Not a Sunday Funday!

Not to derail, but would a supercharger be "safer"...?

Would guages, etc, be needed for that too? Just wondering...

Sometimes it could just be the motor. One weak link failing under added power. I am not saying that is what happened here but I know my stock motor took every bit of punishment I threw at it for over 7K. @rabtech stock motor ran like a scolded cat never a hiccup. @Wrenchmn stock motor lives under the pressure of his lead foot. All I am saying is that it in not necessarily something he did wrong. Sometimes just a combination of events and the weakest part fails.

Some of us built motors in a quest for bragging rights to the highest hp. But in all honesty the stock motor with some minor protective measures I very tuff. We are not the only ones pushing these motors. It has been done for years in cars like the Solstice and the Cobalt. This is also one of the most popular off road racing motors.

Quote from MiM

Not to derail, but would a supercharger be "safer"...?

Would guages, etc, be needed for that too? Just wondering...

Kind of depends on what you want out of boost. The SC has good qualities in that you will not have boost creep. The only way it will over boost is if you get a restriction in your exhaust. A turbo has a lot more items that need to be monitored to have safe boost. A SC is a simple design that only reaches max boost at max RPM so no gauges are needed.
If you desire big HP numbers a turbo is what you want.

I have the 16.5 SS with now 10K miles on it. Running the SC last 2 months but I been running it hard since new, it has put up with all I can throw at it and even more with added boost. Mass produced engines, like everything else, there will be a few weak ones. I have had mine near Redline a few times, so far so good....
It sure is good to hear you got off road safely, that's most important!

Sorry to hear this @Street Doc - this bites hard. After reading your post I am confident you will be back up and running soon and have a stronger engine. Hang in there ... things are going to turn around fast for you and heck ... take some pics of the new engine build and keep us on the edge of our seats while you build the new BEAST!.

Im running stock engine except for SC, ect.
Sounds like your lower end let go by your post. I have always downshifted when I romp on it, you may be on to something with lower RPM's and boost!

I'm not sure what REC 90 octane fuel is..... but that 90 scares me.

I won't even run 92 octane unless I'm stuck somewhere I can't find 93. That 90 number "could" have been something that caused it.

Edit..... I just read your post above.

I would almost bet money you had detonation and it came apart from the low octane..... When you said "5th gear at 65/70 mph and rolled into the gas" that would be prime territory for what happened....

These boosted applications help with low end torque such as holding cruise control at 65mph in 5th.. But it's just because the throttle is just being feathered and the turbo is just adding slight amounts of extra pressure...

But if you are in 5th and running 65 and you open the throttle wide open the turbo will do its job and spool up and fill the intake full of air. The engine just simply can't take that amount of fuel and air at that low of an rpm level based on the weight and drag of the Slingshot. So what you get is detonation. Or the inability to fire the gas and air at the correct time based on how much is entering the cylinder... So imagine all that air and fuel firing and the piston wasn't at the top of its stroke because it was being lugged down..It would basically hammer it down on its way up.... And that will break all the goodies in your engine...

Octane is an additive to regular fuel that helps control detonation. It can smooth out some of these issue.. But it can't overcome all of them.. So we rely on timing adjustments to slow the firing sequence down... However there is only so much retardation of spark that can happen. After that point something has to give...

So in this case you MAY have had this scenario play out..

Everyone should keep thier boosted engine turning a bit or RPM when laying into the gas with wide open throttle.

In lower gears this scenario doesn't play out as much because the load on the engine isn't near as heavy....

After retirement, managed a marina where we had 90 octane non-ethanol fuel for boats at our pumps. The distributor called it a recreational fuel, thus the REC. It was devised to keep octane at least at 90 with no ethanol but at a lower costs than octanes above 90. Not a fuel expert but just my dealings with REC 90.

Quote from Street Doc

Mine is a 16.5 also. Stage 2 with ARP head studs at 2100 miles and 5700 now. I'm thinking perhaps my incident was a combination of things. 90 octane Rec fuel instead of the 91-93 super unleaded with 10% ethanol. Coolest morning we've had since May (62 degrees) and flooring it in 5th gear at 65-70 mph. Possible a weak part in the motor as well. Side exhaust and wind noise didn't help me hearing and engine noise early on either if there was any.

Just putting this out there for everyone. Everything someone blew a motor and posted here, I learned something new. Maybe others here with more experience can add more.

Quote from rabtech

I'm not sure what REC 90 octane fuel is..... but that 90 scares me.

I won't even run 92 octane unless I'm stuck somewhere I can't find 93. That 90 number "could" have been something that caused it.

Edit..... I just read your post above.

I would almost bet money you had detonation and it came apart from the low octane..... When you said "5th gear at 65/70 mph and rolled into the gas" that would be prime territory for what happened....

These boosted applications help with low end torque such as holding cruise control at 65mph in 5th.. But it's just because the throttle is just being feathered and the turbo is just adding slight amounts of extra pressure...

But if you are in 5th and running 65 and you open the throttle wide open the turbo will do its job and spool up and fill the intake full of air. The engine just simply can't take that amount of fuel and air at that low of an rpm level based on the weight and drag of the Slingshot. So what you get is detonation. Or the inability to fire the gas and air at the correct time based on how much is entering the cylinder... So imagine all that air and fuel firing and the piston wasn't at the top of its stroke because it was being lugged down..It would basically hammer it down on its way up.... And that will break all the goodies in your engine...

Octane is an additive to regular fuel that helps control detonation. It can smooth out some of these issue.. But it can't overcome all of them.. So we rely on timing adjustments to slow the firing sequence down... However there is only so much retardation of spark that can happen. After that point something has to give...

So in this case you MAY have had this scenario play out..

Everyone should keep thier boosted engine turning a bit or RPM when laying into the gas with wide open throttle.

In lower gears this scenario doesn't play out as much because the load on the engine isn't near as heavy....

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Very sorry to hear about your engine, but like @rabtech said earlier, very happy to hear that you are ok as oil getting on the back tire can make it a hand full.

From the sounds of it you had a high load failure in the lower RPM range with most likely a rod failure that caused the rod to go through the side of the block and spray the oil all over. If you get a chance to determine which cylinder it is, I would be very interested in knowing. Typically I would guess that it is going to be cylinder #1 or #4 in this failure, with cylinder #4 probably the more likely (the one all the way in the back of the engine).

The tune is based on 91 octane, as that is what Bob at Mefi has out there in California, so running 90 probably was a factor. In 5th gear, at those lower engine speeds, you give the turbo enough time to spool up and create high load on the engine that you will not see in the lower gears like @rabtech mentioned. This high load can create pre-ignition in the cylinders (knock) which creates peak cylinder pressures before the piston gets to top dead center. This puts a lot of stress on the rods and eventually if ran long enough will cause them to break, then holes end up in the block.

If there is anything we can do to help, just let us know.

That number 1 cylinder does have a way to ruin all the fun. Those other three are usually innocent bystanders.

Quote from Street Doc

These are for the "if you don't have pics it didn't happen" crowd. Looks like #4 cylinder.Edit

looks like it happened and I'm very sorry for you. @Dave@DDMWorks will take good care of you I'm sure.
Also well worded @rabtech and Dave on the explanation. Next best thing would be pictured..

Ouch!
That is an ugly site - so sorry bud.

Quote from Street Doc

These are for the "if you don't have pics it didn't happen" crowd. Looks like #4 cylinder.

Damn!!! wow - looks like @Dave@DDMWorks and Rab was right. That's just damn frustrating!! GRRRRRRRRRRRRRRRRRR

That sucks. No other way to describe it...

Quote from Street Doc

On the bright side, I get a famed DDM built motor now. Hope Santa leaves some cash for me.

Doc all I can say is welcome to the DDM Built crowd - you will be very happy, can yo say 400WHP?
I bet by the time your new engine is built @Dave@DDMWorks will have the electronic boost controller set up ready to go! I know he is waiting on a few tuning tweaks and you get to benefit from Dave using the 3 stooges as test dummies. I have 100% confidence in anything Dave and Jeff build so you are in good hands!
I guess this is where I say "everything happens for a reason"