mygt500

I think that was your problem with a more agressive tune you need more fuel and that A/F ratio below is not giving enough fuel most likely. Did you have the GT500 pumps with the kit? Your A/F ratio should be 11.5 at WOT give or take 0.2 IMHO..... do you have a dyno tune or a canned tune? Just curious and sorry about your loss[&o] J-

sevenleaf

Atleast this thread got me scared enough to purchase an Innovate **NEW** XD-16 Universal Gauge System (w/LC-1 + Gauge) from lethal performance I keep putting it off but I want my motor to last a little longer.

OP: Did you have a wideband gauge?

kolb02

Yes, I have an XD-16.

Gene K

Standard FRPP/Whipple HO Kit with the new Series II Blower makes 11-12 psi on the stock pulley at low altitude.
Given the fact that Ford has to warrantee failed engiens with dealer installed units I doubt the boost is excessive.

Blowing an engine is a direct result of peak cylinder pressure and/or rpm. Doesnt matter how the cylinder pressure is arrived at.
Could be detonation, timing advance, or cylinder fill. An engine with ported heads, cams and long tubes could easily have more cylinder pressure at 10 psi boost than a more restricted engine at 12 psi.

12.0-12.2:1 AFR can be perfectly safe on a blown engine. However it requires the correct compression, timing, and cylinder fill for a given engine design and fuel. If it detonated, less of any one of these 3 or a richer mixture may have prevented it.

While many disagree with me I have always been somewhat leary of tuning timing curve on a blown engine on a nonload dyno.
The harder a car is loaded the more likely it is to detonate. To me this means that for a given timing a car may not detonate on a momentum type dyno but may detonate on the track.

zkiller

So why were you running 12 PSI on 93 octane? That was a very bad idea there.
Did Brent White really say 12.2 A/F was spot on? I mean , I know him ,and I find that hard to believe. He was veryconcerned about keeping my air fuelat a safe level when he dyno tuned my car.
You should have been running 100 octane fuel no question though. I run 11 PSI on my KB and I always run 100 octane. Even Kenne Bell will say dont run that high PSI on 93 octane.
Running the stock bottom with a lean air fuel ratio and 93 octane is most likely what caused your problem. My boost hits 13 PSI sometimes because of air density and temperature, but that is okay with 100 octane.
It is not boost level itself that kills the motor it is the detonation you get that will kill it.

forensicsteve

When we were running the 93 octane tune at 11 lbs at the track (before the dynotuned race tunes), we still put ina little116 octane...not for better performance...for insurance.

The two race tunes, 16 and 20 lbs are with the 116 octane only.

kolb02

YeaBrent said anywhere from 11.8 to 12.2 he likes to see it. Thats beside the point now, thats what he told me. It's not his fault, he told me I was pushing the limits.

hotairgypsy

kolb02...ignore zkiller...we both run our cars the way we do CUZ THEY ARE OURS TO PLAY WITH AND DESTROY IF WE WANT TO!! He has nothing constructive too add to the conversation. I know it sucks and every time i run my car i wonder if this is the time it goes boom. I do not think it has a damn thing to do with the octane level. I run 91 octane and totally believe it is all in the tune. When i was getting my car together for the SC I talked to Jim Jr over at JDM and they have several cars at 500 RWHP on stock blocks. I told him everything I was doing and what altitude I am running at(4700 ft) and he said it will hold up. I paid more for thier tune then what it would have ran me locally but I wanted thier knowledge behind the tune. When i am running at the track i have been told I am running rich under hard acceleration. I saw a vid of one of my runs and i saw a puff of black smoke so I assume that is why I got that comment.( go ahead and say some dumbass comment about that zkiller but i trust the EXPERTS at JDM before I will listen to your advice)

I know in my case I am pushing my engine pretty hard but I have done all the research and never started the car without the proper parts to back it up. Prior to starting the car with the SC I installed 60lb inj, gt500 fuel pump upgrade, wideband O2 to monitor, innovate gauge to monitor all, HT0 properly gapped, and lots of calls to JDM too setup all properly.

hotairgypsy

personally i think they gave you some wrong info on your power ratings. I think they are low. I am at 4700 feet so i would have less power than you at 3700 ft. I am running the 2.95 pulley with 8 rib kit from GI JOE with stock size of crack pulley. My numbers are 469.8 RWHP 434.7 RWTQ. Brian at Texas Hotrod is who ran my car..they are also a site supporter. He has a mustang dyno if that makes a dif

zkiller

Whatever hotairgypsy. If you think a puff of black smoke means you are running rich then what is the wideband telling you?If you see it go below 11.5 A/F on forced induction then you are getting a little rich. You want to be at 11.5- 11.8 tops. When you go over 12 you are increasing the chance of detonation.

What doesn't have to do with the octane level? The fact that high cyclinder pressures from boost will cause detonation? So will too much timing advance. Either way you are definatley taking big risk running 91 octane fuel. You can believe whatever youn want.

You thin JDM runs 91 octane on their Saleen blue car?