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What's the most power you've been able to achieve?

260Alpine said:
I think Geoff's work to improve the breathing and intake will help reach 200HP
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Jim,

I've been most impressed with Geoff's work, as well. I think he has the best potential of anyone so far and hope he succeeds. I hope to see him post about more of his work. I wasn't trying to criticize his efforts in any fashion, but I also don't foresee a tractable 200 HP street 2.8L.

That's an opinion I would gladly have proven wrong.

Just me,
 
husky drvr said:
Jim,

I've been most impressed with Geoff's work, as well. I think he has the best potential of anyone so far and hope he succeeds. I hope to see him post about more of his work. I wasn't trying to criticize his efforts in any fashion, but I also don't foresee a tractable 200 HP street 2.8L.

That's an opinion I would gladly have proven wrong.

Just me,
Click to expand...
This is part of the reason to take on the project. So far from a mathematical standpoint it appears very possible. The cylinder heads can be modded to well within range. The headers have to be fabbed to fit these different applications so were good there.
The weakest link I see is the intake manifold. The OFFY has problems with momentum and fuel distribution. It doesn't flow that well as delivered either. I do think it can modified to do better but it would take some work.
One thing about the OFFY that bugs me is that you drive around on the primaries you have a large secondary cavity that isnt moving any air or fuel. When the secondaries come open there will be a delay for the fuel to get to the cylinders, the air will get there quickly.
Cylinders 1&6 dont get the fuel that the others do. This is going to cause detonation sensitivity in those cylinders.
You need to get the compression up to modern levels if you expect modern power levels. If you have two lean cylinders it will force people to lower the compression to the entire engine to crutch 1&6.
The factory manifold has a superior floor in the manifold and the floor is how carbureted manifolds distribute fuel. Stock int. manifold flows bad as delivered with 2 barrel opening and square edge at the plenum transition. Improving the airflow in the stock manifold is going to be the answer. The momentum and fuel distribution are already there.
The short center runners are just a part of the deal on either manifold.
The cam thing has been a PITA and it shouldnt be, I think were getting there but I didn't plan on having to send it back twice.
 
mummert said:
The weakest link I see is the intake manifold. The OFFY has problems with momentum and fuel distribution. It doesn't flow that well as delivered either. I do think it can modified to do better but it would take some work.
Click to expand...
The 2.8 isn't as well served it seems as the Essex V6 ..they have the manifolds to fit 3 down draft Weber carbs... The Capri 2.6/2.8/3100 all can use these ..but the Cologne heads have different intake locations I believe...
Pity...
 
The U.S. version offset the intake ports to help with fuel distribution. A really nice manifold could be built for the 2.8, but I'm not sure the market would support a scratch start part.
 
husky drvr said:
Just for the fun of stirring the pot, here's a few thoughts.

1st> no one seems willing to understand the way horsepower is figured. Horsepower is a number derived from a formula to describe an observation and predict a probable outcome. Horsepower doesn't actually exist.

Torque is used to describe how much force can be applied at a given instant. Horsepower is computed by factoring an amount of torque over a period of time. The factors involved mean that at 5252 RPM. Torque and Horsepower are EQUAL. If you ever see a Torque/Horsepower graph where the two graphed lines for Torque and Horsepower cross anywhere other than 5252 RPM., somebody LIED.

2nd> an engine develops Torque in direct response to how much fuel and air can be ingested and efficiently consumed. Think of the old quip, "No replacement for displacement." Normal aspiration depends on environmental factors to develop maximum power. Forced induction can pack a greater fuel/air charge into the engine, but it's not a free lunch.

3rd> since Horsepower is a product of a measurement of Torque at a stated RPM and a length of Time, it should be obvious that a given amount of Torque at a HIGHER RPM. will compute to a higher number for Horsepower. Jose had this idea down pat because he always said to rev these engines (2.8L) to 7000 RPM - or more. Jose's focus was on racing - not cross country cruising. Hence the general disfavor of his camshaft specs. The elephant in the room is for a given size engine, you can only achieve so much torque for a given design. You can change cam specs to allow moving the maximum torque production to a higher RPM., but you will experience a much lower engine efficiency and lower torque at low RPM.s. The faster you spin an engine, the more pumping losses experienced, the less Torque and Power produced. It's a balance thing.

I checked on one online calculator just for the fun of it. IF you can produce 150 Ft-lb.'s of Torque at 7000 RPM's, that computes to 200 HP. Also, 140 Ft-lb.'s at 7500 RPM's is 200 HP. In a 2.8L, ~1.2 HP per cubic inch would give 200 HP. The challenge is if the Peak is desired at 5500 RPM's, then 191 Ft-lb.'s are required. See the problem?


Last> now for the fun part.

Here's an overview of a BRM engine designed for F1 in the 60's > 3.0 liters, 400 HP @ 10,000 RPM, 12,000 RPM redline. It's unique and didn't last. Notice the challenge of trying to start from a stop.

brm h16 1966 - Search Videos

Watch videos instantly on Bing—enjoy direct playback, discover related clips, and dive into trending content all in one place.
www.bing.com www.bing.com
Click to expand...
You nailed it!
For driveability, you need more torque not horsepower. As you can see in all engine tests done on a dyno, horsepower comes in at the end of the engines rpm capability. Torque is DEVELOPED early in the rpm range.
The point is you can try to reach the highest horsepower number you think you can get out of a motor. Torque is what makes it fun to drive, higher horsepower than torque means you will have to keep the rpm's up to enjoy your ride, otherwise you will feel it bog down.
 
alpine_64 said:
Do you mean for the design of the manifold...or the modelling.. of you know what the design is... The modelling is easy....
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All of it, you need to have, all the port locations, bolt hole locations, manifold V angle, finished surface heights, carb flange detail, port shapes, valve cover rail locations, valve cover bolt hole locations, etc.. The engineering would take some time the modeling would go pretty quick.
 
belmateo said:
You nailed it!
For driveability, you need more torque not horsepower. As you can see in all engine tests done on a dyno, horsepower comes in at the end of the engines rpm capability. Torque is DEVELOPED early in the rpm range.
The point is you can try to reach the highest horsepower number you think you can get out of a motor. Torque is what makes it fun to drive, higher horsepower than torque means you will have to keep the rpm's up to enjoy your ride, otherwise you will feel it bog down.
Click to expand...
I think we're all saying the same thing here. I'm shooting for 200HP which is way under the heads flow potential so I can try to hit my target by 5800- 6000 with decent over rev. The lower are target the peak HP is, the BMEP will come up and torque will up right along with it.
 
You may be right, but at what cost and trouble will it take to get there? My point about the ford turbo engine is factoring cost over benefit, reliability, driveability, parts availability etc.
It appears to me that parts and swap kits for this conversion is not cheap and it takes quite of bit of work to get this into the Alpine bay, hence my question about your ownership. You have to admit that a fuel injection motor is much more effecient than a naturally aspirated one.
 
FWIW. . the 2.8 swap is one of the least invasive and straightforward.. especially with the kit.

The other advantage of the V6 is that it is a period looking motor especially with a few select chosen parts. You can add injection via a Holley sniper or edelbrock EFI kit...they can also sound quite good.

The miata (MX5) swap is very interesting to me... I'm always disappointed nobody done it with an itb setup ..or even a DCOE swap....or even better a jenvey tb setup.. that way they look and sound like a period motor.

I find all the swaps interesting and respect the time and effort people put into them... But I like the ones that go the extra mile to make them look like a period factory install.. which is why I appreciate the turbos..but they don't feel right to me on a holistic car sense.
 
belmateo said:
You may be right, but at what cost and trouble will it take to get there? My point about the ford turbo engine is factoring cost over benefit, reliability, driveability, parts availability etc.
It appears to me that parts and swap kits for this conversion is not cheap and it takes quite of bit of work to get this into the Alpine bay, hence my question about your ownership. You have to admit that a fuel injection motor is much more effecient than a naturally aspirated one.
Click to expand...
Fuel injection has some advantages in turbo applications yes. But after 30 years of building race engines carburetion makes more power easier.
Its takes Pro Stock 10 years to run as quick with EFI as they did with carbs. Nascar engine are only whisper of what they were 10-15 years ago. They used to make 900HP, now they make 650HP. There are other rules involved no doubt, but EFI hasn't solved all their problems. In fact it has created new ones. They have had to try and make their EFI run like carbs to reduce some strange harmonic issues they were running into when they had each cylinder running to similar.
A carburetor is about one step more complicated than a can opener. Its something that every car owner should understand. Many new people today think they can throw good engine building principles to the wind, cam timing, plenum volume, port velocities and EFI will fix it.
It won't. You'll just have a poor engine with EFI
Sure, EFI can have better cold start, can maintain a more even idle speed with temperature changes. But they are mainly using it to control detonation with ultra lean mixtures, trying to control EGR to get better part throttle emissions by raising the part throttle cylinder pressure with an inert gas. etc. etc. Trying to maintain optimum catalytic converter temperature and life. These are things old cars don't need and are one of fascinations of and old car. Going back to a time before the government injected themselves into the car business and tried to dictate what we can and can't do.
Carburetors were installed on vehicles for 80 of the 120 years of their existence. Don't get me wrong I like EFI and use it for certain things, boosted applications mainly.
If you can't maintain a carburetor and tune it to your application you shouldnt own an old car.
Fuel injection has become a fallback for people trying to avoid having knowledge about the physics of a running engine.

If I was going to build a daily driver for my wife out of an old car I would think about EFI. But the truth is there are 10 other things she wouldnt like about the old car and in the end after AC, heated seats , air bags, power steering, anti-lock brakes, backup camera, gps, and host of other things the car wouldn't be an old car anymore and would have lost all its charm.
 
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I like carbs too because they are wonderful when tuned properly as you have done over the years. As you mentioned they are not so good for cold starts, elevation changes, daily driving and we wil get to fuel economy later.
I have a question for you from your years of experience, what changes did you find that actually increased the torque curve? Nevermind the horsepower number, because as we now know torque is what we feel when we punch it to get going. Ideally an engine that has an early torque number tends to maintain that as the rpm's increase. Yes the power will peak at a lesser number, but honestly we are talking about a street car afterall, aren't we?
Race car engines stay at the high rpm range so they can utilize all that power and have no concern for how they got there in the first place.
Thank you for answering the OP question so thoroughly, we appreciate you.
 
Controlling reversion ( a column of air that is headed in the wrong direction) is where power below the Tq pk comes from. Long tube headers, merge collectors, good port speeds, camshafts with short duration that still have decent valve lift, tuning intake length to a more powerful harmonic. Specific anti-reversion devices in the intake tract and exhaust will help bottom end as well. There are focused efforts.
Compression, cooler charge, less drag in the rotating assembly, and careful useage of valve spring pressure are more global rpm band enhancers.
 
mummert said:
Controlling reversion ( a column of air that is headed in the wrong direction) is where power below the Tq pk comes from. Long tube headers, merge collectors, good port speeds, camshafts with short duration that still have decent valve lift, tuning intake length to a more powerful harmonic. Specific anti-reversion devices in the intake tract and exhaust will help bottom end as well. There are focused efforts.
Compression, cooler charge, less drag in the rotating assembly, and careful useage of valve spring pressure are more global rpm band enhancers.
Click to expand...
Good points, all. I found crisp throttle response and punch to be had with turbulent chambers; (piston to deck quench/clearance at 0.035").....laborious tailoring of vacuum and mechanical advance; brazing more mass onto the weights, fitting one standard fit soft spring and one stiff spring fitted loosely so it is ineffective until mid-range RPM. All that required good fuel, good traction, and....humility. Lots of do-overs finding what works.....
 
Mechanical devices can be very effective. They take a little work but help you become a better engine guy. Getting things right is the easiest way to make your life easy.
More cylinder pressure requires less timing. Its a simple concept more pressure equals faster burn rates equals less time needed to burn complete.
Good header design and camshaft selection will help maintain good cylinder pressure across the powerband. The timing curve is much easier to get right when you arent chasing problems.
Stock engines will usually have the least requirement for timing at idle, and most need timing at the topend. ( Bad ports and low compression)
Race engines with larger cams will want more idle timing because the big cam will lower the low speed cylinder pressure, but as the rpm comes up and inertia in the ports start to rise, better port shapes and hi comp pistons will start requiring less timing due to better cylinder fill and smaller chamber volume.
When things get really out of whack the engine will need a lot of idle timing 20+ degrees. In the mid range the engine will actually want more timing than it does on the top end. You cant usually see that with a mechanical advance distributor beause they dont take timing away from 4000 on up.
Low compression, excessive piston to head clearance, big camshafts, restrictive exhaust systems , or short tube headers can all be causes.
 
mummert said:
Mechanical devices can be very effective. They take a little work but help you become a better engine guy. Getting things right is the easiest way to make your life easy.
More cylinder pressure requires less timing. Its a simple concept more pressure equals faster burn rates equals less time needed to burn complete.
Good header design and camshaft selection will help maintain good cylinder pressure across the powerband. The timing curve is much easier to get right when you arent chasing problems.
Stock engines will usually have the least requirement for timing at idle, and most need timing at the topend. ( Bad ports and low compression)
Race engines with larger cams will want more idle timing because the big cam will lower the low speed cylinder pressure, but as the rpm comes up and inertia in the ports start to rise, better port shapes and hi comp pistons will start requiring less timing due to better cylinder fill and smaller chamber volume.
When things get really out of whack the engine will need a lot of idle timing 20+ degrees. In the mid range the engine will actually want more timing than it does on the top end. You cant usually see that with a mechanical advance distributor beause they dont take timing away from 4000 on up.
Low compression, excessive piston to head clearance, big camshafts, restrictive exhaust systems , or short tube headers can all be causes.
Click to expand...
Rod length, another factor involved here, is about more than getting the piston to match the deck height. It makes a difference in how much and how useful the power is. The metric, is the angle of the rod to the crankshaft center at half stroke.... I like about seventeen degrees. Two valve, pushrod motors make smooth power at seventeen degree rod angles. They have good flame speed, efficiently moving the pistons, and so make torque from piston pressure. They don't need extra advance like, say, a twenty degree motor will. I worked at a racing engine machine shop, and heard the sound of different engines on the dyno. (So loud it loosened screws in the building!) The seventeen degree engines (Dodge 440's) were special, not a sharp exhaust pulse, but they twisted the fool out of the dyno. The Dodge 440's are about seventeen and one half degree motors, Alpine V motor is a seventeen degree motor.....
 
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