The Holset he341 3.0L

[Reaper1]

Looks like #4 was knocking a bit too. There's aluminum "salt" all over it. If it ripped the top ringland off, what we may have been hearing is the bottom part of the piston just rattling all around in there while the crown was sitting at the top of the bore kind of protecting the head from the carnage going on underneath. I think that's a stretch, but it could happen.

We won'y know until the heads are popped off.

[Ondonti]

toss a piston in it.

you have some laying around?

Brian

I should. Annoying thing is that these are 2 year old Chrome rings that I gapped and installed which were meant to be a long term engine compliment. They only sell a set.

Looks like #4 was knocking a bit too. There's aluminum "salt" all over it. If it ripped the top ringland off, what we may have been hearing is the bottom part of the piston just rattling all around in there while the crown was sitting at the top of the bore kind of protecting the head from the carnage going on underneath. I think that's a stretch, but it could happen.

We won'y know until the heads are popped off.

Ringlands would break off from small stock ring gaps. If the ringland came off then I know these gaps were still not enough.

I am a bit worried about the cylinder wall being smacked around by the small end of the rod. The spark plug should be dead at this point if it was just a piece of piston.

[Vigo]

If you dont want to run MS, why not pick up something like a used MSD boost retard box and run that? It still wouldnt give you the same total timing from part throttle to full throttle but it might give you enough less that this never happens again..

[Sundance 6g72]

you could run a cheep megasquirt for timing only. Timing is always super easy, especially when you know what it should and shouldnt be.

[Ondonti]

If you dont want to run MS, why not pick up something like a used MSD boost retard box and run that? It still wouldnt give you the same total timing from part throttle to full throttle but it might give you enough less that this never happens again..

I thought about this the same night. I could also just dump base timing. The problem here is that timing is too high at part throttle and mid/high loads. Killing timing across the board either with or without MSD would result in yuck WOT performance. I was thinking today that I should just pull the boost controller off but this was not really a boost issue. More like the turbo creating a "zero vacuum" situation with very light throttle which would not normally be possible. Fact is, the more boost, the more the rising rate regulator will dump fuel and probably make things safer. Without the rising rate regulator, AFR will never hit 10-13:1 with things set to lean burn. This leanburn setup worked great for driving around and racing because I only got high loads with WOT. Towing changed that.
Megasquirt doesn't have these silly part throttle maps that are great for stock driving but terrible for modified performance.

you could run a cheep megasquirt for timing only. Timing is always super easy, especially when you know what it should and shouldnt be.

I honestly think the fuel part is easier to deal with except hot/cold starts, warmup, etc. Might as well go all the way at that point. I think our distributor requires ms2.

- - - Updated - - -

Wastegate is holding back some aluminum so I would bet that I was in boost while this failure occured, possibly a full 10psi since the wastegate would not start cracking open until 7-8 pounds of boost or so. If there was that much boost I don't know what the AFR was but before I had seen 13 AFR range in 5th gear during some mild boost part throttles. The Rising rate should have bumped it out of the 17-18:1 zone but I don't know if you get full WOT fueling when you are not WOT. Just because your OEM n/a map sensor is maxed out I don't know that it actually goes into full fuel dump. With how things are setup the AFR should have been high 10's if I was WOT. I do not think I was even close to that.

Raise your hands if your shortblock can handle 10 pounds of boost on naturually aspirated part throttle timing tables with AFR's not in the safe zone. My forged piston shortblock would have eaten this up and much worse. I do think a set of beefy cams would ease off detonation issues at low rpms.

I think for my first attempted towing I should have had my knock microphone on so I could listen to how the motor was behaving without having to filter out the exhaust note.




Uh oh, that is a piece of ringland. The head actually looks okay. This big piece is just stuck there from the surface tension of oil.





Piston cracked in half when trying to compress aluminum against the head.





So, I have never had a failure at such low rpms so that is probably why things don't look as melty mangled as they have in the past.

Things to check or suspect damaged,
- I will need to look at the intake and exhaust valves/seats to see if there is damage to the surfaces that need to seal.
- Rod bearing might be toast, rod might be bent. Hope the crankshaft is okay because that would save me a whole buncha labor.

The good
-The #6 piston looks intact enough that maybe I can still get use out of those rings. I hope they are not bent......grrrr

I have not turned the motor to check the cylinder walls. I am not terribly worried at this point.

I am only pulling one head off at this moment. I am assuming that the oil on plug #5 is simply backwash from #6 which is directly across from #5 in the plenum. #6 intake port is full of oil.

[Vigo]

Hmm. Well, i would think another option would be a factory computer with the timing tables changed so that part throttle and full throttle are the same. I think Brian Bucar did that for me on my spirit cal and my educated guess is that Rob Lloyd has the sbec2 v6 cal defined enough to do that. Might be worth asking him about it.

Hopefully you can slap in a piston and go but that's yet to be seen. All of this is important to me since i havent fulfilled my boosted 3.0 plans yet and would like to avoid this breakage.

[Ondonti]

Well looking at the 1989 OEM spark tables part throttle actually adds zero degrees at 0psi boost and WOT adds 1.5. PT timing is MAP based.

Now I have two scenarios. Either the small amount of metal is stuck at the wastegate just because it was an easy path to travel and the motor popped at part throttle high timing out of boost, or the piston failed at high boost low timing and the AFR was just way too high at part throttle.

It would help if I knew if closed loop is activated by MAP or TPS or both. If the motor was in open loop then AFRs would be high even with RRR. Probably 13-15s AFR. ECU would think it is running a safe AFR but I am busy lying to it because of leanburn WBo2 settings.

Honestly the way the OEM 3.0 cal looks in 1989, I don't think PT timing in boost is a problem since it actually runs less timing. Fueling is another issue though. I don't know about that part. Rising Rate Regulators are really meant to function with close loop in a predictable fashion.

[Aries_Turbo]

Hmm. Well, i would think another option would be a factory computer with the timing tables changed so that part throttle and full throttle are the same. I think Brian Bucar did that for me on my spirit cal and my educated guess is that Rob Lloyd has the sbec2 v6 cal defined enough to do that. Might be worth asking him about it.

the cal i did for your spirit had more trickery that could be applied to a 3.0L na cal that is going to see boost...

yours was a 2 bar so right before 14.7psi, i added another data point and richened the last point up significantly to add fuel as the map sensor went blind. I also did that to the timing to take out timing right before the sensor went blind to attempt to keep the setup together on a 2bar deal.

depending on how defined the cal is for the 3.0 of your year, that stuff could be done as well?

Brian

[Ondonti]

the cal i did for your spirit had more trickery that could be applied to a 3.0L na cal that is going to see boost...

yours was a 2 bar so right before 14.7psi, i added another data point and richened the last point up significantly to add fuel as the map sensor went blind. I also did that to the timing to take out timing right before the sensor went blind to attempt to keep the setup together on a 2bar deal.

depending on how defined the cal is for the 3.0 of your year, that stuff could be done as well?

Brian

I was looking at a 1987 t2 CSX "stage 2" bin that has your name on it. I see that the computer gives a lot less fuel at part throttle. That and timing seems to flatline as boost gets out towards 1 bar, instead of dropping......I was just looking at it to get an idea of what a well fleshed out cal looks like. 3.0 doesn't have much figured out and the fuel has just about nothing figured out.

[Aries_Turbo]

I was looking at a 1987 t2 CSX "stage 2" bin that has your name on it. I see that the computer gives a lot less fuel at part throttle. That and timing seems to flatline as boost gets out towards 1 bar, instead of dropping......I was just looking at it to get an idea of what a well fleshed out cal looks like. 3.0 doesn't have much figured out and the fuel has just about nothing figured out.

csx stage 2 is a MP factory cal. my name is on it for work that i did helping to return the quite modified "blueberry" cals back to stock and csx stage 2 form.

robs turbonator staged cals would be good ones to look at.

i dont know, do the 3.0l sbec2 cals have 3d maps?

Brian

[Ondonti]

csx stage 2 is a MP factory cal. my name is on it for work that i did helping to return the quite modified "blueberry" cals back to stock and csx stage 2 form.

robs turbonator staged cals would be good ones to look at.

i dont know, do the 3.0l sbec2 cals have 3d maps?

Brian

Rob says they have 3d maps. I was just looking at the stuff on the Shelgame google site.

[Aries_Turbo]

yeah i just looked at some of them too. they do have 3d maps.

it looks like if you swapped to a 1990 ecu, there is enough defined in that cal to do some fooling around with some tables to make it safer to tow and boost.

Brian

- - - Updated - - -

i take it noone has ever got their hands on the 3.0L turbo prototype ecu or did they use something totally different than our ecus?

Brian

[Vigo]

I think i've heard Brent say they never had real ecus. It's something ive been curious about myself, but i always got the impression it was a dead end from the way people talk about it.

[Ondonti]

yeah i just looked at some of them too. they do have 3d maps.

it looks like if you swapped to a 1990 ecu, there is enough defined in that cal to do some fooling around with some tables to make it safer to tow and boost.

Brian

- - - Updated - - -

i take it noone has ever got their hands on the 3.0L turbo prototype ecu or did they use something totally different than our ecus?

Brian

Swapping to an older ECU sounds like more work then Megasquirt. Now, if I bought a 1990 3.0 Spirit, that would make it a bit easier. Piggyback plug and play harness is very easy to setup for megasquirt. It is the complete rewire install that is killer. The real downside is idle and tip in/decel/transitional driving quality with Megasquirt and the time required to improve that + the possibility of never getting it near stock.

I think i've heard Brent say they never had real ecus. It's something ive been curious about myself, but i always got the impression it was a dead end from the way people talk about it.

I don't know how Chrysler or Shelby would perform bench dyno work on an engine that is in the developmental stage and has no predecessors. I don't think they would have anything manufactured for 10 engines. I would assume they used something onsite that is meant for data recording and fine tuning things while also running the engine. I don't even know what year the prototype 3.0 turbo setup was in active development. Had to be quite early with the Dodge Stealth being released in 1991 which means it was sold in 1990 and had probably killed off competing projects before the turn of the decade.

[Vigo]

Swapping to an older ECU sounds like more work then Megasquirt. Now, if I bought a 1990 3.0 Spirit, that would make it a bit easier. Piggyback plug and play harness is very easy to setup for megasquirt. It is the complete rewire install that is killer. The real downside is idle and tip in/decel/transitional driving quality with Megasquirt and the time required to improve that + the possibility of never getting it near stock.

What makes you think going from SBEC2 to SBEC1 is difficult? It could be a simple as changing out the injectors and re-pinning a couple of wires and then plugging in a 1990 ecu.

[Aries_Turbo]

What makes you think going from SBEC2 to SBEC1 is difficult? It could be a simple as changing out the injectors and re-pinning a couple of wires and then plugging in a 1990 ecu.

exactly. same ecu connector. shouldnt be hard at all.

[Vigo]

I wish i could say i had a 1990 ECU to donate but i dont. I had one extra for my old 90 3.0/5spd car, but i had to use it when i pulled up a bunch of traces on the other one like a tard.

[Sundance 6g72]

SOOO I have a picture of something that brent is going to post


HOLY COW

[Spiritman]

swapping to a 1990 computer would be a breeze. my turbo car is a 1994 acclaim that started life as a 2.5na car. i swapped in the engine harness out of my 91 3.0 4spd car. direct plug in. we should find out if rob has figured anything else out with the 89-91 stuff. as i would like to try using my socketed 91 ecu.

[Aries_Turbo]

lemme dig through my pile of ecu's to see what i have. I may have one.

Brian