Are the 968 intake manifolds magnesium or aluminum?

 

I'm going with aluminum, but have no proof other than its appearance, its weight and how it compares to the pieces on the engine that we know are magnesium.

Cliff

 

The S2 and 968 manifolds appeared to be the same material when I swapped mine. Cast aluminum would be my guess.

 

Any issues putting an intake through an engine rebuild shop's parts washer? If I can find an unobtrusive corner can test Al vs Mg.

 

There may be magnesium in the alloy composition but it's going to be mostly aluminum so it'll stand up to a parts washer with no issue. I have a memory of the composition being cast into the part but I may be hallucinating.

Cheers

 

I've sent some to a local machine shop who has a submersion tank. This is so to clean out the carbon that builds up internally. They return spotless inside. Obviously this is not a "hot tank" with the chemical that they used to clean cast iron engine blocks with. That stiff would make aluminum disappear. Any experienced machinist knows what to soak them in.

Cliff

 

Thanks for the info Cliff. Am also debating whether to Extrude Hone, more to polish the runners so that the oily carbon junk doesn't stick as easily.

 

Extrude hone is very cool, but I won't be doing that for mine. No disadvantage IMHO, but I don't see a tremendous or long term advantage to it and I don't think that the small performance gain could be felt while driving the car. The carbon residue sticks to just about everything except air, so I think it may still accumulate over time.

Cliff

 

Extrude hone is an amazing process if you’re looking for a long term, OEM performance modification that will positively affect the resale and longevity of the motor.

Having the process done to the intake, exhaust as well as having the exhaust ceramic coated back to the cat will give a unique growl and preserve the engine bay with lower under-hood temps.

When it’s time, add a quality stainless exhaust and performance cat with a Stg II chip and you’ll have boring reliability that’s maximising its potential without compromise.

It’ll add provenance to the car with modifications known to increase value through conservation that has a side effect of performance.

 

No issues, did this a few times. Wash with water when done. Make sure you have all the ancillary brackets and so forth removed.

 

I had my intake manifold sandblasted years ago.
Still looks new.

944/968 are cast aluminum.
The Cup cars are magnesium, you can visually identify them by their yellow tinge.

 

Guys - I had no idea about Extrude Hone—amazing process and videos.
Petethepug - Interested to know if you have modded your car in this way? Ceramic coated exhaust, etc? I've got a Stage 1 RSBarn chip but that's it for now. Ceramic coating sounds like... too much? ¯\_(ツ)_/¯ ... but hey looks count, right?

 

Apex - I get it. I SO wanted to respond to all 4 of those sentences, but just decided to let it go...

That being said, Extrude hone is an awesome process, but I'll stop there.

Cliff

 

Well, I'll bite, Extrude Hone isn't all AI enhanced greatness. It is entirely possible to break the casting open, something to be cautious of given not very many 968 intakes have been honed.

Runner diameter increases a little. This tends to decrease the "sharpness" of the torque peak, broadening the peak while lowering the RPM and peak level. This is the effect of the increased runner diameter on the primary resonant frequency.

Am still debating it. On other naturally aspirated cars it gives a feel similar to increased displacement.

 

Short of turbo conversion or (heaven forbid) Nitrous, there is no one magic thing that turns a stock 968 into a rolling rocket. If you were to extrude hone your intake, install the best headers available with the best exhaust system available and do nothing to enhance the flow of air through the cylinder head, you are still restricted by whatever the flow capabilities of the cylinder head happen to be. Are all of the aforementioned a performance gain? - likely so. But IMHO, it is overkill and not worth the expense or effort for a street car. With all of that done, you will finally be able to outrun, by maybe 1 or 2 tenths of a second, a 2018 V6 Camry from 0 to 60 who's acceleration times are identical to the stock 968.

It is my opinion that things like extrude hone is when you are searching for that last little bit of performance from an all-out race built engine and you are proving those gains with dyno testing.

Cliff