Rumor about the first blown shelby engine

[KCMO-GT500]

found this rumor over on modular fords, also floating around on svt performance

 

mod ford link

 

 

svt link

 

This unconfirmed rumor has a couple of rods going thru the side of the block. We may have just found the weakest link. May also be that someone was tuning it and just screwed up on AF or something else. Hard to tell without all the facts.

 

I'll follow and post any news worth hearing, if anyone else finds out anything, let us know.

 

John

[carnut]

found this rumor over on modular fords, also floating around on svt performance

 

mod ford link

svt link

 

This unconfirmed rumor has a couple of rods going thru the side of the block. We may have just found the weakest link. May also be that someone was tuning it and just screwed up on AF or something else. Hard to tell without all the facts.

 

I'll follow and post any news worth hearing, if anyone else finds out anything, let us know.

 

John

 

Well, it will likely be a while as to why it really blew up, if it did. The message boards are afire with all kinds of conjecture, everything from rods to meth, I dunno, maybe even someone on meth. Generally with blowers the air fuel ratio needs to be fat to start then safely leaned out. Some tuners get them too lean searching for the highest power output. Unfortunately, this meets with disasterous results. We all need to keep a cool head and wait for the real truth to come out.

 

BOOM

[owenkelley]

If it is a production problem - at least there's warranty. If they were messing with it however, that's not covered under warranty.

[mrfarmdog]

Well, it will likely be a while as to why it really blew up, if it did. The message boards are afire with all kinds of conjecture, everything from rods to meth, I dunno, maybe even someone on meth. Generally with blowers the air fuel ratio needs to be fat to start then safely leaned out. Some tuners get them too lean searching for the highest power output. Unfortunately, this meets with disasterous results. We all need to keep a cool head and wait for the real truth to come out.

 

BOOM

 

 

I posted this on ModFords site but I will post here as well...

 

This morning I was working on consolidating all the dyno results to try to determine what RWHP we could realistically expect from this engine.

 

The driveline HP ratio loss based on 13 dyno runs and 500SAE crank HP rated from the factory is an average of 16.74%. Use that in conjunction with the 650 crank HP number that I have heard this engine should be good to (i.e. safely achieve) and the Max RWHP comes out to be 543. This one failed at 580 RWHP. Based on that same number for driveline loss the crank HP they were producing was approx 694.

 

Given what the data is telling us this failure does not surprise me. There is only so much HP you can produce with this engine and if the safe limit on the stock engine is about 650 at the crank then we will see that in the next month (if we haven't already seen it as a result of this failure) with a combination of standard tricks.

 

I have read some good thoughts as to why this car is not performing better for the HP it is making. Most of these center around weight, traction (or lack there of) and gearing (more than likely in the transmission and not necessarily in the rear end). Does anyone else think this is the case? It seems like it has the power it is just not making the most efficient use of it.

[carnut]

I posted this on ModFords site but I will post here as well...

 

This morning I was working on consolidating all the dyno results to try to determine what RWHP we could realistically expect from this engine.

 

The driveline HP ratio loss based on 13 dyno runs and 500SAE crank HP rated from the factory is an average of 16.74%. Use that in conjunction with the 650 crank HP number that I have heard this engine should be good to (i.e. safely achieve) and the Max RWHP comes out to be 543. This one failed at 580 RWHP. Based on that same number for driveline loss the crank HP they were producing was approx 694.

 

Given what the data is telling us this failure does not surprise me. There is only so much HP you can produce with this engine and if the safe limit on the stock engine is about 650 at the crank then we will see that in the next month (if we haven't already seen it as a result of this failure) with a combination of standard tricks.

 

I have read some good thoughts as to why this car is not performing better for the HP it is making. Most of these center around weight, traction (or lack there of) and gearing (more than likely in the transmission and not necessarily in the rear end). Does anyone else think this is the case? It seems like it has the power it is just not making the most efficient use of it.

 

Thanks for the info. It makes sense, I think we are all interested in seeing how this plays out

[Guest evilchris]

Come on, we all know it is not possible to blow a Carroll Shelby engine. The illustrious membership "flame team" at stangsunleashed ( rufdraft, lsr, 442 etc ) have assured us this engine is capable of 6,000 HP. If you disagree, you're a hater, and envious/jealous.

[JETSOLVER]

The driveline HP ratio loss based on 13 dyno runs and 500SAE crank HP rated from the factory is an average of 16.74%. Use that in conjunction with the 650 crank HP number that I have heard this engine should be good to (i.e. safely achieve) and the Max RWHP comes out to be 543. This one failed at 580 RWHP. Based on that same number for driveline loss the crank HP they were producing was approx 694.

 

????

[Guest evilchris]

Wow somebody needs a hug...or is this not adding useful info to the site?

 

 

This is what you guys want isn't it? Ass slapping, Shelby worshipping love right? We can't have ANY discussions regarding failures.

[mrfarmdog]

????

 

 

Sorry Jet but I am not sure how to interpret your post. Do you not believe the numbers are realistic? After I posted someone on another board pointed out that crank HP does not account for the HP needed to drive the supercharger. So the crank HP could be higher than the 694 I posted originally. Maybe I am off in my calculations? Seems pretty straight forward though.

[Guest evilchris]

Sorry Jet but I am not sure how to interpret your post. Do you not believe the numbers are realistic? After I posted someone on another board pointed out that crank HP does not account for the HP needed to drive the supercharger. So the crank HP could be higher than the 694 I posted originally. Maybe I am off in my calculations? Seems pretty straight forward though.

 

 

Crank HP is after the parasitic S/C loss.

[07 Shelby Cobra]

I wonder how many 03 Cobra Engines Blew up during the First Year of Testing on Dynos'? Quite a few I'd imagine! Give it time people. It's a learning curve. There'll be a few more 5.4s grenading yet! I'll let others be the guinea pigs.

[Guest evilchris]

I wonder how many 03 Cobra Engines Blew up during the First Year of Testing on Dynos'? Quite a few I'd imagine! Give it time people. It's a learning curve. There'll be a few more 5.4s grenading yet! I'll let others be the guinea pigs.

 

 

This thread is about GT500's and the suspected weak rods. 03 Cobra's have much stronger rods.

[07 Shelby Cobra]

This thread is about GT500's and the suspected weak rods. 03 Cobra's have much stronger rods.

 

 

 

If the Air-Fuel was above 12 it doesn't matter what the RWHP was. It'll Blow. (in my opinion)

If this is the case, here, more conservative/realistic numbers will be needed on the Tune. We need to see the Fuel-Air data before we make a judgement on whether the Rods were to blame, or if they failed as a Result of.................

[Guest evilchris]

I just wish it had weak pistons and not rods. A burned piston gives you parts to work with, throw rod and it's a grenade.

[mrfarmdog]

Crank HP is after the parasitic S/C loss.

 

 

Is it? I thought Crank HP was measured at the output of the engine and does not take into account any losses that happen within the engine itself, included belts driven by the crank. Wouldn't be the first time I was wrong about something.

[Guest evilchris]

Is it? I thought Crank HP was measured at the output of the engine and does not take into account any losses that happen within the engine itself, included belts driven by the crank. Wouldn't be the first time I was wrong about something.

 

 

Maybe I'm smoking crack, I'll verify

 

EDIT: no accessories driven by crank sure, but the S/C is obviously more than an accessory so doesn't meet that exclusion

 

EDIT 2: Man that's an f'd up question lol I'm still debating it. Do we determine the actual HP needed to turn the blower at any RPM and add it to the final? I can't get a good definition other than the easy ones like brake HP.

[Jesse_Bolt]

Maybe I'm smoking crack, I'll verify

 

EDIT: no accessories driven by crank sure, but the S/C is obviously more than an accessory so doesn't meet that exclusion

 

Take another hit then remove the timing chain. You'll need to figure out the true horsepower on the crank shaft without the drag of the camshaft.

 

Good luck!

 

JB

[68fastback]

I wonder how many 03 Cobra Engines Blew up during the First Year of Testing on Dynos'? Quite a few I'd imagine! Give it time people. It's a learning curve. There'll be a few more 5.4s grenading yet! I'll let others be the guinea pigs.

 

 

Yeah, on one of the threads they were joking they lost count on the Termies -- and those manleys were tough!

 

Once again, that GT500 rep appears to have told me accurately: 650crankHP was the design point. Then again, I would expect, if A/F ratios were correct (and they weren't fudging to compensate for bogus-engineered MAF mods which can bite you very easily) it would go higher than 650crank on a dyno because there's almost no shock-loading. Still approaching 700HP might be a bit too much.

 

Has anyone seen a pic of the forged cracked-powder rods -- are they an H-beam design like the Manleys or I-beams? Just curious. The cracked-powder tech has some advantages (absolutely round journals) but with the long stroke light-weight had to be an important design constraint too. A pricey set of titanium rods should do the trick if that was the POF <lol>

 

.

[carnut]

Yeah, on one of the threads they were joking they lost count on the Termies -- and those manleys were tough!

 

Once again, that GT500 rep appears to have told me accurately: 650crankHP was the design point. Then again, I would expect, if A/F ratios were correct (and they weren't fudging to compensate for bogus-engineered MAF mods which can bite you very easily) it would go higher than 650crank on a dyno because there's almost no shock-loading. Still approaching 700HP might be a bit too much.

 

Has anyone seen a pic of the forged cracked-powder rods -- are they an H-beam design like the Manleys or I-beams? Just curious. The cracked-powder tech has some advantages (absolutely round journals) but with the long stroke light-weight had to be an important design constraint too. A pricey set of titanium rods should do the trick if that was the POF <lol>

 

.

 

 

I am sure your right, a few more 5.4's will go the way of window block. Curious about the rods myself, I'm not up on this cracked rod technology. Wonder what the pistons look like, should see some failure here if A/f is too lean. I guess we will hear in due time

[68fastback]

This thread is about GT500's and the suspected weak rods. 03 Cobra's have much stronger rods.

 

 

The '03 has nice Manleys but I wouldn't assume they're much stronger (or stronger at all) than the forged cracked-powder GT500 rods.

 

Admittedly an H-beam design is a bit stronger on compressive loads which matters more on low-rpm engines that develop peak power lower in the rev-range -- like a s/c motor. But at higher revs, the primary forces of concern are tensile and I-beams are slightly better for that. All other things being equal (and they rarely are), I'd admittedly prefer H-beams on a a s/c motor that develops torque early since compressive loads are more likely the dominant limiter below 6000 rpm.

 

The cracked-powder rod (whether H- or I-beam) provides a stronger and more perfect fit where the halves come together which reduces stresses and offers the potential for a higher failure stress point for a given design. Also, the hi-temp forging process reduces the likelihood of surface-defect-induced failures and they're also less costly to machine.

 

Having said that, I don't know which design this motor has (H or I), but I'm certain they are forged cracked-powder technology.

[07 Shelby Cobra]

If the Air-Fuel was above 12 it doesn't matter what the RWHP was. It'll Blow. (in my opinion)

If this is the case, here, more conservative/realistic numbers will be needed on the Tune. We need to see the Fuel-Air data before we make a judgement on whether the Rods were to blame, or if they failed as a Result of.................

 

 

 

Anybody have the Dyno Specs?

[TAHOE GT]

 

Having said that, I don't know which design this motor has (H or I), but I'm certain they are forged cracked-powder technology.

 

 

The GT500 supplement to the owner's manual states "Forged steel I-beam"

[68fastback]

The GT500 supplement to the owner's manual states "Forged steel I-beam"

 

 

Thanks, TahoeGT... sort of suspected I-beam but wasn't sure.

 

.

[MeanMachine]

That cant be true cause correct me if im wrong but Evolution has already gotten there shelby to 560 something RWHP with no problems and expect to go higher in the weeks to come.

[JETSOLVER]

Sorry Jet but I am not sure how to interpret your post. Do you not believe the numbers are realistic? After I posted someone on another board pointed out that crank HP does not account for the HP needed to drive the supercharger. So the crank HP could be higher than the 694 I posted originally. Maybe I am off in my calculations? Seems pretty straight forward though.

 

I respectfully suggest that a GT500 has not produced near 700 horses at this early date with the factory parts in it. And if it indeed did so, it wouldn't for much longer than the few seconds for it to blow up. The block itself is in serious danger of the main caps walking at that sort of blower drive strain on the crank, never mind all the other impediments to getting that BIG number. And I'll bet the fact that Ford left 200 hundred horses lying around in the factory set up and componants would be of serious interest to the powertrain engineers who designed the thing. Just about the time they got fired for being incompetant. the rods are the same I shape as the 5.4 Lightning. I begin to wonder if the entire short block isn't the same componant set. I don't think they had many warrenty failures with that project.

[Jesse_Bolt]

I respectfully suggest that a GT500 has not produced near 700 horses at this early date with the factory parts in it. And if it indeed did so, it wouldn't for much longer than the few seconds for it to blow up. The block itself is in serious danger of the main caps walking at that sort of blower drive strain on the crank, never mind all the other impediments to getting that BIG number. And I'll bet the fact that Ford left 200 hundred horses lying around in the factory set up and componants would be of serious interest to the powertrain engineers who designed the thing. Just about the time they got fired for being incompetant. the rods are the same I shape as the 5.4 Lightning. I begin to wonder if the entire short block isn't the same componant set. I don't think they had many warrenty failures with that project.

 

 

¿Incompetent?

 

JB

[JETSOLVER]

¿Incompetent?

 

JB

 

I see we finally got spell check on the board.

[mrfarmdog]

I respectfully suggest that a GT500 has not produced near 700 horses at this early date with the factory parts in it. And if it indeed did so, it wouldn't for much longer than the few seconds for it to blow up. The block itself is in serious danger of the main caps walking at that sort of blower drive strain on the crank, never mind all the other impediments to getting that BIG number. And I'll bet the fact that Ford left 200 hundred horses lying around in the factory set up and componants would be of serious interest to the powertrain engineers who designed the thing. Just about the time they got fired for being incompetant. the rods are the same I shape as the 5.4 Lightning. I begin to wonder if the entire short block isn't the same componant set. I don't think they had many warrenty failures with that project.

 

 

I hear ya Jetsolver, so how do you explain 580 on the dyno? What do you think crank HP is? Even if driveline loss is only 10% then they were producing was still about 645 at the crank. Do you think 10% is realistic or do you think the dyno numbers are wrong?

[JETSOLVER]

I hear ya Jetsolver, so how do you explain 580 on the dyno? What do you think crank HP is? Even if driveline loss is only 10% then they were producing was still about 645 at the crank. Do you think 10% is realistic or do you think the dyno numbers are wrong?

 

I think in part it is a function of using a percentage to calculate parasitic losses. Any loss is going to be present at a very close to constant value whether it be at 500 or 700(or 200 for that matter). If one assumes that the 580 rw at which this one SUPPOSEDLY died is potentially sustainable for some service life beyond seconds, then the loss as a percentage should decrease as a percentage of the total. Without the numbers in front of me, I can only make an educated guess, but it is based on numbers I have seen for bypass turbofan jet engines using air resistance as the parasitic loss, I would suggest that the overall loss to the driveline might be on the order of 75-120 horses. Of course there are other variables such as blower drive, air quality, and even the traction available after friction losses on the dyno drum itself. I don't doubt that for that brief instant the PEAK number might have been higher, but in the same vein as the peak tension on a cable for example, is at its highest just before failure, it has no value as an engineering parameter except as related to its service strength, which is always a much smaller number that peak. Make no mistake, any number beyond 600 on a stock shortblock is a stunning achievement, I strongly doubt that anything beyond the 650 number will be sustainable on a belt driven supercharged car, just as a function of Ford engineering to a failure point of 500 SAE under all the constraints that warranties and cost create. I would love to see the sort of dynamic load testing tools that FORD powertrain has though

[mrfarmdog]

I think in part it is a function of using a percentage to calculate parasitic losses. Any loss is going to be present at a very close to constant value whether it be at 500 or 700(or 200 for that matter). If one assumes that the 580 rw at which this one SUPPOSEDLY died is potentially sustainable for some service life beyond seconds, then the loss as a percentage should decrease as a percentage of the total. Without the numbers in front of me, I can only make an educated guess, but it is based on numbers I have seen for bypass turbofan jet engines using air resistance as the parasitic loss, I would suggest that the overall loss to the driveline might be on the order of 75-120 horses. Of course there are other variables such as blower drive, air quality, and even the traction available after friction losses on the dyno drum itself. I don't doubt that for that brief instant the PEAK number might have been higher, but in the same vein as the peak tension on a cable for example, is at its highest just before failure, it has no value as an engineering parameter except as related to its service strength, which is always a much smaller number that peak. Make no mistake, any number beyond 600 on a stock shortblock is a stunning achievement, I strongly doubt that anything beyond the 650 number will be sustainable on a belt driven supercharged car, just as a function of Ford engineering to a failure point of 500 SAE under all the constraints that warranties and cost create. I would love to see the sort of dynamic load testing tools that FORD powertrain has though

 

 

 

OK jet... dumb it down for me. What I think I got out of that is that you believe drivetrain loss is more a constant and not a percent. Based on all the stock dyno numbers I have been tracking that loss is about 70HP. If the failure happened at 580 then that means crank HP should have still been 650... And that seems like a more realistic number to me as well. Interesting that the number comes out to 650 though.

 

Also I appreciate your feedback. Playing with numbers can be misleading and I don't have anywhere near the experience that most people have on this board.

 

By the way, can anyone with an 03/04 Cobra that has stock dyno numbers PM them to me? I am putting together a similar analysis so I can compare with the GT500.