


An EGT meter will certainly help your on the road tuning but I would also suggest getting a wideband with logging capacity. Reason being is that EGT's can be in the "safe" range while your AFR's are not so you need to monitor both sides.

From what I understand retarding timing eases pressure on the fuel mixture so it tends to reduce pre-ignition(ping) So I would definately say that retarding timing would help you but I do not know how much is enough/too much.

Too much fuel will cause the mixture to ignite in the exhaust/turbo from what I understand so running extra rich is not that good for your turbo since it won't be clean exhaust flow but an explosion inside of the turbine and I don't think it will like it.(if you have read up on "misfiring systems" you understand)

What injectors are you running? What ECU are you running? An EGT gauge is a nice piece but I wouldn't rely on it solely for tuning. It can tell a great deal when something is very wrong... like if you were running way too much or way too little timing.

I'm not talking about my personal car but a friend's car.

I'm running stock ECU with 550's/720's calibrated to roughly stock for an n/a(awaiting boost)

Sorry - I meant to quote the thread starter ;)

:ar: noob

most of this is true, but adding too much fuel will not make the mixture ignite in the turbo, if the timing is very very advanced to the point where the mixture is ignited right before the apex comes around the plugs most of the fuel wont be burned in the engine but in the exhaust thus spooling the turbo and making crazy high EGT readings. Also it's been my experence that retarding (or pulling back) the timing about 1 degree from 9psi on is a good thing to combat detionation. So if you are running 15psi, pull 6 total degrees, 1* total for 9psi, 3* for 11psi, etc...

We've been discussing this in the single turbo forum:

https://www.rx7club.com/single-turbo-rx-7s-23/optimum-egts-401781/

My NA has a knock (according to the SAFC) at idle and under any load. If the RPM is above 3K it seems to be okay.

Yes my NA has a STOCK knock sensor, the Vert ECUs have them.
I still haven't had anyone tell me what's going on, but i'm guessing my car is running lean although I haven't been able to find out from where.

Have you verified that you have the sensor on the rotor housing? TII's have them screwed on the front housing IIRC. Atleast my TII does.

Yeah man, it's there. I'll try to take pics of it when i get off of work.

Dang thats cool. Have you any idea if its the same type as the TII or could it be different?

i have a timing light and i have adjusted my timing before i just want to be sure though retarding is moving the marks behind the pin right?....as you read left to right

Probably want to double check the FSM for that. :)

smarty...... im not at home im out of state:-P

Hmm...well i know i get a reading from the sensor, and i remember plugging it in when i put the engine in. Now i don't remember where it is, can you remind me? :D