The best engine Porsche never built

[fryardds]

Originally Posted by Ducman

Hey Brian - speaking of cross country and California....you planning to do Rennsport? I'm contemplating a driving trip or a ship the car out and meet up with it.

Hi Don,

Yes, I am will be out in Monterey for RR IV. Wouldn't miss it. The bad news for me is that I don't have time to a drive out there.

You should drive your Targa to the event. It will be really loads of fun to have your car there. There will be a nice group of cars converging on Durango, CO then the group will drive some really kick ass back roads to Monterey.

I can put you in touch with a couple of the guys doing this drive. On of them lives there and maybe you could ship your car to Durango and leave from there. That way you avoid the long slog across the plains. Just a thought.

[kevin_fisher2.0]

Well done all! What process was used to coat the cylinder air guide channels? How about the carb linkage? Yellow zinc? Im at this process with my 2.0 right now.

[Canada Kev]

Originally Posted by Henry Schmidt

Short stroke, huge cams, low compression, oversized intake and MFI is hardly the formula for derivability on paper but on the road these little engines always amaze the driver.

An excerpt from Excellence " Short stroke shoot-out". Buy the magazine to read the whole article, it has all the Porsche stuff fit to print.

Which issue?

[fryardds]

Hi Kevin,

I don't remember, but I will send the author's email address in a PM and you can ask him.

[KNIGHTRACE]

Nice work, anyone want a motor like that installed and tuned in Houston area I will be happy to help out, Henry does very nice work. William

[RSTarga]

What are the downsides of the plastic injector lines? They make me a little nervous.

[Henry Schmidt]

Originally Posted by syzygy

Which issue?

October 2009

I can email a copy of the article to anyone who wants one.

[Henry Schmidt]

Originally Posted by RSTarga

What are the downsides of the plastic injector lines? They make me a little nervous.

I can see why you might be scared............

[tadd]

Nylon 6 is fuel resistant and good for 1000 psi, and that's the thin wall. That's 3X what the pump operates at, so one should not have any worries about plastic :-).

Mcmaster Carr is your friend!

t

[356RS]

Like Tadd said, 1000psi is fine. Photo below shows what can happen if one of the injectors gets plugged-up with below standard working pressure nylon fuel line. That line was 500psi working pressure.

[Henry Schmidt]

I can't imagine that result without heat. IMHO

[356RS]

No heat. This happened on the test bench, while testing a customers set of injectors, with a pump running at 1500 rpm 30 degrees throttle. An injector was showing a very poor pattern when all of a sudden it stopped spraying, plugged up, an a second later the line burst. Very rare to have an injector get completely plugged but it happened.

[356RS]

What I have been using lately is the Nylon 11 high pressure 800 psi WP and a temperature range to +200F.

[efhughes3]

That is one awesome motor!

But, don't you know you can't put something like that in a Targa?

PS- I'm not even close to insinuating my 3.4 is anywhere near as awesome as your 2.8.

[Ducman]

Originally Posted by efhughes3

That is one awesome motor!

But, don't you know you can't put something like that in a Targa?

PS- I'm not even close to insinuating my 3.4 is anywhere near as awesome as your 2.8.

Thanks Ed,
I say why put a motor that sounds that good in a coupe...better that I can hear every glorious snarl

[efhughes3]

Exactly, one of the benefits of a Targa.

[Henry Schmidt]

Originally Posted by 356RS

What I have been using lately is the Nylon 11 high pressure 800 psi WP and a temperature range to +200F.

Thanks for the heads up. We will start using the Nylon 11 for future projects.

[YTNUKLR]

Any road reports or dyno sheets for this thing yet? Would love to compare

[Henry Schmidt]

Scott, just to be clear: you want to lay them on the table and see who's is bigger?
I'm sure you built a great engine. Let's try to remember that different owners have different criteria and that there is more than one way to skin a cat.
I'm sure we would all enjoy seeing your results and that your engine would greatly improve the information in this thread.
Cheers

[YTNUKLR]

No ego in this game, just curious. Defensive much?

Numbers: We got 266hp/196lb.-ft. out of this engine on Randy Aase's dyno.

Specs.
3.0 930 case
2.2 S Crankshaft
3.3 930 oil pump
Carrillo rods
ARP head studs
CP Pistons - 10.3:1
Mahle Nikasil 95mm Cylinders
Goetze rings
SC Heads; 40/38mm ports; 49/41.5mm(stock) valves
Ti retainers, Aasco Springs
DC80-102 Cams
RSR Spec. MFI Pump based on '69 S core
NOS RSR High Butterflies
226mm 78-79 SC Fan assembly, early fan pulley, RSR crank pulley
Series900 fiberglass, RSR German Twill
Supertec Twin Plug Distributor, Moroso wires, Single MSD-6AL ignition box
1-5/8" Alex Job Headers and 'phones



Honestly, I was completely underwhelmed with this configuration. Perhaps it is the builder, but I didn't deviate much from the 'recipe'. . .

-I wish I could have done a custom MFI space cam or run this motor on plain old PMO 46's because we got a flat spot right in the power, because of the MFI pump not quite designed right for this engine. The AFRs go lean to 13.5 from 5200-6000 and it flatlines the power right there.

-I think the RSR High Butterflies in stock configuration are much too big for a 2.8 that even dreams of streetability. They are much more suited to something like a 3.4-3.8L, but the owner wanted to use them anyway. I am sure we lost power over standard smaller throttle bodies.

-I think the ports are a little too big, or the valves are a little too small, for this particular engine. Bigger valves or smaller ports (along with std. throttle bodies) would undoubtedly make this engine better on the street and probably not hurt top-end at all.

-It is difficult to get real compression out of this engine. We got 10.3:1 after much fuss. The combination of short stroke (smaller swept volume) and large dome volume in the head conspire against you. I think the 76cc or so on a standard 2.8 is a better fit for the displacement...a better balance of valve size, dome volume, stroke, and displacement. The large combustion chamber is inherently lazy in its swirl and combustion characteristics and more suited IMO to a 3.2L+ . To get compression out of this engine you have to build a mountain of a piston that is both relatively heavy and compromises optimal combustion chamber design (divides the chamber). So much so that you have to run more advance than is really optimal which is really bad for power.

I am now of the opinion that it was probably intelligent on Porsche's part that they never built this engine.

Why? Because the advantage seems to be durability in displacement-limited (2.8L) classes, where the ability to spin it another 500-1000rpm beyond a long stroke 2.8 makes the difference. And everywhere under 8000rpm the engine is only equal to or less than a long-stroke (standard) 2.8 RSR style motor. And these days, Porsche can spin its much larger and more powerful 4.0 GT3 to 8800, or higher if you want. . .

The complication and expense of a 2.8SS does not seem warranted given that a long-stroke 2.8 or standard 3.0 will probably serve the majority of Porsche drivers better. For the 1% of guys where a 2.8SS is better than a 2.8LS in a 2.8 class (like GT4), because you can turn 9000rpm instead of 8000, it seems to make sense. The economics certainly do not make any kind of reasonable sense with this engine. The torque of a 3.0L is better everywhere and if the engine is kept under 8000 and/or driven on the street, can't argue with that. For raw numbers, displacement is king.

Granted, numbers only tell part of the story and I can see why a little high-revving banshee is a blast in the pants. I was hoping the new owner would chime in and say that, because feel is ultimately more important than the raw numbers, anyway.

And, now that I have posted a searing indictment of the 2.8SS, I will qualify that and say that I have nothing against short-stroke motors in general. I would say a better short-stroke motor is a 2.7SS with the smaller dome chambers, etc. If you want more power than a 2.7SS (which is very close to a 2.8SS and lighter by 22lbs. if you use a mag case), build a 3.0L or. . .go all the way to a new GT3. . .

My 2¢!