What alternative engines 'fit' to a 915 box?

911hillclimber · Post by **911hillclimber** » Wed Aug 31, 2011 6:30 pm

The most obvious one is the Subaru 2 litre flat 4 and you can get a kit to make the mating of engine-to-box painless using a 911 clutch.

Has anyone any other ideas of any engine (preferably over 2 litres) that will go on a 915 box??

Any ideas welcome.
I like the idea of a BMW 4 pot or an AUDI 4 pot etc.

Histrally · Post by **Histrally** » Wed Aug 31, 2011 6:48 pm

If you are going the Subaru route why stop at 2 litres. Current STI uses 2.5 four pot with Turbo and there is a version of the Legacy which has a 3 litre 6 pot but normally aspirated. Once you go the turbo route it is easy to find HP.

DIRKBROWNFINGER · Post by **DIRKBROWNFINGER** » Wed Aug 31, 2011 7:02 pm

Smash on here has a subaru in his 914. I think putting a front engined motor in the rear can lead to overheating issues - as in where to locate the rad etc. Or am I missing something like you just leave the fan on constantly!

grannysmith · Post by **grannysmith** » Wed Aug 31, 2011 7:20 pm

A guy I know mated a Citroën diesel to a 901 box in a splitty. Diesels run cooler so no over heating probs, but his bus sounds like a JCB and we don't talk to him anymore.

911hillclimber · Post by **911hillclimber** » Wed Aug 31, 2011 8:03 pm

Thanks for the thoughts.

The engine cooling is not an issue as the car is a full-on race car for hillclimbs, so engine running time is just a few minutes.

A 2 litre turbo STi Impreza will give 270 bhp stock and an easy 350 with a simple tune.

Intercooler is a bigger issue.

Alan @ CanfordClassics · Wed Aug 31, 2011 9:54 pm

Next door to me at work is an Audi 4.2 V8 bolted to a 915.

Alan

KS · Post by KS » Wed Aug 31, 2011 10:14 pm

DIRKBROWNFINGER wrote:Smash on here has a subaru in his 914. I think putting a front engined motor in the rear can lead to overheating issues - as in where to locate the rad etc. Or am I missing something like you just leave the fan on constantly!

Eh?

I have a Subaru 2.5 four-cam motor in my VW Camper – no cooling issues at all. A perfect conversion!

911hillclimber · Post by **911hillclimber** » Wed Aug 31, 2011 10:29 pm

The Audi engines are a good possibility and the V8/V6's are small and alloy.Interesting the box can take the torque.

I'm used to hot Impreza engines in my old hillclimb subaru and they too are alloy, shallow 'cause they are a flat four (deep sump though) but will yield a lot of bhp/torque so easily.

Of the two, the impreza is the favorite, cheap and everything is available inc dry sump.

Any other ideas?

higs356 · Post by **higs356** » Wed Aug 31, 2011 10:45 pm

911hillclimber wrote:Thanks for the thoughts.

A 2 litre turbo STi Impreza will give 270 bhp stock and an easy 350 with a simple tune.

Intercooler is a bigger issue.

Also ...have you ever seen the HP profile for an STI ...quite narrow peak unless its changed in recent models ...fantastic when you are in the "Sweet spot" but not sure what it would be like in a hillclimb car if changing gears a lot.

There must be a huge number of VW type 4 options going up to 3L which can also have forced induction and have huge off-the-shelf spares and options choice ? ...

Nige · Post by **Nige** » Wed Aug 31, 2011 11:16 pm

Going big hp and cc on VW typeIV motor will not be cheap. Subaru motor would be much cheaper to mod and install.

911hillclimber · Post by **911hillclimber** » Thu Sep 01, 2011 6:27 am

I hillclimbed an Impreza for 4 years @ 360 bhp and it was very very good.
The mods were a simple turbo upgrade, bigger injectors and a better mappable ecu.
The turbo came in at 3500 and had full 1.8 bar boost by 4K all the way to 8K.
Off-boost ratings are very good too.

I ran this car in road going Mod Prod so drove it there , raced. drove it back.

I am very dissapointed in my race car which has a 3.2 on PMO's and looking to move on from the old 3.2 to something i know can deliver performance.

The biggest issue with the Impreza engine is it is wet sumped, and a deep one at that. (200mm).

Bruce M · Post by **Bruce M** » Thu Sep 01, 2011 11:40 am

You'll be at the torque limits of the 915 with a suby but the light weight should save the day.

Given your current issues and the frustration of constant tinkering..... Stick to the known quantity of a suby/915. Plenty have been down this route before.

For useful back ground reading google ricola and look at the vw cabrio project on his website. He shortened the sump, for example.

There is also a nice custom sump available from bugat5speed.de plus other useful bits.

Intercooler wouldn't be a problem, either the stock one with a scoop above or a custom one up in the air flow.

911hillclimber · Post by **911hillclimber** » Thu Sep 01, 2011 8:06 pm

I think you are right Bruce.
A proven combo, i know Impreza engines and their 'issues' and thanks for the sump info. Will look into that.

A dry sump kit is a cool £2500.

The 3.2 in the Lola is not well; looks like pistons and barrels which will lead to cams etc and more messing.

Subaru is not as sexy as the 911 but just might actually work.
I happen to have an Impreza gearbox which can be converted to 2 wheel drive and it is perfect and it shifts like a rifle bolt too.

That would save the adaptor plate cost, and i could sell the special 915 box to help.

The Impreza engine is 270 bhp as stock and can be tweeked 'externally' to 360 bhp...

hot66 · Post by **hot66** » Thu Sep 01, 2011 8:25 pm

what about a 2nd hand 993 motor .... easy 300 bhp and 'should' be a relatively easy bolt in

PaulF · Post by **PaulF** » Thu Sep 01, 2011 8:39 pm

Alan @ CanfordClassics wrote:Next door to me at work is an Audi 4.2 V8 bolted to a 915.

Alan

C5 RS6 engine it is then