https://www.youtube.com/embed/bP6o2lNh-_U?si=YM53wytzMp_YXoDW
How does a Caterham 7, with an old-school suspension, compare with a Mazda MX-5 Cup race car with a more modern setup? They're closer than you might think. Our test driver J.G. Pasterjak took one around the Grassroots Motorsports official test track, the Florida International Rally & Motorsport Park (FIRM), to find out.
Not surprised by the result given the lightweight of the Caterham. I'd love to see you guys test some single seat race cars there as they are even lighter than the Caterham.
Fine piece, although I'd like to see them on the same rubber. Going from Falken Azenis to Avon slicks on my 7 was worth at least 2 seconds a lap,
I really enjoyed getting JG's feedback and seeing a competent driver drive my car. I have a extensive racing back ground, but it hasn't been behind the wheel other than go-karts when I was a kid. JG suggest the technology is 70 years old, and while I may be in that class, Caterhams have seen significant improvements sense Colin Chapman did his seventh design in 1956. This car was built in 1999 and what Caterham calls a S-3 has been built the same from the mid 1990's. Chapman's concept for the car, was a car you could drive to the race track and drive home. This car does not have tags, but is street legal. The cops might not like the sound, but that is a easy fix. The car is also set up for me, and I am not a good driver. The brakes could be better. I am not as good as I should be at down shifting and matching engine speed. I could increase the rear brake bias if I was a better driver. JG might like the pads in the car, I don't. I like pads with more friction. JG talks about the compliance, and I believe the key to Caterham handling is the very stiff chassis and soft springs. This car has road springs, but even SCCA nationally competitive E production Caterhams use soft spring rates. One of the comments here was you could take two seconds off the time with slicks. I agree, and would add this: Increase the spring rates some, change the brake bias, Put some rake in the car, ( I have it set up for me and I wanted to stay away from oversteer). Trail braking makes these cars turn quicker because of the short wheelbase and allow you to get on the power earlier. To do that you have to be a much better driver than me, but this car has a lot more in it, than what JG drove. I have one correction to what JG said. The car weighs exactly 1300 LBS as he drove it. When I corner weighted the car the scales were flipping between 1300 and 1301. That is with a iron block engine, a full cage, and a rear bumper. I have been lucky enough to have driven a number of purpose built race cars ( I haven't raced them) and spent some time in very good Formula Fords. Light cars with stiff chassis and no compliance in the joints have a feel that can not be duplicated in a production car. a Caterham is like that and has enough power to point the car with the throttle. A good friend of mine was a SCCA national champion for Group 44 (John Kelly). John was not married until much later in life and had just about every type of car you could have. He told me don't get something with a V-8. Get a Caterham. They will teach you haw to drive and they are the most fun you can have driving.
A buddy drove an Ariel Atom and a BMW M5 at Portland raceway on the same day. The M5 was faster because the track is not very twisty and the M5 has far better aero. Same factors will apply here.
I ran with an early Lotus 7 - the fenders were air brakes and once we hit anywhere near top speed, my MG walked away from it. A fender that went further down at the front would be more aerodynamic. Of course you can minimize that by installing louvers in the top of the fenders to let the air out.
wspohn said:I ran with an early Lotus 7 - the fenders were air brakes and once we hit anywhere near top speed, my MG walked away from it. A fender that went further down at the front would be more aerodynamic. Of course you can minimize that by installing louvers in the top of the fenders to let the air out.
The entire car is an air brake. I used to say that it was a supercar 0-60, a S2000 to 85, an Accord to 100, and a civic to 120, at which time it was all over.
WOW, Karl B's Caterham! I built the rollcage for the car back in early 2023. Cool to see it here getting some love.
Still proves the best thing you can do if you want to go fast is simplify, then add lightness.
Kreb (Forum Supporter) said:wspohn said:I ran with an early Lotus 7 - the fenders were air brakes and once we hit anywhere near top speed, my MG walked away from it. A fender that went further down at the front would be more aerodynamic. Of course you can minimize that by installing louvers in the top of the fenders to let the air out.
The entire car is an air brake. I used to say that it was a supercar 0-60, a S2000 to 85, an Accord to 100, and a civic to 120, at which time it was all over.
Car and Driver did acceleration testing on my 7. I had the windshield in place. I don't remember the specifics, but I do recall that it hit an aero wall at about 90 and acceleration fell off dramatically. My car had cycle fenders.
Around our local kart track, it was very quick. At Thunderhill, less so.
Keith Tanner said:Kreb (Forum Supporter) said:wspohn said:I ran with an early Lotus 7 - the fenders were air brakes and once we hit anywhere near top speed, my MG walked away from it. A fender that went further down at the front would be more aerodynamic. Of course you can minimize that by installing louvers in the top of the fenders to let the air out.
The entire car is an air brake. I used to say that it was a supercar 0-60, a S2000 to 85, an Accord to 100, and a civic to 120, at which time it was all over.
Car and Driver did acceleration testing on my 7. I had the windshield in place. I don't remember the specifics, but I do recall that it hit an aero wall at about 90 and acceleration fell off dramatically. My car had cycle fenders.
Around our local kart track, it was very quick. At Thunderhill, less so.
Yeah even on our data traces at the FIRM—which tops out around 100-110 for a moderately powered car—you can see the acceleration curves really tailing off toward the top. I think this is a clear indication that it needs an LS swap (or at least a turbo K).
For real, though, everyone needs to try one of these cars at least once. They're super predictable and accessible way out at the limit in a kind of counter intuitive way. there's just nothing else out there with th ekind of balance and layout that these things have, so it's hard to even make comparisons to normal cars.
Big thanks to Carl for letting us toss it around.
I think it's the fact that you're almost sitting on the rear wheels, you get far more information about what the back end is doing than just about any other vehicle.
Turbos don't suit them. Even responsive turbos have a slight softness to their throttle response. They work, but they don't add to the experience. What they want is a high compression naturally aspirated engine tuned to have a razor's edge. You could probably manage that with a K :) My car had an 11:1 Miata engine on throttle bodies and a cam that wanted you to spin and spin and spin it. Only 148 rwhp, but an experience like nothing else.
maybe a different nose for the track?
In reply to lotusseven7 (Forum Supporter) :
And you did a great job on the cage.
Anyone running anything newish will get a faster lap time simply due to aerodynamics. Yes, in the old days, "add lightness" was the key phrase to a faster lap, but that was before aero was really understood. Virtually any new car has far better aerodynamics than a Seven, and couple that with how everything sporty these days has a ton more power than the old days, and the whole "lighter" advantage disappears.
Without making large aero changes, making a Seven faster is tough because drag is dependent on speed cubed - Example: you want to go 5% faster, only to fine that it requires 1.05^3 more power, or 16% more. It'll be all but impossible to find that much on an already wound-out engine.
Now, all the above aside, "if" the Seven is run on a twisty course, then yes, its light weight overrides outright power and aerodynamics. Unfortunately, many tracks have long sweeping turns and straightaways, where the Seven loses its advantage.
kb58 said:Anyone running anything newish will get a faster lap time simply due to aerodynamics. Yes, in the old days, "add lightness" was the key phrase to a faster lap, but that was before aero was really understood. Virtually any new car has far better aerodynamics than a Seven, and couple that with how everything sporty these days has a ton more power than the old days, and the whole "lighter" advantage disappears.
Without making large aero changes, making a Seven faster is tough because drag is dependent on speed cubed - Example: you want to go 5% faster, only to fine that it requires 1.05^3 more power, or 16% more. It'll be all but impossible to find that much on an already wound-out engine.
Now, all the above aside, "if" the Seven is run on a twisty course, then yes, its light weight overrides outright power and aerodynamics. Unfortunately, many tracks have long sweeping turns and straightaways, where the Seven loses its advantage.
The "add lightness" mantra is somewhat outdated. I love a light car as much as anyone, but horsepower is so cheap and available right now that weight is a smaller part of the equation.
That said, and this is somewhat outdated as well, but Team Birkinsport (Locost) won the NASA Super Unlimited class in the West coast endurance series twice - 20 years or so ago. They were running a Duratech 2 liter making about 250 HP at the wheels, beating, among others, a twin-turbo Viper.
It's not totally outdated. Horsepower only gets you off the corner and down the straight. Lightness gets you braking, cornering and transitions. Plus, of course, it's more fun.
Aero has definitely come a long way since the late 50s when the 7 was introduced. The closest modern analog is probably the Radical, although they're not exactly streetable.
Man, I miss my Seven.
I absolutely love driving my Locost. It's 18 years old now, but not currently insured, and stored under a tarp.
It is one of the most intuitive driving experiences - it does what you want, you can feel and "sense" it all, you can toss it and catch it with ease, and the raw exposed experience of it is very visceral. I love it.
It's not as fun as a daily driver as you'd like. I've done it. It's raw. It's tiring being beaten by the wind. It's awesome getting thumbs up from everyone.
It does indeed have the aerodynamics of a Russian textile factory, but that's not the point. It's hilarious fun, and I will never sell it.
My first 7 had a 120hp Toyota 4-AGE with dual Mikuni carbs. Totally stock motor and was my DD toy and did occasional track day duty. Tons of fun, would eat up just about anything on a tight infield, but at corner exit onto a straightaway, I was going to install a cup holder for my coffee because it was painful once the car hit 100mph.
The next one was a bit spicier with a Weber fed Mazda 12-A rotary. That one pulled harder thru 100mph because it didn't have a windshield. Same handling characteristics but I was able to hold them off further down the straights before they would get me.
The last one that I just sold was 255RWHP from a turbo/intercooled 13-B and was so traction limited, that when it did finally hook up, it screamed past 125mph before hitting the aero wall. I wish I had more time with that car but it was truly scary to drive. Slower than the others because power came on quite abruptly and it tried to kill me every time it did. If you were pointing straight when the power decided to show up and if traction cooperated, HANG ON, it was quite the ride!
Im building a Honda F20C/6-speed from an S2000 and I think the N/A VTEC power delivery will be the "sweet spot" for a 1400# car. Hopefully it gets done over the winter.
In reply to SkinnyG :
I couldn't agree more
SkinnyG said:I absolutely love driving my Locost. It's 18 years old now, but not currently insured, and stored under a tarp.
It is one of the most intuitive driving experiences - it does what you want, you can feel and "sense" it all, you can toss it and catch it with ease, and the raw exposed experience of it is very visceral. I love it.
It's not as fun as a daily driver as you'd like. I've done it. It's raw. It's tiring being beaten by the wind. It's awesome getting thumbs up from everyone.
It does indeed have the aerodynamics of a Russian textile factory, but that's not the point. It's hilarious fun, and I will never sell it.
I nicknamed mine "heromaker" because it was so predictable at the limit it would forgive most driving errors.
Had an interesting experience driving my friends Locost (195 WHP Duratec) with a group of very fast modern cars: We were never in a position to really race - these were public, rural roads, but the pace was very fast and the terrain varying with lots of turns, elevation changes, damp vs dry, et cetera. The Locost had no trouble keeping up, but it took lots of work to do so. The expensive modern machinery with wide tires were much more planted, while we were skittering to and fro on 225 tires. A guy following us mentioned that it was kind of scary to watch. But we've done thousands of miles in anger with the car, and again, it was the heromaker.
A tech friend likes to say of my cars "They're SO analog!" And the Locost epitomizes that, for better and for worse.
Keith Tanner said:Kreb (Forum Supporter) said:wspohn said:I ran with an early Lotus 7 - the fenders were air brakes and once we hit anywhere near top speed, my MG walked away from it. A fender that went further down at the front would be more aerodynamic. Of course you can minimize that by installing louvers in the top of the fenders to let the air out.
The entire car is an air brake. I used to say that it was a supercar 0-60, a S2000 to 85, an Accord to 100, and a civic to 120, at which time it was all over.
Car and Driver did acceleration testing on my 7. I had the windshield in place. I don't remember the specifics, but I do recall that it hit an aero wall at about 90 and acceleration fell off dramatically. My car had cycle fenders.
Around our local kart track, it was very quick. At Thunderhill, less so.
I think part of the reason my friend's 7 'hit the wall' earlier was that it had a 948 cc BMC engine
SkinnyG said:...It's not as fun as a daily driver as you'd like. I've done it. It's raw. It's tiring being beaten by the wind...
I drove Midlana to work a few times and your comment made me laugh. There is something worse than getting beaten by the wind, and that's being stuck in rush hour traffic.
Keith Tanner said:It's not totally outdated. Horsepower only gets you off the corner and down the straight. Lightness gets you braking, cornering and transitions...
The band aid for modern (overweight and bloated) sports cars seems to be enormous brakes and very sticky, wide, and expensive tires. For those who can afford the tires, it can be frustratingly successful against the add-lightness crowd.
kb58 said:Keith Tanner said:It's not totally outdated. Horsepower only gets you off the corner and down the straight. Lightness gets you braking, cornering and transitions...
The band aid for modern (overweight and bloated) sports cars seems to be enormous brakes and very sticky, wide, and expensive tires. For those who can afford the tires, it can be frustratingly successful against the add-lightness crowd.
Yes. See my comment above.
In terms of top speed, there was a Locost (Stalker) that podiumed at the GRM UTC. It saw over 150 MPH, but it took 500 HP to do so. By way of contrast, the Lotus 11s (Basically a seven with a slippery body) saw 150 MPH at LeMans with a 150 HP Coventry Climax engine and the right gearing.
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