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frenchyd
frenchyd UberDork
10/8/19 3:42 p.m.

In reply to Knurled. :

Exactly. In endurance racing Take a well sorted car over  the fast but fragile.  

The best thing is to have something durable and fast.  Two small T3’s putting out 6 psi or so won’t stress any V12 Jaguar. They will simply let it perform easily. 

Now a 1000 horsepower engine?  Everything would be at the limit. Likely never finish the first tank of fuel. But 450 - 500 horsepower  used at 50-60% of its potential?  

Might I remind you million mile haul trucks, going up and down mountains hauling 80,000 pounds are all turbocharged.  

LeMans has been won with turbocharged engines, As has the 24 hours of Daytona etc etc. 

Plus turbo’s do not carry a penalty not if the chassis is old enough. But that chassis beat Corvettes, Porsche’s, BMW’s  etc. not just here in America but Europe, Australia, and Asia. In endurance racing!  

 

Robbie
Robbie UltimaDork
10/8/19 3:48 p.m.
ProDarwin said:
Lof8 said:

I've done some chump racing and seen some powerful cars do well (I've never seen anything out there with 1000 hp)

This raises a question... what is the highest power level car anyone here has seen on track during lemons/chump/wrl?

Highest power level car that ran reliably/completed a race?

Stock e36s are around 200, maybe some stock v8s in the 250ish range. I can't think of anything higher than that, but it's been 5 or more years since I've been in the chump game.

Robbie
Robbie UltimaDork
10/8/19 3:50 p.m.

In reply to frenchyd :

I'm not worried about the motor. I'm worried about the trans in between 400hp and 3400lbs....

Unless it's an Allison I fear for the trans temp gauge.

Knurled.
Knurled. GRM+ Memberand MegaDork
10/8/19 3:53 p.m.

In reply to ProDarwin :

Interested to know as well.  When I was loosely involved in LeMons, the only V8 anything that could finish would have a lot of effort spent on the cooling systems, and the engines were generally unmodified except for simplification.

 

Basically, though, yeah: the more power, the more likely you'd not complete the 24 hours.

 

One of my friends did a bunch of Chumpcar and said that Honda engines are usually good for 22 hours, which is not good in a 24-25 hour race.  And the between race maintenance was to basically replace everything between the wheels and the accelerator pedal.

 

Also told me funny stories of a BMW Diesel semi-factory effort that they had to do an engine swap after some small number of hours, and the replacement engine didn't make it either.

frenchyd
frenchyd UberDork
10/8/19 8:04 p.m.
Robbie said:
ProDarwin said:
Lof8 said:

I've done some chump racing and seen some powerful cars do well (I've never seen anything out there with 1000 hp)

This raises a question... what is the highest power level car anyone here has seen on track during lemons/chump/wrl?

Highest power level car that ran reliably/completed a race?

Stock e36s are around 200, maybe some stock v8s in the 250ish range. I can't think of anything higher than that, but it's been 5 or more years since I've been in the chump game.

You’re right but you’re wrong.  Your conclusion happens to be right but not for the reason you think. 

Its not horsepower that kills motors in endurance racing.  

I’m going to pick numbers it doesn’t matter if they are correct the conclusion will tell you something.  

Let’s say you have 300 horsepower and it gets you lap speed that average 100 mph. Now you race for 24 hours and you’re telling me that after 2,400 miles the engine should blow up?  

Too small? Not fast enough? Try 400 hp and 200 mph. So a 400 horsepower. Engine now blows up at 4,800 miles?  

So it’s not power, what is it?  

Hint think about oil.  Now think about braking, hard braking from a high speed  braking into a slow corner. Those TW200’s  are nice and sticky  and you’ve got good brakes, the best you can. 

You know what oil does in a race? It gets hot, really hot. Now hot oil gets thin.   Hot thin oil is slippery,  then there is the G force those great brakes  generate more G’s then engines generate. 

 

So so what happens to that oil as you slow down and go around a corner?  The oil slides forward up into the timing chain cover. Plus wherever else it can slide. What it’s not doing is waiting around the pickup to be sucked into the oil pump  and sent on to spinning parts of the engine that need lubrication to avoid wear.

History lesson, Back in 1954 Jaguar was developing disk brakes for their new D type. They discovered that under hard braking like their new brakes starved the engine of  oil.  So they dry sumped it. 

Please don’t try to sell me an accusump. The big one is what a quart or two? At peak RPM how long do you think a quart or two of oil will last?  A second or two?  Then what?  Let’s be generous and assume it’s only a second or two before the oil starts to return to be picked up.  With an accusump  the oil pump will send what oil it can to various parts of the engine but it will also have to charge the accusump  thus reducing oil to the engine. So did it help or hurt?  

That’s right lack of oil control blew up those motors not power.  

 

 

Knurled.
Knurled. GRM+ Memberand MegaDork
10/8/19 8:16 p.m.

In reply to frenchyd :

No, it's horsepower.  Specifically, inability to reject the heat that horsepower creates.  Not just the heat in the engine,  but also the heat in the brakes, the heat in the drivetrain, the heat in the wheel bearings...

 

Have you been to an endurance race?  The seasoned vets will replace entire suspension corners at regular intervals - disconnect ball joints, tie rods, and brake hoses, and renew the whole lot.  Everything has a life.

 

The funny thing is, high power only gets you only a few percent in lap times.  Even without figuring traffic into play.

Stampie
Stampie GRM+ Memberand UltimaDork
10/8/19 8:29 p.m.

First my apologies to those that didn't think math would be required.

Running 6 pounds of boost in theory gives you 40.8% increase in hp.

6/14.7 = ~.408

242hp *  1.408 = 340.736hp

To get 1000hp you're looking at least 60lbs of boost.

(1000hp/242hp) x 14.7 psi = ~60.7 psi

So how is this going to happen?

ProDarwin
ProDarwin UltimaDork
10/8/19 8:34 p.m.
Stampie said:

Running 6 pounds of boost in theory gives you 40.8% increase in hp.

That math only works if your engine is already hitting 100% VE.

 

ProDarwin
ProDarwin UltimaDork
10/8/19 8:44 p.m.
Knurled. said:

In reply to ProDarwin :

Interested to know as well.  When I was loosely involved in LeMons, the only V8 anything that could finish would have a lot of effort spent on the cooling systems, and the engines were generally unmodified except for simplification.

The last race I did was 2010 ( surprise ), but the top position was taken by a Mercedes S500.  There was also a Fox Body near the front that was making good power.  Both of those cars were working hard though as their laptimes were right in the mix with ~120-150hp E36 M3boxes.  IIRC the Fox Body would put down a really good lap once in a while.  The Mercedes had a giant factory fuel tank, a good driver cooling setup (ambient temp was typical east coast july - upper 90s with all the humidity), and was running really long intervals which helped it out a bunch.

For the most part, nothing with a V8 was ever known as reliable, although that may have changed since.

 

frenchyd
frenchyd UberDork
10/8/19 9:19 p.m.

In reply to Knurled. :

My Black Jack made roughly 300 horsepower. 

One race required a complete set of bearings until I dry sumped it. From roughly 1978 until it was put up in the Packard Museum those same bearings lasted.  

Otherwise the engine would have blown up.  I’d start out at 140 pounds of oil pressure  and if I finished the weekend with 10 pounds of oil pressure that was typical. 

We did some endurance racing and once I had the dry sump I entered those and every race.  Every practice session,  speed weeks in the Bahama’s was 10 days of racing practice sessions and other events.  From 1978 to 2003 that’s roughly 6-7 races a year for over 150 races  times 5-6 sessions,   That’s 900+ hours on the track  plus the new owners track time. Original bearings. Well to be accurate bearings I put in in 1978.  

300 horsepower  150+ mph top speed.  Oh by the way at 300 horsepower there were times I had to tape the radiator and oil cooler to get enough heat. 

 

 

 

 

 

 

 

Daylan C
Daylan C PowerDork
10/8/19 9:24 p.m.
Stampie said:

First my apologies to those that didn't think math would be required.

Running 6 pounds of boost in theory gives you 40.8% increase in hp.

6/14.7 = ~.408

242hp *  1.408 = 340.736hp

To get 1000hp you're looking at least 60lbs of boost.

(1000hp/242hp) x 14.7 psi = ~60.7 psi

So how is this going to happen?

You can probably get 60psi of boost. Once.

frenchyd
frenchyd UberDork
10/8/19 9:38 p.m.

In reply to Stampie : the 40% number is pretty straight forward. Typical for most supercharged or turbocharged engines 

as to 1000 horsepower?  Who cares?  It’s a number  of no real value.  Did you want it to? 

To get a V12 to 1000 horsepower you’d need to massively increase the porting,  camshaft timing events, lift and duration. A significant increase in size would also help  stock is 5.3 liters it can be taken out to 8 liters

 

yupididit
yupididit UberDork
10/8/19 9:43 p.m.

Like clockwork lmao

Daylan C
Daylan C PowerDork
10/8/19 9:44 p.m.

In reply to yupididit :

Honestly I'm disappointed. I thought I managed to teach him how to turn off bold text for a second there.

frenchyd
frenchyd UberDork
10/8/19 9:57 p.m.
Daylan C said:

In reply to yupididit :

Honestly I'm disappointed. I thought I managed to teach him how to turn off bold text for a second there.

I keep tapping it but it only works sometimes. 

slowbird
slowbird HalfDork
10/8/19 10:02 p.m.

I will gladly root for a turbo V12 Jag to win a lemons race. I honestly think it's possible, even. But it's going to take a metric berkeleyton of work to build it for $500.

Daylan C
Daylan C PowerDork
10/8/19 10:10 p.m.

In reply to frenchyd :

You also don't have to start at the colon. That's what's triggering bold in the first place.

 

klodkrawler05
klodkrawler05 HalfDork
10/9/19 6:44 a.m.
frenchyd said:
 

 

Please don’t try to sell me an accusump. The big one is what a quart or two? At peak RPM how long do you think a quart or two of oil will last?  A second or two?  Then what?  Let’s be generous and assume it’s only a second or two before the oil starts to return to be picked up.  With an accusump  the oil pump will send what oil it can to various parts of the engine but it will also have to charge the accusump  thus reducing oil to the engine. So did it help or hurt?  

That’s right lack of oil control blew up those motors not power.  

 

Just in case anyone else is reading along in this thread and thinks your wild conjecture means you know what you're talking about:

The big accusump is 3 quarts, do you know how many quarts a LS1 Camaro holds? it's 5.5, so that represents a 55% increase in oil capacity. So with accusump we now have a capacity of 2.12 gallons.

Next, any idea how how much volume the LS1 oil pump moves? I found the graph for you, lets assume they're running right up at 6200rpm because you know, clearly someone would always be braking or going through a corner at redline right? The pump is moving 6.8GPM and we have a capacity of 2.12G so assuming absolutely 0 oil is draining back into the bottom of the engine and getting picked up it would take us just under 20 seconds to drain the pan. Without the accusump it would take 11 seconds to drain the pan. So in truth the accusump buys 9 seconds of insurance at a time. 

But aside from this worst case scenario, one of the other benefits of an accusump is that it acts as a bit of a fluid damper, during those hard braking moments or the initial setting the weight into a corner when oil momentarily moves away from the pickup it will come into play. The graphs below show an evo with no oil control (light blue line) vs the same evo with crank scraper and oil pan baffles (dark blue line) and then finally with an accusump (red graph) I think it's pretty obvious which of the 3 setups is the best (note, not the best possible, but of the available options the best)

All of this to say I don't disagree that a drysump is the way better option, but good luck trying to bribe your way past the Lemons judges with a twin turbo dry sumped v12.

 

ProDarwin
ProDarwin UltimaDork
10/9/19 7:08 a.m.

I always appreciate real numbers and math.

frenchyd
frenchyd UberDork
10/9/19 8:03 a.m.
Daylan C said:

In reply to frenchyd :

You also don't have to start at the colon. That's what's triggering bold in the first place.

 

Thanks, but often I can’t get it to start elsewhere.   I try and try below it and instead of starting I lose the “keyboard?” 

Sometimes though what I’m typing is below the keyboard.  

Oops gotta run I’ll be back to pick up more tips. Thanks 

frenchyd
frenchyd UberDork
10/9/19 8:26 a.m.
klodkrawler05 said:
frenchyd said:
 

 

Please don’t try to sell me an accusump. The big one is what a quart or two? At peak RPM how long do you think a quart or two of oil will last?  A second or two?  Then what?  Let’s be generous and assume it’s only a second or two before the oil starts to return to be picked up.  With an accusump  the oil pump will send what oil it can to various parts of the engine but it will also have to charge the accusump  thus reducing oil to the engine. So did it help or hurt?  

That’s right lack of oil control blew up those motors not power.  

 

Just in case anyone else is reading along in this thread and thinks your wild conjecture means you know what you're talking about:

The big accusump is 3 quarts, do you know how many quarts a LS1 Camaro holds? it's 5.5, so that represents a 55% increase in oil capacity. So with accusump we now have a capacity of 2.12 gallons.

Next, any idea how how much volume the LS1 oil pump moves? I found the graph for you, lets assume they're running right up at 6200rpm because you know, clearly someone would always be braking or going through a corner at redline right? The pump is moving 6.8GPM and we have a capacity of 2.12G so assuming absolutely 0 oil is draining back into the bottom of the engine and getting picked up it would take us just under 20 seconds to drain the pan. Without the accusump it would take 11 seconds to drain the pan. So in truth the accusump buys 9 seconds of insurance at a time. 

But aside from this worst case scenario, one of the other benefits of an accusump is that it acts as a bit of a fluid damper, during those hard braking moments or the initial setting the weight into a corner when oil momentarily moves away from the pickup it will come into play. The graphs below show an evo with no oil control (light blue line) vs the same evo with crank scraper and oil pan baffles (dark blue line) and then finally with an accusump (red graph) I think it's pretty obvious which of the 3 setups is the best (note, not the best possible, but of the available options the best)

All of this to say I don't disagree that a drysump is the way better option, but good luck trying to bribe your way past the Lemons judges with a twin turbo dry sumped v12.

 

That’s a lot of information.  Thank you. 

Out of brevity, not rudeness, why did GM dry sump instead of accusump?  

Why do  most serious racers dry sump instead of accusump? 

Your graph doesn’t allow for the time recharging the accudump while also feeding the engine requirements, does it?  Or are stock oil pumps  big enough to do both at the same time? Just looking at the size of the lines feeding back to the accusump compared to the internal  passageways  of an engine won’t more oil go back to the accusump than various parts of the engine?  

 

 

 

infinitenexus
infinitenexus Reader
10/9/19 8:38 a.m.
ProDarwin said:

For the most part, nothing with a V8 was ever known as reliable, although that may have changed since.

 

I've read that the Ford 4.6 mod V8 has a pretty good reliability record there, much moreso than the old 5.0.  

kb58
kb58 SuperDork
10/9/19 9:22 a.m.

Another aspect of the oil supply is air entrainment. At high rpm, as much as half of the "oil" being sucked up by the wet sump pump is air; the coveted oil wedge that keeps the bearings insulated from the spinny bits is now half as effective and half as thick as expected. A dry sump system, by design, helps remove that air, something an Accusump can't do properly, and can cause problems on its own. When the air-containing oil is pumped back into the Accusump reservoir, it out-gases, forming a bubble in the oil side of the piston. Over time, that bubble gets bigger and bigger, and eventually, that one last time the Accusump has to push its contents into the engine, it'll include that big air bubble.

I realize the thread that this is in, and that a dry sump system simply isn't a consideration, but felt it helpful to spell out situations where an Accusump isn't all that.

Lastly, as others have pointed out, a "1000 hp" engine will hardly ever be run at full throttle on-track, so a lot of the assumed heat issues simply won't be an issue. I agree that since average power over a lap is a lot less, it would be better to derate the engine and improve its reliability rather than going for that last 1% of power.

klodkrawler05
klodkrawler05 HalfDork
10/9/19 9:24 a.m.

In reply to frenchyd :

I'd say because drysump is better than accusump? (as I mentioned at the end of my post) 

Although it should also be mentioned that the factory GM "drysump" is really more of a hybrid wet/dry sump and has plenty of it's own warts/oil starvation problems on track cars. which is why most seriously tracked corvettes wind up with an aftermarket dry sump rather than the factory supplied one.

I did over simply the accusump calculation certainly, but my calculation also assumed 0% of the oil ever got back down into the oil pan, which we assume to know isn't true. Assuming when you brake you are also downshifting or lowering revs below redline the time it would take to totally drain the pan gets even longer. The accusump also doesn't have to fully re-charge to be able to supply oil again, it simply needs to have some oil in it to push into the motor, which is why you can see in the graph I shared the oil pressure is a much smoother curve, if you were to completely run the accusump to empty that would be were you would expect a big dip in the oil pressure as seen in the pre-accusump graph.

Again, I'm not saying that it's the best solution, but it is a simple solution that's much cheaper than a drysump. The car which that data came from now runs a proper drysump system as it has approached levels that the accusump cannot keep up with (2G cornering loads on square 315 hoosiers with 800+ hp) and I don't use an accusump system on my current track car. However I have in the past and simply wanted to correct the comment that they only buy you 1-2 seconds of insurance because that's not the reality at all.

frenchyd
frenchyd UberDork
10/9/19 9:53 a.m.

In reply to klodkrawler05 :

 You also mentioned bribing your way with twin turbo’s and a dry sump?  That’s one of the thing I most like about Champ Car  

the 500 point system. A 40 year old car has plenty of points. More than enough to get the dry sump and the turbo’s past inspection.  

Since a dry sump isn’t a power enhancer  but an engine longevity device  frankly I think they should be allowed even on newer cars.  ( Yes if you want we can debate windage)

I used a big 4 stage Weaver because of the size of bearings and the 4.17 inch stroke but clever people could just stack pumps in the oil pan and use one or two to pull oil from wherever and then feed the main one from a remote tank.  

 

 

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