Why My Engine Blew....

[wbt]

This

That -

I know the motor was rebuilt however when you were having issues with the motor prior to, there was mention that the motor was running before being pulled from the car however was hurt. Based on the pics you posted of the carnage, I fail to see how the blown motor could have run.

BTW - why did you go with a dished piston? These motors seem to like the compression even in boosted applications.

 

[mustang_fan]

Woah..

Which long tubes use Caspers Electronics o2 extension harness? Just Stainless Works and American Racing?

 

[KJGT]

Im gonna have to jump in on this, as I myself had an issue thursday at Bradenton.

First of all these cars DO NOT run closed loop all the time.
Second, It is possible to run them OPEN LOOP all the time.

Now, I roached a piston, maybe two on the dyno before we left for FL.... and here is the story.
As i was tuning our car in 2# increments up to @12 # EVERYTHING was spot on. Developed a bunch of tune files in the process both race gas and pump gas @ lower power levels.
Once I was happy with the 12# race gas file, I started to bump up the boost, Starting with 14#. Because I was completely comfortable with my a/f on the 20 or so pulls i was a little laxxed on watching the a/f monitor, no longer "hawkeyed" on the a/f gauge, but a bit more focused on the boost level.
Let me just say, Shame on me! COMMANDED A/F shifted to 1.0 lambda (14.6:1) at 4400 rpm, which happens to be at peak torque (660lbft), I missed the shift in a/f for nearly 1 second, at which time the damage was done.

So why did commanded lambda shift to 1.0? Well it seems that the ecm will do whatever it takes to control torque. The added 2 psi and ignition timing caused the engine to exceed a few of the torque values in the tune. Appearantly Ford thought it was a great idea to cut fuel as well as a few other things to limit the engines torque. Needless to say, not a good thing for a turbocharged/supercharged 5.0........

After a breif discussion with a few other folks this is a relatively common issue, and has been realized before, but not mentioned.....

So if youre a tuner and were unaware, or a customer that thinks he is going to just bump up the boost by a pulley change or a turn on the boost controller TAKE NOTE!

Sorry about the 02 harness, that sucks. Sounds as though Bradenton was hard on a few 5.0 cars!

Curious why on earth Ford would lean the car out to reduce torque, cutting fuel 100% is one thing but leaning it to 14.7 a/f would cause issues with a stock engine under a lot of load. Why not max out the torque values or isnt it that easy?

I'm sure there are quite a few things no one knows yet that will cause some high HP issues, especially the nitrous guys if it decides to back off the throttle hard or fuel cut.

 

[beefcake]

That -

I know the motor was rebuilt however when you were having issues with the motor prior to, there was mention that the motor was running before being pulled from the car however was hurt. Based on the pics you posted of the carnage, I fail to see how the blown motor could have run.

BTW - why did you go with a dished piston? These motors seem to like the compression even in boosted applications.

When I hurt the motor, it was hurt, period. However, I was still able to drive it back to the pits, and it would run. Sounded like it had a miss to it.

Drove it on the trailer, and drove it back off. But yes, with the carnage, you wouldn't think it would run.

As far as dished piston, that's what Bischoff recommended. I know Justin is going even higher with his motor, 11.5 to 1 i think.

Justin said it best. Every builder has their own recipe, and that is his.

I think 10 to 1 is a good balance.

Woah..

Which long tubes use Caspers Electronics o2 extension harness? Just Stainless Works and American Racing?

SW isn't using them as they are not needed.

I don't think a/r is either now

 

[Steedman07]

This thread should be stickied.

 

[KJGT]

When I hurt the motor, it was hurt, period. However, I was still able to drive it back to the pits, and it would run. Sounded like it had a miss to it.

Drove it on the trailer, and drove it back off. But yes, with the carnage, you wouldn't think it would run.

As far as dished piston, that's what Bischoff recommended. I know Justin is going even higher with his motor, 11.5 to 1 i think.

Justin said it best. Every builder has their own recipe, and that is his.

I think 10 to 1 is a good balance.

If you are limited by blower size then the more compression the better, just harder to control detonation. Good combustion chamber design and common sense can make a high compression FI motor live. Heck people are throwing Vortech superchargers on stock 12:1 compression, 8400rpm BMW S65 engines. Cam design/timing is more critical as well.

Dropping the compression means you need to move more air to make the same power, it will also make less heat when compressing the a/f mixture IF your compressor is big enough not to add the heat at higher airflow levels. But there is also more room for the a/f charge so the power potential is greater as well.

You can melt a couple pistons out of it and it will still run/drive, it will just look like a freight train out of the breathers when its running, been there many many times.

 

[Mike@PowerHouse]

Curious why on earth Ford would lean the car out to reduce torque, cutting fuel 100% is one thing but leaning it to 14.7 a/f would cause issues with a stock engine under a lot of load. Why not max out the torque values or isnt it that easy?

I'm sure there are quite a few things no one knows yet that will cause some high HP issues, especially the nitrous guys if it decides to back off the throttle hard or fuel cut.

Maxxing out the torque values is not that easy, remember that these cars are drive by wire, the driver demands engine torque with the pedal, and the ECM commands throttle angle by torque request, this all goes in to the redundancy of checks and balances to make sure the throttle is doing what it is supposed to. if you simple jack everything up the ecm begins to have throttle hangin and "sticking" issues...before you know it youve got a toyota mess on your hands!
And here is the reason for DBW, economy. The ecu actually tells the tb to kick way open compared to a cable operated system. The aadvantage is that the motor does not have to draw air accross a mostly closed throttlebody, so in order to limit torque with a basically wide open TB it will change spark, A/F, and cam timing.....

 

[beefcake]

If you are limited by blower size then the more compression the better, just harder to control detonation. Good combustion chamber design and common sense can make a high compression FI motor live. Heck people are throwing Vortech superchargers on stock 12:1 compression, 8400rpm BMW S65 engines. Cam design/timing is more critical as well.

Dropping the compression means you need to move more air to make the same power, it will also make less heat when compressing the a/f mixture IF your compressor is big enough not to add the heat at higher airflow levels. But there is also more room for the a/f charge so the power potential is greater as well.

You can melt a couple pistons out of it and it will still run/drive, it will just look like a freight train out of the breathers when its running, been there many many times.

I have a T Trim, the vortech production kit uses a smaller blower. The T Trim really needs some r's in it.

Once I add the heads and cams, it'll probably drop the boost even more,

 

[KJGT]

Maxxing out the torque values is not that easy, remember that these cars are drive by wire, the driver demands engine torque with the pedal, and the ECM commands throttle angle by torque request, this all goes in to the redundancy of checks and balances to make sure the throttle is doing what it is supposed to. if you simple jack everything up the ecm begins to have throttle hangin and "sticking" issues...before you know it youve got a toyota mess on your hands!
And here is the reason for DBW, economy. The ecu actually tells the tb to kick way open compared to a cable operated system. The aadvantage is that the motor does not have to draw air accross a mostly closed throttlebody, so in order to limit torque with a basically wide open TB it will change spark, A/F, and cam timing.....

I'm been ding GM stuff for a long time and spent a lot of time on on etc vettes, this ecu is pretty new to me and I havent received the prp software yet (which is about all thats out there) so I can see whats there Only info I have is looking over what little SAE/Ford info on this ECU/OS right now.

Its fairly common practice on high hp Gen3/4 GM etc cars to just up the max torque values to avoid any torque management silliness. Never affected drivability or hung the throttle but thats a different ECU, now tuning for big cams and idle airflow is a different story - but its apple to oranges comparing a GM ECU to a Ford I know. Just asking questions.

I would think since the ecu can control the throttle at will, and on these the throttle moves damn quick when the TC says so, plus having full control of timing that screweing with the a/f would be kind of a last resort for torque management.

But I didnt design the thing lol, I cant say much until I see whats going on myself. I'm sure there are lots of things people will discover about these, I'm all for learning..

I have a T Trim, the vortech production kit uses a smaller blower. The T Trim really needs some r's in it.

Once I add the heads and cams, it'll probably drop the boost even more,

T-trim is a good blower, only bad thing is a slight loss of lower end power by dropping the compression when the blower isnt making a lot of boost. But torque converters and gearing can make up for that, not like you will spending much time under 5500rpm on a dragstrip..

 

[JEREMYUPR]

Interesting fact:

One of my customer bought Kooks longtubes for his 2011 GT500
He plug in the harness for the extensions and never felt that they snapped in correctly. Like most he said oh well it must be right. A few miles down the road the check engine light came on. At that point he decided to test each wire when he discovered the issued was the extension not making contact. Thank the lord is what he said when he was smart enough to stop and figure this out.

I was just discussing this with the owner of UPR and said we would have hurt our engine as well--who pays attention to check engine lights.

Crappy deal all the way around!

 

[kyoshosp2]

I heard an SCT rep tell Chris at Blow by that there was a hidden torque limiter that they couldn't see or read with the tuners now.

 

[Mike@PowerHouse]

Not so much hidden as much as they cant find it.....

 

[beefcake]

Not so much hidden as much as they cant find it.....

lol

 

[Evolution Performance]

Not so much hidden as much as they cant find it.....

lol x2

 

[mustang_fan]

Ok. So is every manufacturer of long tube headers using these Caspers Electronics o2 extension harnesses?

 

[pacettr]

Subscribing.


Great info

 

[beefcake]

here are all the pistons. some say it could have been gas, etc..

but,

only the 4 pistons on bank 2 are damaged, along with a bent rod. I know gas doesn't pick which side of the motor to send bad gas too. lol

 

[KJGT]

Well if thats the same side the WBO2 connector failed, then I doubt it was an fuel pressure issue. Since the #2 bank (LH side) is fed first the RH is usually a little down on fuel on a returnless system. On this car Cyl 1-2 would be the the ones going a little lean if the fuel system wasnt keeping up. Assuming you have the stock rails/lines.

It could be is extremely bad intake design (doubt that) or for some reason the LH bank was running way hotter then the RH. I havent looked at the coolant flow paths on these engines but I doubt thats it since no others have been wiping that bank out. Nitrous guys usually discover that problem first.


Kind of hard to blame anything else if the other side looked fine. My guess would be you diudnt have a complete loss of connection, some added resisance may have skewed the reading enough for that bank to start leaning out without throwing a code. If you are running a fairly lean a/f 12-12.5: it doesnt take much to hurt pistons. If it leaned out to 14.7:1 you should have felt a good sized power loss, but sometimes when going down the track its hard to tell.

Either way it sucks. An old saying we had when we used to test new products/parts a lot was 'you could always spot the pioneers, they are the ones with the arrows in their backs.'

 

[Mike@PowerHouse]

Did you happen to log that particular run?


The broken ringlands and especially the bent rod are an indication of detonation. ultimately from heat.
That is why we run richer a/f ratios under load than at cruise, It helps keep everything cool, and increases spark tolerance, ultimately making more power.

Ford has sprk and fuel multipliers/cylinder, because of uneven fuel distrubution and temperature imbalances from cylinder to cylinder.


How much do you want to know. Because this can be a 30 page write up.....

 

[Mike@PowerHouse]

Maybe its just the pic, but a few of those rods look to have a little "swirv" in them.