3.3 L short stroke

[pu911]

Anyone have experience with one of these.
Phil

[cstreit]

Phil,

You mean a 70.4mm crank with 100mm P&C's?

I'm built and am running one this year... Can I help ya?

[pu911]

Chris,
that's the one, how do you like motor.
Phil

[cstreit]

Phil,

I like it! THe increase from 3.0 to 3.3 wasn't this monumental change in engine characteristics, just more torque and HP across the band. My 3.0L with Mahle 10.5:1 was putting out around 221 RWHP. This 3.3 dyno'd at 262 RWHP. (312 HP, 275 ftlbs at the crank).

I know there is more in the engine with some tuning of webers or a move to EFI, probably 15 more HP or so. I built it with mild specs, 10.5:1 spinning to 7300 (good to 8500) so it should last quite a while. I'm running LNEngineering cylinders with J&E pistons and webers currently, webcam 120/104 cam with slightly ported heads. 39I/38E.

It's an all-around strong engine...

[cstreit]

Dyno run...

The HP curve flattens a bit which I think is due to improper jetting, slightly too large exhaust and cam timing needed to be tweaked.

[pu911]

Sound pretty similar to what we are doing, will run more compression but we arun high elevation so you need it. I assume you are running IDA 46's, I may swap the PMO 50's off my street hot rod. 40 more HP is nothing to sneeze at.
Phil

[cstreit]

Phil,

Higher compression should be really nice. I was conservative because I don't like buying race gas, however at the prices of reg. 93 octane lately, not much difference any more!

With 11 or 12:1 compression I bet you'll get a nice 100HP/liter out of this, maybe a bit more!

[pu911]

Race gas is expensive but so is anything to do with racing. I can buy 115 octane right at track so it's a no brainer for me. I'll post dyno results once I get them. Should have my 3.5 on dyno soon
Thanks,
Phil

[Facey]

if your talking 3.5L then your talking my engine.

or is that your hot rod street engine?

do the 50mm PMO's really give 40 more hp??? that seems like alot... as it with w/46's i'm not reving high enough to make full use of the possible air-flow. (right now rev limiter is 7200, and i can't keep up with the car at that pace, so instead of raising the limter to the planned hp peak, it'll stay here until i'm ready....lol)

one thing to check w/the 46mm webers IDA's is that you have the made in italy stamping.... i forget why, but where ever it was made elsewhere , they weren't as great

i'm running a very high c/r just like yourself... on the street here we are able to get some good gas.

though i sometimes can found be talking about more hp.... its more because i hate it when the ricers (my friends, i'm only 19) start talking about their 400-500-600hp thingers....lol.... and when someoen who knows nothing about cars asks me, expecting an even more outrageous number, i cna;t bring myself to say anything other then the truth..

"i have around 600 of that type of hp" or "just above 300 german horses"...still fustrating...

sorry for the rant...watching hockey at the same time... don't even remember what the original reason of the post was...

cheers
Nick

[pu911]

Chris,
What do you run for cams in your 3.3
Thanks,
Phil

[cstreit]

Phil,

I'm running the WebCam 120/104 cams...

[pu911]

I should of just re-read your posts above, you had already answered my question,Doh!. We are using a similar approach, keep revs down to increase life. I can't wait to try, really had to rev the 2.8 to get power, not much below 5K, really came a live above 6500, it took a lot of work to keep motor in powerband. A torquey motor should help me from having to shift so much.
Thanks,
Phil

Phil

[cstreit]

Actually meant to write more Phil, got pulled away by my son whose dinner decided to make another grand entrance the wrong way....

I like this grind as the power feels pretty good above 4700 and really comes in at about 5200 or so The graph above got the RPM's cut off but the middle where the HP seems to "level off" is at 5500 so you'll see it reaches a nice band even before that. The level off is not the cam, rather the mixture was a bit off above there (addressing that this winter).

This cam works well for me in NASA GTS where peak horsepower determines your allowed minimum weight, so a wider power band but less peak gives you a more useful range without a bigger weight penalty. If peak-power is desired, you're probably back to a similar cam as your 2.8, sounds like it might be right for you though.

I estimate about 2-3 seasons on this engine before a refresh, mainly to replace the hi-po valve springs. Everything else should last much much longer than that.

[pu911]

Chris,
Got it with the wrong way deal, I went through plently of that as well. How old is the little shaver.
We are starting from scratch with this motor so everything will be brand new. Everything will be top notch stuff GT3 oil pump, pauter rods etc so my expectation is to not have to worry about a race motor for a while. My 2.8 was basically garbage not atypical of a used race motor so we needed a new program. Good luck with your racing and rasing your son.
Phil

[Porschekid962]

Built one for my dad and it sounds mean. No power numbers yet though. LN's, JE's, Jenvey throttles, autronic ecu, drcamshafts, racing springs with Ti retainers, stock rods, arp bolts and headstuds, 993 heat exchangers, bosch motorsport injectors, all going through an MK exhaust with twin 3 inch tips dead center.

Had some silly problems totally unrelated to the internal parts of the motor but slowed things up a bit.