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There's nothing wrong with Swift springs. They are one of the better brands out there, with some of the lowest coil count for a given spring rate among spring manufacturers. Swift is up there with Eibach and Hyperco. Which is better than the others depends mostly on who you talk to and where you get your biased news.
I can't find the article at the moment, but I read from some chassis engineer in a pro series that the Swift springs aren't nearly as consistent compared to the advertised rate as Hyperco and Eibach.
And I typically only see companies like Fortune Auto and the like offering them as an upgrade over whatever their stock garbage brand is.
Also considering a hardtop spoiler with small vortex generators to feed the wing since it is limited to OEM roof height and a 2d airfoil like the GT250 would barely be in clean air at that height.
This is a video that I have done on vortex generators (have some more tests to do soon). The placement of the generators is critical to getting them to do what you want them to do, you will need to do some testing to get the optimum location and shape. Hence if your wing is too low then the air getting to it will not be used effectively.
Recent testing for Kyle Engineering (who has designed my new wing) shows that the GTC200 wing has issues with separation at the mounts! By the way Kyle Forster is very easy to deal with if you wanted him to do some design work for you. If you get a chance meet him in person as well.
This is modeling that Kyle has done that shows the impacts of the mounts on the GTC200, this supports the video above. I have posted this info in the aero thread as well. The wing that was designed is a dual element however the gap between the elements is minimal and taping it up would have no real impact in your class. The calcs show about 500kg of downforce at 300kmh and has LESS drag than the GTC200, bonus.
You need to work on reducing drag. The rules made no mention of being able to use a bumper cut, this alone will reduce drag by significant amounts. A bumper cut would be a better choice than a rear difusser because of the rule limitations.
..You need to work on reducing drag. The rules made no mention of being able to use a bumper cut, this alone will reduce drag by significant amounts. A bumper cut would be a better choice than a rear difusser because of the rule limitations.
The bumper cut idea comes up a lot. I have never seen any repeatable, conclusive data showing that it actually reduces drag. I get that intuitively it seems like it would but, it's just a guess. As such it is a myth until proven otherwise.
Do you have any good data on the bumper cut to share?
Do you have any good data on the bumper cut to share?
This was done at Queensland Raceway last year. It is an acceleration plot down the back straight. The Blue dots are when the car had its bumper 'trimmed' and the red dots are with the full bumper and difusser. The good thing about this form od data analysis is that I can use any track as it is about acceleration and I can set the parameters to suit.
Data from the sprint session also shows the same trend, acceleration has improved. It should be noted that there was over a 20°c intake air temp difference with the two laps.
The real reason why I was not faster with less drag was driver error :( The 'early' brake into T3 really did cause some time to be lost, this was on the sprint layout above (green - PB with bumper cut/difusser and orange with cut bumper)
Lastly my comments on the day I first tested the cut bumper (butt dyno). I had to increase the rear wing AOA to keep it under control. This was more than likely a result of the weight removed as well as the less drag. I'm going to corner weight the car soon and reset the corner weights.
As tested
This was the bumper cut and the difusser installed, I have data on this as well. However not home for a few days so can post it then.
This is the next bumper cut I will test, not as aggressive as the one above.
Before with Full bumper and Jetstream difusser. I have to get and do some more dirt sprints it is so much fun! The car is used the same as it is on the track, no change in heights etc.
If I am reading your notes correctly, the test wasn't fully controlled. Pressure different, and different size tires? Interesting data but not what most would consider conclusive. Thanks for sharing.
I have a theory as to why bumper cut data is so skewed. It depends on what sort of rear muffler you're using. A standard transverse muffler fills in a lot of the gap people assume is trapping the air. Look at a lot of OEMs you'll see more and more use of mufflers as a flow control (as well as packaging). I remember reading an article somewhere about an engineer who talked about how the muffler setup was specifically placed to reduce drag on a certain car (vague I know, sorry). So a straight pipe or center exit is really going to leave more volume for the air to take up. In theory if you could make your own muffler, you could design it to perfectly fill in the area between the subframe and rear bumper for drag reduction. It would just need to be lighter than standard.
Another super uncontrolled test, but... a few years ago at an open track day I decided to do a quick and dirty test of rear bumper drag. I ran a session with the stock bumper in place, a session with the bumper fully removed, another session with, and another session without. The only data I was looking at was lap time and max straightaway mph on the AIM Solo, and neither of them saw consistent enough changes to attribute to bumper drag.
If I am reading your notes correctly, the test wasn't fully controlled. Pressure different, and different size tires? Interesting data but not what most would consider conclusive. Thanks for sharing.
Agree that it is not conclusive, however it is more about evaluating a change and being consistent in the evaluation. Provided I keep good notes (which I do, hand written into a note book) and remember to add the notes (not so good) I can note the changes done to the car. In the future I will be bring the suspension (linear) sensors into the racepak as well as adding a steering angle sensor. This is so I can work with Danny Nowlan from https://www.chassissim.com/ . Danny I have exchanged emails for a few years now, met him in person at WTAC 2016 where we worked a plan out as well. The interesting thing for both Kyle and Danny is that do not normally do much work for Clubsprint class as the rules are strict, however they are enjoying working within these to come up with innovative solutions. Since I have no desire to increse the cars power (boost) all I can do is reduce drag/weight and improve the driver and the cars handling
A few notes on the data.
On the day the main testing was done with the bumper cut, yes the car was running 225/40/15 tyres. The previous testing was done on 205/50/15 tyres, however the software was changed to take this into account. Racepak data is stored with the parameters when it is recorded. Even if the change was not done I use a formula to correct that channel and model of this channel.
First test
This was done with the cut bumper and the difusser still in place, plus I was heat cycling the 225/40 tyres and none of this data has been used in the posts with the exception of the G Plots. What it does show was that the wing angle needed to be changed as the car was oversteering in high speed corners. Whilst drifting maybe fun, it is not when trying to do a fast lap. Therefore this day was more about finding the right setup to do some proper testing.
Acceleration channel
Within the Racepak software I created a maths Chanel called ACCEL = 'Accel G'*9.80665. This converts the Accel G into acceleration m/sec², then I smoothed it to 100. Acceleration can be impacted by change in power, drag and or weight (F=ma). This data is from 2015 and 2017 at World Time Attack, this time the car was running the same tyres and uncut bumper however a different splitter, power had increased by 6 RWHP and a few other minor changes. The data could be made more accurate by excluding any data points where there was a lateral G force however I do not believe in filtering data as it can then be misrepresented. I'm not saying that there is a correlation for decreased drag and the bumper cut as this would need to be proved statistically and in controlled testing. I'm not a consistent enough driver to do this testing nor do I have the funds to do controlled testing. The data shows that something has made the car accelerate faster, why is it so?
This is where Kyle Forster steps in. At WTAC 2017 he had some suggestions to try to reduce the drag on the car. One was to decrease the rear wing angle as he commented that this should have been done when the air dam was installed as I pointed out I have not played with the wing angle in a very long time. The wing was backed off to about 2° from 10°. Car was very twitchy going through T1 at SMSP and did not inspire confidence, hence was no faster. A few more practice sessions and a few tweaks to the wing angle a suitable angle was found. I manged a PB at WTAC 2017 without the bumper cut. Hence why I am now working with Kyle on the new wing, next will be a splitter that takes advantage of the Clubsprint rules.
This may not help in the bumper debate, but it is something
There's nothing wrong with Swift springs. They are one of the better brands out there, with some of the lowest coil count for a given spring rate among spring manufacturers. Swift is up there with Eibach and Hyperco. Which is better than the others depends mostly on who you talk to and where you get your biased news.
You need to get them on a spring dyno and see for yourself, I used to say the same things you just did lol. Take measurements of physical dimensions before and after as well and note the differences in a set. Comparing them to Eibach and Hyperco is a stretch, there is a reason why red and dark blue springs dominate the pro motorsports world.
You need to get them on a spring dyno and see for yourself, I used to say the same things you just did lol. Take measurements of physical dimensions before and after as well and note the differences in a set. Comparing them to Eibach and Hyperco is a stretch, there is a reason why red and dark blue springs dominate the pro motorsports world.
The "everyone in motorsports uses red and blue springs" thing is why i use Hyperco, but. BUT.
I also have yet to see spring dyno testing showing Swifts being inferior. So while i use Hyperco springs, i also still bother building and driving my car despite the fact that i don't have a factory-backed Ford GT Le Mans car.
Can you share the results of your spring dyno testing in which you saw this for yourself?
The definition for parroting is to repeat or imitate without thought or understanding, so that's a pretty **** poor way to describe my post. I didn't tell you to believe me, I told you what to look for on your own in terms of actual data. Feel free to form your own conclusion after that.
The definition for parroting is to repeat or imitate without thought or understanding, so that's a pretty **** poor way to describe my post. I didn't tell you to believe me, I told you what to look for on your own in terms of actual data. Feel free to form your own conclusion after that.
You seem to have a pretty strong opinion on the subject. I figured you had some actual data when you said this:
Originally Posted by You
You need to get them on a spring dyno and see for yourself, I used to say the same things you just did lol. Take measurements of physical dimensions before and after as well and note the differences in a set. Comparing them to Eibach and Hyperco is a stretch, there is a reason why red and dark blue springs dominate the pro motorsports world.
That's the conclusion i drew, and one brought me to ask you for more information, figuring you had gone down this path that you're telling me to find, now. I'm in the research stages, i haven't taken a stance either way without having any data beyond what Paul Yaw said once on social media. That would be parroting, and as the kids say: I ain't bout dat life.
You're right he didn't publish specifics or data on social media (from what I recall) but if you look at my location and where ID is located you can probably put two and two together.
That would be parroting, and as the kids say: I ain't bout dat life.
Call it whatever you want, but when someone alludes to the results of some proprietary testing data they've been privy to but cannot directly share, I tend to not look that gift horse in the mouth quite as hard as you seem to be.
There wasn't alluding. There was "use this color spring, because reasons." I suspected there was testing, but heaven forbid i try to get more information.
Because as of right now, the only actual testing between the brands to be found on the internet shows Hyperco to be inferior. I don't believe that, so i use them anyways, and not the yeller/green springs. I just question things on the internet that don't have data behind it. Much as you do, and everyone else does on this forum. I thought.
There wasn't a "gift" here. We don't need to make this out to look like i'm ungrateful for something i didn't receive. Speaking of... email coming your way.
01-08-2018, 03:54 PM
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