-370ci forged internals except stock crank.
-stock 317 heads (patriot extreme springs)
-TU1 cam
-9.8:1 compression
-E85
-Timing 14.5 degrees
-A/F 11.4:1
-PT76GTSH Wastegate closed mechanical gauge said 20psi electronic said 21psi
-Standard GM MLS gaskets (<-----Failure I know)
-ARP head studs.


So I got my Eboost2 working and my set on kill stage did just that. Last year I had it set on 18psi and ran what the vid in my sig shows.. Upping the boost just this little seem to make quite a bit of a difference.

Anyone ever re-torque the heads after its ran? I dont know if that would have helped? Seems like a pain in the *** to do..

The heads trashed. Glad it was just a stock one.. I have spares. Everything else looks ok. The LS9 gaskets I think were back ordered or something so thats why i didnt get them then.

Im going to get the LS9 gaskets, put it in the car and run it w/ no manifolds to heat up and then re-torque them before putting it all together.

Sound good?

Kind of hard to see the head, but those grooves cut in are about 1/8" deep.
At least it was fun breaking it...lol.

 

fuel? IAT?

 

E85
My test runs n the day it hit 105 degrees. This was at night when it was cooler.

 

What did you have the heads torqued to when this failed? If you have an iron block I think most people pushing big power over torque the heads beyond the stock recommendation.

 

i had the same thing happen to me except i was running 26psi 18* of timing and a 100 shot in the middle of august with no intercooler and my iats got into the 240s. this was on the number 3 and 4 cylinders.

 

There is aluminum peppering all over the heads / pistons from detonation. That much boost on a 370 with that turbo has to have a ton of back pressure and well you can see the results from that much back pressure. I bet the turbo was done at 18lbs yet all you did was increase back pressure. Could you post a picture of your plugs?

 

Guesing not logging when it happened? At track or on street? Long highway pull if on street?

 

Previously I'd have said detonation caused this too. Ive been there myself, you've seen the damage.

Now I'm starting to think. When a powerful engine like this does blow a head gasket, is actual alloy damage to head/block just expected ?
I find it hard to believe, but it does seem to happen quite a lot. So is there no such thing as a simple head gasket blow and almost no damage ?

Which studs, how were they torqued, were studs installed loose ?

Ive never had a head gasket failure per-say, but I have had serious damage like the above and believed detonation was the cause. And still do in my case.
I've never re-torqued once installed in the car though. On occasion I have torqued, let sit for a few hours, then undone each nut and re-torqued one at a time.

Cant say if it makes a difference, as sometimes Ive done it, some I havent. Usually torque to around 75-80lbft cold with regular ARP studs and GM gaskets.

 

I didnt see any signs of detonation...? Pistons wipe off and look like new yet. There is a lot of dirt in and around the area.
Plugs looked ok except for one missing electrode. It might have been done at 18 but made a lot more this way I probably wont push it that hard again.

No logging... Yes. I was passing someone on the interstate at a reasonable speed.

Studs installed finger tight, ARP studs torqued to 80. Reason I ask is I have a Eagle Talon i put head studs in, same kind. They are super accesible to after I ran it up to temp a friend told me to check them. Sure enough I got about another 1/4 turn out of the nuts before they were at the proper torque. This was running it up to operating temp and then letting it cool.

 

Is that 80 o an iron or alum block/heads?

 

iron 6.0 block , aluminum 317 heads.

 

proper way to torque ARP is to cycle them multiple times. this way, you won't need to retorque after running it.

I use the ARP "Ultra-Torque" lube (the most consistent lube available) and torque each fastener in steps to its final torque rating. for example - install studs by hand - torque the cylinder head in the proper sequence to 20lbs. then the whole sequence to 50lbs, then 80lbs. then undo all of them. Repeat 5 times. I know this is overkill, but helps to get a more accurate torque reading, and better consistency between each stud. It takes me about an hour to torque down the heads doing it this way, but it helps to stretch the studs, so that they won't stretch during use.

im not saying this is what caused your failure, just advice for when you put it back together

 

Off topic... Do you know how much power you were making at 18 and 20 psi? I was under the impression that this turbo would run out of steam somewhere around 17psi on a 370.

 

was your car just eating coolant or were oil and coolant mixing?

 

No idea. At 18psi I ran 9.76 @ 141mph but my tune was still pig rich, I had made a few passes and progressively pulling fuel out it picked up a couple mph and had room to go but my brakes started squealing so I loaded it up and went home.
The HP calculators online say 141mph @ 3700lbs = 850hp. ??

Adding the 2-3 lbs of boost and getting the A/F dialed in made a big difference. The car turned into an animal.

Heres the only vids of when it blew. The guy said the supra just dynoed 1033whp before they left, this is about a 60mph roll. First run the car was running hard. Second run it didnt hit as hard when I hit it...we were about dead even and then I just lost all power and created one hell of a white smoke show for my friends following us. Thats about the only thing I got to compare it to.




Vids of the car I found and his ebay ad.
http://item.mobileweb.ebay.com/viewi...917&cmd=VIDESC

 

It was eating coolant.... all the hotside and turbo were full of coolant, and it also ventilated out the side of the block also. My oil looked new yet.

 

Im looking for LS9's right now as well...that car is a beast and hope you get everything sorted out. I think its just the gaskets though, new heads and LS9's should be the solution...hopefully.

 

not much experience with e85 exactly, but i would say you seem a bit lean. My experience is with M5 and we run 3.8:1 to 4:1 with 45lbs of boost and if things are going well 55lbs of boost. But i would say 11.4 is really lean to me. the afr looks closer to a pump gas afr to me lol.

 

Last year when I was tuning it, it went 137mph on 18psi, I think the fuel was 10.5:1 I leaned it out to 11.2 and ran the 141mph. I pulled some more out and then couldnt get it to hook with the drag radials. Im launching at 11psi and then as soon as it hit 18psi it would blow the tires off... that and the squeaky brakes I didnt make any more passes. So it makes more power at 11.4:1 than it did when it was richer...and nothing else changed.

I really dont know what its "supposed" to be... All I do is guess and check.

 

i got ya. mine is eating coolant too but the hotside is fine. it just blew the overflow resevoir cap off and lifted the rad cap which blew coolant all over the engine bay. no mixing or white smoke from mine either. the headgasket has to be toast but i dont think/hope its as bad as yours.

he's just using the gasoline scale. its a little lean but nothing crazy. mine is tuned on E85 and on a gasoline scale it reads ~11.0-11.2 and thats pretty safe. on the lambda scale im pretty sure stoich is .79 for E85, dont qoute me on that though, you can look it up.