Turbo 455

Bruce Hart

Active member
Oct 18, 2011
1,414
6
38
Helping a friend get the bugs out of his 73 23' GMC that has a turbo. An old GMCer buy the name of Westerfelt(sp) more than likely installed the
turbo. The issue at hand is when the turbo kicks in it has power, than bogs down, than jumps forward and bogs down again. This also is apparent when
climbing a long hill. My belief is the turbo sucks out all the gas in the carb reservoir and causing the bogging down. Fuel pump is an electric Carter
4070 so it has the capacity to keep the carb reservoir full at 72 gph.

Any ideas on how to get this issue solved so we can take to the street races on Saturday night! :lol: :lol:
--
Bruce Hart
1976 Palm Beach
Milliken, Co

Got Mechanic Coming
 
> Helping a friend get the bugs out of his 73 23' GMC that has a turbo. An old GMCer buy the name of Westerfelt(sp) more than likely installed the
> turbo. The issue at hand is when the turbo kicks in it has power, than bogs down, than jumps forward and bogs down again. This also is apparent when
> climbing a long hill. My belief is the turbo sucks out all the gas in the carb reservoir and causing the bogging down. Fuel pump is an electric
> Carter 4070 so it has the capacity to keep the carb reservoir full at 72 gph.
>
> Any ideas on how to get this issue solved so we can take to the street races on Saturday night! :lol: :lol:

Bruce,

My short answer is No, but maybe with better descriptions of the system and the case we can get closer.

Several decades back, I was at the heart of several OE turbo projects. After those experiences, I came to the conclusions that conventional
carburetors and turbo-chargers are destined to not cooperate. This is not a bolt-on ever and in any case.

There are two ways to do this and both have a select set of critical issues.

Some, like the Studebaker Super Hawk do a "blow through" by putting the carburetor in a pressure vessel so it is all at the manifold/boost pressure
and then run a pressure compensated fuel pump. Other "blow thoughs" had a carburetor that was a special build that I can not begin to describe
without drawing pictures. Just understand that there could be no atmospheric reference anywhere. (In a memorable case, the test engine crashed when
the boost pressure crushed the brass float and it went so rich that there was wet fuel dripping out the exhaust joints.)

The other side is "draw thought" and while this is mechanically more simple, the problem is that carburetors really don't work the way you probably
think. Every Detroit OE used to have Carburetor labs. They had wizards on the payroll that could make these things behave as needed. When you take
a working carburetor and try to change the regime of its operation more than a few percent, there is every chance that it will end up out in the
weeds.

Now, you say "When the turbo kicks in", by this do you really mean "When the manifold pressure goes positive" or are you using some other criteria?

Other side note, what have you done about spark control? If you are still using the control diaphragm, that is another area that might be an issue.

At this juncture, I am going to swing at the pitch and tell you that if it were my program, I would convert the engine to a dry throttle body and port
injection with EBL and an ECU controlled spark. That is the only way to be able to get you arms around all of the variables that you are fighting
here. For three of those programs above, this was the only way to get a system that even had a shot at being commercial. Only two of those went into
limited production.

Matt


--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
That old GMCer was famous for his engine rebuilds and innovation. Darrel J.
Winterfeldt of Gunbarrel, CO was a GMC Guru in his day. 1980s and 90s.

bdub

-----Original Message-----
From: Gmclist On Behalf Of Bruce Hart via Gmclist
Sent: Friday, June 26, 2020 6:16 AM
Subject: [GMCnet] Turbo 455

Helping a friend get the bugs out of his 73 23' GMC that has a turbo. An old
GMCer buy the name of Westerfelt(sp) more than likely installed the
turbo. The issue at hand is when the turbo kicks in it has power, than bogs
down, than jumps forward and bogs down again. This also is apparent when
climbing a long hill. My belief is the turbo sucks out all the gas in the
carb reservoir and causing the bogging down. Fuel pump is an electric Carter
4070 so it has the capacity to keep the carb reservoir full at 72 gph.

Any ideas on how to get this issue solved so we can take to the street races
on Saturday night! :lol: :lol:
 
Bruce, I am very familiar with Turbo systems as I have had one that was
reliable since `1988 and even communicated with Darrel W. as we sort of
exchanged info.
All my Turbo was with the EFi, not carburetor.
Monitor your fuel pressure at Carb inlet and see that the pressure is there
when it boggs down.

On Fri, Jun 26, 2020 at 6:32 AM Billy Massey via Gmclist <

> TZE033V101385 Canyonlands?
>
>
> _______________________________________________
> GMCnet mailing list
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--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
Problem sounds like fuel starvation under boost conditions. It could be as simple as clogged filters. It could also be that when boost builds, fuel pressure is insufficient to overcome the boost pressure that would exist in the float bowl, preventing fuel flow. The float bowl is normally vented to atmosphere, but on turbo blow-thru setups, the bowl is pressurized. You probably require a fuel delivery system that can adjust fuel pressure several psi above boost pressure.

As Matt said, we need precise details on the setup in order to assist you better.

Les Burt
Montreal
'75 Eleganza 26'

>
> Helping a friend get the bugs out of his 73 23' GMC that has a turbo. An old GMCer buy the name of Westerfelt(sp) more than likely installed the
> turbo. The issue at hand is when the turbo kicks in it has power, than bogs down, than jumps forward and bogs down again. This also is apparent when
> climbing a long hill. My belief is the turbo sucks out all the gas in the carb reservoir and causing the bogging down. Fuel pump is an electric Carter
> 4070 so it has the capacity to keep the carb reservoir full at 72 gph.
>
> Any ideas on how to get this issue solved so we can take to the street races on Saturday night! :lol: :lol:
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
>
> Got Mechanic Coming
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
As Matt said, complicated subject. Much more information would be helpful to
all
the GMC gurus. Talk with Jim K. Fascinating sounding coach, surprised I had
not heard
of it. First thing I would do is change ALL, ALL, ALL of the fuel filters!
My 2 cents.

Marsh (rarely post) Wilkes
Perry Florida

-----Original Message-----
From: Bruce Hart via Gmclist
Sent: Friday, June 26, 2020 7:16 AM
To: gmclist
Cc: Bruce Hart
Subject: [GMCnet] Turbo 455

Helping a friend get the bugs out of his 73 23' GMC that has a turbo. An old
GMCer buy the name of Westerfelt(sp) more than likely installed the
turbo. The issue at hand is when the turbo kicks in it has power, than bogs
down, than jumps forward and bogs down again. This also is apparent when
climbing a long hill. My belief is the turbo sucks out all the gas in the
carb reservoir and causing the bogging down. Fuel pump is an electric Carter
4070 so it has the capacity to keep the carb reservoir full at 72 gph.

Any ideas on how to get this issue solved so we can take to the street races
on Saturday night! :lol: :lol:
--
Bruce Hart
1976 Palm Beach
Milliken, Co

Got Mechanic Coming

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Unsubscribe or Change List Options:
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I think as MAtt and others have said...you could make this work with a carb with lots of goofing about.

First off is this a new turbo build or was it already on the coach AND running before? If it was i'd be looking for clogged filters to start with then
a messed up fuel float.

If this is a new build i'd ditch the carb and go EFI......so much simpler to make work reliably.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
As others has mentioned, turbos and carbs are a difficult mix BUT, there were quite a few commercial applications that worked. From International
Scouts, Corvair Spyders, Olds 215 V8's, Pontiac Trans Ams, all worked with carbs and I'm sure I missed other domestic applications. I've turboed
everything from a 4 cyl Chevy in a 16' Glasspar boat to sand rails with 2000 Pintos to 140 Corvairs, all with carbs and all worked (well, maybe the
boat wasn't the best :lol: ). Of course the diesel and a turbo is by far the best application, IMHO.
The fueling would be the first place to look but check the spark and the advance. He probably use a spark retard in the distributor which could be
plumbed wrong or replaced with a conventional vacuum advance pot. You want to pull spark at boost, just the oposite of a NA motor.
Have fun, Hal
--
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."

1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
Bruce,
I'm leaning toward those who have mentioned turbo boost overcoming fuel pressure. The Quadrajet requires a rather low fuel pressure (about 4 - 6
psi IIRC) lest it flood out at idle and deceleration. Since most turbo systems run just about that much boost pressure, and the carb is vented to its
air inlet, full boost would effectively block any fuel from entering the float bowl. This would, I think, cause exactly your symptoms: good power
until the (relatively small) float bowl empties, than a major bog which kills the boost, allowing the float bowl to refill, lather, rinse, and
repeat.

This is all theoretical, meaning I haven't actually worked on such a system, but I also recall reading about them back in the day. I seem to
remember people adding a supercharger (or turbo) would sometimes drill and tap the back (linkage) side of the fuel pump, and run a hose to the carb
inlet. Boost pressure would thereby act on the back of the fuel pump diaphragm, aiding the pump spring and boosting fuel pressure proportionally.

Another fix you could try would be to add a relatively high pressure (~8-10 psi or so) electric pump, controlled by a pressure switch to turn it on
when the boost comes in. This could be a quick fix.

When GM used turbos back in the 60s, the usually drew THROUGH the carb (Corvair Spyder) so didn't have to deal with this. OTOH, Daryl Winterfeldt
was a pretty good mechanic in his day. (I met him briefly when I first got my GMC. Took my steering knuckles to his house/shop to do wheel bearings,
and he gave me a good deal on a used knuckle when one of mine proved worn.)

HTH, Give me a call if I can help.

Rick Staples


--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
 
Hal, do the boat and the dragsters really count? The boat runs at constant load, and the dragsters need only work right at WOT. The OEM corvairs
did work well, as did the Scouts. I suspect that's where the carb wizards Matt speaks of won their stripes. Injection, be it diesel or gas, seems to
be the easy way to make MAP over 29 inches or so work well. I suspect the direct injection engines like my Kia would be easy enough to boost, in Fact
Kia offers one. It wants a heads up engine control system though lest one beat the bottom out of it. The Diesels are already heavy to stand the
compression pressures but even there they knock the CR down a bit. My big Cummins genset engines ran turbos with no waste gate which always kind of
bugged me but they ran constant speed so I suppose the turbo was sized to make the required boost at that speed. As the heat output went down under
lighter loads the thing simply boosted less I guess. Ask M - B about the value of a working waste gate on their in- line sprinter. Or just look at
the stack of busted motors over in the corner. My electrician went through three of them in his Sprinter, all replaced freebie by M - B.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Johnny, our boat was a pleasure craft that we did a lot of skiing behind and never really what you'd call constant speed-but it wasn't the best
application for sure. When you're 25 years old you try most anything. Never ran a dragster with one but the buggy did run well in the sand or rocks.
The TA motor I installed in an El Camino and it was a blast. The diesels were not waste gated generally until fairly recently if I recall. We simply
adjusted the fuel to determine the boost. It was a balancing act keeping boost/fuel/exhaust/temps in order but thats how we managed it. The waste
gates were required when emissions found the diesels and have made them more responsive at lower speeds.
Hal
--
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."

1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
Turbocharging! Free horsepower! Just call turbo city, or turbonique, give
them your credit card number, tell the you want a turbo to go on an
Oldsmobile 455.
Leave out a few details like final drive gearing, vehicle weight,
state of tune of the engine, manifolding, etc. and see what you get.
I personally have a 2.4 litre P.T. Dream Cruiser, turbo. Little over
2400 pounds all up weight. Dual overhead cams, 4 valves per cylinder,
intercooler, fuel injection, multispeed automatic transaxle, computer
controlled shift points, traction control. 220 S.A.E.net horsepower. Every
component exactly matched to the turbocharger.
It burns 92 octane premium fuel. A lot of it, if you run it hard. It
goes like jet stink. Best Hot Rod I have ever owned, and I have owned a lot
of them.
So, to improvise a wrong sized turbocharger onto a vehicle like our
motorhome, and expect a positive result is a tall, tall, order indeed. Odds
are against you, particularly with a non-computer controlled blow through
Carburetor.
Will it work, ever? You better know what you are doing, or have some
very, very highly trained assistance. And lots of money.
My take on it. Yours may vary.
Jim Hupy
Salem, Oregon

On Mon, Jun 29, 2020, 4:14 PM Hal StClair via Gmclist <

> Johnny, our boat was a pleasure craft that we did a lot of skiing behind
> and never really what you'd call constant speed-but it wasn't the best
> application for sure. When you're 25 years old you try most anything.
> Never ran a dragster with one but the buggy did run well in the sand or
> rocks.
> The TA motor I installed in an El Camino and it was a blast. The diesels
> were not waste gated generally until fairly recently if I recall. We simply
> adjusted the fuel to determine the boost. It was a balancing act keeping
> boost/fuel/exhaust/temps in order but thats how we managed it. The waste
> gates were required when emissions found the diesels and have made them
> more responsive at lower speeds.
> Hal
> --
> "I enjoy talking to you. Your mind appeals to me. It resembles my own
> mind, except you happen to be insane."
>
> 1977 Royale 101348,
>
> 1977 Royale 101586, Diesel powered,
>
>
>
> 1974 Eagle Bus 45',w/slideout,
>
> Rio Rancho, NM
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
We have a 2018 Kia Soul Exclaim with the turbo engine.
Goes like stink on regular 87 Octane and handling is also
stepped up. Color is "Wild Orange" and we love it! It's
Coming up on 24,000 miles! Gets 25-26 mpg around town
and around 30 on the open road at 70+ mph.

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com

________________________________
From: Gmclist on behalf of Johnny Bridges via Gmclist
Sent: Monday, June 29, 2020 17:54
To: gmclist
Cc: Johnny Bridges
Subject: Re: [GMCnet] Turbo 455

Hal, do the boat and the dragsters really count? The boat runs at constant load, and the dragsters need only work right at WOT. The OEM corvairs
did work well, as did the Scouts. I suspect that's where the carb wizards Matt speaks of won their stripes. Injection, be it diesel or gas, seems to
be the easy way to make MAP over 29 inches or so work well. I suspect the direct injection engines like my Kia would be easy enough to boost, in Fact
Kia offers one. It wants a heads up engine control system though lest one beat the bottom out of it. The Diesels are already heavy to stand the
compression pressures but even there they knock the CR down a bit. My big Cummins genset engines ran turbos with no waste gate which always kind of
bugged me but they ran constant speed so I suppose the turbo was sized to make the required boost at that speed. As the heat output went down under
lighter loads the thing simply boosted less I guess. Ask M - B about the value of a working waste gate on their in- line sprinter. Or just look at
the stack of busted motors over in the corner. My electrician went through three of them in his Sprinter, all replaced freebie by M - B.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, GaI forgive them all, save those who hurt the dogs. They must answer to me in hell

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Unsubscribe or Change List Options:
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> Turbocharging! Free horsepower! Just call turbo city, or turbonique, give
> them your credit card number, tell the you want a turbo to go on an
> Oldsmobile 455.
> Leave out a few details like final drive gearing, vehicle weight,
> state of tune of the engine, manifolding, etc. and see what you get.
> I personally have a 2.4 litre P.T. Dream Cruiser, turbo. Little over
> 2400 pounds all up weight. Dual overhead cams, 4 valves per cylinder,
> intercooler, fuel injection, multispeed automatic transaxle, computer
> controlled shift points, traction control. 220 S.A.E.net horsepower. Every
> component exactly matched to the turbocharger.
> It burns 92 octane premium fuel. A lot of it, if you run it hard. It
> goes like jet stink. Best Hot Rod I have ever owned, and I have owned a lot
> of them.
> So, to improvise a wrong sized turbocharger onto a vehicle like our
> motorhome, and expect a positive result is a tall, tall, order indeed. Odds
> are against you, particularly with a non-computer controlled blow through
> Carburetor.
> Will it work, ever? You better know what you are doing, or have some
> very, very highly trained assistance. And lots of money.
> My take on it. Yours may vary.
> Jim Hupy
> Salem, Oregon
>
> On Mon, Jun 29, 2020, 4:14 PM Hal StClair via Gmclist <

>
> > Johnny, our boat was a pleasure craft that we did a lot of skiing behind
> > and never really what you'd call constant speed-but it wasn't the best
> > application for sure. When you're 25 years old you try most anything.
> > Never ran a dragster with one but the buggy did run well in the sand or
> > rocks.
> > The TA motor I installed in an El Camino and it was a blast. The diesels
> > were not waste gated generally until fairly recently if I recall. We simply
> > adjusted the fuel to determine the boost. It was a balancing act keeping
> > boost/fuel/exhaust/temps in order but thats how we managed it. The waste
> > gates were required when emissions found the diesels and have made them
> > more responsive at lower speeds.
> > Hal
> > --
> > "I enjoy talking to you. Your mind appeals to me. It resembles my own
> > mind, except you happen to be insane."
> >
> > 1977 Royale 101348,
> >
> > 1977 Royale 101586, Diesel powered,
> >
> >
> >
> > 1974 Eagle Bus 45',w/slideout,
> >
> > Rio Rancho, NM
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Where was it stated this was a blow through carb? They sure weren't the norm when we were playing with them.
Hal
--
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."

1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout,

Rio Rancho, NM
 
Didn't Maserati at one point build a blow through turbo?
I have the normally aspirated version of Mac's Kia. Often now when we can't go 'out' we run up through the Georgia hills in it. Steams along nicely
and sticks like glue. 3K rpm on the freeway gets a happy 72 mph or so. 33 - 35 mpg highway, 26-30 in town.I'm at 167K miles, only tires and brakes
and filters and oil changes so far. I'm watching to see if the turbocharged cars run that far. In the Soul, turbo is like a diesel, it's a direct
injection engine. I will note, four up tells you there's only 96 CID up front. One or two, it steams along.
Next project - serpentine belt and idlers/tensioner and hoses. It still has the 8 year old originals. They look OK, but.....

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Yes, additional weight plays a very noticeable role in performance. We used
to say that for every pound of weight we took off the race car, that was
equal to adding 2 horsepower.
We can do more with less, it just takes longer. These small
displacement, high strung engines can only do just so much. Keep them in
their "happy spot" and they are amazingly good at their jobs. But, outside
of it, shortcomings appear quickly.
The old adage still is true, "There ain't no substitute for cubic
inches"
Jim Hupy
Salem, Oregon

On Tue, Jun 30, 2020, 7:44 AM Johnny Bridges via Gmclist <

> Didn't Maserati at one point build a blow through turbo?
> I have the normally aspirated version of Mac's Kia. Often now when we
> can't go 'out' we run up through the Georgia hills in it. Steams along
> nicely
> and sticks like glue. 3K rpm on the freeway gets a happy 72 mph or so.
> 33 - 35 mpg highway, 26-30 in town.I'm at 167K miles, only tires and brakes
> and filters and oil changes so far. I'm watching to see if the
> turbocharged cars run that far. In the Soul, turbo is like a diesel, it's
> a direct
> injection engine. I will note, four up tells you there's only 96 CID up
> front. One or two, it steams along.
> Next project - serpentine belt and idlers/tensioner and hoses. It still
> has the 8 year old originals. They look OK, but.....
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me
> in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
early Maserati biturbo"s were blow through

then fuel injection

> Didn't Maserati at one point build a blow through turbo?
> I have the normally aspirated version of Mac's Kia. Often now when we can't go 'out' we run up through the Georgia hills in it. Steams along
> nicely and sticks like glue. 3K rpm on the freeway gets a happy 72 mph or so. 33 - 35 mpg highway, 26-30 in town.I'm at 167K miles, only tires and
> brakes and filters and oil changes so far. I'm watching to see if the turbocharged cars run that far. In the Soul, turbo is like a diesel, it's a
> direct injection engine. I will note, four up tells you there's only 96 CID up front. One or two, it steams along.
> Next project - serpentine belt and idlers/tensioner and hoses. It still has the 8 year old originals. They look OK, but.....
>
> --johnny

--
1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
 
I perceive that it is a blow through as the carb is encased in an aluminum
box with the air from turbo connected on the side.

On Tue, Jun 30, 2020 at 9:59 AM Mike Hamm via Gmclist <

> early Maserati biturbo"s were blow through
>
> then fuel injection
>

> > Didn't Maserati at one point build a blow through turbo?
> > I have the normally aspirated version of Mac's Kia. Often now when we
> can't go 'out' we run up through the Georgia hills in it. Steams along
> > nicely and sticks like glue. 3K rpm on the freeway gets a happy 72 mph
> or so. 33 - 35 mpg highway, 26-30 in town.I'm at 167K miles, only tires and
> > brakes and filters and oil changes so far. I'm watching to see if the
> turbocharged cars run that far. In the Soul, turbo is like a diesel, it's a
> > direct injection engine. I will note, four up tells you there's only 96
> CID up front. One or two, it steams along.
> > Next project - serpentine belt and idlers/tensioner and hoses. It still
> has the 8 year old originals. They look OK, but.....
> >
> > --johnny
>
>
> --
> 1977 Kingsley 455 as stock as it gets except lots of Ragusa parts
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class