Offy 3x1bbl vs Magnuson M90

[Nick1966]

:help:

Hello, I am in the process of setting my goals up for my 1966 Ford Mustang (200). I feel like after all of the modifications I would like the car to produce about 300hp. Originally I wanted to go with the Offenhauser 3x1bbl intake setup primarily because it looks amazing. I would like to know if it is still possible to get to the 300hp marker with that set up?

The alternative what I have come up with is to not run a naturally aspirated motor and go with a little boost. If it gets completed I would be leaning toward Magnuson M90 supercharger (seen on ClassicInlines.com). I like the idea of a supercharger more than a turbo. My problem with the supercharger is that I would need to upgrade the pistons and some other things which would dramatically increase the prince on this project.

Any insight on this dilemma is GREATLY appreciated. Thank you very much.

 

[jamyers]

I only know what I've read here about tri-carbs and boosted 6's, but I'd think that for 300 hp you're going to want forged pistons and good rods no matter which route you go - triple carbs is going to mean a high-winding engine...

Probably easier to get there with boost, though...?

 

[Soldmy66]

If you have not done so, it may be helpful to look at the dyno test numbers on the Classic Inlines site to get an idea of realistic horsepower estimates for various configurations.

 

[MPGmustang]

you won't make 300hp out of a stock 200... or radical 200... maybe a boosted 200 like Does10s but they have a 250 making 343hp under 18lbs turbo boost with the alum head and custom cam. then your looking for cheap, realisticly you can't go cheap on the 200ci and make 150hp... I'm at 135rwhp and I could've had a v8 350+hp power house for the same price, but I'm young and wanted to keep the i6, still do.

okay that was the downside... the bright side is you can get 100% more hp from what you started with with little mods here and there.

cheap:
get a rebuildable block, get it tested and build it your self measuring everything and have it balanced. that's the block
get a 78-83 log head, port it out, put largest intake valves you can, keeping stock exhaust valves, 2bbl direct mount
use the 274/274-114 .450 cam, will help low end torque and increase top end breathing.

naturally, I would guess 130hp-140hp at the tire. with a m90 I could see up to 215hp with 15lbs boost. you'll beat most v8's at the track due to extreme bottom end torque.

all in all, the price for the engine would be roughly 1200-1600 depending on sales and timing... the super will be another $x,xxx amount

the triple 1bbl's I have seen some guys make 166hp at the tires, which is astounding.

I have thought of Xtacy's idea of 6 independant runners to 6 carbs, but that would be a pita to tune and modify for no leaks... but it is possible, IIRC he estimates 190hp from them.

the thing that costs the most would be others doing the work for you, if you're patient and want to do it yourself you can save ALOT of money on these engines IF you stick with mild, when you radical like 300hp you'll need a comfy cushion of cash to get it finished.


Good Luck!!

 

[jdn21758]

Hello nick,,there is much posibble but my advice is when you use the
triple carb. setup go for the looks,when you want horsepower go for
the super charger,and yes you need other pistons and some other
things,,its more expensive than the triple carb. setup but if you want
300 HP is this the best choise.

my choise where the looks,,,


good luck, have a nice weekend....JD..

 

[CNC-Dude]

At the minimum, you would have to buy one of the CI aluminum heads and have it ported pretty good to reach 300 HP in naturally aspirated form, and then you still might fall short of it even still. I doubt you could ever make 300 HP with the log style head with a blower or nitrous or both together out of just 200 cubic inches. That old saying keeps coming to mind: Speed costs money son, how fast do you want to go!

 

[FalconSedanDelivery]

Actually Kelly's Falcon is making more like 450HP ( credit where credit is due )!! 300 hp in a 200 with a log head possible but not at all practical , once 1hp per cube is reached street-ability becomes secondary ( on say under 300 cubic inch motors ) with a turbo or Blower , its easier but NOT cheap shoot for say .75 x per cube and that is about the realm of most owners wallets ( and also why I will always recommend a 250 over a 200) Unless its a say your starting with a144- 170 then a great bang for the buck is a 200, but Id still do a 250!Realistically , (and I was a kid / Newbie Once) , you need 3 things Time , Money , and Talent , to do any project , look at what you have and make a decision based on reality and not a dream,AND and as for the ( triple carbs are for looks ) 14.39 @ 91.75 isn't bad about 200hp , if your triple isn't making close to that , its not the Carbs fault , just saying

 

[xctasy]

Its not one, or the other, but you'll have to do all three.
250 plus intercooled M90 blower plus tri power.

With optimized ignition, log head induction, cam, exhast, pump gas and compression ratio to suit, your best power at 5000 rpm is

engine cid*rpm/6500 for 1-bbl carb, or 150hp with 200 ci
engine cid*rpm/5500 for 2-bbl carb, or 180hp with 200 ci
engine cid*rpm/5000 for 3 x 1-bbl carb, or 195 hp with 200 ci
engine cid*rpm/4500 for 3*2-bbl or port EFI, or 220 hp with 200 ci

The 90 cid blower won't make a realiable 230 hp unless its intercooled, and the tri power won't make more hp unless all three carbs are 1:1 linked. A 250 won't show a 25% power increase unless the rods are lengthend or the pistons or block are resized to close up the 90 to 110thou piston short fall all 1968-1981 250 sixes found in the Mustang/Maverick/Ranchero/Torino/Granada/Monarch/Varsailies 4.1 engines suffer from.

Add 25% for CI alloy head if you use the right recommended cam, carb, exhast. Add 25% for 250 if you use Ford Tracer/Taurus 2.5 hsc or 4.0 Barra 6 inch rods, or custom 6" small block Chevy rods. With port on port induction (efi or three 2-bbl carbs), you'll get a 10 to 25% boost in power and torque right throughout the rev range.


Over in Australia, triple carb 3.3 sixes out run carbed 351's and EFI 5 Liter V8's on a regular basis because they have a really good intake which allows more than twice the area of a restrictive Offenhauser/Edelbrock Tri-power system. Just three 1.75" carbs would mnake 215 at 5500 rpm, and three 1.75" 45 mm Webers would make 295 hp at 6200 rpm.
250 cubic inche sixes would see 300 hp at 5500 rpm with three 1.75" 45 mm Webers.

Without disrespecting the intregty of the 52 year old Tri-power design, unless you design the camshaft around its restrictive 3 sq inch throttle area, you won't see 300 hp with it unless you rev it to 7500 rpm, or 6000 rpm. The overall size is equal to the 48 mm carb used on Argentine racing 188 cube engines, and they are limited to about 390 hp at 9000 rpm with a carb area that small.

 

[Nick1966]

Thank you all for the reply's it's been very helpful. I guess I should have said I am in no way shape or form a mechanic but am willing to try and do as much work on the car as I can myself. Time is also not an issue. (i've already had the car for 10 years and would sell my first born before the car). Ok with that out of the way...

It seems like my dream of 300hp out of the 200 just isn't realistic, no problem there. I do want to keep the original engine though. If i'm going to engine swap I would probably go the 5.0 Roadrunner route.

I don't really need a race car. I just want something that would be fun to drive. (Speed + handling = fun to me). So, I guess maximizing hp & suspension is the way to go (suspension to come later). I figure start with the engine get her running then worry about keeping her on the road.

Not just so I understand everything everyone has said correctly I can get close to the 200hp marker with the 3x1bbl set up. I would still want to upgrade the camsahft, get a CI head, and forged pistons. No problem there either. Put to get close to the 200hp a 3x1bbl set-up can get me to I first need to rebuild the engine, bore the pistons and intake valves. Sounds like I should buy the pistons, cam etc. all at once then rebuild the engine and put it all in at once. Instead of taking the engine apart over and over.

It doesn't seem like the supercharger is going to offer that much better performance vs. cost as the 3x1bbl.

Thank you all for the thoughts and time, it's really very much appreciated!

Nick 1966

 

[CobraSix]

Don't overestimate the amount of power you need for fun.

Right now, I'm at 147 RWHP with the mods below. I'm a twisty fun kind of guy. A 200, making 147 RWHP with a 5 speed transmission and 3.40 rear end is a lot of fun on back roads. Remember, these mustangs are relatively light. And, without a plethora of emissions junk, power steering, AC, and half a dozen other unneeded systems dragging on the engine, the HP is very usable and fun. Then, just slap in a good suspension set up, tight steering, good tires, shocks, springs, Shelby Drop and you'll have a car that will be tough to outhandle on back roads with low end torque to really pull you around the corners but not so much power where you have to be timid about going around the turns.

The Tri-power set up is a really fun way to make power. It results in the engine sounding like a beast under the hood. But, you have to look around. An Offy set up, with 3 carb, and rebuilding the head with larger valves (which should be done) you are realistically looking at investing $1k-$1200. Save a little more and go for the CI Aluminum head and pick up a 4V Holley, and make your life easier, though poorer.

 

[chad]

"...Save a little more and go for the CI Aluminum head..."

I thought there was such a backlog (or other issues) you might hafta wait yrs.?
How much money (not askin 4 myself - unemployed off the acreage)?