914 big engine build

VW based Porsche. In a league of its own.

Moderator: Piledriver

Post Reply
Mikedrevguy
Posts: 2
Joined: Mon Nov 09, 2015 5:10 pm

914 big engine build

Post by Mikedrevguy » Tue Aug 30, 2016 8:40 am

I'm beginning to compile the parts to build a big motor for RevWife's 914.
Looking at the AA type 4 crank - what avantage or pitfalls will there be staying with 2.0 rods vs going with type 1? How will the rod choices affect the deck?
What clearancing of a stock 914 2.0 case can I anticipate?
Any draw backs to going with an 82mm over a 78mm?
AA biral 96mm pistons/cylinders
Cam - 163/86b
Hpmx 44

What should be done to enhance cooling? Anything necessary?

This is her commuter car, fun weekend car, have fun on the 1/4 mile track.

Thoughts? Comments? Revisions..

: have stock 914 2.0 heads. What size valves would be best, were I to open them up?

Thanks in advance.
Mike
_________________

User avatar
Piledriver
Moderator
Posts: 21752
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: 914 big engine build

Post by Piledriver » Tue Aug 30, 2016 1:19 pm

Welcome to the STF!

If going stroker on a t4, the shorter 78mm stroke and a smaller rod journal make it easier to clearance, as the rods do not clear the cam lobes as on a T1: t4 lobes are much wider due to wider cylinder spacing.
A reduced base circle cam may still be helpful, but a 78mm with the EMW 2.0 liter journal should clear most everything.

A 914 transmission is not recommended for drag racing--- 1st gear cannot take the abuse of a proper launch, its supported only on one end. Think of it as a 4 speed with a granny gear.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

Mikedrevguy
Posts: 2
Joined: Mon Nov 09, 2015 5:10 pm

Re: 914 big engine build

Post by Mikedrevguy » Wed Aug 31, 2016 11:12 am

Thanks Piledriver. Am leaning more toward the smaller 78 stroke - just didn't want to discount anything out of hand without exploring.

any suggestion/recommendation for putting the 914 on the strip? Launch soft?
any other options?


Thanks,
Mike

User avatar
Piledriver
Moderator
Posts: 21752
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: 914 big engine build

Post by Piledriver » Wed Aug 31, 2016 12:45 pm

Autocross tracks can be ~1/4 mile :lol:

The 914 is ~ideal for that.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

User avatar
sideshow
Posts: 3214
Joined: Mon Oct 27, 2003 2:00 pm
Location: suth'ern oraygun yusa
Contact:

Re: 914 big engine build

Post by sideshow » Thu Sep 01, 2016 6:45 am

The autocross track is closer to you than a quarter mile track! Who cares about ones ability to drive in a straight line from a light?

If you lack the ability to make left and right turns the obvious solution to middle engine linkage/901 trans is a modern front engine automatic transmission. You would be on your own for a kit but it has been done (normally using both the subaru boxer/trans combo).
Yeah some may call it overkill, but you can't have too much overkill.

User avatar
Piledriver
Moderator
Posts: 21752
Joined: Sat Feb 16, 2002 3:01 am
Location: Van Alstyne, Texas

Re: 914 big engine build

Post by Piledriver » Thu Sep 01, 2016 11:03 pm

There is a SubaruGears ACVW engine<>Subaru trans adapter, I have been eyeballing it myself for my 914 when it gets the 2466.
(The adapter/flywheel combo seems a bit steep but I haven't priced Kennedys adapters in years)

Buidling a ~high HP capable VW or early Porsche trans would probably cost 5X what the subaru trans would, a converted 915 or G60 is just as rediculou$$S and likely no stronger. (I think they have to be run upside down?)

Most of the cost is a one time deal (adapter/flywheel/drive stubs) so even if you DID kill a Subaru trans, you still have all the conversion parts, so you just get another victim.

The Subaru automatic is a short, fat little sucker. Not sure specs or fitment, strength, or even if an adapter exists, but having a flexplate fabbed up won't cost any more than an adapter flywheel.

(I was eyeing Audi FWD transmissions in much the same way)
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

Post Reply