Educate me on a '77 Turbo please

[Nux]

During all of 2018, I've been more or less obsessed by the idea of building a Turbo 911. It started out with with the idea of turboing my own '78 3.2SS. But I just rebuilt that, and it has ITB's and the works. A little too high CR anyway.

I also have a very nice 3.6 setting. It's been looking at me for some time now. But it's too nice to take apart for a build. I'm going another direction with that (or just sell it).

So yesterday, I stumbled upon this baby:





So this should be a fairly rare beast: A 1977 3.0 US Turbo (with tranny). Now, these were rated a very low 6.5:1CR - for US smog reasons at that time I guess?

It will likely need a rebuild. With a more modern turbo and some generel upgrades, should I change compression to say, 7.5:1 or should I just throw 1.4 bar of boost at it (wild guess)?

Any limitations or issues that I should be aware of with this engine?

Oh, and I would probably convert it to EFI. I simply love EFI

[lite75]

The 3.0 responses well to the typical 930 modifications, if you need to pull it apart I would bump the compression. Note that's not a 930 trans.

[RarlyL8]

I don't believe that is an early 3.0L, there are too many 3.3L parts on it such as the intercooler and turbo oil pump assembly. What is the engine type number?
Either way makes a nice engine to hot rod.

[Nux]

Originally Posted by lite75

The 3.0 responses well to the typical 930 modifications, if you need to pull it apart I would bump the compression. Note that's not a 930 trans.

Yes I know - would have been nicer with a 930 trans

[Nux]

Originally Posted by RarlyL8

I don't believe that is an early 3.0L, there are too many 3.3L parts on it such as the intercooler and turbo oil pump assembly. What is the engine type number?
Either way makes a nice engine to hot rod.

hmmm I thought they were just bolt on mods - but you definitely have a point. I'll see if I can get that number.

[lite75]

3rd number, its a 1977.

[Nux]

uhh the plot thickens....




Does it say 930/63?

I'll see if I can get a better picture tomorrow.

[flightlead404]

It's in pretty bad shape, but interestingly a new fuel filter? Interesting A/C mount, is that for the older style compressor?

Wonder why the fuel pressure accumulator and fuel filter are plumbed like that and not against the wall of the engine compartment as per usual.

What's the grey cube above the fuel filter, looks like it might have a vacuum switch attached to it?

[RarlyL8]

This may be a late 1977 engine but I do not think it is a 3.0L early 930. Too many later Euro 3.3L parts on it. The accumulator and filter have been removed with the engine. Add the trans to the mix and this looks like a drivetrain that was pulled out of a 911 conversion car. Type number will tell for sure.

[lite75]

687 is a 3.0 turbo motor, should be a 930/53.

[quattrorunner]

3.0 turbo would be 930/50 or 930/51 or 930/52 or 930/53?
Any other number would be either restamp or not turbo 3.0

[RarlyL8]

If that engine serial number indeed belongs to this engine and is for a 930/53 then someone went to a lot of trouble to convert a 3.0L turbo engine to a 3.3L turbo engine. Need to see that type number stamp and prove it comes from this engine.

[Rawknees'Turbo]

Originally Posted by flightlead404

. . .
Wonder why the fuel pressure accumulator and fuel filter are plumbed like that and not against the wall of the engine compartment as per usual.
. . .

It looks like the person that scavenged the engine decided to upbolt those from the inner fender and remove them with the engine (lines still attached to fuel head, etc.) - they appear to just be laying there.

Originally Posted by Nux

. . .
So this should be a fairly rare beast: A 1977 3.0 US Turbo (with tranny). Now, these were rated a very low 6.5:1CR - for US smog reasons at that time I guess?

. . .

That super low static compression ratio was a built-in safety margin against detonation under boost, since those engines did not run an intercooler.

[TurboKraft]

Originally Posted by Nux

During all of 2018, I've been more or less obsessed by the idea of building a Turbo 911. It started out with with the idea of turboing my own '78 3.2SS. But I just rebuilt that, and it has ITB's and the works. A little too high CR anyway.

I also have a very nice 3.6 setting. It's been looking at me for some time now. But it's too nice to take apart for a build. I'm going another direction with that (or just sell it).

So yesterday, I stumbled upon this baby:

So this should be a fairly rare beast: A 1977 3.0 US Turbo (with tranny). Now, these were rated a very low 6.5:1CR - for US smog reasons at that time I guess?

It will likely need a rebuild. With a more modern turbo and some generel upgrades, should I change compression to say, 7.5:1 or should I just throw 1.4 bar of boost at it (wild guess)?

Any limitations or issues that I should be aware of with this engine?

Oh, and I would probably convert it to EFI. I simply love EFI

We can help you with all the EFI parts.
As long as you keep the 915, you'll have to keep the power very conservative.

An intercooled 3.0L Turbo with EFI and a few bolt-on upgrades makes an easy 350whp @ 1.0bar, and can do 400whp with more boost and/or more displacement (98mm 3.2L).

Originally Posted by flightlead404

What's the grey cube above the fuel filter, looks like it might have a vacuum switch attached to it?

"The Power Box"
A manually adjustable fuel pressure regulator, plumbed in place of the WUR.
Single adjustment.

Haven't seen one of these snake oil parts since the mid-90s, Windward Performance sold a ton of them. Horrible idea.

[flightlead404]

Originally Posted by TurboKraft

"The Power Box"
A manually adjustable fuel pressure regulator, plumbed in place of the WUR.
Single adjustment.

Haven't seen one of these snake oil parts since the mid-90s, Windward Performance sold a ton of them. Horrible idea.

Sounds like a recipe for melted pistons

[Nux]

1977 3.0 Turbo engine!!!

[JakobM]

Yes, as lite75 pointed out in his posts -> both the engine vin (3rd number "7"), and the engine type 930/53 proves this is a 77 turbo.

As you can tell previous owners have done what many others did before the value rise - they changed whatever they could to increase power and did not care about stock value. Just like this one. Some times displacement increase was part of the package as well - try and see under the engine tin whether it has non-finned cylinders on top side, those are early style oem 97mm cylinders (would require other rods). 97 and 98mm cylinders also come fully finned, 97mm from the 965 and 98mm from aftermarket.

Having low compression is also a sort of displacement increase in regards to power output. You can compress more mixture (energy) in a larger camper volume with low CR. Of course this means a bit more "ketchup syndrome" between off/on boost, but more ketchup on the plate on boost in the end 7:1 CR with the fully finned 97mm OEM 965 cyllinders, and German Wösner forced pistons + efi is a nice setup IMO. The 95mm 6:5mm oem setup can make great power on boost with efi.

With the 77 930 you get the 6 bolt crank and 70,4mm stroke fixed. The rest you can change
The heads have the different casted alu material used for turbo models in those years. I believe 3.0 turbos runs a bit smaller piston squirters as compared to 3,3L, not 100% sure. It has a smaller pump compared to 3.3L, but still used in many applications/race cars or simply mount larger pumps if you like.

[RarlyL8]

Yes, as lite75 pointed out in his posts -> both the engine vin (3rd number "7"), and the engine type 930/53 proves this is a 77 turbo.

Not necessarily, the first 3.3L 930's were produced late in 1977. Type number is what I would be looking for. Someone went to a lot of trouble to convert this engine to 3.3L style.

[JakobM]

Originally Posted by RarlyL8

Not necessarily, the first 3.3L 930's were produced late in 1977. Type number is what I would be looking for. Someone went to a lot of trouble to convert this engine to 3.3L style.

Sounds like you are mixing it up with production dates which are not linked to either vin or type numbers, OR components installed. All cars/engines with early vin numbers for a specific year, regardless what year - not only 1978, they are obviously produced the year before launching for the year the vin no indicates. That is clear and nothing special about that. You find the date of production in the COA, and even on the cast stamping on some parts, but never would the vin number or parts be wrong, it would always match the year model matching the certificate.

Are you saying Porsche deliberately, or by mistake, launched early 1978 930's engines with 1977 engine vin no. starting 687XXXX (US) or 677XXXX (ROW) ???? I find that very hard to believe, if that is the case, then please kindly inform where you came across that information...

IMO there is nothing special about this or any other 930 3.0L engine with upgraded parts, IMO it is properly more typical to find the early turbo engines upgraded with 3.3L parts than finding a stock version.

[RarlyL8]

I understand the correlation of engine VIN number and type number. What I was pointing out was that physically this engine looks like a 3.3L version from 1978/9 and that Porsche started producing the 3.3L version late in 1977. If you have one of those early engines (and I did) it would not be incorrect to call it a '77, albeit confusing. In this age of shady internet business dealing I would not trust that the pictures of the VIN number belonged to that same engine. I would want to see the type number and inspect the engine closely.

Yes many 3.0L engines had an intercooler added after the fact, but very rare for this to be a factory 3.3L intercooler. In order to do that you would have to change out the intake, BOV, and throttle body. Much simpler to add the aftermarket intercooler designed for the application.