To Turbo or Not to Turbo

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SeamusNZ
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To Turbo or Not to Turbo

Post by SeamusNZ »

Hi all again from New Zealand,

I have a lovely ‘62 Spyder convertible fitted with a healthy, but not original non-turbo engine. It is a standard ‘62 85 horse engine. I also have a fully reconditioned turbo unit.

My question:- I understand that, ideally the engine that I have, should not be turbo’d. However, given that the car is driven lightly, mostly at weekends, what is the worst that can happen if I fit the turbo to this engine?

I would really like to have the car as original as possible.

I understand that it may be possible to tame the turbo down to protect the engine. Is this a possible option??

Also, my engine is fitted with an electronic distributor. I understand that I may not be able to use this distributor if I add the turbo. Why is this???

Any help and wisdom is greatfully appreciated.

Cheers SeamusNZ


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bbodie52
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Re: To Turbo or Not to Turbo

Post by bbodie52 »

The Corvair turbocharger unit is not just a bolt-on affair. There were many other internal design changes that had to be made by GM to make a working system. Cylinder head combustion chamber differences, an oil feed and return line for the turbocharger, engine sheet metal and fuel system changes, and distributor ignition timing and pressure retard differences keep the engine from self-destructing by managing fuel and ignition needs under boost to prevent detonation in the combustion chambers. The camshaft design had to be changed, and the pistons, connecting rods and crankshaft had to be strengthened to handle the additional performance under boost. The turbocharged engine cannot tolerate anything less than high-cost, high-octane Premium fuel.

The Corvair Forum post at the link below will describe the differences between the Corvair turbo and non-turbo engine.

:link: viewtopic.php?f=55&t=14251&p=99040&hilit=turbo#p99040
SeamusNZ wrote:...I would really like to have the car as original as possible...
To return your 1962 Spyder back to its original nature, you would need a complete Spyder engine, You cannot accomplish this goal with only a turbocharger portion and none of the other components.
Brad Bodie
Lake Chatuge, North Carolina
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66vairguy
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Re: To Turbo or Not to Turbo

Post by 66vairguy »

Brad covered it. Also note in 62 and 63 heavy duty connecting rods were installed on Turbo engines to withstand the additional power.

The stock Corvair turbo system was basic, which made the system reliable and slow to boost.

Turbo engines did NOT use a vacuum advance distributor like the regular engines. Instead a pressure canister RETARDED the mechanical timing when the boost came on. Today this function can be emulated with a computer controlled ignition that uses boost and detonation sensing.

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SeamusNZ
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Re: To Turbo or Not to Turbo

Post by SeamusNZ »

Thanks for your comments. They are all very well documented elsewhere thank you. My point however is that I do not intend driving the vehicle at anything like peak performance. Surely the mods that were necessary to handle the turbo were for peak performance at maximum revs. Is this assumption correct or not??

Cheers SeamusNZ


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acarlson
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Re: To Turbo or Not to Turbo

Post by acarlson »

SeamusNZ wrote:
Sat Jun 23, 2018 2:55 pm
Thanks for your comments. They are all very well documented elsewhere thank you. My point however is that I do not intend driving the vehicle at anything like peak performance. Surely the mods that were necessary to handle the turbo were for peak performance at maximum revs. Is this assumption correct or not??

Cheers SeamusNZ
SeamusNZ, It seems to me that despite the highly qualified feedback you've gotton from members of this forum, you are still looking for someone to approve your plan to slap a turbo onto a non-turbo engine. I'm guessing that approval just ain't going to happen. I will point out that even if you put the turbo on the engine, it still would not be stock - the numbers would not match (or even come close).

The turbo engine was designed to handle boost at all pressures not just "peak performance at maximum revs". Your engine was not.

However, if you're hell bent to do it anyway, here's what I would do if I were you. Split the turbo shell and remove the turbine. Do NOT run the oil feed line to the turbo (without the turbine there is nothing to lubricate). With no oil feed line you won't need the turbo oil outlet pipe which drains into the right cylinder head (on your engine you wouldn't have the drain tube in the cylinder head anyway). This would give you the look of a Spyder without ever having boost which would eventually destroy your engine. You could run the same timing, same vacuum advance and same distributer. Basically you're just replacing the twin carbs with the Carter side draft carb - everything else stays the same.

I haven't actually tried this and someone may reply to this and say "this won't work because _______" (fill in the blank). :my02: My 2 cents: Take the Forum's advice and do NOT increase the pressure in your stock cylinders by adding a turbo !!

Alec
Alec Carlson
Dahlonega, GA
1965 Regal Red Corsa 4 Speed Turbo Convertible
Restoration "In Progress"...

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toytron
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Re: To Turbo or Not to Turbo

Post by toytron »

acarlson wrote:
SeamusNZ wrote:
Sat Jun 23, 2018 2:55 pm
Thanks for your comments. They are all very well documented elsewhere thank you. My point however is that I do not intend driving the vehicle at anything like peak performance. Surely the mods that were necessary to handle the turbo were for peak performance at maximum revs. Is this assumption correct or not??

Cheers SeamusNZ
SeamusNZ, It seems to me that despite the highly qualified feedback you've gotton from members of this forum, you are still looking for someone to approve your plan to slap a turbo onto a non-turbo engine. I'm guessing that approval just ain't going to happen. I will point out that even if you put the turbo on the engine, it still would not be stock - the numbers would not match (or even come close).

The turbo engine was designed to handle boost at all pressures not just "peak performance at maximum revs". Your engine was not.

However, if you're hell bent to do it anyway, here's what I would do if I were you. Split the turbo shell and remove the turbine. Do NOT run the oil feed line to the turbo (without the turbine there is nothing to lubricate). With no oil feed line you won't need the turbo oil outlet pipe which drains into the right cylinder head (on your engine you wouldn't have the drain tube in the cylinder head anyway). This would give you the look of a Spyder without ever having boost which would eventually destroy your engine. You could run the same timing, same vacuum advance and same distributer. Basically you're just replacing the twin carbs with the Carter side draft carb - everything else stays the same.

I haven't actually tried this and someone may reply to this and say "this won't work because _______" (fill in the blank). :my02: My 2 cents: Take the Forum's advice and do NOT increase the pressure in your stock cylinders by adding a turbo !!

Alec
Alec,
I would not doubt that it could work. I received an engine from someone (free) that had a 150 turbo on it. It was just for show because they just had a bolt, washer and lock nut in the plate hole to block it. I have no idea if it worked but from the look of the bolt it had run. The engine was shot but I think it was for another reason.

Ed Stevenson

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66vairguy
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Re: To Turbo or Not to Turbo

Post by 66vairguy »

Alec summed it up well.

A turbo provides boost even at partial throttle and it main attribute is developing a lot of torque at lower RPM. The 85HP engine would not survive.

You could disable the turbo and just draw through the carb and long manifold, but driveability would not be good. Besides it would be a fake.

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SeamusNZ
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Re: To Turbo or Not to Turbo

Post by SeamusNZ »

Thanks for the feedback. Cheers SeamusNZ


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azdave
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Re: To Turbo or Not to Turbo

Post by azdave »

66vairguy wrote:
Sun Jun 24, 2018 7:57 am
A turbo provides boost even at partial throttle and it main attribute is developing a lot of torque at lower RPM.
I have to strongly disagree with that sentence in two places. A Corvair turbo hardly ever makes boost at partial throttle and certainly doesn't add low RPM torque. Most don't even make good boost until above 3000-3500 RPM in 3rd or 4th gear.

I have added a turbo to a high compression factory NA engine and it is a delicate matter to say the least. You are always on the ragged edge of destruction and I would not recommend it on a Corvair engine unless you have money to burn.
Dave W. from Gilbert, AZ
65 Corsa 140/4
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66 Corsa 455 Toro V8
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SeamusNZ
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Re: To Turbo or Not to Turbo

Post by SeamusNZ »

Thanks for your advice. I appreciate your experience. This is what I was looking for. Cheers SeamusNZ


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miniman82
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Re: To Turbo or Not to Turbo

Post by miniman82 »

Detonation is your enemy here, unless you know exactly what you're doing and have a plan of attack to keep it at bay, I would not attempt this.
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