GAMI presentation from OSH '24

[Shadrach]

4 minutes ago, Fly Boomer said:

Is it typical for the torque curve to be so flat?

yes with Forced induction.

[Shadrach]

1 minute ago, N201MKTurbo said:

I imagine the flattening of the torque curve is where the boost controller kicks in.

Indeed. Volumetric efficiency remains nearly constant regardless of piston speed. Same push for every power stroke all the way up...

[Fly Boomer]

1 minute ago, Shadrach said:

yes with Forced induction.

That makes sense.  Didn't occur to me that the Corvette is turbocharged.  I guess that's about the only way you can shoehorn 1,000 hp into a Corvette.

[Shadrach]

4 minutes ago, Fly Boomer said:

That makes sense.  Didn't occur to me that the Corvette is turbocharged.  I guess that's about the only way you can shoehorn 1,000 hp into a Corvette.

It has two turbos. Not the only way but certainly the most prudent way to get that kind of power.

[N201MKTurbo]

I had a sports car once. I found it very frustrating to drive. It was a 280ZX. If I was to take you out on a highway without traffic and cover the speedometer and told you to drive 55 MPH (the speed limit at the time) and then uncovered the speedo, you would be going between 90 and 100 MPH. Driving it 55 was like driving a normal car in a school zone. Who wants to drive school zone speeds all the time? I have a Yamaha Vino 125 scooter I bought for my wife. She never drives it, so I drive it sometime. I can drive that thing like a maniac! and never get a ticket. I can go full throttle at every stoplight, listening to that little engine roar! Way more satisfying than driving the ZX at 55.

[EricJ]

36 minutes ago, Fly Boomer said:

Is it typical for the torque curve to be so flat?

With forced induction a good controller can do that.    On an NA engine if the intake is well designed, or at least not a limitation, then the torque curve can also be very flat.   Basically, on an NA engine with a decent intake the torque curve can be flat until the intake (or something else, e.g., valves) becomes the limitation.  Once the intake can no longer flow sufficiently to support the demand at increasing rpm, torque starts dropping off.   There've been a lot of trick intakes in the automotive world that change geometry based on rpm to better optimize flow across a wider rpm range and flatten the torque curve.    

https://en.wikipedia.org/wiki/Variable-length_intake_manifold

Many of our horizontally-opposed GA airplane engines have relatively large displacement but turn very slowly (in comparison to auto engines), and wind up with a pretty flat torque curve without any fancy tricks in the intake. 

[Pinecone]

52 minutes ago, EricJ said:

On an NA engine if the intake is well designed, or at least not a limitation, then the torque curve can also be very flat.   Basically, on an NA engine with a decent intake the torque curve can be flat until the intake (or something else, e.g., valves) becomes the limitation.  Once the intake can no longer flow sufficiently to support the demand at increasing rpm, torque starts dropping off.   There've been a lot of trick intakes in the automotive world that change geometry based on rpm to better optimize flow across a wider rpm range and flatten the torque curve.    

My 2002 BMW M3 is like that.  Very flat torque curve.

Strange to drive as you never get the rush, it is just all of a sudden going a LOT faster.

Hard to read the numbers, but around 242 at 2500 RPM, peaks at 270 at 4500 RPM, and is still over 200 at 8000 RPM.

[Shadrach]

24 minutes ago, Pinecone said:

My 2002 BMW M3 is like that.  Very flat torque curve.

Strange to drive as you never get the rush, it is just all of a sudden going a LOT faster.

Hard to read the numbers, but around 242 at 2500 RPM, peaks at 270 at 4500 RPM, and is still over 200 at 8000 RPM.

That is a nice, usable torque curve,  that surely makes for a fun driving experience. A torquey, high revving, NA engine mated to a good gear box can be sublime. However, that is not a flat curve compared to forced induction engine…the tuner was starting the runs at 2000 but peak torque is available at 1500rpm.

 

Posting Auto torque curves = Maximum thread drift accomplished!

[EricJ]

Here's a fairly flat torque curve for an NA engine.   This was a chassis dyno session for classing my non-M BMW 328i TT car with a stock engine and computer.   Torque doesn't vary much until it gets to about 5500 rpm where it just can't support the air flow any more and starts dropping off, so hp starts dropping off with it.

Somewhere I saw (and I thought I had a copy) a dyno plot for a typical GA engine, and it also had a very flat torque curve right up to red line.   I can't find it now else I'd post it.   If I do find it in the near future I'll pop it up here because I think it's interesting.

   

[Shadrach]

46 minutes ago, EricJ said:

Here's a fairly flat torque curve for an NA engine.   This was a chassis dyno session for classing my non-M BMW 328i TT car with a stock engine and computer.   Torque doesn't vary much until it gets to about 5500 rpm where it just can't support the air flow any more and starts dropping off, so hp starts dropping off with it.

Somewhere I saw (and I thought I had a copy) a dyno plot for a typical GA engine, and it also had a very flat torque curve right up to red line.   I can't find it now else I'd post it.   If I do find it in the near future I'll pop it up here because I think it's interesting.

   

That is flat.  What year? I imported a Canadian E91 with the N52 six. It feels very linear. It’s proven to be robust in the extreme after 15 years and 220k. 

[EricJ]

14 minutes ago, Shadrach said:

That is flat.  What year? I imported a Canadian E91 with the N52 six. It feels very linear. It’s proven to be robust in the extreme after 15 years and 220k. 

1998.   It was a stock M52 other than deleting the DTC throttle.   I had an M50 intake for it that I never installed because I decided I'd rather keep the low-end torque.  It was bullet-proof.   It did about eight years of full-season regular track use and needed very little maintenance.   Won a couple regional championships and set some track records with it.   

[Rick Junkin]

Just saw this on Beechtalk. If you can swing self-fueling and local storage of 55g drums is allowed where you are you may want to have a look. G100UL distribution on a small scale could be commencing very soon. It’s a start anyway.

https://www.beechtalk.com/forums/viewtopic.php?f=7&t=231502

[Fly Boomer]

10 hours ago, Rick Junkin said:

G100UL distribution on a small scale could be commencing very soon. It’s a start anyway.

Got to love the posters on BT who incredulously ask "You mean it will cost MORE than 100LL?  That can't be right!!!!!!!"

[Andy95W]

On 8/9/2024 at 6:06 PM, N201MKTurbo said:

I had a sports car once. I found it very frustrating to drive. It was a 280ZX. If I was to take you out on a highway without traffic and cover the speedometer and told you to drive 55 MPH (the speed limit at the time) and then uncovered the speedo, you would be going between 90 and 100 MPH. Driving it 55 was like driving a normal car in a school zone. Who wants to drive school zone speeds all the time? I have a Yamaha Vino 125 scooter I bought for my wife. She never drives it, so I drive it sometime. I can drive that thing like a maniac! and never get a ticket. I can go full throttle at every stoplight, listening to that little engine roar! Way more satisfying than driving the ZX at 55.

Totally agree!  I’ve always said it’s a lot more fun to thrash an underpowered car than to hold back a thoroughbred like a Ferrari.

(My first car was a 1967 VW Karmann Ghia.)

[N201MKTurbo]

4 hours ago, Fly Boomer said:

Got to love the posters on BT who incredulously ask "You mean it will cost MORE than 100LL?  That can't be right!!!!!!!"

So, I have only seen UL94 for sale at one airport. It was Watsonville CA. It was $7/gal. Over $1 more than 100LL. UL94 is just 100LL without the lead. So By their reasoning, it should be cheaper.

After all 100LL is a boutique fuel product. the unleaded fuels are custom runs with very low volumes. Of course it costs more. Once the world settles on an unleaded fuel and it totally replaces 100LL, It will probably settle to about the same price.

[Fly Boomer]

15 minutes ago, N201MKTurbo said:

So, I have only seen UL94 for sale at one airport. It was Watsonville CA. It was $7/gal. Over $1 more than 100LL. UL94 is just 100LL without the lead. So By their reasoning, it should be cheaper.

After all 100LL is a boutique fuel product. the unleaded fuels are custom runs with very low volumes. Of course it costs more. Once the world settles on an unleaded fuel and it totally replaces 100LL, It will probably settle to about the same price.

And, I think some of these people have engines that would cost north of $100k to replace, so anything that might get a few more trouble-free hours might be worth it.  I suppose that claim remains to be seen, but the pictures of the internals after running G100UL look remarkably clean.

[Pinecone]

6 hours ago, Fly Boomer said:

Got to love the posters on BT who incredulously ask "You mean it will cost MORE than 100LL?  That can't be right!!!!!!!"

The ones that drive me nuts are the ones taking about "a lot more expensive" or "large increase in price" or "go up frmo $6 to $11 a gallon.

People, Vitol is selling in wholesale quantities for $1 per gallon more than 100LL costs.  If someone raises their fuel price from $6 for 100LL to $11 for G100UL, they RIPPING YOU OFF.

 

[Pinecone]

2 hours ago, Andy95W said:

Totally agree!  I’ve always said it’s a lot more fun to thrash an underpowered car than to hold back a thoroughbred like a Ferrari.

(My first car was a 1967 VW Karmann Ghia.)

I had a student at the track who was driving a Ferrari F430 Scudaria.  He let me drive it.   It was almost boring as the car was SO GOOD.

[Shadrach]

8 minutes ago, Pinecone said:

I had a student at the track who was driving a Ferrari F430 Scudaria.  He let me drive it.   It was almost boring as the car was SO GOOD.

Analog cars will always be more engaging. Performance has reached crazy levels but the cars are becoming less and less engaging. even the exhaust notes sound like they were designed in a studio. I’m not an old man, but when it comes to sports cars, I feel like a curmudgeon. 

Ferrari builds beautiful cars, but their decision to drop manual gearboxes over a decade ago is puzzling. Perhaps a larger percentage of Ferraris see the track than I think.

[EricJ]

37 minutes ago, Shadrach said:

Ferrari builds beautiful cars, but their decision to drop manual gearboxes over a decade ago is puzzling. Perhaps a larger percentage of Ferraris see the track than I think.

Paddle shift with a dual clutch >> manual stick.

 

[Shadrach]

45 minutes ago, EricJ said:

Paddle shift with a dual clutch >> manual stick.

 

Faster is not the same thing as better. Hence my comments that perhaps more are being used as track cars where absolute numbers trump the pleasure of rowing while heel and toeing. 

Don't get me wrong new generation of autos are great…heads and tails above yesteryears slush boxes. Whether dual clutch or hydraulic (ZF 8hp) they’re great. I have driven many, many PDK Porsches and I would only choose one if I was trying to be as fast as possible…not for fun.

[Pinecone]

1 hour ago, Shadrach said:

Analog cars will always be more engaging. Performance has reached crazy levels but the cars are becoming less and less engaging. even the exhaust notes sound like they were designed in a studio. I’m not an old man, but when it comes to sports cars, I feel like a curmudgeon. 

Ferrari builds beautiful cars, but their decision to drop manual gearboxes over a decade ago is puzzling. Perhaps a larger percentage of Ferraris see the track than I think.

A lot do.

But the paddle shifted manual (with a clutch and gears) is so superior that it is like putting in modern avionics.

[Pinecone]

15 minutes ago, Shadrach said:

Faster is not the same thing as better. Hence my comments that perhaps more are being used as track cars where absolute numbers trump the pleasure of rowing while heel and toeing. 

Don't get me wrong new generation of autos are great…heads and tails above yesteryears slush boxes. Whether dual clutch or hydraulic (ZF 8hp) they’re great. I have driven many, many PDK Porsches and I would only choose one if I was trying to be as fast as possible…not for fun.

Isn't the PDK a manually shifted sluchbox?

My E46M3 has the same transmission as the manual cars (and same clutch), just hydraulically actuated.

The first time I came into turn one at full tilt, hit the brakes and tapped the down paddle a few times, I was SOLD.  MUCH more brain power on getting the braking just right and hitting the turn in just perfectly.

[EricJ]

4 minutes ago, Pinecone said:

My E46M3 has the same transmission as the manual cars (and same clutch), just hydraulically actuated.

The DCTs were great until they broke or needed replacement.    

[Shadrach]

7 minutes ago, Pinecone said:

Isn't the PDK a manually shifted sluchbox?

My E46M3 has the same transmission as the manual cars (and same clutch), just hydraulically actuated.

The first time I came into turn one at full tilt, hit the brakes and tapped the down paddle a few times, I was SOLD.  MUCH more brain power on getting the braking just right and hitting the turn in just perfectly.

PDK stands for…Doppelkupplungsgetriebe

Which literally translates to

Dopple - double

Kupplungs - clutch

Getriebe - gear

Definitely a double clutch transmission.

Like most German, it sounds beautiful when spoken…