Ariel Atom Cup Car vs. Spec Race Atom Information

[cvjoint]

I'm finding that there were some differences between the North American track spec Atom and the one designed for the rest of the world. It would useful to know what differences there are in case we would like a different part choice.

Here are some of the bits I believe are different, but feel free to correct and pitch in with more insight.

• The upper suspension a-arms are shorter on the Cup Car to allow more camber gain whereas the SRA has Atom 3 a-arms and specifies far less camber

• There is an electric water pump on the Cup Car but the SRA has the mechanical pump and the thermostat is removed

• The fire extinguisher system is button activated and deploys in the engine bay and occupant space on the Cup Car whereas the SRA has a standard bottle

• The suspension is built by Ohlins on the Cup Car whereas the SRA gets the QA1.

• Tires are Yokohama on the Cup Car whereas the SRA gets Hoosiers.

• All Cup Cars get the 245hp K20a2 whereas the SRA gets either 230hp K20z3 or 230hp K24z7

Am I missing something? Is the Cup Car built on the 3.5 chassis whereas the SRA is built on the 3 chassis?

[HenryJS]

FYI the Cup Cars were not a K20A2 (Atom 2 Engine) they were K20Z4 as per Atom 3.

Other than that - seems spot on.

Yes the Cup cars are an Atom 3.5

[cvjoint]

Thank you Henry! That information is gold.

Do you happen to know whether the SRA has the Atom 3 chassis? I am having the frame reinforced as we speak, it would be useful to add in the 3.5 chassis improvements.

I'm also adding an electric water pump since I can't bring the engine up to temp on rainy track days with the thermostat removed and mechanical water pump. The shop says there is no electric water pump kit for K24Z7 engines which I assume is the same setup as K20Z4. Would you sell the kit or point me the right direction?

[HenryJS]

Very welcome.

My rough guess would be it depends on when it was made... As i think the SRA cars were produced in both eras? I would ask Ariel North America for specifics. They would also be able to upgrade the chassis to 3.5 for you.

Adding an electric water pump wont increase your temps, what you really want for that is probably some form of 'manual' thermostat? (is this a thing?)

Any water pump kit will do - give Ariel NA a ring - they should have the pump and brackets in stock ready to ship out. If they don't have it i can certainly arrange one to be dispatched from here (probably not worth the shipping though??)

[cvjoint]

This one is a 2013. I know the 3.5 was already out at the time but I don't want to assume it is based on the 3.5. I will try to ask TMI about it. Trying to fix and upgrade it it locally as I'm 2000 miles away from the factory.

The idea with the electric pump is to slow it down on cold days, something I can't do with the mechanical one. We've tried to implement the factory 2012 Civic SI thermostat but it won't open. The shop thinks the water circuit is too long compared to the Honda vehicle and the water doesn't circulate well at low RPM, it's hot on one side and cold on the other and the thermostat won't open because of it. Others have tried to add a thermostat and failed as well.

[cvjoint]

Is the electric pump kit tailored for the Z series, so that it doesn't require any fabrication or the B/D series alternator? I'm looking for one that completely replaces the mechanical pump, not just an add-on pump.

[HenryJS]

Ariel NA will be able to help re the chassis.

If the car is damaged, it needs to be returned to Ariel NA. There isn't anywhere else that will be able to repair it to a satisfactory standard and to be honest, if the chassis is damaged, it could be twisted and require replacement. Only Ariel NA have the jig to check this. 2000 miles isn't worth your life if the chassis is repaired poorly...

My advice would be to strip the car and have the chassis shipped to Ariel NA so it can be inspected and repaired / replaced as necessary.

No its a generic electric water pump kit that is an additional pump to the mechanical one, mainly to get the water moving in traffic etc.

If you want to slow the coolant down, i would suggest fitting a thermostat that is jammed open. However you might need to remove it for those hot days... a bit of a pain in the bum!

[cvjoint]

Adding another difference. The cup car is equipped with a large capacity catch can mounted low by the fuel tank. The SRA doesn't have a catch can, there is merely a valve cover breather filter fitting.

[John Scherrer]

Here's the UK Atom Cup Oil Vapour Catch Tank

Picture taken at the Atom Cup Silverstone Meeting 23/04/2013

[cvjoint]

The US car has that ITG filter on the reservoir mounted on the valvecover. I bought the catch can from the U.S. factory and got a tiny one 1/3 of the size of the cup car one you posted and it's mounted high on the back hoop.

[s2kseven]

"Do you happen to know whether the SRA has the Atom 3 chassis? I am having the frame reinforced as we speak, it would be useful to add in the 3.5 chassis improvements."

Just look at the difference between the chassis of Atom 3 (on top) vs Atom SRA in the bottom.
You can see the SRA has more stiffness (maybe 20% more?) due to the added roll/bar and protection to pass SCCA.
Notice the framing on the tub area? Missing in Atom 3. I don't know if 3S even have the stiffness of the SRA.

FB_IMG_1540477255851.jpg (119.48 KiB) Viewed 833 times

[cvjoint]

"Do you happen to know whether the SRA has the Atom 3 chassis? I am having the frame reinforced as we speak, it would be useful to add in the 3.5 chassis improvements."

Just look at the difference between the chassis of Atom 3 (on top) vs Atom SRA in the bottom.
You can see the SRA has more stiffness (maybe 20% more?) due to the added roll/bar and protection to pass SCCA.
Notice the framing on the tub area? Missing in Atom 3. I don't know if 3S even have the stiffness of the SRA.

The SRA has some reinforcements that the road cars do not, that was known and visible in the pictures you posted.

What is also noticeable is that the road car frame has some reinforcements the SRA does not have, see if you can spot them!

Since I have started this thread I have sorted it out. The SRAs do not have the 3.5 reinforcements though the road cars in the US do have them. My understanding is that the Euro spec cup cars did get the 3.5 reinforcement.

Whether the SRA is stronger than the road Atoms is a difficult question now, I presume they are stronger in areas but weaker in others.

[s2kseven]

Yes, I can see some differences at the rear just because the Atom 3 didn't have the rollbar of the SRA.
The SRA has a lot of reinforcements mostly at the rear.

.....and what are the 3.5 reinforcements have that the SRA didn't have? Is it significant?
I want to know too...thank u

[cvjoint]

Yes, I can see some differences at the rear just because the Atom 3 didn't have the rollbar of the SRA.
The SRA has a lot of reinforcements mostly at the rear.

.....and what are the 3.5 reinforcements have that the SRA didn't have? Is it significant?
I want to know too...thank u

I marked "A" one of the 3.5 frame reinforcements that you can see on the road going U.S. car but not on the SRA. I marked "B" another 3.5 frame reinforcement that you can see on the road car. Unfortunately, due to the angle in the photo the SRA chassis lower subrame corner is not viewable. But if you have an SRA or look at web photos, it doesn't have this reinforcement.

[s2kseven]

If that's the only changes between the two, its not significant enough to compare how strong the chassis but I do know
the addition of the rollbar to the SRA was a major bracing all around. Whether stiffness is good or bad - can't argue. It is what it is
and it depends on how you want to use it.
For me, has a good thing & bad thing. I love it in track but hard in the street..... i feel safe.

Thank you!