3.6 swap vs 3.4 cans?

[intense1]

I'm toying with the idea of either swapping in a 3.6 or changing the cans on my 3.2. Goal is just more powwwwer, cause I'm maxed out now. I have about 220whp, with a bigger throttle body, open headers and had Steve Wong live tune it. I've driven my buddies g body with a 3.6, and it's a lot faster than mine, but I've not driven a 3.4. Anyway... Discuss!

[Bill Verburg]

Originally Posted by intense1

I'm toying with the idea of either swapping in a 3.6 or changing the cans on my 3.2. Goal is just more powwwwer, cause I'm maxed out now. I have about 220whp, with a bigger throttle body, open headers and had Steve Wong live tune it. I've driven my buddies g body with a 3.6, and it's a lot faster than mine, but I've not driven a 3.4. Anyway... Discuss!

Here's a comparison of fresh well built 911 motorss

[intense1]

Wow, thanks for sharing! Do you have a HP chart to go with that first Torque chart that you posted?

[Bill Verburg]

Originally Posted by intense1

Wow, thanks for sharing! Do you have a HP chart to go with that first Torque chart that you posted?

probably but hp isn't a useful predicative quantity, it is a derivative metric,

you want torque at higher rpm, that is the metric to predict performance

compare the 996GT3 w/ the air cooled versions at higher rpms

[darrin]

Intense1 -- very happy with the bump I got going from a stock 3.2 to a 3.4 with Mahle max Moritz pistons, enlarged throttle body, M&k active cat (need to pass smog) and a re-tuned chip. No, not as much as a full-blown 3.6 swap, I'm sure -- but definitely screams like it never did before at/above 4k and doesn't leave me wanting more. IMO, worth seeing if boring to 3.4 gets you where you want to be, especially since you've already done the external mods to increase flow through your 3.2. Worst case, you'd have a sweet, freshly rebuilt 3.4 to sell to fund a hot 3.6 . . .

[intense1]

Did you twin-plug your car too? Leave the stock intake or go with ITB and coil-on-plug?

[intense1]

Originally Posted by Bill Verburg

probably but hp isn't a useful predicative quantity, it is a derivative metric,

you want torque at higher rpm, that is the metric to predict performance

compare the 996GT3 w/ the air cooled versions at higher rpms

I don't disagree, I'm just not skilled at reading dyno charts, and I don't really know what my engine tq is, so I can't really equate it. I think that I have about 180tq.

[darrin]

intense1 -- my engine has a bored throttle body and single plug/stock ignition. Folks had previously determined that the twin plug setup (which will run a few k to implement) is only good for around 5 additional HP over the single plug max Moritz wedge shaped pistons. Stuck with stock motronic ignition system, distributor, etc. and a hot wire (vs stock barn door) throttle body. Also, due to issues my mechanic team had witnessed going with hotter cams at altitude, stuck with the stock Carrera cam grind (a # of folks that have done 3.4 conversions have gone with 964 cam grinds). Worth reviewing sal Carceller's posts/experience with 3.4 conversions, he's produced some good numbers/has a good system worked out re 3.4 conversions and chip mapping.

[Shaun @ Tru6]

I have driven a Sal Carseller MAF twin plug 3.4 in a lightened SC and it was substantially quicker than my lightweight car with a 3.2 with headers and Sal's chip.

Completely subjective but the 3.4 was a hot car by comparison.

[thetorch]

3.4 with ITBs, Motec and 964 resonant intake is quite nice.

I made a second intake because I would love to build another 3.4 if the chance arrives...

[GG Allin]

Bore and stroke it. There's a 964 crank available in the for sale section.

[spuggy]

Originally Posted by intense1

I'm toying with the idea of either swapping in a 3.6 or changing the cans on my 3.2. Goal is just more powwwwer, cause I'm maxed out now. I have about 220whp, with a bigger throttle body, open headers and had Steve Wong live tune it. I've driven my buddies g body with a 3.6, and it's a lot faster than mine, but I've not driven a 3.4. Anyway... Discuss!

Porsche didn't leave a lot on the table; not like you can open out the ports and clean up some casting flaws and find 50HP. So gets exponentially more expensive to get more power from an N/A motor. And the result not only costs wheelbarrows full of cash to build, they tend to get increasingly less practical/fun to drive In Real Life. You really want an RSR power band? I mean, sure, it'd be a hoot at the track in a stripped-out car...

You can run a low-boost turbo setup on the 3.2 quite easily. Protomotive do kits in various stages, which I believe are still available.

Stage 1 (non-intercooled, stock pistons/exhaust). Essentially a chip and bolt-on. Good for 100HP. At the wheels:



They also do Stage 2, Stage 3 and Stage 4 kits, but these get progressively less "bolt-on"...

Some have just done the conversion themselves to both SCs and 3.2 - surprisingly cheaply, in some cases.

Modern injectors, ECUs, turbos and COP all tend to much work better than their 40 year old counterparts, go figure. This seems quite apropos, however:

[Bill Verburg]

Here is an acceleration comparison of 2 well built motors in the same chassis, weight, aero, tires and gearing are the same.

both have stock rev limit and bottom ends.

[spuggy]

Originally Posted by Bill Verburg

Here is an acceleration comparison of 2 well built motors in the same chassis, weight, aero, tires and gearing are the same.

Do you have a spreadsheet that generates this graph Bill?

Would be very curious to compare the same car with N/A vs a custom (mix of -50 and -02) G50 ratios. Y'know, before I spend a lot of money actually having those fitted, LOL...

[Jeff Higgins]

You do not state the year of your car. Does it have a 915 or a G50?

The 915 has much lower limits than the G50, which should be considered regarding how much power you hope to put through it.

[Bill Verburg]

Originally Posted by spuggy

Do you have a spreadsheet that generates this graph Bill?

Would be very curious to compare the same car with N/A vs a custom (mix of -50 and -02) G50 ratios. Y'know, before I spend a lot of money actually having those fitted, LOL...

yes, i have quite few dyno run data sets from my cars and other cars that I have consulted on.


The main reason to regear a pre '94 car is for a specific purpose like dedicated track use or if the motor rev range has been significantly enhanced.

the gros through the g50/03 were well matched to the engines that they came w/ for most purposes.

from the g50/05 on the EPA influence prioritizing fuel milage got increasingly heavy handed.

[Bill Verburg]

Originally Posted by Jeff Higgins

You do not state the year of your car. Does it have a 915 or a G50?

The 915 has much lower limits than the G50, which should be considered regarding how much power you hope to put through it.

My 915/67 wis ok w/ a slightly modded 993 3.6 but was very unhappy w/ a 3.8RS

[intense1]

I have an ‘84, with a 915.

[Bill Verburg]

Originally Posted by intense1

I have an ‘84, with a 915.

'84 911
US 915/68
RoW 915/67

the difference is trans cooler on /67, w/ shorter 2nd, and taller 4 & 5

[Jeff Higgins]

Everyone I know who has ever hung a 3.6 on a 915 has eventually broken something in that 915. Some took longer than others, dependent upon modifications to the 915 and use. The unmodified 915's seeing heavy track (DE) use have demonstrated the shortest lifespans. The ones that are suitably reinforced, that see only street duty (rare in my circles, especially having gone through this trouble and expense to begin with) last the longest. But all have eventually broken something.

Even my hot 3.0 appears to be close to the limit. In what is now 110,000 miles of use, with a good number of track days in the mix, I have broken parts in it twice. First time was the second gear synchro, second time was a couple of teeth off of the large gear of the second gear set.

So, something to think about. If you're pining for more power, it follows that you are driving it hard. You might want to hedge your bets and perform the "usual mods" to your 915 just as a preventative measure.