Atom vs. Radical Track Performance Q's

[CosmosMpower]

Has anyone here owned or driven both a Honda powered Atom 2/3 and a Radical SR3? Debating both cars right now for track duty. The Atom's big advantage is that you can drive it to the track so you don't need to buy/store/maintain a truck and trailer but I'm curious how much all out track performance I'd give up vs. a Radical SR3 1500cc.

I'd love feedback on any of these assumptions if they are wrong. From what I've gathered so far:

1. Atom should have slightly better acceleration with 50 more hp and a lot more torque (with S/C K20).
2. Radical will have a lot more lateral grip and be more planted and easier to drive. I've seen videos with Atom on track that require the driver to counter steer a lot.
3. Radical should have slightly better braking with 150 or so less pounds.
4. Both will have fairly poor performance at over 135-140 mph due to aero drag.
5. Does anyone have some real life lap times on the same track for both cars? Guessing on a 2 minute track with a mix of good turns and a long straight the Radical will be 2-3 seconds faster per lap?

Thanks for helping me clear up any incorrect facts floating around in my head.

[mrlizard]

Has anyone here owned or driven both a Honda powered Atom 2/3 and a Radical SR3? Debating both cars right now for track duty. The Atom's big advantage is that you can drive it to the track so you don't need to buy/store/maintain a truck and trailer but I'm curious how much all out track performance I'd give up vs. a Radical SR3 1500cc.

I'd love feedback on any of these assumptions if they are wrong. From what I've gathered so far:

1. Atom should have slightly better acceleration with 50 more hp and a lot more torque (with S/C K20).
2. Radical will have a lot more lateral grip and be more planted and easier to drive. I've seen videos with Atom on track that require the driver to counter steer a lot.
3. Radical should have slightly better braking with 150 or so less pounds.
4. Both will have fairly poor performance at over 135-140 mph due to aero drag.
5. Does anyone have some real life lap times on the same track for both cars? Guessing on a 2 minute track with a mix of good turns and a long straight the Radical will be 2-3 seconds faster per lap?

Thanks for helping me clear up any incorrect facts floating around in my head.

Cosmos

I have only driven the SL radical (which is road legal over here) very quick but didnt feel as quick as a supercharged atom - unfortunately not tried either on a track, there are a few video's on youtube comparing the two and around some twisty tracks what you say is essentially correct, the atom loses a little in the first half of the corner as it struggles to get to same level of stability as the radical - however on corner exit the grunt and power makes up for it and in fact a lot of the laptimes I have seen have been almost identical... if not the atom slightly ahead...

have a look at this (though this is the road legal radical) Julio Cezar Kronbauer's Blog: Fifth Gear: Ariel Atom Supercharged vs. Radical SR3 SL

[MadMaxAtom]

I've driven both..the Radical Sr3 is nice with its sequential shifter and ultra high revving motor.…but has chain drive and the life of the engine is 50-60hrs of track time..so BIG advantage for the Atom on those two points alone. I do believe the Radical to be a tad faster IF both cars (Atom vs Radical) are set up to 100% track attack mode (proper tires/suspension etc) and driven flat out by skilled people.
I trailer all my track cars as shit happens on track quite often that is beyond your control and it sucks trying to find a tow home.

[CosmosMpower]

I've driven both..the Radical Sr3 is nice with its sequential shifter and ultra high revving motor.…but has chain drive and the life of the engine is 50-60hrs of track time..so BIG advantage for the Atom on those two points alone. I do believe the Radical to be a tad faster IF both cars (Atom vs Radical) are set up to 100% track attack mode (proper tires/suspension etc) and driven flat out by skilled people.
I trailer all my track cars as shit happens on track quite often that is beyond your control and it sucks trying to find a tow home.

SR3 is not chain drive, it's direct drive through a bespoke Quaife unit. I think the 1500 is 50-60 hrs for track time but the 1340 is about 120 hrs. Of course the Honda K20 will last a long time without major service.

I haven't seen any evidence that an Atom is nearly as fast in lap times. I'm mainly curious about the handling of the Atom, really don't want to drive a super twitchy car that has understeer and oversteer.

[CosmosMpower]

Cosmos

I have only driven the SL radical (which is road legal over here) very quick but didnt feel as quick as a supercharged atom - unfortunately not tried either on a track, there are a few video's on youtube comparing the two and around some twisty tracks what you say is essentially correct, the atom loses a little in the first half of the corner as it struggles to get to same level of stability as the radical - however on corner exit the grunt and power makes up for it and in fact a lot of the laptimes I have seen have been almost identical... if not the atom slightly ahead...

have a look at this (though this is the road legal radical) Julio Cezar Kronbauer's Blog: Fifth Gear: Ariel Atom Supercharged vs. Radical SR3 SL

Thanks, I've seen that clip before. From what I read that Radical was not setup well at all, raised ride height, and not using the slicks it was designed for. The consensus on the sport racers board is with proper setup it would not have been close. I don't really care too much about flat out lap time more about HOW the cars drive.

[MadMaxAtom]

Oops…guess I drove the Sr1..which was a chain drive..and broke.. I think for all out lap times the Radical will be faster,however,it was designed as a real race car. I was a bit cramped in it..(6'2"-240lbs) but not to the point of not being able to drive. Both cars (Atom and Radical) have immediate response to driver inputs…so garbage in,garbage out...etc etc.
For me,the choice was no contest as the Atom has much more service life and the added ground clearance is great when you are not "on track"..and even at some tracks,the low clearance of the Radical can be a bother. I've been to some tracks where radical owners take a few laps and then park the car as it is scraping too much. Plus,I find the Atom very roomy..

I have never had understeer in my Atom (with the exception of driving it on the factory 048s) and oversteer is about on par with a Porsche 911 or an Exige.
The Atom will never be as neutral as a Miata,but once you get use to an Atom..there is NO going back.

[beckertb]

I have 3 radicals a 1300 1300 turbo and sr8lm with the 2.8l v8. I ran the v8 and my aa2 with harrop sc this weekend at msr houston......atom is on r888 vs the dunlop slicks.....to make the story short the radical is in a completely different league......over 50 mph faster on the back straight. 10 seconds a lap quicker. Same driver same day. So from a performance standpoint no comparison. Imo

[MadMaxAtom]

^No surprise there..the Toyo R888 is a great all around performance tire (for heavier cars, in my experience)...but is a DOT rated tire with tread,and even driven hard on an Atom will NEVER give you the performance of a real track only race slick.I'm surprised the difference was only 10 seconds. That SR8 is a beast..try putting R888s on that and watch the lap times rise..

If you are going to compare the lap times of both cars they must be on equal grip tires as there is NOTHING more important than proper sticky rubber when trying to extract the fastest way around a race track.

No,I am not saying the Atom will be quicker than the Radical..but if you are going to compare apples to apples..you must use apples.

[CosmosMpower]

^No surprise there..the Toyo R888 is a great all around performance tire (for heavier cars, in my experience)...but is a DOT rated tire with tread,and even driven hard on an Atom will NEVER give you the performance of a real track only race slick.I'm surprised the difference was only 10 seconds. That SR8 is a beast..try putting R888s on that and watch the lap times rise..

If you are going to compare the lap times of both cars they must be on equal grip tires as there is NOTHING more important than proper sticky rubber when trying to extract the fastest way around a race track.

No,I am not saying the Atom will be quicker than the Radical..but if you are going to compare apples to apples..you must use apples.

SR8 is in it's own league. SR3 1300 is a better comparison to an AA2/3. The 50 mph faster on the back straight thing sounds nuts. My GT-R wasn't even 50 mph faster than a Spec Miata on the 3/4 mile long back straight at COTA. Can't imagine something being 50 mph faster than an upgraded supercharger Atom.

[Lane]

I've seen videos with Atom on track that require the driver to counter steer a lot.

I've seen that in videos far too much as well. My Atom came from the factory set up such that I'd consider it a serious handful and borderline dangerous. But with the proper alignment, ride height, suspension settings, and some sticky wider tires, it provides much more confidence with very little need for countersteer input.

I commented on this also in this thread. Eddie's video is worth watching to see how a properly set up car should be.