Performance upgrades for a 912 engine

[Ashley James]

depends what you're trying to achieve

Easier & cheaper to build a hot VW based ( type1 or type4 ) motor if its power youre after and put the original motor on a pallet in the garage.

Sometimes its better to leave original motors alone as you can end up spending a fortune to achieve very little

I think this sums it up well. If you want a worthwhile increase in power, you can probably get a very useable 125bhp or more from one of the Type 4 kits, but they seem to cost $25/35k, which is more than a very good older Boxster.

The standard SC/912 is at the limit of what it can give other than buy a change of camshaft, which will give more power by lifting the rev range. This makes unpleasant road driving and risks unreliability.

As I said it’s worth reading the threads on the 356Forum where there are quite a few who’ve done all this.

[jury]

Add stickers...it makes them faster

[Bathtub57]

Add stickers...it makes them faster

Had that on the last one and it was like a different car! Also 1720, Webers and performance exhaust and all excess weight removed (save my own).

I'm going to take Neils advice and hit the rolling road to see what I've actually got.

I do have a John Maher 2276 motor in my Beetle..

[Splitty64]

So I have built a 2270 type4 motor, lots of power as Max at Revival will agree after a ride in my bus. I have also moved this to full EFI. You need to understand EFI will not give you more power over a correctly setup carb motor, but it will give you its optimum performance at any revs, and the cleanest running engine possible.

I have also built a mildly tuned 912 motor- 1720cc, mild cam etc. Most relevant info was with a mild flow job on a flow bench keeping stock valve sizes the heads maxed out at a potential 134hp. Obviously more radical porting can be done but up goes the cost. For me I will continue up specing the 912 lump as this is the route I want to go, anyone can "buy" more power using different engines but its not my thing.

If you are considering VW power or EFI I would strongly suggest talking to Alan at GAC raging, he builds a lot of the VW drag racing engines plus the winning Formula V engines, plus is an EFI expert.

Also consider shedding weight and improving handling, both are far cheaper and more effective than buying horse power.

Just my thoughts.

Martyn

[Bathtub57]

Martyn your bus sounds mad! Thanks for the input, what's the rest of the spec on your 912? Are you still on carbs?

[neilbardsley]

So I have built a 2270 type4 motor, lots of power as Max at Revival will agree after a ride in my bus. I have also moved this to full EFI. You need to understand EFI will not give you more power over a correctly setup carb motor, but it will give you its optimum performance at any revs, and the cleanest running engine possible.

Thank you for the input this was my understanding too.

"I have also built a mildly tuned 912 motor- 1720cc, mild cam etc. Most relevant info was with a mild flow job on a flow bench keeping stock valve sizes the heads maxed out at a potential 134hp. Obviously more radical porting can be done but up goes the cost. For me I will continue up specing the 912 lump as this is the route I want to go, anyone can "buy" more power using different engines but its not my thing."

What is very interesting. Can you give more information about what dizzy, cam, carbs, manifold you are running? What was changed after the flow bench? The shape of the head? Do you know what your compression ratio is? Do you have a torque curve? 134 on a mild cam is pretty blood good.

[Splitty64]

Martyn your bus sounds mad! Thanks for the input, what's the rest of the spec on your 912? Are you still on carbs?

Spec is stock crank and rods, 9:25cr JE pistons, stock manifolds and carbs but playing with jetting still on pilots. Raised trumpets on the carbs. Full flow oil filtration, ditched the stock filter as no longer needed and heavy. Alternator replacement for dynamo (higher voltage at low revs) 911 rsr engine mount- big weight saving again. Stainless heat exchangers and one of Nick T's exhausts, again a great weight saving.

I calmed down the bus motor so its only making 137hp, but I have 100 lbd ft of torque from just over 1000 rpm, rising to 150 so its got solid grunt through the rev range.

About to build a 2366 type for the "the yellow one" s 914 (my son) based on 103 barrels, plus a webcam 96b cam which was previously in my bus engine.

[Splitty64]

So I have built a 2270 type4 motor, lots of power as Max at Revival will agree after a ride in my bus. I have also moved this to full EFI. You need to understand EFI will not give you more power over a correctly setup carb motor, but it will give you its optimum performance at any revs, and the cleanest running engine possible.

Thank you for the input this was my understanding too.

"I have also built a mildly tuned 912 motor- 1720cc, mild cam etc. Most relevant info was with a mild flow job on a flow bench keeping stock valve sizes the heads maxed out at a potential 134hp. Obviously more radical porting can be done but up goes the cost. For me I will continue up specing the 912 lump as this is the route I want to go, anyone can "buy" more power using different engines but its not my thing."

What is very interesting. Can you give more information about what dizzy, cam, carbs, manifold you are running? What was changed after the flow bench? The shape of the head? Do you know what your compression ratio is? Do you have a torque curve? 134 on a mild cam is pretty blood good.

Stock dissy with Electronic ign module for low maintenance, Newtek SX2 cam, stock carbs and manifolds. Heads cleaned up around the valves etc, plus mild un shrouding of the inlet valves but not too excessive. 134 is the max theoretical hp based on the airflow, I'm probably making less but not dyno'd yet. Its quite a shouty rev hungry engine, little rough though at below 3000rpm which I'm working on.

[Nine One One]

After much reading up, I think I am inclined to buy a Winterburn Capacitor Discharge Ignition System, which seem very good. Can someone tell me whether or not I would need a tach/rev counter adaptor if I purchase one of these. The 912 has a take off for the rev counter from the coil.
http://mgaguru.com/mgtech/ignition/pdf/ ... tering.pdf

Thanks in advance

Ian

[mycar]

Tricky to give a definitive answer to that. The tach might just work. The tach might not.

This from the Winterburn site...

"It will also trigger RVI(Smiths) and voltage sensing tachometers without a special tach adapter in most cases*. Enquire for compatibility or I will ask what you have for a tachometer if you don't ask first! Exceptions noted to date that require an adapter: early Fiat Spiders, Porsche 356 with electronic tach (in house adapter available as special order for modest fee, but lead time to build required), early Mercedes 350SL: adapter for those can be found at: http://www.ashlocktech.com/Home.php The MSD 8920 adapter works well in most other applications. *The later style Smiths RVI with the sensing loop internal to the tachometer (single transistor type)requires the MSD 8920 adapter."

I'd either just fit the kit and see what happens, if it doesn't work the 8920 is readily available.... or call Winterburns with your tach spec and enquire.

[jamie]

Spec is stock crank and rods, 9:25cr JE pistons, stock manifolds and carbs but playing with jetting still on pilots. Raised trumpets on the carbs. Full flow oil filtration, ditched the stock filter as no longer needed and heavy. Alternator replacement for dynamo (higher voltage at low revs) 911 rsr engine mount- big weight saving again. Stainless heat exchangers and one of Nick T's exhausts, again a great weight saving.

Similar spec as my engine, right down to the alternator and the engine mount. I'm not sure on the power - never bothered to check.

Next project for me is electronic ignition. Actually, an oil cooler first, since it runs hot at extended motorway speeds on warmer days.

I considered EFI for a while, but enjoy the carbs and get great mileage, so nothing to be gained.

Not concerned about originality on this motor or the car - it's just a thing to keep me distracted from doing anything productive with my spare time.

[Jonny Hart]

I'd really like to try our CDI+ ignition on a four banger. Given that the head is also a large hemi design, 2V with an offset plug, I would have thought you'd get another 10% power at least.

If you're up for giving it a try, give me a call!

Offer still stands to try out a CDI system designed and built in the UK by a DDKer. No takers?