piston damage apex gt s.c.

blown apex

blown apex

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*burnt piston #1 cyl, straight through piston and
rings at middle intake valve only
*burnt hole in cyl 1/8 deep 1/4 down
below center intake valve
*looks like plasma cutter cut groove
*14 pounds boost
*torco unleaded fuel additive and 93
*lake run at 90-110 on speedo
*temp 160 egt 1100 on racepake udxr
*IS THIS DETONATION OR LEAN
*0/2 senser and 9-1 pistons on the way
*i like the power but need reliability
*ANY HELP PREVENTING THIS IS APRECIATED
*thanks nose pro/swissledder/bluedog and all
for helping me off lake
****OH 10 HRS PISTONS OUT****
 
Hello

Duane, Bob let me know there was a lot of damage, sorry to hear that!!! When will it be back together? I'm trying to decide on whether to head to Manitoba with Nos and Swiss or wait and go with you and Hayden... I gotta decide by end of the day this Saturday... What are your thoughts? Invited Hayden and them over for Super Bowl party, your family is invited also....

Dog
 
Anwser is simple. Too much boost, not enough octane. The Torco does VERY LITTLE TO NOTHING to raise octane. I've tested it myself in trusted knock detection systems, and there was as much knock with it as without it at any given boost level.
 
Sorry to hear about your problem, but I never liked the fuel additives their just not the real thing. With stock compression and timing 14 lbs. is real boost and need high octane turbo fuel like VP C16. The superchargers I've installed for reliable performance 7lbs. pump gas max. :D
 
blown apex said:
9-1 pistons and 93 octane
what boost is safe
Click to expand...

I would go 14 PSI with 9:1 no problem ........you were at 11.5:1 before .
Get a knock sensor just to be safe .And always be sure your getting fresh gas and not stale.
 
Stage-I compressor ???

My Stage-I, at 5900ft elevation, overdrive pulleys, and over revving the engine at 10,300rpm (accidentally) made 11lbs boost at wide open throttle (you will see higher numbers at part throttle if your gauge is reading off the intercooler)... I run a 96 motor octane VP race fuel in mine, overkill, maybe a little, but a nice insurance policy for those hood vents plugged with powder no airflow days I have experienced lately... MPI recommends 50/50 pump 110 octane leaded racing fuel mix and 9800-10,000 MAX engine rpm with the overdrive pulley combination... Approximately 10psi give or take for elevation... So to get 14lbs, even at low elevation, you must be spinning it real hard, that equals hot discharge air, lots of hot discharge air, especially on the small Stage-I compressor... The intercooler will only remove so much heat, for so long, then it heat soaks, especially with the stock Apex hood configuration... Higher intake temperatures would require more octane and I don't think the Pump/Torco combo was enough to offset the Boost/Heat combo... In addition the MPI baseline fuel controller settings are not meant for 14lbs boost (unless you specifically asked them for different settings)...

Disregard above comments if you’re running a Stage-II as I have no experience with those.
 
Fuel,Fuel Fuel sounds like the issue here..........He has to be running a stage2 kit.
 
Have to agree need better fuel to run that kinda boost.
 
With no head shim or different pistons You are only good to 8 lbs on that fuel..... No doubgt...........
 
I think you ran to much boost for pump gas. I for one woouldn't run anymore then 11 or 12 pounds on a decompressed motor on pump. the problem with pump fuel is you never really know what your getting.

For 14 pounds I'd run a VP fuel. Like 105 red
 
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