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Learning how to build Lotus Seven replicas...together!
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PostPosted: March 3, 2023, 4:25 pm 
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Location: Easley, SC
I’m using a 2.0 liter Duratec from a Focus, less than 10k miles. The 2.0 is higher revving with less vibration than the 2.3 . I’m not up much on the Ecotechs and the 2.5, I’m sure they will have good torque too. This 2.0 liter is also what was very commonly used in the UK club racing, so Emerald, OMEX, and SBD’s ECU’s have had a lot of development time in mapping, that are available for the 2.0
With OMEX, they provided a program for this engine with these Jenvey’s that should plug in and run out of the box with their larger Bosch injectors. I can find a shop with a rolling road (dynamometer) to refine the tune later. I liked the idea of the higher revving sound, and the tuned length of the throttle bodies, intake and horns should be a realistic compromise of torque and horsepower for good usable performance on the twisty mountain roads, and street driving. I found a guy in UK who was very helpful in giving me all of the design criteria for optimizing exhaust headers, and a shop in WI to build them for me from a mock up kit.
Although, the beauty of these little jewels were like the song of the sirens to me….


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PostPosted: March 3, 2023, 4:38 pm 
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Location: Easley, SC
I suggest looking into the flow characteristics for different runner lengths from the valve to the tip of the air horn on throttle bodies, there can be much gained or lost in setting the length when you fabricate your intake manifold.
For anyone who cares, with Jenvey, if you size up the throttle bodies from 45 mm on a 2.0 Duratec, there is a good chance that the intake opening will NOT match the port on the head. They are made to match the 2.3 liter, which is noticeably taller than the 2.0 ….. ask me how I know. ( 3 weeks of my life I’ll never get back )
Skidzzz

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PostPosted: March 3, 2023, 6:41 pm 
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Joined: January 14, 2021, 12:19 pm
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Location: San Dimas, CA
Yes they are taller, different shape bit as well. Mine is the 2.5, so it's even bigger. I have a 2016 Fusion 2.5L that has a very very flat oil pan. I wasn't expecting that. The engine can sit on it without tipping over at all. Mine is a 49k northern Cali engine(got the car's picture as well) picked it up from LKQ for $348(!).
I think that I have some drawings for those manifolds. They have a bend, which most likely I can't replicate. I may even make mine horizontal, to fit better under the hood. My engine sits about 6 degree to one side. I thought that it should sit at 10 degree, but taking the oil pans angle into account, it is more like 6 degrees.
How you are dealing with the driveshaft? Mine is way to long. You will be shortening it, or a shop? I'm a machinist, I have dial indicator, but I don't know if I trust my welding. I'm a beginner. Though the chassis is welded by me after all.

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PostPosted: March 4, 2023, 3:32 pm 
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Location: Easley, SC
Between the NA donor, the upgrade to the NB LSD, and the NC six speed transmission, I now have 3 driveshafts. (If anyone needs a spare ….) I have to use the front end of the NC to mate with the trans, the rear seems to be a match for any Miata diff. I’m sure you could accomplish this cut and fit with your experience, and there’s nothing saying you can’t hire the welding part out. I think ( with no calculations or engineering basis) that as these driveshafts become so short and relationship of transm to diff never really change, we could get away with a little bit of inaccuracy with the refabrication. If all else fails, it may only require some balancing. Many have done their own.
Another line of experiences I’ve read about, guys who take their drive shaft to a drive shaft shop intend to have their shaft modified, yet get persuaded to let them build one from parts for the same money….with the advantage of replaceable u-joints.
Skidzzz

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PostPosted: March 4, 2023, 3:50 pm 
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Do you know how much has to "stick out" the yoke from the trans, before it would bottom out? 1/4"-1/2" would be enough right, since they won't be moving much, if any at all.

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PostPosted: March 4, 2023, 8:30 pm 
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Location: Easley, SC
I’m not sure. I used to have a good idea about what to allow for, but it has just been a long time. Memory fades, I think it was a little more than that. Once you slide the splines in and out some you kind of get a feel for what is a significant amount of engagement. There may be some telltale signs of exposure on the front shaft section that indicates how much was typically engaged in the Miata. I seem to remember that if you leave enough so you can move the shaft forward enough to dismount the rear of the driveshaft from the pinion flange, that would be convenient and more than enough engagement on the splines. Remembering that all these components are designed to withstand all the forces from a car that weighs 800 pounds more than our Sevens.
Maybe someone else can chime in…..
Skidzzz

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PostPosted: March 4, 2023, 8:52 pm 
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Ditto. Make the shaft as long as possible:
1) without distorting the output seal with the slip yoke shoulder
2) and short enough to clear the pinion coupler and nut for removal without loosening the diff or trans mount.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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PostPosted: March 4, 2023, 8:57 pm 
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I have found on the net a picture where they compare the new Miata to the Fiat Spider chassis, and to me it seems like there is around 1" space.
https://s1.cdn.autoevolution.com/images/news/mazda-mx-5-miata-rolling-drivetrain-chassis-compared-to-fiat-124-spider-abarth-137526_1.jpg

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PostPosted: March 4, 2023, 9:11 pm 
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Access denied so I can't see but you should not go by a picture.

I'd say 1/2 to 1 inch for clearance. You can hold the pinion flange coupler off of the pinion flange to determine how much room is actually needed to clear dropping the shaft. It isn't critical to be off by a half inch.

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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PostPosted: March 4, 2023, 9:20 pm 
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Location: San Dimas, CA
https://www.autoevolution.com/news/mazd ... 37526.html

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PostPosted: August 20, 2023, 1:22 pm 
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Location: central Arkansas
Miatav8,MstrASE,A&P,F wrote:
However, very few known builders use sheet steel to isolate the fuel tank and no lotus seven or caterham comes with steel sheet isolation. Just another consideration if you regularly drive in a congested, accident prone area.


The fuel tank of a DeTomaso Pantera is behind the driver, snuggled up against the left exhaust manifold. The bulkhead between the engine and passenger compartment is steel on the sides and fiberglass in the middle; it's removable for engine maintenance.

The fuel tank of my old 1965 pickup truck was in the cab, behind the seat. That was standard from the 1930s to... 1969, somewhere around there. Not really a bad location; higher than most carb bumpers, and the cab offered a bit more protection than hanging outside the frame rail like the saddle tanks.


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