Time to go Stage II!

[Dusty Bradford]

Who's to say a 3.625 stroke can't turn 9,000 rpm??

 

[Alky V6]

Who's to say a 3.625 stroke can't turn 9,000 rpm??

That's kinda like saying, who says a 200-4R can't stand up to 1,000+ hp?? Or, building up a 109 block to do 8s.
It might. But, for how long?

 

[turbobitt]

I'm sure you're right. Unfortunately, for the turbo I'm using now, there isn't a smaller a/r ratio turbine housing available. I suppose I could see what Bullseye could do for me, if I find I want more after getting it running. Or, I could inject nitrous/methanol directly into the turbine housing to create extra exhaust energy to drive the compressor harder. That nozzle is already set up and being used to spool the turbo. I could simply keep that one nozzle on to feed the turbine housing for the duration of the run.
But the real limiting factor is going to be the cylinder pressure. Not so much a problem with the stroked configuration, but then max rpm becomes an issue. I want to build a screamer.
What I'd like to do first is get the engine running and tuned to the limit of what it can do up to 40 psi, get some track results, collect some data then decide where to go after that. It could very well be that my chassis will have a hard enough time as it is with the projected 1400 bhp.

Traction may not be as bad as you think. Power will probably ramp in slower and help get off the line.
Allan G.

 

[Alky V6]

Traction may not be as bad as you think. Power will probably ramp in slower and help get off the line.
Allan G.

Traction has not really been a problem at the launch. Actually, I could use a little more power about 15-20 feet out. Power wasn't ramping in quick enough. A problem associated with having the boost ramp-up closely tied to the rpm ramp-up. The ramp-up association was very safe. There was little chance of ending up with too much boost at too low of a rpm. Still, I was able to coax a 1.27 60' out of the car.
The traction problem came in at the 1-2 shift, about 80 feet out. Much of the problem is associated with the track, though. The owners of the track have been discussing what to do about the track, lately. Maybe they'll have the track fixed by the time I have the car back together. Otherwise, I'll be traveling to Vegas, or some other well prepped track to do the big boost testing.

 

[Dusty Bradford]

That's kinda like saying, who says a 200-4R can't stand up to 1,000+ hp?? Or, building up a 109 block to do 8s.
It might. But, for how long?

What's different in a Buick than every other engine in the world that doesn't allow it to turn 9000 rpm with a 3.625 stroke when there are engines with more stroke than that turning that same rpm?

 

[Alky V6]

What's different in a Buick than every other engine in the world that doesn't allow it to turn 9000 rpm with a 3.625 stroke when there are engines with more stroke than that turning that same rpm?

Split journal.

 

[Alky V6]

An interesting quote from a book in my library.
"In comparing and contrasting the even-fire/odd-fire 90-degree V-6s of Buick and Chevy, the even-fire design appears preferable (though marginally so) for performance applications. Torsional stresses imparted to the crank by uneven torque pulses seem to be more detrimental than unbalance forces. Use of a heavier flywheel to dampen torque fluctuations (as is Detroit's practice) also reduces engine response. And the uneven firing sequence could cause some ignition problems."

 

[Alky V6]

Another early book I have states, even before the unmachined BMS forged cranks would actually become available, the announcement from Buick's Product Engineering department was that the stroke capability for the expected new forging would be 2.66" to 3.40".
Why the early recommendation to only 3.4"? Were the Buick engineers skittish about suggesting pushing the split journal to a 3.625" stroke?

 

[Alky V6]

The initial plans are to pull the old engine, tear it down and mount the block and new heads back in the car so that I can start fabricating the new intake and exhaust headers. I have a Stage II tunnel intake that I may use as a starting point for the intake. It's had some modifying done to it by a previous owner, but that shouldn't be a problem.
The exhaust headers are going to be like nothing ever seen before. The specs will be surprisingly outrageous.

 

[Dusty Bradford]

Hmmmm. I know of several 3.625 stroke engines turning 9000 rpm. I have never heard of a problem with it if the engine was built right. To me if rpm is the issue then it's time for more stroke...less rpm....same power. Benefits will be extra low end torque and increased reliability.

 

[Alky V6]

Hmmmm. I know of several 3.625 stroke engines turning 9000 rpm. I have never heard of a problem with it if the engine was built right. To me if rpm is the issue then it's time for more stroke...less rpm....same power. Benefits will be extra low end torque and increased reliability.

The issue of the split journal 3.625" stroke has nothing to do with the engine being 'built right'. The issue is the cycle life of the part. Lessening the area of the split journal AND pushing it to extreme stress levels (high rpm) has to lower the cycle life of the part. For those shooting for a record, and can afford to pull an engine down after so many cycles and have the crank checked for cracks, I'm sure it's worth the expense to them. For me, I can only afford to worry about valve springs. I expect this engine to last around 3 years with nothing more than valve adjustments, oil and filter changes, and maybe a valve spring set replacement.
Didn't Neal bring up that he recently came across a couple of stroker cranks that had cracks in them? Obviously coming from a source that had learned when to change out their stressed to the limit cranks before the whole engine got taken out.

 

[norbs]

Donnie what gear is in your car that will bring you to close to 9000 rpm at the traps?

 

[Alky V6]

Donnie what gear is in your car that will bring you to close to 9000 rpm at the traps?

3.73:1 with 29.5 x 10.5 - 15W tires. Actual running diameter 28.4" with a 3.3% tire growth. With the present TC, 12% slippage, should cross the finish around 8500-8600 rpm.

 

[norbs]

I would talk to Dusty 12% slippage is unacceptable.........the ptc units slip about 3.5-4% max.

 

[Alky V6]

I would talk to Dusty 12% slippage is unacceptable.........the ptc units slip about 3.5-4% max.

I know, Norbs.
It's best to fully understand an application before a TC is picked out for it. When I feel I have enough information to relay to Dusty, I'll be looking for his help. Picking out a TC using sim work alone isn't going to do it. Let's wait until this thing is running, first.
I'm sure this is going to be a very unique match up for Dusty.
First things first.

 

[Alky V6]

Lately, I've been revamping the ECM software for the upcoming changes. More rpm, more fueling and more boost.
The fuel demand for a 1500 hp target using a BSFC of 1.35 for methanol fuel will be 2025 lbs/hr.
I plan on using 2 large Weldon electric fuel pumps, 2 - 160 lb/hr electronic injectors per cylinder and one mechanical nozzle per cylinder. This should cover the fueling needs, just barely.

 

[Dusty Bradford]

I would talk to Dusty 12% slippage is unacceptable.........the ptc units slip about 3.5-4% max.

Funny thing about short stroke motors. Sometimes they prefer more slip. 8-9% may be needed for it to perform the best. Donny will have a unique application for sure. I've done a few converters for these engine that will see 9,000 rpm and I can say the commonly used 9.5 like I use in most of these cars will likely be too tight for that much rpm. I feel I would end up with something more like a blower converter in it. Something with a high flash rpm that won't get so tight with rpm. This is the great thing about a high rpm range. It allows you to loosen it up down low to aid in spool-up.

 

[Dusty Bradford]

The issue of the split journal 3.625" stroke has nothing to do with the engine being 'built right'. The issue is the cycle life of the part. Lessening the area of the split journal AND pushing it to extreme stress levels (high rpm) has to lower the cycle life of the part. For those shooting for a record, and can afford to pull an engine down after so many cycles and have the crank checked for cracks, I'm sure it's worth the expense to them. For me, I can only afford to worry about valve springs. I expect this engine to last around 3 years with nothing more than valve adjustments, oil and filter changes, and maybe a valve spring set replacement.
Didn't Neal bring up that he recently came across a couple of stroker cranks that had cracks in them? Obviously coming from a source that had learned when to change out their stressed to the limit cranks before the whole engine got taken out.

When I say "built right" I'm meaning avoiding the Chinese junk. A billet crank and good rotating assembly is a must. Usually these types of engines are ran on the ragged edge so something usually gives up before the crank. Head gaskets...aluminum rods that need replaced at 60-80 passes. But these are also pumping out 1800hp so you can expect some maintenance on them.

 

[Squid4life]

The fuel demand for a 1500 hp target using a BSFC of 1.35 for methanol fuel will be 2025 lbs/hr.
I plan on using 2 large Weldon electric fuel pumps, 2 - 160 lb/hr electronic injectors per cylinder and one mechanical nozzle per cylinder. This should cover the fueling needs.

Holy smokes... This thing is going to be busy!

 

[Alky V6]

The preliminary fuel map is ready for testing.
Two step downs. The first for when the other set of E injectors come online, and the second for when the set of mechanical nozzles come online.
The fueling will be just enough to allow a 42 psi boost level at 9,000 rpm. The fueling will be maxed out at that point.