[Ice-947]

So, long story short, car felt down on power.

Dyno'd it, it was down about 200hp and generating allot of heat. Checked the charger, the cooler, everything.

Trans then let go on the dyno. Went back with a FTI Billet Converter and Fully Built Tim King.

Car goes back on dyno, down 200hp still, and feels like there's a dragging on the car. Car rolls fine in neutral.

Compression has come back perfect across the board. All fluids no metal everything looks perfect.

The only thing left is the diff.

Has anyone seen an eLSD let go on these cars? I mean the amount of resistance would have to be massive.

Specifically asking bigger high hp guys with 800+ to the tire.

 

[Mbai2]

Any codes? I assume you checked the IC circuit for air and bled it already since you mentioned checking the coolers?

 

[MrSurly]

Curious about this. Your position seems to be that you had dynoed the car previously and everything was as expected and it was making X RwHP.
Now, it seems low on performance so, as a diagnostic you put it back on the dyno and verified it’s putting 200RwHP LESS on the drum.
So now you have documented this delta and you are suggesting (speculating) that the engine is actually producing the same power…. but that dramatic parasitic drag is responsible the lower power read at the drum.

Did I diagram that correctly?
It seems to me that the first thing to determine is whether the engine is, in fact, producing that same gross output. The biggest clue is (should be) available in the logs from the two dyno runs.
Look at the fuel pressures and injector Duty Cycle at x RPM. If it is producing the same output before the drag, it will be consuming the same amount of fuel.
im not familiar with the LT4’s electronics but is it able to log MPG or GPH during the runs?

If the IDC is lower now, then that would point to a tune issue not drag-induced loss.

If it IS drag, pull the ABS or Traction control fuse(?) to see if the effect changes?
200HP is around half a million BTUHr… like three household furnaces at once. If it’s drag, something is GLOWING bright red during the run.

 

[Ice-947]

Checked iat. Fp, it's literally down power. Same boost level... Obviously there's more to check. I'm hoping it's not the pinions... I mean maybe need to hit the diff with a heat gun.. Either or draining fluid tomorrow to check what's going on inside.

One would think the logic and I don't disagree but the Trans did grenade. So if it did have smoked bearings and the diff was in the process of welding itself together... That "could" explain it. I suppose engine load would be another stat would state things because obviously the load would change if the parastolic loss was that extreme...

The dyno is accurate because... I know what time it fell on its face at the track which directly correlate the hp. So something is definitely going on.

No knock retard either.well due to high iat not to actual knock .. I'll know more tomorrow.

 

[MrSurly]

I feel like you need to post the logs. Not for me but for people smarter than me who
can decipher them.
What’s the timing doing? All those questions.

 

[Ice-947]

I will shortly. Want to see what the diff looks like.

It would be my luck I have the one defective diff...

 

[djdonte]

I find it hard to believe your diff is sucking up 200 hp... thats a lot. What about the ABS and traction control system? Or a combination of? The traction control engages the rear brakes I believe. Either way I think you are looking in the wrong spot, but I am interested to hear what the findings are. Whatever is holding up that much power would be giving off massive amounts of heat. Look in your logs for sure. Maybe your MAF flow rate since you have that monster blower. Im going to guess you are catless? Clogged cats would do what you are describing.

 

[Ice-947]

Dj, totally agree...tc everything disabled...and absolutely. If it's pushing that much heat you'd think it would've welded itself together by now. However.... Trans grenaded... Power loss... The engine isn't going to drag on the trans... The diff.. So far no new info... When I do hear something believe me I'll let everyone know.

 

[random84]

I'd think that if any part of the drive train is creating enough resistance to suck 200 HP off a dyno, it wouldn't last very long.

And there would be lots of heat, smell, smoke and a "bang!" In short order.

Belt slip or a poorly adjusted boost bypass valve? Vacuum leak? Your engine coolant is clear with proper levels?

When you said the motor was making a lot of heat - can you expand on how you know this and what you saw?

Sent from my SM-G991U1 using Tapatalk

 

[MrSurly]

Yes. What they said. Again, 200HP worth of parasitic drag would be converted to over 500,000 BTU/h of heat. If the differential had the ability to bind up that much, the diff would be stinking/smoking/GLOWING and howling.
There would be a very REAL danger of fire.
You repeatedly say there is excess heat on the dyno... where, specifically? engine bay? wheels? Brakes? Do you see actual evidence of high heat? Where is the smoke?
If the diff had this much drag it could only be the pinion bearings or the carrier bearings... the pinions inside the carrier wouldn't be in play, here.
As Jesse stated; If the diff could create this much bind, it would either lock up OR break in two in very short order.
My bet is that your 200HP deficit is loss of engine performance and not drag. But we need more info.

 

[rcubed3r]

cats?

 

[Ice-947]

No cats, IATS were what were high, no knock retard. pulled 2* due to heat...

I still have no info back further, once I do I will absolutely fill you guys in.

I also now that you're mentioning it, you're exactly right, with that much heat, things would be melting. Supposedly the IC has been checked, the bov, turbine wheel. Dumped the oil. Comp check. I'm going to go see the car next week.

 

[Mbai2]

No cats, IATS were what were high, no knock retard. pulled 2* due to heat...

I still have no info back further, once I do I will absolutely fill you guys in.

I also now that you're mentioning it, you're exactly right, with that much heat, things would be melting. Supposedly the IC has been checked, the bov, turbine wheel. Dumped the oil. Comp check. I'm going to go see the car next week.

If IATs we're high, you probably have an intercooler problem. Check to make sure the intercooler pump is functional. Also, check the circuit for air and bleed it out. Hopefully it's not a coolant leak in the intercooler circuit.

 

[MrSurly]

IATS were what were high,

HOW high?

 

[Ice-947]

Ok log file below....and I've been saying IC from day one....I'm reading this and I like to think that I am, but now under a microscope...The Coolant temps are fine....everything is good except the effing IATs...which...19-200+... on a run, total retard round 4*.....coolant is fine...

 

[Ice-947]

I offer a beer to someone who wants to give me a better answer. Or perhaps a bottle of vodka. At this point, I'm ready to drive the car off a cliff. I do know what I'm looking at, I'm not the tuner, perhaps I'm missing something crazy, but here I am, and I can't see it..perhaps more trained eyes can.

@Rubber Duck
@MrSurly
@random84
@Mbai2



Anyone who can offer anything, this is what the forums are for right?

 

[Ice-947]

@Rubber Duck
@MrSurly
@random84
@Mbai2

6-10-22-cecil pull.hpl

Shared with Dropbox

www.dropbox.com

There ya go...

 

[kittyboy]

"Compression has come back perfect across the board."

Just curious, any before/after comparison? What is the current compression?

 

[Ice-947]

As of a few pulls ago it was 200 across all with 205 and 205 on #1 and #3...this motor is factory fresh after an oil pump failure under warranty that took 4 months to get from Caddi during covid. The motor was fresh and fine as frog fur...

Again nothing leads to motor....the motor isn't hurt.....unless In the history of hurt motors it leads to be perfect, but the oil pulled twice shows no signed of any sparkles or bearing mess....and compression remains the same...again, why do you think I'm reaching out.

This is the gremlin of all gremlins...

 

[Rubber Duck]

Yes. What they said. Again, 200HP worth of parasitic drag would be converted to over 500,000 BTU/h of heat.

Knock, Knock. . . Is this the same guy that does not like 'Math'..