250 I6 =~ an M3

[Anonymous]

Has anynoe built a 250 I6 that has the same power as a BMW M3 CSL? What does it take to create a really strong street maybe race 250 I6?
I see the super torque head and great cams, but I haven't seen any really strong hps/tqr numbers to back these claims. Aussie headed engines seem to make great power/torque curves but stationary log manifold engines seem to suffer.
I am looking at 3x1bbls probably YF's from a 300cid, roller rockers, big valves strong springs, 10:1 compression. As far as cams go?????
Yes I have the Falcon book, but it doesn't put together a complete engine package, great suggestions but no final plans.
Any suggestions to help make driveable hps/tqr gains are appriciated.
Thanks,
Ken

 

[xctasy]

The reason for the lack of stove hot sixes is that the expetise was lost in about 1969...when the Cleveland and Bosses and Lima engines with canted valve heads hit town. There was M-U-C-H more power to be had with the 302 Boss, much more with the 351C's and any other 385 series big block engine.

In Australia and Argentina, both countires are far more six cylinder orientated than any other country, and V8's were either imported and outsold by sixes 5 to 1.


Soo from 1969 to onwards, 164 hp net 221's and 170 hp gross 250's were common, not to mention 215 HP triple Carb Torinos (with the old 3.8 Kaiser OHC), or 306 hp triple Weber 265 Hemi sixes (the old Chylser Valiant). Even little 186 or 202 cube Holden sixes came out with triple Stromberg CD's and 160 to 195 hp. In America, the famous Offy triple intakes and Hillborn injection and Ak miller turbos , propane Maverick 250 Turbos which did low 14 sec quarters, and quadruple carbed 200 sixes found in bulk 1962 to 1972 car mags just faded away.

The answer is that supercharging or turbos are the easiest way to get power today. In order to get a streetable 250 with V8-style grunt, you have to make the engine more efficent firstly, and then do transmission and cam and valve gear modifications to get the rev range.

Triple carbs give power, but the engine has to be built around a target power requirements.


To get into the low 13 second quarters, the M3 has to have official power ratings of about 333 hp at 7900 rpm and 262 lb-ft of torque at something like where the stock 250 redline is. They have six speed gearboxes.


For a 250 or 300 in a Maverick to eclipse an M3, you have to make 333 hp at the lowest rpm you can without a turbo. That means triples, a close ratio 4 or 5 speed gearbox, and a usable rev range that can be used regularly. The low end torque must be enough to allow street driving.

You do this by copying a race specification Argie 183 Falcon with over 300 hp net with a huge 330 degree cam, SP head and with a huge IDF carb, or a 202 Holden Torana with 312 degree cam and triple Weber 45DCOE'S which can get about 295 hp, or a 265 Chysler Valiant with a 302 degree cam, and triple 48 DHLA's which is right on about 330 hp.

These are circuit racers which drop 13 second quarter miles with ease. You couldn't drive them on the street like a BMW, because there inefficent breathing and 4-speed gearboxes make them like caged animals.

If you turbo it, you can run an engine more or less stock, and have a great old time.

Enjoy yourself

 

[MustangSix]

You can't get there. The M3 engine is a very sophisticated, highly tuned, extremely well designed engine that takes advantage of every concievable tuning measure to optimize airflow. You simply cannot mimic that behavior in a 250 with any available head and cam combination.

Behind all of this is a Motronic control system that optimizes spark, fuel, cam timing, injection timing, intake volume,.........dozens of inputs and outputs, most of which are simply not applicable to our engines.

You can make comparable power levels, but it will take forced induction to match the M3 airflow potential. Even at that, you will have an engine with a different character.

Frankly, the M3 engine is in a league of its own. Now, if you were to transplant one of those into a Falcon......!!

 

[Anonymous]

Thanks xctasy and Mustang Six,
xctasy thanks for your explaination, it is right on. The V8 took over. What web site(s) can I go to, to read about Aussie engines

Mustang Six, yep the technology has taken over. Dual weight flywheels, multiport injection, computers, etc.

Sometimes you have to aim high!!!
Thanks again,
Ken

 

[xctasy]

Info on old Aussie homologation specials isn't easy to find on the net.

The best inforamtion was on paper in Australian Wheels Magazine in 1982, 1983 and there much sought after Muscle Car 1 and 2 books. Everything has been a rehash of the info since then.

There is a subscriber site called http://autospeed.com for post 1995 Fords and Holdens.

For stuff earlier than that, try the http://www.chevron.com.au/musclecar_masters.html, and try to secure back issues of Austrailan Muscle Car, which covers everything you need to know.

There are some websites for six cylinder Toranas

http://www.google.co.nz/search?hl=en&q= ... arch&meta=

and Valiant Chargers.

http://www.google.co.nz/search?hl=en&q= ... arch&meta=



Halcyon days of street legal race cars was 1967 to 1972, when all the sixes came out.

You have to search by model letter as Aussie cars never got year to year updates. So for
Holdens, LJ, LC Torana GTR186 and GTR XU1 202

For Mopars, Chrysler Valiant VE, VF, VG, VH,VJ Charger and Pacer, R/T, E37, E38, E48, E49 245 and 265

For Aussie Fords, just the 1971,72,73 Falcon XY/XA/XB 2V 170 HP engines, and then no real perfromance sixes until the 1992 EB Falcon XR6

 

[mugsy]

Ken,

I thought the very same thing: the German engineers got 333 bhp out of 3.2 litres of diplacement; FoMoCo boys got roughly 90 bhp out of 3.3 liters (200 ci) . I *know* there is more power in there, we just have to find a way to extract it out . I have read that the M-3 engine has piston speeds close to F-1 engines. But there is more to the power equation that just piston speed. As mentioned before, the Bimmer has SFI, cam phasing, and a bunch of other technology that Fordz couldn't afford or have available 40 years ago. But I agree with you, it should be used as a goal or guide...

tanx,
Mugsy 8)

P.S. I ask people: between an M-3, 330i and my '65, which has the largest motor? most are shocked that the Mustang does.

 

[83F150]

Whoa?

Since when has Technolgy taken over?

The eaisest, cheapest, best way to get big power is through a Big Cube Engine with a Big ol' Carburator, a hot cam, good intake, heads that flow like a air compressor, and a set of points. Hardly high tech if you ask me.


Sure you can slap a turbo on a 4 cylinder and get 250hp. But how logn will the engine last....how high does it have to be revved....and how much other beefing has to take place?


Give me a Tire Smoking, Gas Guzzling' Big Block any day of the week.

 

[TxAgs66]

Interesting fact... and I'm not sure of some of the models

Only 3 cars in the world produce more than 100 hp per Liter with a naturally aspirated piston engine.

Ferrari 550 Maranello - I don't know the numbers
BMW M3 - 330 HP - 3.2L
Honda S2000 - 260 HP - 2.4L

Of course you could always look at a 3 rotor with a twin turbo. I believe you can get around 750HP with 2.0 liters.

 

[wallaka]

Most "Hi-Po" Hondas approach or break this. The B16B did it in the early 90's, and he B18's did it too. It's easy to get horsepower if you shift the power curve up because it's a function of torque and rpm. I've never heard of a N/A Honda (street driven) that will get anywhere near 200 ft/lbs of torque though. You have to have bigger displacement or forced induction for torque. There really is no replacement.

The rotaries are a different story. Because of the way that their combustion chambers move, their effective displacement is twice their rated displacement. So the 13B should be compared to a 2.6L engine and so forth. Anyways, the most reliable way to make over 300 hp in a RX-7 is to stuff a small-block in there.

I dunno, 83F150. A lot of R&D went into those high performance intakes and heads. It's easy to spend 10-20 G's on a 460 to get 800 hp. A nice turbo system on a 302 will do the same thing for about 6 or 7,000. (Less if you do the fab work) The car it's in will go faster because it weighs 300-400 pounds less too. Ever notice that there aren't any big-blocks in the quick street classes? They're all turbo (or centrifigul supercharged) 351's and 302's. It's because it's cheaper and easier to do it that way.

 

[XFlow_Fairlane]

actually a turbo 4 cyl will last longer than an NA one built for the same power. with forced induction you get a longer/slower burn that doesn't hit hard on the rods/crank. I have seen plenty of 2.3L ford turbo cars with 150K+ on the clock and still running fine. If you built a motor with forged slugs and decent rods/bolts (just a step up from factory) it will live plenty long. I have a friend putting out 500hp in a twin turbo mark 7 that still gets 20 mpg on the highway. show me a 500hp big block that can do that.


back on topic though...

you will never make that with a stock headed 200/250 with mikes head you will still be hard pressed to do it NA and make it drivable.

 

[Anlushac11]

8)

My 1980 Mustang project is being built to try to emulate the BMW M3.

One thing in my favor is that my Mustang weighs almost 500lbs less than a BMW M3 (2866lb versus 3300lbs). I have also been working on reducing the weight of my Stang.

Therefore we dont have to match horsepower for horsepower, just power to weight ratio.

 

[TxAgs66]

I'll have to disagree about the reliability of a rotary. Yes they can be troublesome, but I have seen many rotaries with over 300 hp on daily drivers that were trouble free.

another thing is that I meant to say PRODUCTION cars. Yes no doubt can you get a lot of hp out of a piston car, but this were production numbers.

 

[addo]

While the M3 motor may provide some degree of benchmarking for high-output six cylinder engines, what about looking at cam-in-block sixes? That is, unless you plan some kind of OHC conversion.

I see some people would still back Goliath against David.