how much horse can you get out of your six?

[Anonymous]

I have a 200ci in my 65 mustang. I put the T-5 behind it which is nice. Originally I was thinking of doing the V8 swap but a recent article in mustang monthly has made me reconsider. but how much horse can u get out of a inline six? I don't want anything radical since it's my daily transportation. But I would like some more pep. So how much is typical? 200? 250? 300? What can u get that is reasonable for a daily driver?

 

[Asa]

well, without forced induction, around 225 is the max i think... (at the crank IIRC)
with a turbo, or 'charger, pretty much the sky, and your wallet is the limit, there are people down in Oz that are makin 700+ with twin turbo's

Jack, the owner of the site, is working on a mod that will get the I6's even higher up there, i think i remember reading something about maybe BMW levels...
but he's been pretty busy as of late, so we have no clue as to where that part is

how much power are you looking for?

 

[xctasy]

If you use three 500 cfm Holley carbs, with 46 thou jets and 4.5 power valves, and rig it so the inner one is running, and the outer ones are are vaccum operated, and you get a tubing rod spring tower brace, you'll get a cost effective 240 hp at 5900 rpm, by may calculations. This is a 'poor mans' version of the Argie Weber IDA carbed 221's you can see. You'd need a 4.56:1 set of gears, reving to 6500 rpm through the traps for a 100 mph quarter, and a 13.7 sec ET. Not much would happen below 4000 rpm, with maximum torque about 225 lb-ft at 4200 rpm, by my calcs.

This was the link to the argie Falcons, to get an idea, but its not working right now. http://galeriasfalc.netfirms.com/galmotor.htm

You must use the last of the 1.75" D8 onwards heads, and a good 290 degree cam and Tempo pistons with the largest chamber head should give you enough compression to run pump gas. Great headers, and a good SVO/LX T5 would be ideal with this engine.

The trick is ensuring you have no hidden costs. Unless you are as shrewd and broad-shoulderd as Jack Collins, or have a confident approach to car building like Jimbo 65, who will possibly end up with injection any way, don't go injection. It will give good power and better driveablity, but its a nightmare to set up unless all the bits, linkages, and pumps, and injector mounts are specially fabricated. A single point discharge will not give good mixture distribution, and will not allow pulse tunning like triple carbs. Throttle body injection is not the way to go unless you accept a milder state of tune. Holley system is very good, but the manifolding must be good to suit, and I'm not sure if the 2-bbl Holley EFI is as good as the 4-bbl.

 

[Anonymous]

I only know of one guy that has actually dynoed his car, Mustangroo. For the most part the engine was stock save for an Aussie head. His car dynoed at 105hp I believe. This is a car dyno. So 105 at the wheels. For an automatic I believe you loose around 25% or so they say. So at the crank that would be around 131 ponies.

Now if you were to upgrade the cam, valve train maybe some head work you might get up to 150 at the wheels at least that is what I'm hoping for.

I'm doing an aussie head coversion but I also got a 262 ISKY cam with lifters, rods, bigger valves 3 angle job. Electric fuel pump and 2bbl carb. We will see what all those additions make. I hope to have it up and running before the end of the year.

 

[simon]

yup, thats the difference between gross and net HP numbers.

a loss of horsepower of about 25% is right when dynoed at the rear wheels (or whatever wheels are driven), due to drag of belts, accessories and rotating masses and friction losses (water pump internals, alternator internals, transmission, driveshaft, rearend...)

dynoing a motor without accessories and tranny is kinda bogus IMO.

it only shows how powerful an engine can be without the drag caused by secondary systems which are mandatory (!) for a running engine.

 

[mugsy]

Well think of it this way. Way back when in the late 60's, the big news was when the OEMs would/could sell a car that had the magical "1 HP per cubic inch". So one of our 200 if it had a big mechanical cam, big carburation, etc. and would put out 200 HP. Tops.

Now with that said, the modern cars with fuel injection and computer control timing are better than that. But remmeber, you buy "horsepower" but drive torque. I think a reasonable HP level would be much less than 200 HP. Remember air flow is horsepower (roughly speaking) and if you stick with the log head you are all limited.

Mugsy

 

[xctasy]

The latter log head is perfect for a triple carb set-up which has one carb barrel per cylinder. This set-up allows the intake charge to be pulse tuned in a way that is impossible for a two barrel, four barrel or single barrel carb. The log head is bad only because of the 90 degree bends and poor mixture distribution at some points higher in the rev range.

It isn't a lemon, and has, on the later heads, nice, large runners which can be turned into an independant runner system.

Injection, Aussie/Argie heads, alloy heads, and cut off and plated conversions with multiple carbs are all time consuming. On early Minis, good runner isolated intake manifolds improved the performance out of sight compared to any other set-up, including fuel injection. A similar thing happens with the log head because its porting ends up very similar to the best British Mini IDA 48 manifolds, with no nasty saimesed ports.

Additionally, these are much more able to distribute less fuel more evenly, with better power.

I think Clifford were onto the right thing with the earlier triple carb conversion, but we need to take the next step with bigger dual barrel carbs in all three parts of the manifold. And if it could operate as a 2-bbl carb most of the time, and the two outer barrels coming in when needed, you'd end up with a cost effective rocket engine!

Just my opinion, though. In Aussie, its nothing to push the 245 hp barrier with a triple carbed 202 cube Holden six-inliner.

 

[Anonymous]

I can only speak with the experience I have with my 200

1hp per ci is doable (200 hp) with a highly modified 200 n/a log head with the proper bottom end, cam and direct mount 500 cfm Holley.

From a couple of other members cars a 200 engine fit with a Argie or Oz 250 2V head should be able to crank out anywhere in the neighborhood of 225-250 hp.

Supercharged or turbocharged daily driven 200's should be able to produce anywhere from 200-250 hp and will be more "drivable" than a highly modified n/a motor with similar hp ratings.

If your talking about a nice n/a modified daily driver (that you can live with and drive comfortably) figure 150hp tops

All these numbers are measured at the crankshaft of course!

Later,

Doug