User not logged in - login - register
Home Calendar Books School Tool Photo Gallery Message Boards Users Statistics Advertise Site Info
go to bottom | |
 Message Boards » » Lotus 7 replicas / kit cars Page 1 [2], Prev  
theDuke866
All American
51604 Posts
user info
edit post

Engine longevity? Who cares? How much are you really gonna drive a 7?

Just throw a new Busa motor in it. They're a wear item, haha.

I think it would be fine, though, unless you got too crazy with boost or something. The bigger issue is oil starvation under lateral g for a bike engine. I'd baffle the oil pan thoroughly, and add an Accusump or something similar.

...and yeah, solid axles have an inspiring weight penalty and get upset more over bumps, but they're simple and work well on smooth pavement. Depending on what you use, I'd say it should be easy to find an LSD. That's another good thing about Miata IRS, though (which is also pretty simple). You just get a Torsen unit from a 1.8L car equipped with it.

Also, not all IRS is created equal. double wishbone type is generally the best.

I've always thought the De Dion setup is a nice happy medium for a car like a 7.


...and finally, Colin Chapman himself said "Any suspension will work as long as you don't let it." Hahaha. A good 7 is gonna be light and stiff, where the suspension isn't gonna travel much anyway.

[Edited on May 2, 2014 at 11:32 PM. Reason : ]

5/2/2014 11:22:10 PM

Jek
All American
709 Posts
user info
edit post

This R1 engined one looks pretty cool, despite not being street legal:


http://www.roadraceautox.com/showthread.php?48977-Lotus-7-Caterham-Style-car-for-sale

5/6/2014 12:43:40 PM

Ahmet
All American
4265 Posts
user info
edit post

Looks a bit shoddy to me, still, I wonder what it would take to make it street legal...

5/6/2014 2:22:50 PM

Ahmet
All American
4265 Posts
user info
edit post

Whops, solid axle. I’m sure it’d do fine, but I don’t want a solid axle.

5/6/2014 5:16:31 PM

Jek
All American
709 Posts
user info
edit post

Ah, I was trying to figure out if it was solid or IRS but hadn't noticed the picture where you can see through to the rear axle. That does suck, although it probably isn't the end of the world for some folks.

5/6/2014 5:35:37 PM

theDuke866
All American
51604 Posts
user info
edit post

Well, I got my 7 aligned yesterday. I had them dial in all the rear toe-in they could give me (1.5 degrees each side), then just a little more negative camber in the rear (-1.1 degrees, I think).

The front was pretty good on camber (I think they were both around -1). The front toe was all screwed up; both wheels were aimed a degree or two to the left. I had them give me a quarter degree of toe-in on both front wheels (this car has no issue with turn-in; I figured I'd rather have a little more stability). Caster wasn't really adjustable; it has about a degree or so.

The car is 49/51% weight distribution, weighs about 1300 lbs, and has 450 lb-in springs on all 4 corners. As you would expect, it will still oversteer very easily, but I played with the tire pressures to reign it in, ending up with 19 psi front, and 12 psi rear. At those pressures, it sometimes actually understeers. I was in the process of further reducing the front pressures, but I ran out of autocross runs to keep testing.

I think this run was with 21 psi front and about 12.5 psi rear. It was overall the best I did, except I got penalized because I couldn't get it stopped in time after the finish line.



The surface is slick sealed asphalt, and my tires are R-comps, but probably 5 years old or something like that. I think I'm finally ready to take this thing to a track day as soon as I finish burning through these tires and put some fresh rubber on it. I bet it is a beast on a good surface with good rubber.

6/22/2014 6:10:55 PM

theDuke866
All American
51604 Posts
user info
edit post



New hood and fresh paint.

Not an outstanding picture, as I had to take it with the front-facing camera on my iPhone (main camera wasn't working right) and then it's compressed by Facebook...but you get the idea.

7/28/2014 11:22:49 PM

Ahmet
All American
4265 Posts
user info
edit post

A few notes (lotus notes yea yea);

1, does your car have IRS, I forget?
2, are those headlights round? Cause if they’re not, they need to be! Like ASAP.
3, I’m officially jealous, car looks great. Slightly funky w/the rear wheel offset/fender, but still.
4, careful on fresh tires, car handling can be dramatically different at different grip levels, especially with “custom” suspension.
5, did I mention I was jealous?

7/29/2014 1:46:22 AM

sumfoo1
soup du hier
41029 Posts
user info
edit post

What are the examples of the good, average, and cheap lotus 7 kits.

7/29/2014 6:24:47 AM

theDuke866
All American
51604 Posts
user info
edit post

1. Yes. The rear is actually a Miata subframe grafted in, minus the sway bar.
2. they're round.

3. thanks. yeah I think it actually needs more rear rubber, which may require new rear wheels anyway. I haven't checked to see what I can fit on those wheels. It used to oversteer massively under all conditions. Between tire pressures and alignment settings, I've got it pretty neutral now. I'm going to put the widest tires I can fit on the wheels on the rear whenever I replace tires, though...then maybe I won't be so dependent on big adjustments in tire px and alignment.

4. yeah these tires are old...like several years old. i'm interesting in seeing what it'll do on a newly scrubbed-in set of R-comps.
5. I'll probably get it out of my system and have it up for sale at some point, haha.

7/29/2014 9:40:23 AM

Ahmet
All American
4265 Posts
user info
edit post

Updates? What’s the power to weight on yours nowadays btw?

8/6/2014 7:23:16 PM

theDuke866
All American
51604 Posts
user info
edit post

I think it was about 245 rwhp on a Mustang dyno, and somewhere around 1300 lbs. 4.30:1 gears with Torsen diff.

8/6/2014 8:22:37 PM

theDuke866
All American
51604 Posts
user info
edit post

Did another autocross with the 7 today:

4/26/2015 8:37:15 PM

smoothcrim
Universal Magnetic!
18303 Posts
user info
edit post

that thing looks pretty dialed. time to get outta 3rd

4/26/2015 9:23:19 PM

sumfoo1
soup du hier
41029 Posts
user info
edit post

Ok... so i may be wrong so don't take offense to this because i'm trying to learn not be a douche

but if this were a video game i'd say its a lil understeery and since you are very gentle with the throttle i assume it snaps to over steer with not too much throttle input?

4/27/2015 7:14:18 AM

Noen
All American
31343 Posts
user info
edit post

Snap oversteer is a defining characteristic of pretty much every Lotus vehicle ever made. This is the same in most video games that feature Lotus vehicles. So, good attention to detail that it looks like Mr Duke is slightly understeering, because the alternative is very bad news.

4/28/2015 11:52:03 AM

theDuke866
All American
51604 Posts
user info
edit post

^, ^^

Pretty accurate. I'll describe more later. On phone/at work now.

4/28/2015 12:35:01 PM

theDuke866
All American
51604 Posts
user info
edit post

So, uhh, I'm a little slow to follow up on that last post...

When I first got the 7, it worked fine, driving it on public roads. The first time I autocrossed it, it was damn near undriveable, though. If you were really trying to hustle, the oversteer was just unmanageable. Too much throttle? You're going around. Lift the throttle? Going around. Brake while cornering? You must not know what's good for you. I thought maybe I sucked and didn't know it or something, so I tossed the keys to a state or regional champ, and he promptly spun it a couple of times on one run.

I was perplexed; the guy who built it had videos of autocrosses and track days, and it didn't seem anything like that. In retrospect, maybe he wasn't pushing it as hard as I was, because I was headhunting on every run, trying to take fast time of the day.

Still, though, somewhat was off. Turns out that the car has 49/51 weight distribution, with a completely square tire setup and the same [stiff] spring rates all the way around (450 in-lbs). I'd like to experiment with either a little stiffer up front or a little softer in the rear, but what I ended up doing was having it aligned to very understeer-producing specs (don't remember about the custom front setup, but the Miata IRS is as far towards understeer as the stock adjustments will allow). Crucially, I also found that I was using WAAAAY too much tire pressure before, judging by the shoulder rollover I saw at my early autocrosses. A 1300 lb car on aggressive R-comps (NT-01s) is a totally different thing from a 2800-3500 lbs sports car on regular summer tires. By reducing the front psi to the upper teens, and the rear to the high single digits or very, very low double digits, it tamed the handling. I mean, it'll still bite your ass if you provoke it stupidly, but it does exactly what you tell it to now, and it does it forcefully and immediately. Every driven those huge go-karts at Myrtle Beach? The ones that that look like slightly downsized formula cars? It drives kinda like that, but with probably 10x the power. It's not like any street car I've driven. You feel everything--you feel the chassis load up in the corners, you can feel every little texture of the road through the steering. It feels like a coiled up spring just exploding out of corners. You feel the car rotate on and off throttle in a way unlike anything else I've driven...you really learn to balance the car and keep the traction where it's needed.



At any rate, I plan on selling it in the upcoming months, if anyone's interested. Time for a boat, or a sailboat, or an aerobatic airplane or something. It's a ton of fun, but I don't drive it enough to justify keeping it.

[Edited on August 20, 2018 at 1:31 AM. Reason : ]

8/20/2018 1:25:47 AM

 Message Boards » The Garage » Lotus 7 replicas / kit cars Page 1 [2], Prev  
go to top | |
Admin Options : move topic | lock topic

© 2018 by The Wolf Web - All Rights Reserved.
The material located at this site is not endorsed, sponsored or provided by or on behalf of North Carolina State University.
Powered by CrazyWeb v2.37 - our disclaimer.