3.4L project

Hmm, do you think going to a 34 or 36 will ruin throttle response? I certainly thought about going larger but I don't want to ruin any response. The large increase in displacement will certainly help things along but I want to tread lightly at first not changing too much, unless of course your experiences have been that this is the way to go.

 

bought! thanks David! I searched for it some time ago but could not locate it. Huge thanks for pointing this out

 

Going for 320bhp with 270lbs tq. So around 260-270 at the wheels. I'll expand on this a bit.

I don't think this is an unreasonable figure considering I have seen like-Porsche 911 2 valve engines with less total intake flow capability churn out 340bhp at the flywheel. And those are not race engines. Within the past year a very nice 3.3L 911 engine (10.5:1 cpr) was tested with PMO carbs and DC80 cams which are a very hot cam and sort of a track cam and it made 334bhp. For the race end of things, I know of a solid 3.2L 2valve carbureted engine with basically a P6 cam duration but with a bit more lift made 338bhp, and that was with just 3.2L yet of course spinning the thing to kingdom come. So expecting a little less than that but with a bit more torque with 3.4L is within sane conjecture. The computer simulator says 336bhp IIRC with 274lbs tq and it's roughly accurate when used within a degree of correctness.

The simulated torque curve is nice and flat starting very early at around 2k rpm with a big chunk of the bhp coming in around 4-5k with max bhp being a simulated 7500rpm (stock max bhp rpm is usually 6500rpm-ish). Big torque in the lower rpms is what I was looking for though as that's really what's needed when just noodling the thing around town.

 

Just ordered some 36mm chokes. Tons more flow and per the weberfiles out there (Russ, Iean you!) I am going to give them a shot. I figured Russ is getting away with 38mm chokes with 44dcnfs with a good bit less cam and less displacement so 36mm with more displacement should be gravy

 

IT RUNS! The thing is literally alive under my right foot. Unreal throttle response. I never thought a 308 engine could snarl, but this snarls. I ran it for 20 minutes to break in the cam and am currently having it cool down. At first I thought something was hitting something due to a ticking sound, but it went away shortly. I'm guessing it was pistons rattling around a bit until they warmed up. Strange considering I'm running .0025-.0032ish piston to wall clearance. No worries though as it sounds very nice once it was warmed a bit. I'll get a vid going once I have stuff figured out a bit further. But for now, life is good.

 

Russ, I was constantly running rich and fouling plugs last night! That was with 145/200 F24 tubes and 55 idles. I think it just wants to be driven. Weird



As a side note. I can't say enough about how awesome the megajolt programmable ignition system is. I just pop on the laptop and change the curve to whatever and however I want. Easy.

 

And one more shameless plug. People need to get with the program and get one of my awesome radiators. I cannot make this thing overheat. I had it outside yesterday in 80 degree weather sitting at 2500rpm-3500rpm for 20 minutes without the fans on, ever. Great radiator and I'm tickled it's working out as I wanted it to.

 

You know what it is. I bet it's some bad fuel I've had sitting in the tank for 7 months. I did add a couple gallons of fresh fuel before starting it and thought I had maybe a couple gallons of the old stuff in there thinking the new fuel would even stuff out. Stupid mistake. That stuff shouldn't sit for more than a couple months I hear.