Would this engine combo Work??

[RonD922]

Hello,

I was just bored and thinking...A very expensive thing to Do!!

I was wondering if any of you tech wizards and performance Guru's would be so nice as to tell me if this is feasible...

2.7 7R case

-Twin Plug heads with the same combustion chamber and intake/exhuast valves as stocki 2.7 heads..

-2.8RSR pistons-10.3 : 1 in RSR-Bruce Anderson says 11.4 : 1 becuase of the smaller combustion chamber for the 2.7 heads but I understand that with twin-plug heads I can safely run one compression point higher and stil run on 93 Octane-Pump Gas

-E cams-to keep a nice powerband-or Suggestions for a driveable cam profile??

-46mm Webers-if nessecary?

-3.6 litre twin plug distributor with some sort of dual coil system...

What do you guys think??

Any suggestions??

Am I insane or no??

I am thinking of modifications that can be done to a 2.7 with only top end work...But I l,ike to be different even if costs more, blows up or takes more time!!

Thanks,
Ron

PS Just a thought I am not Knee deep and work, and nose level in debt, in this project...Just dreaming!!

[RLJ]

Great thoughts, sounds like rock and roll, get rid of the carb. thoughts!

Build something with injection. Don't care which style but injection.

46mm Webers/PMO's on a 2.7 motor needs to spin so fast only dogs can hear it, to keep the plugs from fouling.

Dual plug and 10.2:1 is were I ended up and it works great!!!

To much carb for my 3.2 on the street I'm changing.

Randy Jones
1971 911

[RonD922]

How many HP on your 3.2 Twin Plug??

What setup did you use with the coils??

What injection do you suggest??

I thought carbs becuase I have 46mm webers and MFI is too hard to setup for the engine and the costs are way too constrictive for me??

Thanks For the Input!!!

[Bobboloo]

You can find used MFI setups far about $400 complete. The cost of rebuilding the pump to 2.7 RS specs are around $500 last time I checked. The way I see it. Your into to MFI for what you could sell the Webers for.

Besides the motor your talking about sounds like $10k to me.

Bobby

[RonD922]

Hello,

I have the:

1. Webers
2. 7R case
3. Heads $600.00
4. Distributor and wires $400
5. MSD $300.00??
6. Cams-Shouldn't be more than $300.00
7. Only thing left is the pistons!!

So why 10K...

I have 1600 plus pistons...add another $500.00 on for intangibles...

Let Me Know

[Zeke]

Originally posted by Bobboloo
You can find used MFI setups far about $400 complete. The cost of rebuilding the pump to 2.7 RS specs are around $500 last time I checked. The way I see it. Your into to MFI for what you could sell the Webers for.

Besides the motor your talking about sounds like $10k to me.

Bobby

Next time you see one of these $400 deals, give me a quick courtesy notice on PM.

[zuffenhausen]

RonD922,

The engine won't live long with an 11.4:1 CR on 93 octane pump gasoline, so you'll need different pistons. 9.5:1 is considered a safe maximum for single plug engines, so bump that a point to 10.5:1 maximum for a twin plug engine.

Also, 46mm Webers are too big for that engine. In BA's book, there are formulas and examples for determining the right carb and venturi sizes.

While I like fuel injection as much as the next guy, there's something to be said for the tunability and reliability of a good set of Webers. They are a perfectly fine choice.

It sounds like a fun project.

-zuff

[82SC]

When you twin plug a motor...is it necessary to get the dizzy recurved? to match the engine?

I have a pretty good layman's understanding of the mecanical aspect of an engine, but the electronics (igniton) I am still learning...what does it mean the ignition curve?

I plan to put in a 2.7L (un modded) into my targa project until I can gather the funds to rebuild...

I was hoping for a RS clone or an improved version of the RS (like wayne always says)

I think in his book he will cover performance enhancements...

but I was thinking to build a 2.7RS bump up the CR to 9.x:1 not go so far to twin plug...and to put a set of racey cams...MFI setup...SSI exhaust...etc...

remember for the 964 dizzy you either have to change the gear on your crank or change the gear on your dizzy if you are using a SC or 3.2L crank (the SC and 3.2L dizzy runs reverse of the 2.7 and the 964) or to look authentic you need to find an old RSR dizzy or cover your SC dizzy for 1500 (andial) then twin pluggin the heads is pretty cheap...you'll need sp conectors...mod your engine tin...mod your rocker covers...also if you use the 964 you'll need a donor dizzy to transplant the trigger mechanism since the 964 is not CDI...you'll need two coils and 2 boxes....

i looked into it and it gets pretty exhausting...I would do it if I wanted that authentic RSR look of 12 wires out of 1 dizzy...looks so cool...plus you are talking 1 CR point here...I think if you are building a race car or at the upper limit of size (3.5-3.8) then you at the upper limit of HP...so everything counts...

but then again this is all opinion...just from researching my 3.5L "to be" engine...let us know what you come up with

[beepbeep]

Hey, year is 2002!

Ditch webers and go for unified EFI and direct-ignition. Better poweb, better driveability and mpg.

You can have complete system from SDS for ~1200$ including direct-fire ignition and injectors.