As most of you guys already know im on my second turbo setup, and my second set of pistons (still stock). Now the thing is im not really sure why i cracked pistons #2 + #4. These were the conditions :
One thing i recently learned is that an A/F guage that is hooked up to a stock o2 is no longer accurate after ~600F ...so even though when i was boosting 12psi and my guage red "rich" it might have been otherwise.
My initial response was : too much boost ! but then i learned that most of you guys are running 10-12psi.. next i thought the hot sparkplugs that i was running could have contributed, but i dunno how relevant that is.
Just wondering what other senerios exist, and what possible explainations exist for why i ended up w/ two cracked pistons.
#220, "RE: Blow motors & why ?" In response to Reply # 0
I have heard from alot of guys that some plugs don't work well for turbo cars (i.e. spilt fire,...). If you can I would use a higher octane gas. None of the guys up here (Canada) will use anything but 94 octane unless it is an emergency and thats even on daily drivers running low boost. I think 12psi is a little high for daily driving on a stock motor. I think 8psi might be a little safer unless your at the track. Just my 0.02
While on the topic of sparkplugs.. Has anyone tried the Iridium plugs ? Supposedly they have much smaller electrode which requires less power from the coil to create a better spark.. and according to turbo mag. it added 20hp @ the wheels on a stock skyline..
I run denso iridium (HKS racing) spark plugs in my stealth turbo. they are good. the O2 sensor won't even READ until it gets to 600 degrees F. per my EGT from when I was N/A (and my car could still run)
I run denso iridium (HKS racing) spark plugs in my stealth turbo. they are good. the O2 sensor won't even READ until it gets to 600 degrees F. per my EGT from when I was N/A (and my car could still run)
#226, "RE: Blow motors & why ?" In response to Reply # 0
platinum plugs run hotter than normal..get the NGK's that everyone recomends..BKRE7-11...i think that is the number...just make sure you get the 7 heat range..thats what i run, and not a sign of detonation on them at 9 lbs. of boost.
second of all, 12 PSI is way too much on stock injectors. the pistons are pretty much able to handle it, but you are not giving them enough fuel, even with the 12:1 FMU. our cars can run 310 CC injectors on the stock ECU, you might wanna look into those if you wanna keep stock internals, otherwise, to run more boost you'll need a Programmable ECU, like there has been discussion about.
Other reasons why people have blown there motors:
using the center screw in the deltagate to controll boost...that ain't what it is there for, get a manual boost controller.
too much boost, not enough fuel, your problem i am guessing...
fuel cut? i wouldn't know about this really...i got a 95..
anyway...i am sure there are other reasons..but basically, if you blew your motor, it is cus, you have too much air, and not enough fuel.
#227, "RE: Blow motors & why ?" In response to Reply # 0
I seriously question those plugs for any application, especially for turbo. I tried a set once. Runs better with the NGK's. Stick with the NGK's. And motors blow because of tuning. They either weren't running right before the turbo or they weren't tuned properly after the install. IE, the things mentoined here, boost and fuel
