which would you do...2.7RS or 3.0

[82SC]

well for the targa I have been planning a 2.7L transplat for now...then down the line build a 2.7L RS clone engine...maybe with a slightly higher CR...but I'd keep it MFI

but then again I see some cheap 3.0L pop up here and there...

what do you think the driving characteristics woul dbe between a 2.7L RS and a 3.0L RS

both would be MFI...single plug...SSI exhaust and a cam that is streetable

any opinions?

thanks

MJ

BTW for those keeping up with the Free Targa project
I've got most of the suspension pieces and brakes
just got a set of H1
and have 2 paint shops in mind...
and I am working on some sport seats too

[CamB]

Well, all other things being equal the 3.0 is 11% bigger.

So an extra 11% if you are lucky.

Alternatively, the 2.7RS had 210hp and the (very limited edition) 3.0RS was 230hp (despite higher compression ratio).

[82SC]

well I guess my question is less about numbers and more about driving...it is going in the targa...which I don't want to be an all out fuel spewing monster...I'll build one of those when I am done with the targa...

everyone says the 2.7RS is the pinnicle of 911...driving experience...even though it's horsepwoer and 0-60 times will be eclipsed by the 2003 honda accord...obviously the driving experience is paramount...

in terms of feel and reponsiveness etc...what do you guys think is the better bet...(plus you get that rock solid reliability of the SC bottom end and the better engine case...) but the 2.7L RS clone formula is tried and true and less hiccups I assume

for the 3.0L...buy Mahle replacement pistons with high CR and deep pockets...keep the cyl...then do an MFI conversion (which is the unknown territory...MFI pully...space cam...)

[Dana_Drury]

Eclipsed by the Honda Accord... Look at an RS's 100-200 km/h time and show me how well the Accord eclipses that.... Come on, I would gladly take a RS on the track against an Accord anyday.

Anyway, enough of my anti-anything that is not Porsche sentiment. Paul Freire wrote in his "Porsche 911 Story" that the Carrera 3.0 (Stock 200 HP, not the RSR etc) had better Torque than the RS 2.7 despite the higher HP of the RS 2.7. If you were to build a car to similar specs as the RS and you put a 3.0 Carrera engine in there are you going to get similar performance?

[Halm]

Interesting topic because I have started the mental process of "what am I going to do" with my 2.2 E (MFI) in about a year. If I read you right, I would go for the 3.0 simply for the torque. Around town that translates directly to responsiveness and IMHO "feel".

[DavidPorter]

I have a '72 T with original 2.4 MFI engine that needs rebuilding, and a 73.5 CIS 7R long block engine with no injection system. I think my ultimate goal is a 2.7 MFI engine with RS 8.5:1 P&C and E cams, as has been done by others on this board, but I'm open to suggestion. Keep the updates coming.

[82SC]

ok ok ok

my honda accord statement is off the mark...

I guess I am just amazed at the rise in HP across the spectrum of cars...the honda will have what...240...260 (i forget the exact number)...the infinit has 260...M3 makes 333

it is crazy...now 300 is the minimum to be a fast sports car...then when you hear numbers like 210 190 etc...just makes you wonder...

I guess my point is...I don't care about pure hp or torque numbers...I want to know more about characterisitics...like throttle responsiveness...flatness of torque curve...etc...from people who have driven both...

thanks

MJ

[skinnerd]

One thing you're not factoring in is the curb weight of the vehicle. Do any of these high hp new cars weigh in at 2365 lbs. or less ??? I don't think they do; most are overweight when compared to the earlier 911's. A 2.7 or 3.0 in a lightweight 911 is going to munch up most vehicles on the road today.

I don't think the 3.0 MFI is that much into "uncharted" territory. It also is a tried & true recipe, that is very reliable; it's just that not as many people do this motor as the 2.7 MFI. A 2.7 vs 3.0 MFI will not be all that different around town. The 3.0 will have slightly more of everything.... torque, hp, etc. Few people do the 3.0 MFI setup because they likely do not already have the MFI system, which can be tough to locate and costly as well. This is why you see a lot more 2.7 MFI conversions.... they all came from 2.4 MFI T,E & S's for the most part.

If you could build yourself a 3.0 MFI with about 9.3 to 9.5:1 compression (so you could run premium w/o twin plugging), you'd end up with an incredible engine putting out about 260-265hp, and able to rev to 7500rpm. What could be nicer to putt down to Safeway in???

Just another opinion.

[Early_S_Man]

Characterwise ... the two engines will be close! All else being equal, it is probably less expensive to do the 3.0, so go with it!

[Dana_Drury]

Originally posted by 82SC


it is crazy...now 300 is the minimum to be a fast sports car...then when you hear numbers like 210 190 etc...just makes you wonder...

Not really. Look at the weight of some of these cars including the 911. To add the luxuries that people expect these days you need to add weight, to counter weight you need to add in more power, and as such you then end up with cars putting out over 300HP.

If you look at the performance of a 30 year old RS, in comparison with an M3, you will find that the RS is not that far off the mark, and I would dare say very competitive around a track. All this on an engine that is 100HP down.

You also have to put things in perspective, its a marvel of engineering that the RS you want to replicate is 31 years old in design, and your comparing it to cars that have had 30 years of evolution. I think thats bloody impressive if you ask me.

On to the engines, the torque of the 3.0l Carrera engine is excellent, even over the SC 3.0L. Also, you can do a lot more with the 3.0L Carrera engine over the SC because the crank case is the same as the 2.7 but with the spacings and configuration of the SC 3.0. They are most sought after.

I haven't driven an RS, or even a replica RS, but the accelerator response is excellent too in the Carrera. This is in a CIS car as well, so I am sure MFI will give you slightly better performance characteristics.

The 2.7L in my 1977 Targa was replaced with a 3.0L Carrera when it died. My car weighs just under 1100 KG's. When I was doing a lot of work on it, I had all the carpets removed, no space saver and pretty much nothing but myself in the car and it was a wonderful performer, I can't imagine what a 3.0L Carrera in a car that weighed as much as the RS would be like. Especially with some performance mods, I think you would be looking at a wonderful machine.

I also found that the power didn't outmatch the cars abilities. That said, I think that the upgrades that people do with 3.6L engines while they produce monster cars, require a lot of thinking about in terms of brake upgrades, suspension etc to make the car perform as it should with such a good engine.

[Superman]

Porsche has been taking small-displacement cars to race events all over the world, for the past forty years or so, and trouncing other race cars with three times the displacement. This happens in so convincing a style that it is almost obscene to watch. To this very day, a stock 356 Carrera will probably make a new Honda Accord seem pathetic on the track. Certainly, you can take all those fancy modern cars and square then off with one, just one healthy 2.7RS and a good driver, and all those other guys with 3 and 400 hp engines will be competing for a distant second place. If the race is long enough, they could get multiple opportunities to see the RS....as it goes by again and again.

And if the race were REALLY long enough, there would only be one surviving vehicle on the track. Guess who?

That being said, I sure like the torque and drivability of my 3-liter.

[82SC]

ackkk

looks like I stirred up a hornet's nest with my honda accord statement..

OKOKOKOK I understand all the power to weight ratio...etc...

I was just trying to keep from people saying 3.0L is better cuz of xxxhp xxxtorque...numbers don't mean everything which the last couple posts have clearly illustrated...

also as much as I'd like to work on a carrera platform, I think the SC case etc... it what I will work with...

well sounds like it is almost a tossup...having a 2.7 is just plain cool since it is a 2.7RS clone...but the 3.0 sounds like it has its advantages too...

I'd love to get a ride in a RS clone to see how it really is...guess it will come down to which engine 2.7/3,0 with the right price crosses my path first

[CamB]

If you are talking 2.7RS vs 3.0RS, few people have driven both.

I have 3.2RS. It is freakin' nuts. But I have only ever been in one 2.7RS and only at 30kph (it was real and a drive isn't going to be available). Therefore, I am unable to make a comparison.

The 3.2RS still comes on cam at 5000rpm and still sounds like a 2.7RS. In fact, I struggle a little to see why there would be disadvantages to identically specced engines where one has a greater displacement (and power and torque).

Cam

[82SC]

hey Cam

can you post your engine specs...just in case I plan to emulate your engine...in a 3.0L variant

MJ

[Bill Verburg]

I went from a '72 S to a '76 Carrera 3.0, to the uninitiated 190 hp to 200 hp sounds like a trivial change. It's not. The torquier 3 liter Carrera is a far more enjoyable street car than the S . The S was a far more enjoyable track car.

Torque is the paramount metric for street cars, torque comes from displacement (or turbo/supercharging). Besides the al. 3 liter case will be more stable and less prone to leaks.

The 930 case, euro 9.8 cr p/c(maybe even 98mm if budget alllows) , mild cams(964 or webcam 20/21), make for a very nice tractable street motor.

[CamB]

Originally posted by 82SC
hey Cam

can you post your engine specs...just in case I plan to emulate your engine...in a 3.0L variant

MJ

Rather than copy and paste it all back in, have a look further down this thread:

Engine Update and Exhaust Question!!

In a nutshell, short stroke 3.2, S cams, SSIs, MFI (sort of). Twin plug for high compression and heaps of power (270hp).

And driving impressions here:

New Zealand Sunday drive - Awhitu peninsula (lots of words and 300k+ of images)

I spent too much money. It would be MUCH cheaper if you didn't copy the fancy MFI/EFI bit. It would mean figuring out how to make the MFI pump work with a 3.2 or 3.0.

[Dana_Drury]

Just remember though, the 3.0L Carrera case is a lot better for building a base engine than the SC 3.0 Case if you can get a hold of one. While the 3.0L Carrera can suffer the stud issue that 2.7's had, the case is far more robust and a open to a lot more modification.

[Bill Verburg]

The al. cases suffer from broken studs(btdt) the mg. cases suffer from a different malady, pulled studs. The Carrera 3.0 engines are popular because they use the 2.7 crank and dist. w/o the mg case problems. They are perfect for use in older cars. But for use in an 82 they offer no advantage.

[82SC]

hey bill wht advantages?

sorry to be confusing, but the engine will be for a 73 targa chassis...not my 82SC chassis...

I'd like a really cool motor goor for about town and spirited drives...the car will prob see very little to no track time...it is my cruiser...I was imagining a 2.7RS convertable when I started planning (the targa glass will be ommitted and a custom soft rear window installed)

so at this point I think a 2.7LRS clone with slightly higher CR

or if a nice cheap SC 3.0L presents itself, new pistons, higher CR, deep pockets, hotter cams, MFI, single plug...

BTW just for my own information...how did the 2.4 - 3.0 Carrera crank differ from the 3.0SC crank? also what is the diff between the carrera case and the SC case?

MJ


PS CAMB thanks for those links...how did I miss the driving impressions one!!! looks awesome...you have to change your signiture now no? it still says the 911S is in bits!!??

[CamB]

Nah, I still have a 911S in bits and the car in the pics is the T.

It isn't finished. The freakin headlight circuit has a short somewhere and I have no time to find it...