You might want to think about a programmable ignition controller. Bill Sims who had an 3.0 S blew up his engine a week or two ago. Now Greg may disagree with me on this, but you really SHOULD have some control over you ignition advance once you start applying boost to a high compression motor with cast pistons. What is $600 compared to a con rod poking through your block? Gotec only cost $600 for the Milano and you have full ignition and fuel control.
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junglejustice
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Greg Gordon
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It's not fully diagnosed yet. This is unrelated to the production kit since it's a much higher stressed racing application (ie. a lot more boost).
I do agree with Zamani that GoTec or other programable units are better then L-Jet. I never said otherwise. However programable injection would not have helped in this case. Programable ingition would have, then again a lower rev limiter would have too.
The motor was above the effective compression ratio limits for pump gas, above the limits of the injectors and I think above the power/rpm limits of the stock rods. Racers typically exceed safe limits in the search for an advantage.
All the facts are not in yet but here is what I know so far, Bill's motor threw a rod at 7000 rpm AND had a piston fail on a different cylinder. Which happened first is hard to say. Either it threw a rod and that took out a piston or a piston broke apart on took out a rod.
In any case the rods were highly stressed with 7000 rpm and nearly 300 horsepower to handle. This pistons were subjected to harsh conditions too because the motor was set up with a lot of boost for the amount of compression. A high effective compression ratio and PUMP gas is a recipe for detonation. The air fuel ratios were fine up to 6000 rpm (verified), at higher levels the injectors couldn't deliver enough fuel.
I do agree with Zamani that GoTec or other programable units are better then L-Jet. I never said otherwise. However programable injection would not have helped in this case. Programable ingition would have, then again a lower rev limiter would have too.
The motor was above the effective compression ratio limits for pump gas, above the limits of the injectors and I think above the power/rpm limits of the stock rods. Racers typically exceed safe limits in the search for an advantage.
All the facts are not in yet but here is what I know so far, Bill's motor threw a rod at 7000 rpm AND had a piston fail on a different cylinder. Which happened first is hard to say. Either it threw a rod and that took out a piston or a piston broke apart on took out a rod.
In any case the rods were highly stressed with 7000 rpm and nearly 300 horsepower to handle. This pistons were subjected to harsh conditions too because the motor was set up with a lot of boost for the amount of compression. A high effective compression ratio and PUMP gas is a recipe for detonation. The air fuel ratios were fine up to 6000 rpm (verified), at higher levels the injectors couldn't deliver enough fuel.
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Greg Gordon
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Ok, I just got off the phone with Bill and got some e mails from him with details.
Here are the facts,
Engine failed when throttle was released for an upshift at 7100 RPM. Bill normally shifts at 6200, he went higher because it wasn't a good place to shift on the track.
Number 1 connecting rod came off both the crank and the piston.
Number 4 piston was destroyed. Not with a hole blown in it or broken, just plain GONE and in lots of small pieces.
#4 connecting rod and wrist pin were still together in the cylinder like normal less of course the piston.
All other pistons and all spark plugs show no signs of detonation damage or stress.
Air fuel ratio was 12.4:1 at normal redline of 6200. It would have been leaner at 7000, Bill guesses about 13:1, quite possibly leaner still.
Original Dyno outputs were well shy of what the engine was putting out on the day it failed. It's original dyno run had one cam set incorrectly and a boost leak. Bill estimates power output was really between 330-340 flywheel horsepower.
So, what happened?
Theory #1. The #4 Piston failed due to high speed detonation brought on by a relatively lean mixture encountered above redline, heat and various other factors including a possible failure of the water injection system. Then a piece of the destroyed piston caused interference with the #1 rod causing the rod to come off both the #1 piston (which stayed in its cylinder) and the crankshaft.
Theory #2. The motor threw the number 1 connecting rod due to power output and RPM well beyond its original design specs. The rod or rod cap then interfered with piston #4 shattering it.
Theory #1 comes from the absolute top U.S. experts in Alfa Forced induction and is the one Bill agrees with. Theory #2 comes from my dad and I.
Here are the facts,
Engine failed when throttle was released for an upshift at 7100 RPM. Bill normally shifts at 6200, he went higher because it wasn't a good place to shift on the track.
Number 1 connecting rod came off both the crank and the piston.
Number 4 piston was destroyed. Not with a hole blown in it or broken, just plain GONE and in lots of small pieces.
#4 connecting rod and wrist pin were still together in the cylinder like normal less of course the piston.
All other pistons and all spark plugs show no signs of detonation damage or stress.
Air fuel ratio was 12.4:1 at normal redline of 6200. It would have been leaner at 7000, Bill guesses about 13:1, quite possibly leaner still.
Original Dyno outputs were well shy of what the engine was putting out on the day it failed. It's original dyno run had one cam set incorrectly and a boost leak. Bill estimates power output was really between 330-340 flywheel horsepower.
So, what happened?
Theory #1. The #4 Piston failed due to high speed detonation brought on by a relatively lean mixture encountered above redline, heat and various other factors including a possible failure of the water injection system. Then a piece of the destroyed piston caused interference with the #1 rod causing the rod to come off both the #1 piston (which stayed in its cylinder) and the crankshaft.
Theory #2. The motor threw the number 1 connecting rod due to power output and RPM well beyond its original design specs. The rod or rod cap then interfered with piston #4 shattering it.
Theory #1 comes from the absolute top U.S. experts in Alfa Forced induction and is the one Bill agrees with. Theory #2 comes from my dad and I.
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Greg Gordon
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junglejustice
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Good job staying on top of this Greg. Thanks for the feedback.... Time and again we hear of this - boosted revs above 6800 (in fact, ANY revs above 6800) on a stock sub is no gouda.....
Boosted power above 250 on a stock bottom-end is also not such a hot idea after 17-20 years....
I wonder what it would be like to take one of Dawie's motors, (maybe some forged rods), one of Domingo's GoTechs and one of your superchargers and putting it all together...?
Seems like this would be the best of all 3 worlds!
Boosted power above 250 on a stock bottom-end is also not such a hot idea after 17-20 years....
I wonder what it would be like to take one of Dawie's motors, (maybe some forged rods), one of Domingo's GoTechs and one of your superchargers and putting it all together...?
Seems like this would be the best of all 3 worlds!
...to Alfa, or not to Alfa? That is the question...
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Greg Gordon
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Hi John. I am glad somebody here commented. I was getting bored reading about shoes and watches over on the Alfa BB. I am stuck in Detroit right now with nothing to do but internet stuff. Everything is Closed because it's Easter.
You are onto something there. A Dawie Motor with lower compression, supercharger, and Gotech should be good for 400-500 reliable streetable horsepower.
You are right about power and RPM. A 3.0 with 250 boosted horsepower and 6000 RPM is no problem. At 7000+ and well over 300 horsepower.....BANG.
You are onto something there. A Dawie Motor with lower compression, supercharger, and Gotech should be good for 400-500 reliable streetable horsepower.
You are right about power and RPM. A 3.0 with 250 boosted horsepower and 6000 RPM is no problem. At 7000+ and well over 300 horsepower.....BANG.
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Greg Gordon
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junglejustice
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Hhmmm...
You see,
A newer model sub-assembly (such as a 164 24 valve block) takes care of any lubrication/piston cooling issues (oil-squirters in the base)
Forged rods - an obvious cure for another weak spot... (Thinking of using Pauter this time - different " + " design from Carrillo and Arrow's I-Beam designs - takes care of "windage"...)
Forged pistons (we see what just happened - another solution)
The opportunity to lower the compression a bit comes with that rebuild...
Dawie's steel-ring inserts is another must, as they would actually allow a 9.5:1 CP safely....
The GoTech takes care of the fuel issues at ANY rpm levels...
Greg, what model SC on a big-bore engine with 24 valves would you suggest?
You see,
A newer model sub-assembly (such as a 164 24 valve block) takes care of any lubrication/piston cooling issues (oil-squirters in the base)
Forged rods - an obvious cure for another weak spot... (Thinking of using Pauter this time - different " + " design from Carrillo and Arrow's I-Beam designs - takes care of "windage"...)
Forged pistons (we see what just happened - another solution)
The opportunity to lower the compression a bit comes with that rebuild...
Dawie's steel-ring inserts is another must, as they would actually allow a 9.5:1 CP safely....
The GoTech takes care of the fuel issues at ANY rpm levels...
Greg, what model SC on a big-bore engine with 24 valves would you suggest?
...to Alfa, or not to Alfa? That is the question...
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Greg Gordon
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The 3.0 24 valver needs a MP90 (90 cubic inches). The 62 cubic inch blower I use on the 12 valve motors won't put out enough for a 24 valve 3.0. This could yield and easy 400-500 horsepower but as you pointed out the motor would need serious mods to hold together, not to mention the driveline! Forged low compression pistons and rods would be a MUST. So would really big injectors and some system to drive them. I have injectors that big although they are not on my site since there is no Alfa motor that can use them.
If I was to build a motor like that I would go with 7.5:1 or 8.0:1 compression. There is no reason to go any higher. It's not like a turbo setup where this would cause a loss in power at low rpm until the turbo spins up. You would still have a huge amount of power right off idle.
If I was to build a motor like that I would go with 7.5:1 or 8.0:1 compression. There is no reason to go any higher. It's not like a turbo setup where this would cause a loss in power at low rpm until the turbo spins up. You would still have a huge amount of power right off idle.
Greetings Greg,John.
Following this very intently.My piston in my n/a 2.8 that greeted with a bang also dissapeared totally.Sorry NOT piston,but gudgoen pin.
Look at new rod bolts at the minimum on a rebuild.Greg,Ive run cast pistons on turbos at 1.4bar boost for over 2 years and had no piston failures.I think Z might have something here regarding timing.In the early days of turbos(1980`s)I would machanically restrict the dizzy advance curve to limit max timing.
John,mail my jou mail addr. seblief-het my hardeskyf ge format .Will graag gesels.
Following this very intently.My piston in my n/a 2.8 that greeted with a bang also dissapeared totally.Sorry NOT piston,but gudgoen pin.
Look at new rod bolts at the minimum on a rebuild.Greg,Ive run cast pistons on turbos at 1.4bar boost for over 2 years and had no piston failures.I think Z might have something here regarding timing.In the early days of turbos(1980`s)I would machanically restrict the dizzy advance curve to limit max timing.
John,mail my jou mail addr. seblief-het my hardeskyf ge format .Will graag gesels.
French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.
Barry: mee too, the 75 T pistons are casted and they seem to hold up pretty well.. 
There is a guy over here that is running 1.9 bars of boost now with the original pistons and he is planning to raise it further.
There is a guy over here that is running 1.9 bars of boost now with the original pistons and he is planning to raise it further.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
Greetings Mats,Yes .the std Alfa piston works well.Im busy with a 2.8 tt at the moment and am using 164 24v pistons in the 12v engine .This motor will see 1 bar all day long .Cr 8:1 on a 12v.
Please send me your mail addr. as Ive had a mother of virusses and had to format my h.d.
Sorry Greg,dont mean to jack the thread.........
Barry
Please send me your mail addr. as Ive had a mother of virusses and had to format my h.d.
Sorry Greg,dont mean to jack the thread.........
Barry
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French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.
hey barry,
those 164 24v pistons? on the 2.8 are you going to do anything about the grooves for the valves?
or are they going to be jus a stright fit in?
also i have been qurious to ask what clutches you have been using? on the alfa gearboxes. what max power did u run on a stocky single plater
thanks
those 164 24v pistons? on the 2.8 are you going to do anything about the grooves for the valves?
or are they going to be jus a stright fit in?
also i have been qurious to ask what clutches you have been using? on the alfa gearboxes. what max power did u run on a stocky single plater
thanks