what is the best way to get more power out of a chrysler/force

[lucas_chrysler_1]

im just wondering what is the best way to get max power out of chryslers and forces, i have a quite a few of these motors, and I am very mechanicaly inclined, and understand how 2 strokes (and 4 strokes) work, but I wanted to know if there is a be all end all best way to make max power out of these outboards ( i have a 135 that i can do anything too, i got lots of parts, and the tools)

 

[lucas_chrysler_1]

what is the best way to get more power out of a chrysler/force

what is the best way to get more power out of a chrysler/force. I have a 135 chrysler(well I have many chryslers) and want to get maximum possible power out of this engine, engine needed a rebuild any ways, so what can i do to make it faster? work, parts, and time are no objective, I have lots of experience working on these motors, just not modifying them for top hp/speed. any input is appreciated.

 

[haulnazz15]

Re: what is the best way to get more power out of a chrysler/force

Sell 'em and get a Merc, lol.

 

[steveclv]

Re: what is the best way to get more power out of a chrysler/force

Err, sell it and buy a bigger engine

Not trying to be smart but you will find that outboards are pretty much at their limits when it comes to power output for their capacity.

Plus they are built light, small and are pretty stressed so unlike car engines there isn't much scope for upgrading.

 

[foodfisher]

Re: what is the best way to get more power out of a chrysler/force

Go to the force forum and Frank will keep you busy for a long time.

EDIT: Moved to Force/Chrysler and merged with thread there. JB

 

[BuzzStPoint]

Re: what is the best way to get more power out of a chrysler/force

Here's a post by Frank.

Squeezed a bit more out of them.
Reed Valve Change

 

[tater76]

Re: what is the best way to get more power out of a chrysler/force

Port the exhaust ports, I did my 55hp and it perked it up a little.

Edit, I meant the intake ports. Dang adult beverages:facepalm:

 

[pnwboat]

Re: what is the best way to get more power out of a chrysler/force

There are ways to squeeze a little more out of these motors. Frank A. has some experience in this area and I've used his guidelines successfully (Thanks Frank!). When I rebuilt my 1988 125HP motor, I took a die grinder and squared the round by-pass ports on the intake side of the cylinder and chamfered the edges to make the ports a bit more aerodynamic. Essentially, I increased the size of the by-pass ports that feed the combustion chamber. You have to be careful about grinding the top and bottom of the ports as this will change the timing/duration of the intake charge in relation to the piston. Replaced the factory reeds with a set of Boyesen composite reeds. After I did all of that, the motor definitely did perform better but there wasn't a huge power increase. The biggest change that I found was when I replaced the lower unit from the factory 1.73:1 ratio with a lower unit from an 85 HP with a 2:1 ratio. This really woke the motor up. I suspect that by slightly increasing the size of the by-pass ports I moved the power band of the motor to a slightly higher RPM. I also went up from a 17 to 19 pitch prop when I changed the lower unit. After all this work, I increased my top end by about 8 MPH. I think the combination of re-building (new rings and pistons), the porting and the lower unit gear ratio change, the motor has much better throttle response and great hole shot. Motor ran pretty good before I did all this and it topped out at about 35 - 37 MPH. Now I top out at 45 MPH. Was it worth it? For me it was more of a learning experience which I find very satisfying and I really got to see the inner workings of the motor. As far as increasing performance, maybe not worth it, but I think that's more of a personal thing.

 

[lucas_chrysler_1]

Re: what is the best way to get more power out of a chrysler/force

thanks every one. i knew i would be porting it. but you cant touch the exhaust ports on these motors. i was just wonderign what the best set up was. i was thinking i would shave the head slightly just to raise compression a little (150-160) and port it. and i got lots of parts so ill swap to a 3 cylinder lower unit (2:1 ratio) and up the prop pitch. its going on a vanguard banshee (glastron gt 150) so it will be pretty quick. thanks

 

[lucas_chrysler_1]

Re: what is the best way to get more power out of a chrysler/force

thanks! i figure some one would tell me to get a merc. lol but i liek driving my boat, not working on mercs!

 

[fucawi]

Re: what is the best way to get more power out of a chrysler/force

get a bigger one

 

[Frank Acampora]

Re: what is the best way to get more power out of a chrysler/force

Depends upon how badly you want power!

On the two and three cylinder models, you can port the bypass and exhaust sides. By enlarging and squaring these ports and streamlining the inter-port webs you can acheive significant power increases. However, on the two carb 55 ,60, and 65, this has already been done by the factory and there are no further gains to be had. These engines are bears anyway and will outperform any other Chrysler or Force two cylinder engine. Possibly some OMC and Mercs too.

On Four cylinder engines gains can be had by porting the bypass side. If you try to port the exhaust side, since there is a 30 degree overlap between 2 and 3 and since they fire alternately (1,3,2,4) you will actually lose power from stock.

Your 135 did come from the factory in an elongated exhaust port version for racing. This engine had two tunable exhaust "trumpets" servicing the top two and bottom two cylinders separately. They stuck out the side of the special hood. Last ime I saw a set, the water cooled manifolds and trumpets sold for 1600 bucks on ebay.

If you have machining facilities and can separate the top two cylinder's exhaust from the bottom two, porting a 4 cylinder engine will yeild 10-15 HP more per cylinder.

 

[RRitt]

Re: what is the best way to get more power out of a chrysler/force

im just wondering what is the best way to get max power out of chryslers and forces, i have a quite a few of these motors, and I am very mechanicaly inclined, and understand how 2 strokes (and 4 strokes) work, but I wanted to know if there is a be all end all best way to make max power out of these outboards ( i have a 135 that i can do anything too, i got lots of parts, and the tools)

isn't that a bit like trying to turn a camry into a porsche?

 

[lucas_chrysler_1]

Re: what is the best way to get more power out of a chrysler/force

@RRit, no not trying to do that. but trying to make a camry that can kill a porsche! thanks Frank, its just a regular 135(the one that had the smaller carbs), it was origonaly a mag-II but it was converted by a chrysler dealer long ago. it was sold to me with the owner thinking it was a 105(cowl said 105), the pan said it was a 75hp( i know 75's are 3 cyl), but the dealer sale tag on the exhaust cover read 135*** (i forget the other 3 digets) so its a 135. so ill try it. thanks! btu i would have to seperate 2 and 3 to get that gain of 5-10 hp right?

 

[Bustedknuckle84]

Re: what is the best way to get more power out of a chrysler/force

isn't that a bit like trying to turn a camry into a porsche?

whats wrong with that? making a 15k car run faster then a 40k+ car is awesome!!

 

[RRitt]

Re: what is the best way to get more power out of a chrysler/force

whats wrong with that? making a 15k car run faster then a 40k+ car is awesome!!

the camry is already a better family car than a porsche. hop it up too much and it might lose some of its appeal.

 

[Frank Acampora]

Re: what is the best way to get more power out of a chrysler/force

I have for a long time wanted to try welding a bent plate to the stainless exhaust plate to separate the top two from the bottom two cylinders until they both dump into the downtube. There are acouple of problems associated with this approach and I have not yed experimented with it.

However, even without doing this read again the reply by pnwboat: He gained 8 MPH which translates into a significant gain in horsepower. --Probably about 30 HP over the claimed 125 and probably just a little more actual HP than 125.

Me? As long as I have people saying at the ramp when it starts first turn "That's a Chrysler?" in surprise, I'm happy.

 

[lucas_chrysler_1]

Re: what is the best way to get more power out of a chrysler/force

Im the same, i love the looks and comments i get at the marina (buying gas lots, lol) when people see its a chrysler, on my banshee, i only got a 1973 70hp on it and i raced a guy with a 14 foot hydrostream voodoo, with a 70 johnson (1980's), it was a race just for fun i was expecting him to fly out ahead but to my suprise, i ended up winning by a quite a bit. i get about 38-40 mph with the 70 on the banshee, and this 70 is the best motor iv ever owned (its a long list with many brands but iv always loved chrysler) after sitting weeks, prime the buld, choke, and it fires as soon as the starter hits the fly wheel, instant. its an all origonal not a bolt has been touched(except when i converted it to a car coil) and it has trim tilt, and it was only $100 (i get these motors free to $100 all the time) but i want to go faster so the 135 will be fun. thanks for the help every one.

 

[Frank Acampora]

Re: what is the best way to get more power out of a chrysler/force

I have a bone stock Force 1990 125. All I did was replace the lower unit with a 2 to 1 ratio and add a 12 X 21 stainless cleaver prop. It turns 5900 at 60 MPH on a 14 foot flat bottom hull--quite a ride.

Interestingly enough, a 21 pitch ballistic turns only 5200 (I think--I wrote it in another post) and the same 60 MPH.

So, You should expect the same performance level from your 135.

Uh--No! Before you ask, It is not an 85! The action photo actually shows it at 55 with a 90 Force but the 85 photo is actually a 125.

 

[lucas_chrysler_1]

Re: what is the best way to get more power out of a chrysler/force

http://ontario.kijiji.ca/c-cars-veh...essories-Propeller-23-inch-W0QQAdIdZ271949910


this is a prop i was going to buy regardless that i put it on the 135 or not, i talked to the guy he said he had it on a 85 chrysler and could run 40 + mph with it on a 14 foot sidewinder. should i drill exhaust relief holes? i know with 2 strokes they make best performance with a tune pipe (because of the back pressure), but since out boards dont have tune pipes is open relief exhaust the next best thing?