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Learning how to build Lotus Seven replicas...together!
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PostPosted: September 11, 2020, 6:57 am 
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Starting the process. It might work. Here is my Part 1 video. If you have ideas, add to the thread!
https://www.youtube.com/watch?v=fyqcj25p2eo

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South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


Last edited by locofinn on September 16, 2020, 3:42 pm, edited 1 time in total.

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PostPosted: September 11, 2020, 8:42 am 
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You said it was getting a little floaty on the straights, what speeds are you hitting? The straights as Gingerman are not that long?

Graham


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PostPosted: September 11, 2020, 9:59 am 
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Not sure exactly as I was not data logging and just having fun. I guess around 100?

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South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: September 11, 2020, 11:24 am 
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I routinely get mine over 125, I think 128 is the max, and I have no feeling of lightness, I know Caterham 420 can jet into the 135+ range without issues. I am it Mid Ohio next weekend and will record my speed again.

Graham


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PostPosted: September 11, 2020, 1:48 pm 
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My issues are more than just aero. I need to run firmer springs and work on shock adjustments. I have rarely run my car a track speeds but I plan to run Time Trials so it will be more routine so that will be the base setup going forward.

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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: September 11, 2020, 3:05 pm 
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Joined: April 23, 2006, 8:26 pm
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Without watching your video, "floaty" makes me suspect front end lift.

You might consider one big central wing (think "sprint car wing") that can be fine-tuned fore-aft. One Super Stalker owner (Meinhart?) did that and was hitting something like 160-170 down the straights (using all 500hp of the LS3...). Here's a video of it and you can just see the big wing above on sort of an outrigger.

https://youtu.be/WkvZRFXndeo

I hit 150 at Autoclub Speedway in Southern California and Midlana was very stable. The difference is that both the hood and windscreen are angled more than a Locost, the bottom is flat in that area (being mid-engine) so no air exits out the bottom, and radiator air exits sideways into the low pressure area between the chassis and front tires.

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PostPosted: September 11, 2020, 5:44 pm 
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Was this floaty feeling with, or without, the full air-dam/splitter/spoiler setup?

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PostPosted: September 14, 2020, 7:56 am 
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My point was that is you have a floaty feeling at 100mph I think you have more than a aero problem. Do you know what front geometry your running, from your video, the angle is strange but it looks like you have more tire on the front than the rear, but I am sure that cannot be.

Graham


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PostPosted: September 14, 2020, 8:39 am 
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Yes. There is more to this than aero. The front tires are 10" wide and the rears are 12" wide. Geometry checks out on roll centers etc., but the spring rate is too soft for the calculated wheel rate. I could also play with shock settings as they are adjustable. The previous air dam and splitter set up was better suited for low speed aero as it greatly increased the frontal area of the car and the splitter angle could have been improved. The splitter might have even angled up a a degree or two after a recent impact. Much to do.

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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: September 15, 2020, 7:43 am 
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AutoX is a very special event were single run, cold tires you need as much grip as you can get. But for a track day he car will be way over tired. You will never be able to get it to rotate, you might if you have incredible skill level. But it will also pop like a slot car if you get it wrong. The only time I have seen 7's wrecked on a track day both were AutoX cars, lots of aero, big slicks. The last time was a NJMP the last corner before the start finish straight. Most cars if they get it wrong just spin off onto the grass. This one lost the rear, no big problem, but it did a 90 degree spin and stuck again. Shot straight into the pit wall the driver had no chance. Too much tire is worse than too little tire on a track.

Graham


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PostPosted: September 16, 2020, 3:44 pm 
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Good advice on tires. That is the plan. Thanks.

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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: September 28, 2020, 7:49 am 
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Much reading and a little math and starting to fab the front wing.


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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: November 13, 2020, 2:30 pm 
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This is what I'm basically going for.


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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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PostPosted: November 13, 2020, 5:43 pm 
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I'm not in a position to give you technical feedback, but it looks very cool.

Cheers,

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: November 16, 2020, 1:31 pm 
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I still have to trim down the side plates a bit. but I am ready to work on the frame attachments to the car.


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Building a whole car from scratch is a 1,000 little tasks, done 1 task at a time, while thinking 10 tasks ahead, then redoing it anyway.
South Bend Region SCCA D-Modifed Class Autocross & Track-Day/TT. Chevrolet 1.4 L Turbo Ecotec Power


Link to my build log:
http://www.locostusa.com/forums/viewtopic.php?f=35&t=3356


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