Alternative Injection - raising the bar for the 2.7
 

So, I've finally found an engine upgrade for my car that should be worthwhile, a 2.7 Carerra spec engine that has 500 miles on it and a spare no expense rebuild with tons of bells and whistles, including full case work, line bored, 3.0 crank, B&B muffler. I'm going to pick this up in about 2 months, I have it on hold already. Wrench estimates about 220hp from this engine.

Always thinking ahead, I'm wondering what the next step would be to increase power. It's still a CIS motor, but I'm considering changing injection systems if it's a good cost/hp gain ratio. I'm not really familiar with how alterative injection would affect the hp output of the motor, so I'm wondering what sort of hp gain I could expect to get if I used carbs, MFI or programmable EFI, and if it would be even worth it to change. If large amounts of engine mods are necessary to exploit these, it might not make sense to implement them.

Any thoughts?

Jason

I suppose it partially depends on what type of pistons were used in the rebuild. Sounds like they were probably CIS pistons. While they will work with carbs or MFI, they will not be "optimal". If I were in your position, I would give serious consideration to Tbitz's EFI setup.

Ask for a dyno chart ... and be very, very wary!

His claim of 220 hp -- 45 hp more than a 1974 911S engine used ONLY in the USA joke called a Carrera ... is highly questionable, and the description is full of 'buzzwords' intended to snare the novice 911 owner! The only problems with his choice of 'components' is that none add power ... and all 2.4, 2.7, and 3.0 cranks from '73 thru '76 were the same, except of course for the 2.4S, RS 2.7, and RS 3.0 MFI engines ... which used the Nitrided version, and I seriously doubt he could have found an RS 3.0 crank, as nobody in their right mind would waste one on a CIS 2.7!!! What cams did he claim to be using?

Which heat exchangers, and which B&B muffler? Single in??? Don't wast your time on this engine if he is still using the '75+ heat exchangers, as he is claiming 55+ hp more than the original engine ... and that is a pipe dream!

I'm seconding Warren's post.

while it's possible he's got a 3.0 crank in there, it would have to be from a 3.0 carrera, while is the same crank that's in a 2.4 and a 2.7( save the nitriting)

Also if he's claiming 220+ out of a 2.7 CIS motor he's either REALLY good, or he doesn't know what he's talking about. The MFI 2.7 RS motor only made 210 and that had cams that don't work on a CIS motor, they're too wild.

I hear what you're saying here, but I do trust the source, with a grain of salt (for normal car guy exaggeration). He's a friend and wouldn't screw me. I trust him with all the regular work on my 911 and he's an honest wrench. I personally don't think it'd be that high.

There's a bunch of other stuff done to the engine as well, but I forget the list off the top of my head. Of course, I will get a list and dyno results before I pull the trigger. I can also try before I buy.

[Edited] Oh, and thanks for looking out for me: SmileWavy

Jason

Sounds like a fair deal if he'll let you run it in your car for a month before deciding. You'll soon know if it is really pushing 200+ hp :)

I would look into cams, exhaust, compression, block mod's, heads porting and intake mod's. I too am interested in how he surpassed an RS 2.7 MFI with CIS. I'm sure your car will have more bottom end torque than mine, but hp usually happens with rpm. Rpm requires cam timing and air flow in and out of the engine. If your considering EFI, what is limiting you to a 2.7 CIS?

Wow, Jason: 220 hp from a 2.7 CIS engine. I can see 180 or 190. The only 2.7s that I've heard of cranking out that power are S-cammed with 10+ compression and Webers. Like Warren said, be careful. If it's not up to snuff, your friend may be your ex-friend.