j9fd3s

that is a huge problem, the factory had different goals, but who knows how many engines they blew up tuning for the stock t2/fd/rx8?



they spent 5 years developing the racing turbo engines 81-86, and they ran 1 race and bonneville



they have more time, more money, more everything, how do you compete with that?



well for one, you can copy them....



we know the intake air temps, we know the turbos, the porting, egt's, compression etc etc

Maxt

Is the motor apart yet?, put the apex seals face to face, if they are sunk in the middle, there is the source of your pre ignition.. Hold them up to the light.. Stock mazda seals are bowed outward, in the centre, when they are not worn out. Every aftermarket seal I have see so far is sunk inward in the middle even when new and unused, but it becomes substantially worse after a little mileage and boost . Check the seals for colour difference, if the centre is different from the outer corners, thats combustion leakage between chambers..Been there done that...

BDC

What's the link between inwardly bowed apex seal centres and pre-ignition?



B

j9fd3s

hot gasses from one chamber can go into the other and heat up the charge....

j9fd3s

spent an interesting afternoon with our reps cx7, two engineers from japan, looking for better response under 2500rpms. we talked about it, drew a bunch of graphs, they plugged their stuff into the car, made and datalogged some changes, and we'll see, maybe they will have a TG reflash for it.



the hopeful thing is that they didnt have too much in the way of datalogging, their 2 boxes plugged into the car and added 1 sensor.

BDC

Yeah, that's true. I guess I'll know when I tear it apart. I still don't think that's what caused it, however. I still think it's ignition-related as in something abnormal going on per the symptoms and how it felt.



B

Lynn E. Hanover

I know so little about turbocharging anything, that I would get hold of the factory manuals for the twin turbo engine and see what ignition advance those things use at high boost, then run a little less than that. Make sure the controller is actually pulling out advance for each lambda hit. Find out what mechanism is used to determin that, and apply it. I would run about 10% glychol and a dose of Redline Water-Wetter or a teaspoonfull of dish washing detergent, and the rest distilled water for coolant.



Bring up the fans with boost no matter the coolant temp. Add water spray onto the intercooler and radiator with high boost. Maybe even some intake spray at high boost.



You might consider tuning for just 450 HP peak and hang on to the engine for much longer. Add an intake air temp gage. Add a datalogger. Tune a bit richer than ideal for any boost.



I remember when Electromotive was trying to get a full lap out of the Nissan V-6 twin turbo GTP car. They ended up with (among other things) an engine that was tuned so rich under boost it looked like a diesel truck. But it stayed together.



Lynn E. Hanover

j9fd3s

well we played with the cx7 today, and even doing something dumb, like trying to get the turbo spooled quciker, was hard, if you advance the timing, it maybe make pinging sound. if you retard the timing, turbo might spool quicker, but long term it might be bad, and then it also raises air temps, and also make pinging sound.



we talked about loosening the converter on the transmission, which they can do with the laptop, but they gas mileage goes down. tons of tradeoffs



road racing is different than a street car too, street car doesnt have to have the cooling, as full throttle is a much shorter time period....

BDC

Provided it's not too dang hot to work tomorrow (it's supposed to be 104* degrees!), I'm tearing down Luke's motor to get a peek at the damage. I'll get some photos and get back to this thread with them.



B

j9fd3s

i'm building a miata engine, its supposed to be 107! here!