I'm still trolling for some flavor of 340/340A. Some have RAM IV, some have AA intercoolers, some have both, some have none. The AA intercoolers are pretty common (and relatively cheap to add) but the RAM conversions are NOT cheap to add.

So my questions are:

How much does a RAM IV conversion actually help on the takeoff roll? I know this may be impossible to answer as there are no published performance numbers, and it seems unlikely someone here measured pre-conversion takeoff rolls, converted, then measured post-conversion rolls..

So perhaps a better question is, how accurate are the factory takeoff charts for the 310HP engines? If these numbers are somewhat accurate, then I may honestly not care if a given plane has a RAM conversion as long as it has AA intercoolers for the benefits at altitude.

The numbers are good. My 340A only had the stock engines so that’s what my comment is based on.

Andrew

A RAM anything with AA intercoolers is the same as a RAM VII the way most people fly them. The point of a RAM VII is the larger turbocharger (and intercooler, which you can use the AA version not from RAM) which has limited use at lower altitudes, and people for whatever reason are hesitant to fly them much above FL230. I fly 250/260 and in the summer with the larger turbo see meaningfully faster cruise speeds than any other variant.

A non-VII with AA intercoolers is probably the best value, and you can stay at FL220/230 where the cabin alt is better for sea level living passengers. Stock intercooler was undersized.

I'm a relative 340A newbie, and offered as such.

I don't think the book is far off. I have a non-RAM, VG's (not sure I would fly a 340 without them), and rarely fly anywhere close to Gross - and I always beat the TO, Landing, Accelerate Go and Accelerate Stop distances. I am a dork and practice all that cr@p. Since I beat the book less than Gross, I believe the book is probably pretty close.

I would do Intercoolers before RAM as RAM has had a fair amount of recent negative press re QC. Others do a "non-RAM" (same conversion, but they can't call it a RAM) that I am likely to do after AA Intercoolers and Strakes.

Intercoolers, Strakes, VG's (all 3 of those are very easy) and a decent panel and I think the 340A is the ultimate personal aircraft.

You looking for two engine ground roll, accel-stop, accel-go?

The extra hp AT THE SAME WEIGHT should make the OEI performance much much better

I generally see the HP upgrades getting weight upgrades that bring the hot/heavy OEI numbers back to scary land

Two engine ground roll doesn't seem so important to me. With a RAM VII and the extra 400 lbs of gross weight, I think it'll about match the stock numbers at stock weight.

The better intercooler & scoop is worth it, IMO, better detonation margin with cooler intake air at high power as you climb. The VII turbo is nice to make full power up to FL230. Maybe not such a big deal if you aren't going up there.

Will Robertson STOL kit added to above conversation help?

What is the goal? Are we trying to operate from a 2000' field?

If I could safely operate from a 3000ft field (with currency/practice) somewhat near MGTW that would be more than enough. My home field is 7000 but I don’t want to chop too many fields off my operating profile.. Staniel Cay for example is 3000 ft with no real obstacles that I’m aware of. The extra power on takeoff would be nice, but if the POH numbers are accurate than I don’t really need it, which opens up more plane possibilities.

AA inter coolers for efficiency in the air, and probably strakes for more efficiency and yaw stability (pax comfort), but neither of those will make much appreciable difference on the runway.

I operated a RAM VI (“six”) 340A from KSQL for 7 years. 2600’ runway at sea level. I went out at gross maybe once or twice during that time, it was doable but not long enough for accel-stop. In such an event (unlikely), I’d have been off the runway at a decelerating speed, but the insurance company may have owned the airplane.

Mostly, I was usually under gross.

My home field was 2800ft when I had my 340A. It was never an issue.

The 340A is my favourite plane, they are awesome. Economical to operate and a serious capable plane.

Go for it.

Andrew

Thanks for the feedback Andrew. However, I believe you are the first person I've heard describe the 340 as "economical to operate" without a few modifying words before that phrase

The AA intercoolers actually are a benefit on a hot day take-off or higher altitude take-off as well as in climb and cruise. On a standard day at sea level at take-off power, the AA intercoolers reduce the induction air temperature so under those conditions, you are supposed to run less manifold pressure than red line to keep from exceeding 310 HP. (or whatever HP the engine can produce. In the 1970's, I remember Continental said "they used the minimum engine concept." They explained your engine will put out a minimum of 310 HP and up to 5% more, so up to 325 HP) At sea level at 80 degrees F, no reduction in MAP is required with AA intercoolers so you have more power than the stock engine can produce at that OAT, improving runway performance, as well as single and twin engine climb.

It really was economical to operate but I have heard of horror stories as well. I was doing 200 hours a year in over 5 years and the only issues of any significance was changing out a turbo, waste-gate and a couple of cylinders.

It important to have a good A&P working on it who knows the plane backwards, which I was fortunate enough to have.

If you haven’t already make sure you joint TTCF, the forums are great. There is a guy on their Dick Welsh who has an incredible knowledge base on the planes and how to operate economically. I went and saw him at TRM a few years back just to thank him and meet him.

Good luck in your search.

Andrew

I saw that and laughed so hard that I almost spit out my drink. Good thing I was drinking the cheap stuff... as my 340A maintenance bill doesn't allow me to drink the good stuff.

I guess when the aircraft on your profile are a CJ and a Nav, it's all relative!!!

Kidding with Andrew aside, he's right. TTCF has loads of wisdom. The right A&P is paramount. Folks love TAS and honestly at first I thought it was marketing crap... It wasn't. They are the real deal.

I took over the 340A I had been "borrowing" for a while. I had noticed a recent split fuel flow reading that the well a very well known shop in WI (who had been servicing the aircraft for 15 years) had dismissed and they couldn't identify it. ("probably a spec of dirt in the line to the gauge"). I went to TAS for an oil change and mentioned it. The shop boss had the cowling off, made an adjustment, and had the cowling back on in 8 (literally) minutes. No more split readings. With these birds, you need a shop that does more than 5-7 twin Cessna's a year... you need a shop that knows the Bird. Pretty much like any bird as you step up in complexity.