951 internals??

[wwhalenc]

I'm trying to figure out exactly how different the 951 motor is... is there thread with the differences? I did a search, but I"m not coming up with any specifics.

I gather lower compression pistons, but are components forged/vs cast? Is the head the same (I think yes, but not sure). Beefier oil pump I imagine? Like I said, lots of snippets out there, but not exhaustive lists of specific differences. Any help would be appreciated. Thanks!

[legion]

Porsche ran an add in 1986 that was a picture of all of the parts that were different.

1986 Pistons and rods were forged, at some later point (don't remember) they were cast.

[wwhalenc]

For anyone who cares, there's a little bit of info on this at clarks-garage.com

[Porsche-O-Phile]

'83 n/a pistons & rods are also forged. I think some of the '84 ones were too.

Other than the pistons, cam, and head, the engines are the same. There's also a tap for the turbocharger oil supply line at the upper balance shaft housing. That's about it. The blocks themselves are absolutely interchangeable with n/a blocks.

[AaronM]

I believe that the crank, rods, and pistons are all forged in the 951. I have heard rumours that the later 951 pistons were cast and not forged, but I have never been able to confirm that.

Different head as well, the 951 uses sodium-filled valves for better heat transfer. Cam was also different.

[jgp0rsche]

Originally posted by Porsche-O-Phile
'83 n/a pistons & rods are also forged. I think some of the '84 ones were too.

Forged n/a rods showed up in Feb '84, it's weird that they had 2 different types of rods for the same car.

also the exhaust ports were ceramic coated on the turbo head.

[nize]

the turbo head is completely different. it's not ceramic coated, it's actual ceramic inserts. the entire head was molded around the ceramic inserts. it also has different coolant channels (presumably for better cololing).

[Porsche-O-Phile]

True on the head differences. Actually n/a heads with the sodium-filled 951 exhaust valves are preferred by a lot of tuners since the exhaust ports can be enlarged on those. Not so with the ceramic-lined 951 head ones.

[nize]

that's if you don't know what you're doing. you can increase the flow without enlarging the exhaust ports. porsche engineers went through great pains to put the ceramic ports in for a reason; it performs better on a turbocharged motor.

read here for more;
http://www.lindseyracing.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=LR&Category_Co de=944CYLHEADS

[gt37vgt]

porsche said in the factory service the the rods were scintered metel alloy wich "can be better or worse than forged .
i also herd but not confirmed that the 951 block has full lenth through studs from the bottom of the cradle to the top of the head . and also has oil squirters to cool the pistons .
i can confirm that the turbo has 14 degreess less exhust cam and the atmo cam is a worthy upgrade

[ae1969]

Originally posted by gt37vgt
porsche said in the factory service the the rods were scintered metel alloy wich "can be better or worse than forged .
i also herd but not confirmed that the 951 block has full lenth through studs from the bottom of the cradle to the top of the head . and also has oil squirters to cool the pistons .
i can confirm that the turbo has 14 degreess less exhust cam and the atmo cam is a worthy upgrade

....... uhmmm I have always read and seen the 951 rods all being forged.

.... also the head studs are the same on the 951 as the 944. Virtually identical block to the NA.

..... oil squirters I believe were only found on the 968

What is the atmo cam?

[pozican]

So to sum up -- The differences in the engines are the pistons, cam, and head. And the upper balance shaft housing tap for the turbocharger oil supply exists on N/As? Or does not? Any body / suspension differences? Other than the turbo ensignia

Thanks,
-Alex

[nize]

yeah, the only difference is the turbo emblem.

[pozican]

I was thinking about putting a turbo in mine -- Where is the turbo placed?

[nize]

unless you have;
1) lots of money and
2) lots of time

it's not a worthwhile endeavor.

if you do this properly, in the end, it will cost you more than if you had just bought a turbo car from the get-go, and your franken-turbo will be worth much, much less and be slower.

[pozican]

Well, at the time I was having the engine rebuilt, I was going to have him install / tune it for me. However, I'm rebuilding my engine for roughly 4k for the new parts required for turbo it'll bump me to 5k.

Selling price of nice 944 -- 6k
Buying price of nice 944 turbo -- 10k

My franken turbo tuned -- 11k

However, it will have a rebuilt engine instead of the 10k car with 80,000 miles on it.

[nize]

mileage means very little when dealing with the 951.

i have over 192,000 miles on my car and it runs better than ever.

why do you need to rebuild your engine?

also, there's no way you can properly turbo the n/a for 1k. i'd be wary of whoever told you they could.

[pozican]

Well, my N/A has 208,000 miles on it.

I'll need a timing belt at 215,000.

It's getting REALLY sluggish in 5th gear, which is a problem.
I can take my brother's integra until I hit 5th, and it's just an annoying issue to have the acceleration equivalent to coming off the line in 2nd.
Granted, on curves I rarely hit 5th, but I still would like a bit more power.

I'm burning oil. ( no leaks though )

I'd love another 200k from this car, and the only way I'm gonna get it is to just go have it rebuilt.


Besides, even after the rebuild I know I'm going to want more power... Why not turbo it during the rebuild?

[nize]

have you had a compression test done? know what the numbers are? the symptoms you're describing sounds like they may be unrelated.

if you want more power, why not just install a nitrous system? if you're planning on doing a bargain-basement job by just installing a turbocharger (without an intercooler, oil cooler, bigger injectors, stronger valves, reinforced/shielded exhaust, etc.), you'd be lucky if the motor lasts another 20k miles.

i'm not trying to rain on your parade, and if you could pull it off it would be great. i'd just hate to see another porsche get trashed because it's been 'performance modded' ricer style.

edit; read this thread for the proper way to do a turbo conversion. note how much time, money, and parts it's taking and the car's still not finished;
Project "alpinen Wolf" Official Thread

[nize]

and here's what it takes to properly turbocharge a 944;