new engine build input please. 3.2 or 3.4?

[haycait911]

building a new engine for the hot rod this winter. 3.0 case, 3.2 crank, webers, single plug, cams (?)( will be talking to JD ) . I already have JE 95 pistons ready to go but I'm getting the big bore itch.

would go to 98/9.5:1 JE pistons and bored/replated 3.2 cylinders from EBS.

the question is................ is it worth it?

it'll cost about $2000 for the p/c's and another $400 for head work, piston coating, etc. I can recoup probably $900-1000 for the p/c's I have now.

so, a net investment of $1500 gets me .2 liters. almost sounds silly to me when I think about it but what do you guys think? I know the 3.4 has a lot of potential.

any and all input much appreciated.

current configuration, just cause pics are always fun.

[s5uewf]

I had the 3.2 in my former 911 rebuilt as a 3.4, including 20/21 cams and a Wong Chip. All other factors remained as was with the 3.2 config.

I realized a significant improvement in all around performance: more torque, more speed, better acceleration. Much better performance at DE track events.

I reecommend the 3.4 liter upgrade, when combined with better cams, adjusted timing and fuel (chip), and freer exhaust.

I enjoy my 3.3L turbo 10x more. There is no comparison. You may want to explore a low boost turbo upgrade for your 3.2 ... ??

[gtc]

$1500 for a 6.25% displacement increase does sound silly.
But...
Are there cheaper ways for you to make ~15 hp? (maybe a serious exhaust set-up?)

[sp_cs]

Originally Posted by s5uewf

I reecommend the 3.4 liter upgrade, when combined with better cams, adjusted timing and fuel (chip), and freer exhaust.

I think this the key with 3.4 conversions, the cams/timing/remap is what makes it work. Mine realised ~273bhp/245ftlb after the work i had done (see link in signature), so non-VRAM 3.6 figures or thereabouts.

The engine builder at the time reckoned a 3.4 he built but on Webers dyno'd at just over 290

[mnez]

Do the 3.4. $1500 is not huge in the P-car universe, and you will forget about it once you have the smile on your face. Leave it as a 3.2 and you will always wonder, what if...

For comparison, rebuilt my 3.2 as a 3.4 with Autothority MAF, bored throttle body, WebCam 20/21 cams, balanced rods, ARP rod bolts, SSI's, Sach's aluminum power cluch kit and custom Steve Wong chip. Dynoed at 243 wheel horsepower (apply your own conversion to flywheel power). It is a real hoot to drive, and I've forgotten about the cost.

Have fun!

[lindy 911]

I went through the same torment when building my 3.0 SC as to go to 3.2SS or not. I ended up at "not" mainly because I had very good Mahle nickle cylinders. Had they been Alusil it would have been a no brainer. I personally think a 3.0 crank with 95mm pistons is a better build for you as a shorter stroke will rev a little better. You might consider a bump in compression, twin plugs and a cam with about .500 lift (GE 60). I did that and although under 3000 rpm it seems very stock, above 3500 it sings. Mine is light at 2450 lbs so the power made feels like more. 350Z Nissan, 4 out of 4, is no match, not even close...

[Jeff Alton]

Don, The 3.4 is a great motor. Normally we would recommend going that route when one needs to replace worn out p/c anyways. Your 3.2 with carbs, exhaust and cams will be one fun motor with lots of power.....

Cheers

[haycait911]

well, thanks for all the input guys. helpful as always.

I forgot to add the cost of a set of core 3.2 cylinders. that put's the change-over cost to around $2000. at this point I'm leaning toward the long-stroke 3.2. I'm all about the bottom end torque, and the 'porsche fund' is looking pretty sad right now so the extra $$$ would be tough to find.

to re-cap.............

-long-stroke 3.2
-9.5:1 JE's
-36mm intake ports
-weber IDS carbs, 36 venturis
-ARP rod bolts
-msd 6AL-2 with programmable advance curve and nitrous retard ( locked dizzy )
-georges headers
-M&K 2 in one out
-cams - to be announced ( my plan is to put everything together them call JD. )
-and of course, the occasional 100hp N2O shot

here's the dyno for my 3.0 currently in the car.



I'm looking to add about 25 to both numbers. and with the stroker even a flatter torque 'curve'. pushing around 1900 lbs it should get the job done. as you can see, with the port size, I'm not looking for top end hp. when I went to John for the cams in the current engine, I told him I wanted it to pull like a truck. he delivered - it does.

I'll have to leave the 3.5 till next time.