Repowering with the Tohatsu TLDI 90

[Dimitri-2000X-Tampa]

Duane, if anything, yours could have more fiberglass in it. Boat builders traditionally overdesign at first, and then start removing materials later when its deemed that there is adequate strength. That is why you see some of the early (60's ish) type fiberglass boats with really thick hulls. They just didn't know exactly how strong it needed to be, so they over-engineered it. Of course, boats that are designed to be light for trailering are designed a bit differently as we all know from our Macs.

[Bobby T.-26X #4767]

Met with Rolf ('02-X) and Chris ('05-M) today at Amber Marine in Costa Mesa, CA (just down the street from The Plant).
In fact, prior to meeting at Amber Marine, Chris and I strolled a block down the street (BTW-sunny and 70 degrees) to The Plant and met with Mr. Bill in sales.
Chris has ordered a new M from "Bill @ Boats for Sale" and will pick up at The Plant in several weeks (He will then power with the 90 TLDI).
So we walked the entire facility and talked Macs with Mr. Bill.
Chris was impressed with the program!
Anyway...we then ventured back to Amber marine and saw "THE BEAST". The 90 TLDI, that is...
Rolf's will be installed first, then my '02-X, then Chris' '05-M.
Needless to say, we're all in awe.
It's a monster, but weighs so little.
The powerhead is nice and thin...narrower than my Suzuki 50, easy to walk thru the transom.
I had previously downloaded the transom mod pics off Mark P's website onto my laptop. We all had a chance to view them and discuss our opinions of how best to mount this animal (Dimitri & Chip are drooling right about now).
We all came to an agreement of what additional plates/brackets/supports are needed to keep this monster in it's place.
We all went away feeling good about our decision.
We will all meet again next week when Rolf picks up his finished product.
More to come...

[Dimitri-2000X-Tampa]

Yea, you're right about that....its too bad you guys are so far away or else I may have gotten in the deal with you as well.

I can't seem to find very detailed specs on the web site. I'm curious what diameter prop the TLDI motor uses as well as the size of the motor (mostly concerned with width) compared to something like my current Merc 50 BigFoot or a Merc 115 4-stroke. Guess while we are at it, the Suzuki 140 too.

Another thing that will be very interesting to learn after you guys install your motors would be some real-world fuel consumption data with your Macs. Also some observations about the noise level.

[Rolf]

I agree Roger is not going to spend a dime if he doesn't have to, but torque aside, he did have to take into consideration the 4 stroke 50s were heavier than the 2 smokers he originally designed the x for. I agree he probably didn't do anything unless it was absolutely necessary--only he, his wife, and a hundred guys who don't speak English will ever know.

Met up with Bob T and anothe 90tldi convert at Amber Marine today where I finally dropped off my Mac. Damn that spanking new TLDI90 packed in a styrofoam box looks beautiful! I was impressed with Brad and Doug(owner and installer)'s installation knowledge. I feel very comfortable and confident in them. They will also be installing a pivoting kicker bracket on the starboard transom for the 4hp 4 stroke I'm also purchasing from them. This little motor is tuned to have the power of a 6 horse, has a half gallon built in fuel tank, and costs less than the 6hp by $150.

They are also doing odds and ends for me like installing a transom swim handle, 12 volt recepticles, the teleflex steering cable, and hopefully my sptpilot + autopilot if the damn thing ever arrives. I will be taking a bath on my 50 tldi, however. I will report installation results next week.
Rolf

[kenny]

Rolf, sounds very interesting. Let us know for sure how the 90 TLDI works; I've got an '01 X and thinking I need some more power at my 3500' elevation.
Also, what brand of 4 stoke 4 HP kicker did you buy with the small internal tank. Can you hook up a main tank as well or just refill.
Look forward to hearing how you 3 make out on the 90 experience. Looks like a great motor from the specs.
Ken

[Bobby T.-26X #4767]

at 3500' the recommendation by most experts is to go with a heavy 4-stroke or an evinrude 2-stroke etec over the nissan/tohatsu TLDI.
the TLDI low pressure direct system requires sufficient oxygen to maximize power. the less oxygen at altitude, the poorer the performance.
high pressure direct systems such as the etec, although running extremely hot, perform much better at altitude.
also, the etec 90 weighs only 305# and is three star emission rated.
there has been talk that nissan/tohatsu will be adding a MAP sensor to their TLDI which will automatically alter spark timing and fuel mixture to enhance performance at altitude. but at this time, no such luck.
we chose the tohatsu based on price, our use is primarily in the ocean vs high altitude lakes, and the fact that's it's been a proven commodity in the far east for generations.

[Frank C]

. . . the fact that's it's been a proven commodity in the far east for generations.

TLDI injection has been proven for generations in the Far East??

Really!

Looking forward to your reports, but I'll be very surprised if TLDIs match EFI four-strokes for cruise speed fuel efficiency, and especially, in quietude.

[Bobby T.-26X #4767]

Frank C... not the TLDI technology, but the Tohatsu brand. Look, I'm not a Tohatsu rep, I just want my X to go faster cheaply. I would have gone with the evinrude etec 90, but couldn't get the same deal.
regarding 4 strokes today...bottom line is that for me they're heavy slugs.
the technology will eventually change. and when it does i'll buy a "super light", "high output", "extra-quiet", low cost", "environmentally friendly", 4 stroke.
But until then i'm going with a "super light", "high output", "extra-quiet", low cost", "environmentally friendly", 2 stroke.
Hey! I'm using it in the pacific ocean, not in a 50 acre, high altitude, pristine trout lake.

[Frank C]

. . . But until then i'm going with a "super light", "high output", "extra-quiet", low cost", "environmentally friendly", 2 stroke.

Bob,
I'm just waiting to learn how many of, and to what degree, ". . . . "super light", "high output", "extra-quiet", low cost", "environmentally friendly" " are really applicable.

Nonetheless, "more power to ya" IS really applicable. Fair winds.

[kenny]

Bobby, thanks for the input on the high alt. negatives for the TLDI. Not sure why high or low pressure injection would really make a difference since amount of oxygen/fuel will be the same UNLESS an engine has mass air flow sensing (MAP) to reduce fuel input at high altitiude. In any event power will fall on any engine technology, since with reduced oxygen to burn with, power will be down, and the engine simply runs too rich. (which I assume is not good for either emissions or longevity due to heat level)
Thanks again for the comment on hgih altitude in any event. I'll still look foward to how your changes pan out.
PS: I've the older 50 Nissan (non TLDI) and it's BULLETPROOF beyond belief. Never touched in 3 years, starts first crank even at 40F temp( last weekend) Wish you the same success with the TLDI models

[Rolf]

Frank,
What Bob was refering to is the tohatsu(nissan)2 stroke engine block. It holds the world record for continuous use and the TLDI is the same basic motor minus a carburator. Also Trailer boats mag had a 90hp head to head "shootout" recently with Suzuki(4 stroke), Evinrude(2 str), Honda and Merc if I remember correctly. Tohat and Evinr came out on top when comparing noise, economy, acceleration, top speed. The Coast guard's new "swift boats" use direct injection 2 strokes exclusively over the 4 strokes because of the acceleration performance. It is proven, as well as simpler, technology.

That said, Kenny, the kicker I bought is a 4hp tohatsu 4 stroke. It can be hooked up to my large tohatsu gas tanks if needed as well. The use of an ECU in the TLDIs requires a marine battery, a drawback for small tenders and thus no tldis under 40 horses.
R

[waternwaves]

Kenny,
overly leaning out mixture raises engine temp., an overly rich mixture does not typically raise engine temp in any engine that I have played with.. too much unburned fuel can raise exhaust temp a slight amount if there is oxygen injection into the exhaust, (some four stroke possibly), but just like aircraft, cars and other boats, excessive leaning of the mixture raises Cylinder head temp first, and puts you at risk for detonation problems if timing is not adjusted.

In fact all the old recips I trained in, had you lean the mixture till you saw about a 20 to 25 deg cylinder head temp increase (about the minimum detectable on those spark plug mounted bimetallic thermocouples and crappy gauges we had in those days), and then back off a bit, for maximum efficiency.

So an intelligent computer controlling spark duration and timing could much easier maintain rated output at altitude. Same for the outboard, Cooler air at altitude 3500 should be no problem for an etec to make rated horsepower.

BTW, Having been in contact with both Nissan and Evinrude reps (not dealers) in the last week, I can only give high praise to both companies on the promptness of their responses for technical info on their engines.

furthermore, some over the transom measurements on sound levels on the E-tec. are as follows....measured on another open cockpit 17' 4"ft fiberglass boat., and part of this noise is from a boat going faster than our boats go..


location Engine speed rpm sound pressure level
rpm / dB
helm(5ft away) / 700 / 63
transom / 700 / 68
Helm / 3500(cruise) / 84
Helm / 5400(WOT) / 92

By comparison, inside the passenger compartment of an Escort driving down the freeway 70 mph can get above 82 dB, depending on road surface.

and for fuel economy, using my old NS 50D on a mac loaded as follows, for a 6 week cruise,

boat, sails+mast+boom, bottom paint, ballast less than 15 gals (estimate),
bimini+dodger+doors+connectors+windows
2250+115+40+130+21 =2556

36 gal fuel =223
35 gal water =291
210 lb operator =210
Electronics/cabling =44
cushions, =65
Head/plumbing/tank/pumps = 115
2 additional 85 AH house batteries = 125
safety gear/docking =71
anchors/chain/rode =104
luggage, gear, books/charts. tools =200
stove/galley gear/fuel/cooler/ food = 81
Dinghy/paddles/lines =84
Outboard/lines/controls =217
Total 4386

Well beyond what the mac trailer is rated for.

Now throw in the ballast tank, which for my year claims 1500 lbs (hopefully already calculated for salt water, but the owners manual and the sales brochure dont clarify this) and you have significant load Of 5886 lbs. Which is why I am being extremely careful on bracing the transom with more triaxial fabric and glass. A 90 hp engine would put the boat over 3 tons in this configuration.


The old 50 does the following. Tested during slack, mast up. Seas rippled

Rpm gps speed mph
700 / 2.4
1000 / 3.3
1500 / 4.2
2000 / 5.3
2500 / 6.5
3000 / 7.1
3500 / 10.8
4000 / 12.8
5100 / 16.9

a quick change to drop mast and rigging resulted in 1.8 mph increase. (interesting) and the boat finally had no separation between bow and stern wave. (planing)

total estimated (your mileage will vary)

now for the fuel consumption at WOT of the old 50D (my Actual load) Etec90 and the TLDI 90, (per factory testing, averaged static load)

Engine RPM gph
50D 5100 5.9

TLDI 90 5500 8.5
Etec 90 5400 7.9

the 2 90's Close enough that on the boat testing will be necessary to find a winner. But having the airflow sensor, bigger support network, and just cool looking factor I am heading for the E-tec. Since I boat on cool mountain lakes also.

E-Tec partial throttle numbers have been tested as follows.
Rpm / gph
1000 / .4
1500 / .7
2000 / 1.7
2500 / 2.5
3000 / 3.2
3500 / 3.7
4000 / 4.6
4500 / 5.4
5000 / 6.7
5400 / 7.9

and I have heard (and lost the documentation) at partial throttle up to 4000 rpm, the TLDI 90 burns even less fuel,


Looks like a 5-6 knot cruising range of about 200 nautical miles, for my boat
(if I can keep my hand off the throttle) and hopefully a true 24 mph boat.

Sources included Trailer boat magazine Feb 2004, Nissan Marine, Evinrude,

[craiglaforce]

Sorry, I read it wrong. My mistake.

[Chip Hindes]

Nah, I think those are actually just mph. No gph listed until further down, 5.9gph at 5500RPM. All that data seems about right as well based on my own numbers for the Tohatsu 50.

Interestingly, all the data I've seen seems to show no major difference between the four strokes, whether carbureted or injected, carbureted two strokes and TLDIs, when they're all run at WOT. It appears they're all optimized for WOT operation.

The difference, and the killer for the carbureted two strokes is, the mileage doesn't get much better at part throttle, because at part throttle they dump tremendous amounts of unburned fuel into the exhaust stream. So other things being equal, you might as well run them at top speed. You'll get there way faster and your mileage will be roughly the same.

[Mark Prouty]

Rpm gps speed mph/ gph
700 2.4
1000 3.3
1500 4.2
2000 5.3
2500 6.5
3000 7.1
3500 10.8
4000 12.8
5100 16.9

Waterwaves, I believe you mislabeled you heading. It should be:

Rpm gps speed rpm/mph
700 2.4
1000 3.3
1500 4.2
2000 5.3
2500 6.5
3000 7.1
3500 10.8
4000 12.8
5100 16.9