Soliciting Opinions, Thinking of building a motor like this.... Options

[ClayPerrine]

I am thinking of building a motor like this for my 914...

Short Stroke 2.8L Six


I already have the 76 turbo engine to use as a core. I can buy JE pistions for the cylinders I have, and get the cams reground to the correct profile. The heads on the motor I have would work fine by adding additional spark plug holes and the insert for the MFI injector. I can buy these to use for intakes instead of the pricey S MFI stacks.


I should be able to get 280HP out of it.

Anyone have any comments, opinions or just want to tell me I am full of (IMG:style_emoticons/default/stromberg.gif) ?

[Jeroen]

those throttle bodies have a fuelrail, so why make provisions in the head for MFI style injectors?

the 76 turbo engine is a 3.0, right?

[J P Stein]

Step #1
Gather up a whole pee pot fulla money.......
Step#2
Spend it all on a bunch of hard to find parts......
Step#3
Put it all together in a car and then whut?

[ClayPerrine]

The parts are not that hard to find. You use a 2.2 E or S crank. It fits in the 76 turbo case. The turbo compression ratio is too low for NA operation, so you replace the pistions with JE pistons at 10.5 to one. You put the correct cams, dual plug, and oversized valves, and MFI.


You end up with a 300HP screamer motor.


By using the 2.2 crank, you lower the displacement to 2.8L, but raise the redline to 9K.

[brp914]

very interesting to think about. but as stated, very expensive, time consuming, and, what is the purpose of the car? Will the mfi pump tolerate the de-stroking, re-camming, and dual ig'n? Even if it did, wouldn't it be peaky, laggy, and so unsuitable for street use?

estimate the $ and time to do it. multiply each by 2. estimate the eventual selling price. multiply that by 1/2. Are you comfortable with the difference?

[ClayPerrine]

very interesting to think about. but as stated, very expensive, time consuming, and, what is the purpose of the car? Will the mfi pump tolerate the de-stroking, re-camming, and dual ig'n? Even if it did, wouldn't it be peaky, laggy, and so unsuitable for street use?

estimate the $ and time to do it. multiply each by 2. estimate the eventual selling price. multiply that by 1/2. Are you comfortable with the difference?

Selling price is irrelevant. I am never selling this car. There is not enough money in the world to make me sell it.


Time is free.. It's my hobby. Money.. well.. that is another story.

The MFI pump is not being destroked. It just gets configured as an S spec pump.

It's going to be peaky, and a dog at low RPM ranges. It should be fun to drive though.

[Aaron Cox]

sorry MFI is a waste of time on that motor....

bigger hp and drivability will come from an ITB EFI motor....

MFI is cool, but alot of money for the cool factor....

crankfire and EFI (not megasquirt) will go further

and who will rebuild your MFI pump and make a space cam for it?

[ClayPerrine]

The whole reason for considering it is that I have everything but the 2.2 crank, the pistons, the stacks, and the cams. Beyond that its just a rebuild for me. And its not the first time I have rebuilt a 911 engine.

I was just wondering if anyone thought it would be a fun engine in a 914.....

[Aaron Cox]

fun: yes
money pit: hell yes
Cool factor - SCHWING!!!

PEFI/Crankfire > MFI

[TravisNeff]

That sounds like a very interesting engine. Since you have most of the parts, why not? Sounds like a screamer.

[zen motorcycle]

Let me know if and when you start builidng it so I can learn me some! (IMG:style_emoticons/default/biggrin.gif)

[Brad Roberts]

Proven fact that engine is a screamer. Do it. The crank will be fairly cheap. This combo is down on torque (for a FAT 911) but works well in the 914 with a decent geared box.

I have always loved this combo. The only real custom pieces are the pistons (big deal)

Mild cleanup on the intake and exhaust ports is all that is needed.

We do the same thing with 3.6 engines. Destroke them with custom rods and pistons to 3.4. Dont even have to port the heads for a reliable 350hp. Under 10k plus core to build one.


B

[ClayPerrine]

fun: yes
money pit: hell yes
Cool factor - SCHWING!!!

PEFI/Crankfire > MFI

I like the Old School aspect of MFI.....


AND PEFI can't match the injection pressure of MFI. More injection pressure means better atomization of the fuel.


And I have a short geared 4 speed with a tall overdrive 5th in my 914 right now. 5th is probably too tall, but I have a F that I can flip for 5th.

[JPB]

YES & NO. Build, thats a big fat yes. As for using it no unless you want it use it to adorn your luxurious ocean front work office. Ya know, next to them Rolls Royce antique aircraft engines or a Wenckel.

(IMG:style_emoticons/default/beer.gif) Velly plitty.

[Brett W]

PEFI can beat MFI in every category. If you want High pressure Fuel injection you can turn up the pressure. You can go up to 100+bar with modern injectors. Stock injectors from the later model Porsches and 911s can handle up to 75PSi without any problems.

PEFI is light years ahead of MFI. You can tune the part throttle much better than your can with MFI. Your fuel mileage and drivability will be much better.

Otehr wise the motor sounds like a cool setup.

[ClayPerrine]

sorry MFI is a waste of time on that motor....

bigger hp and drivability will come from an ITB EFI motor....

MFI is cool, but alot of money for the cool factor....

crankfire and EFI (not megasquirt) will go further

and who will rebuild your MFI pump and make a space cam for it?

Then you don't know MFI..... It atomizes fuel far better than EFI because it runs at a much higher pressure.

Pacific Fuel Injection can convert any 911 T pump to S spec.

And I like the fact that the car will be period correct.

Oh.. and I also have to think about the cost of getting my tach rebuilt with a 10K scale. (IMG:style_emoticons/default/happy11.gif)

[Aaron Cox]

PEFI can beat MFI in every category. If you want High pressure Fuel injection you can turn up the pressure. You can go up to 100+bar with modern injectors. Stock injectors from the later model Porsches and 911s can handle up to 75PSi without any problems.

PEFI is light years ahead of MFI. You can tune the part throttle much better than your can with MFI. Your fuel mileage and drivability will be much better.

Otehr wise the motor sounds like a cool setup.

(IMG:style_emoticons/default/agree.gif)

[propricer]

Had a 2.8L in my 914-6 ... real screamer - mucho fun - unbeatable except for a 900cc Ninja. Key was, IMHO, the GE80s which really wake up the engine and the 40IDAs which tune all the pump to the low end acceleration ( vs 46s at the top end ).

Will freshen the engine over the winter, twin plug, etc and stick in my race car for a sprint engine - vs the more endurance 2.7L twin-plug that's currently in there.

It's fun ... do it !!!

[ClayPerrine]

Had a 2.8L in my 914-6 ... real screamer - mucho fun - unbeatable except for a 900cc Ninja. Key was, IMHO, the GE80s which really wake up the engine and the 40IDAs which tune all the pump to the low end acceleration ( vs 46s at the top end ).

Will freshen the engine over the winter, twin plug, etc and stick in my race car for a sprint engine - vs the more endurance 2.7L twin-plug that's currently in there.

It's fun ... do it !!!

If you are talking carbs.. I have a set of 914/6 carbs sitting in a box at home. (IMG:style_emoticons/default/idea.gif)


GE80s huh....

[Matt Romanowski]

Clay - Sounds great to me. I think it would be a fun build and fun motor. *Whisper* "Build it and they will follow....."