dumb engine upgrade question, 1.7 - ?? Options

[dale73914]

Hi All,

Rather than trawl for hours ( and i know the info is probably here ), i just thought i would ask.

My 1973 is a 1.7 , running original injection.

Motor is in good running condition, however as is always the case i would like a bit more oomph...

Now i'm pretty new to type4 engines, and know very little about them, aside from performing basic maintenace tasks.

I've worked on most of my cars over the years, but this is only my second aircooled ( used to have a 73 911E 20'ish years ago that ended up as my house deposit (IMG:style_emoticons/default/sad.gif) , but it was serviced by a Porsche dealer)

If i wanted to replace the 1.7 , or upgrade it to a 2.0 or 2056 ? ish sized motor, can i use the original block, the injection etc, or does the whole lot get replaced with a later model 2.0 system.

I dont want to go to carbs if possible, and would prefer to retain the standard look.

Or is there work i can do to the 1.7 possibly to make it that little bit quicker ?

Given i'm also in Australia, hunting for the right parts, and advice is not as easy as it is in the US.

It is just a dry weather Sunday car, i have no plans for any type of motorsport with it, i just want a bit more off the line performance.

Cheers

Dale

[ConeDodger]

The ultimate upgrade for the 1.7 is the McMark Turbo done on an otherwise stock 1.7. I am pretty sure McMark would put you together the stuff you need to do this for a price. I should have driven Mark's 1.7 Turbo when I was down in Sonoma earlier this week but I forgot to ask. I am told by people who have ridden in it that it feels like a Raby 2270. That, and trust me on this I have owned one, is all you could want out of a TypeIV.
Short of that, the only things you can do are to increase displacement with crank, rods, P&C's...
Or, you can get a marginal increase by bolting on a header with free-flowing exhaust. Carbs are pretty much a lateral move used to cure the aging EFI problems. They do sound different but I'm unconvinced that they actually are an improvement.

[Mblizzard]

As the old saying goes in relation to car performance, the only thing that beats cubic inches (centimeters in our case) is cubic dollars!

I know there is a thread somewhere where the god of air cooled engines himself (AKA Jake Raby) outlined what had to be done to take a 1.7 to a 2056 and beyond. The reality of the upgrade is that most of the 1.7 gets replaced with other parts.

With the 1.7 you are limited by the heads and how well they flow. You could put 103mm cylinders on it but you would never realize the full potential of many of the possible upgrades. By the time you switch heads, get a 71 mm crank, and so on you have encountered some serious costs.

There will be others that will have more detail or you can PM me and I can send you the link to the information. But my thoughts are that it would be cheaper to upgrade to a 2.0 than it would be to upsize the 1.7.

On the other hand you may want to touch base with McMark at Original Customs and ask about his turbo 1.7. But I am sure that is cubic dollars as well.

[jcd914]

I don't know what McMark might want to turbo a 1.7 but I rode in his at WCR and it performed very well, probably not quite like a 2270 though.
It would definitely be something I would consider if I had a running 1.7, instead of a 2.0.

As far as upgrading a 1.7 you can make a relativly simple and cheap jump to a 1911 by going to 96mm P&Cs. The 1.7 heads have to be opened up to fit the new cylinders but a machine shop can do that while they do some valve work that your heads probably need anyway.
Using the stock 1.7/1.8 crank and rods with 96mm pistons & cylinders make a nice peppy 1911cc engine that is very drive-able.
Your existing FI, intake, exhaust, etc is all compatible with this upgrade.

Jim

[mepstein]

Just drop in the 3.2 six. It will be cheaper in the long run.

[ConeDodger]

I don't know what McMark might want to turbo a 1.7 but I rode in his at WCR and it performed very well, probably not quite like a 2270 though.
It would definitely be something I would consider if I had a running 1.7, instead of a 2.0.

As far as upgrading a 1.7 you can make a relativly simple and cheap jump to a 1911 by going to 96mm P&Cs. The 1.7 heads have to be opened up to fit the new cylinders but a machine shop can do that while they do some valve work that your heads probably need anyway.
Using the stock 1.7/1.8 crank and rods with 96mm pistons & cylinders make a nice peppy 1911cc engine that is very drive-able.
Your existing FI, intake, exhaust, etc is all compatible with this upgrade.

Jim

Mark has turned the boost up a bit since then. He was running 6psi which is less than most factory systems just to make sure he didn't need a ride home on a trailer.

[dale73914]

Thanks all, a 1911 sounds like it might be a plan.

Although, if I put a 2.0 type 4 in, can I run the 1.7 injection,, or do I change everything ( and is the wiring loom much of a challenge to swap over ?? )

Cheers

Dale