I got an email from an Atom client, Rich B., who bought an SRA from us earlier this year. He found the initial springs and settings were too stiff at one of our local tracks, Buttonwillow. We found the same issues with our SRA so we undertook some suspension testing and development as reported: HERE.
After we completed our work, Rich brought his SRA to us and had us make the same changes to his car. He recently took it to the track and had the following report:
I just
got back from Buttonwillow .... I'm very happy to
report that the new spring and damper settings worked great. I ran a full 5
seconds faster than last time; the difference thanks to the springs is HUGE. So
much more comfortable pretty much everywhere around the track so I'm not
bouncing around under braking, through corners or on the straights and I can
hit a couple of berms without any trouble now too. You can also easily see the
difference from my on-board videos, the whole car now rides better.
-Rich B.
The SRA is a fun car that requires your 'A' game while driving at the limit. I think it is an excellent car for track day enthusiasts and an even better race car, thanks to it's low running costs and reliability. This simple reminder also proves that tuning a car for specific conditions becomes key to going fast with confidence.
We tested and conducted suspension development on both the Lotus Elise and Spec:Race Atom last week at Spring Mountain. We had a new street suspension from Nitron that needed a proper track test and also recruited Dave T. to help dial in the SRA's suspension. After four days of testing and tweaking, we achieved good results.
Nitron Street Series for Lotus Elise/Exige:
We have been working with Nitron to develop an affordable alternative to a stock Lotus suspension. Typically most OE shocks are showing wear by 40k miles. The degradation happens slowly, so most people don't notice that their shocks are worn out. These Nitrons feature valving that is fixed. The adjusters shown in this picture will not be on the final parts. A key feature of these shocks is that they have a threaded body which allow for ride height adjustment and corner balancing. The stock shocks do not allow any adjustment.
We installed the test set of shocks on a normally aspirated Elise with stock rims and Toyo R888 tires. We set the ride height to a stockish 135-140mm. I drove the car on Spring Mountain's 2.2mile config and rode up every bump and curb that I could. I put 277 track miles on the car and set a fast lap of 1min 58s with dozens of laps under 2min. A fast time is about 2min on this configuration. Overall the suspension performed beautifully. It was compliant and delivered great grip. Yes, it sways, pitches and squats more than a Nitron NTR series but it is designed as a street shock that may see occasional track use. We will now place it onto a street car and run through some street testing to confirm that it works properly on the street as well.
Spec:Race Atom Suspension Tuning: West coast tracks can be quite bumpy and a real challenge for stiffly sprung cars. Previous track testing that I conducted with our SRA showed that it is very stiffly sprung. The SRA features double adjustable coil-overs with a bell crank and pushrod suspension. The car comes stock with 400# front and 500# rear springs. I spent one weekend at Spring Mtn with the car, comparing it to an Atom3 with the Bilstein adjustable shocks. The Atom3 was far more compliant through bumps that would fully upset the SRA. I called the factory and they suggested I test the softer springs they had sent with the car.
I asked our Ride & Handling expert, Dave Thilenius to help us set up the SRA. We decided to test spring rates on Saturday and then vary rebound and compression on Sunday. Rebound and compression settings were left alone as we first tested the following rates:
Baseline: Front 400# & Rear 500#
Front 400# & Rear 300#
Front 300# & Rear 400#
Carlos swapped the springs and reset the ride height to stock for each configuration. The pushrod on the SRA sets ride height - which is much easier than on a Lotus. We ran 1 warm up lap, 2 hot laps and 1 warm down for each configuration. We then ran the car on the skid pad in both Clockwise and Counter Clockwise directions. The SRA comes with Race Technologies data logger, dash and video. We downloaded the data after each session to see what the data revealed. Dave also took notes after each session to record his impressions. Watch the video below to hear some of his comments from one test session.
The skid pad became the test that best determined the balance of the car. It was clear that the first and third spring config were the best balanced. The second config. delivered a car that understeered more than the others - the softer spring kept the rear planted! The skid pad lap times were also the quickest in the third set-up. Actual lap times were close but we ultimately used Dave's qualitative comments to select the third (Front 300# & Rear 400#) spring config. This set up managed to soak up the bumps better than the first and delivered a neutral car. Dave did suggest that the second config. would be the most comfortable to drive for beginners.
On Sunday, we began to vary the Rebound and Compression settings. The QA1 shocks that come standard on the SRA feature 18 clicks of adjustment for each variable. Again we downloaded data and recorded comments to evaluate the handling. We tested ten different settings. Dave ended up running lap times that were significantly quicker than on Saturday.
I tested the SRA at the end of the day - I couldn't let Dave have all the fun! I'm at least as fast as the average Atom driver so felt my opinion would be relevant for most. The car was much better than the original with plenty of grip through the bumps. It was more compliant but remained stiff. Unlike with the original set-up, I was able to climb the curbs with confidence. Ultimately, we landed on settings for the SRA that I think are better suited for bumpier tracks. Great job Dave and Carlos for wrenching!
The Atom will always be a 'loose' car, especially when compared with other cars - like a Lotus. The SRA has no wings so remains a car that relies solely on mechanical grip. The rear bias and power-to-weight ratio make it a car that is even closer to a formula car. This is not a beginners track car nor one for the faint-of-heart. Even with our tuning, you need to keep a high level of focus to go quickly. I suspect this is one of the reasons why the Atom delivers excitement in spades...this car is not for wimps!
Overall we had great results with the Dry Sump and are ready to release it to other race teams and shops. Amazingly we ran the car with no oil coolers. Oil temps slowly climbed over the course of the day to about 280degF. Clearly a small cooler will be a good idea when the ambient temps are hot. I think a laminova oil cooler will be perfect and should allow us to delete the front coolers. We think the complexity of a Dry Sump does not lend itself to the average shade tree mechanic. If you are interested in a solution, give us a call so we can discuss your needs.
The TRACKpipe is our new track muffler. We've been running it for a few weeks and have shown sneak peeks of it and sound clips in recent videos like this and this. The sound is not loud and has a great tone to it. We think track guys are going to be pleased with the price and quality.
The DSbrace is our new affordable toe link brace. It uses the same components as our tried and true RTD & RTVbraces. We eliminated the central brace and added lower cost, but still effective, brackets to place the toe link joint into double shear. This product also bolts on with absolutely no modifications to the chassis. This kit delivers the highest joint strength of any solution we are aware of.
The ETHOS wheels ended up coming off the car as we experienced some rubbing at the rear. We ran 245 Hoosier A6s at race ride heights and experienced some rubbing on the outside fenders. We took them off and installed our back up wheels/tires. We think these will work with Lotus that are running flares. They are perfect for their primary application: the Ariel Atom.
We recruited our good friend Dave T. to push the car hard. He turned some of the fastest times of the day with only 211s beating his times. This allowed us to push the car hard and see how it would perform. He turned 2min56s times on the 3.5mile config. Overall it was a long but productive test day for our team.
