Here are a pair of pictures of the car with the new custom fabricated front splitter, which has an undertray that extends back. It is robust in its construction and will not shred apart like a venetian window blind in a storm the way many of the body kits typically do.



The combination of the splitter and the big APR wing worked very well on our first test session at Laguna Seca this week. For the high speed turns it was outstanding, and as you would expect, in the slow turns it was a non contributor as the air flow was just not sufficient to deliver meaningful help.



I got busted for over 92db sound levels, so now we are fabricating a couple of elbow tips to direct the sound down and away from the right side microphone at the sound station after Turn 5, and hopefully that will avoid having our track day ended early the next time.

The Jim Wolf 700 ball bearing turbos are putting out prodigious power, sufficient to just bull through the resistance/drag on the straights, so we were passing Porsche GT3 and Corvette Z06 cars on the track without a fuss. The difference from running just a month ago was clearly the higher corner exit speeds made possible with the aero mods. The weight advantage those cars have is tough to battle, but when you get a smooth exit with another 5-8mph exit velocity, and carry that all the way down the straight, they not only do not pull away, you reel them in. We still have some fine tuning to do on the balance of downforce between front and rear, but the first report card, is that it is a "good thing".

We will prep and paint the splitter now, oem white, and do the same to the wing and supports.

 

That's a biggun! You should be getting a lot of front aero load from it. Turns 4 and 10 must have been noticably faster with that front and the wing. How did it feel in traffic?

 

Hi John.
Turn 4 was amazingly faster, perhaps the most noticeable of all the turns. I think that corner entry was more than 5mph faster, and on track out there was still four to five feet of track left, so there is a lot more throttle to apply earlier than I am used to. The end result was that max velocity heading into the braking zone at turn 5 was hugely faster, and I was really hustling up on folks in that segment.

Turn 10 is a bit trickier. Coming down the Rainey Curve of Turn 9 the downforce helps on track out as the camber rolls away from you, and again the result is higher exit speed on the downhill run to set up for the turn in to Turn 10. This turn has positive camber early in the turn, but then it rolls away, so it is easy to enter hot and then lose it on track out to the left. It is high enough speed that the downforce helps, but I never got the technique and feel down solidly enough that I could push it more to the limit. There is a lot more left in that corner to improve upon.

Turn 5 and 6 benefit, of course, but surprisingly, Turn 3 even more. Although turn 3 is slower than 5 and 6, the diminishing radius nature makes it an insidiously dangerous one to the early apex or too fast entry driver. The downforce on the car with aero really helped a lot with grip and that increased speed, carried all the way down to turn 4, paid a very significant dividend. I passed a GT3 coming out of turn 3, and a ZO6 coming out of Turn 6 and up the Rahal straight. Those are not places where one typically gets a good jump on a high hp car, but the faster exit speeds allowed a launch that before aero I just could not get.

Traffic is an interesting issue! if you get tucked in behind somebody it robs you of some of the front aero, and less of the rear with the wing up high in the airflow, so you have to be mindful of an understeer risk at turn in if you are tight on somebody. Overall, since we are not trying to draft when running HPDE, there was not a lot of instances where one got close enough to notice interference. Even advanced group drivers were committed to giving point by signals for this session with TMR and Coastal Driving School, with a big contingent from the Sacramento Valley Porsche Club in attendance. So a lot of nice cars, experienced drivers, and good etiquette displayed. the result was that they knew how to watch their mirrors, when you came up they promptly let you by, and you really did not get held up much with the traffic even though there were 20 cars on track.

Quite a number of folks came up to check out the car. We did not get passed all day, and nobody was approaching in the mirror either. Still have a lot of learning to do with the set up, and there is a lot more speed in there to tap, but for a start up adventure on aero, it was a good day.

 

He, Ed, that's MY WING on there!

Seems like I should get some royalties or something...

Anyway, sounds like the combo is working very well for you. It will take some experimentation to get the balance right. Every track will have it's issues, and every driver will have a different feel to what they think is best, of course. But 5 to 8 mph out of a corner is HUGE, and tranlates into that much more speed at the end of the next straight. Should really improve your lap times along with the new power snails that you have now!

 

Looks good - what were you using previously for front downforce?

 

There was no front aero before whatsoever, and the rear was just the oem spoiler. Mike borrowed Steve's rear wing, which is that really neat APR unit that appears to have been modeled from a humpback whale tail. We did that because Steve's car is undergoing some upgrades, and the wait time on the wing was longer than the track date I had reserved at laguna seca (THANK YOU STEVE!). And the other reason was that Mike A had been working on his concept for a robust front splitter after witnessing Mike B thoroughly demolish his C-West front end on a very mild OTE at Buttonwillow during the Redline Time Attack a couple of months ago. So he did an integrated front undertray diffuser and splitter, with some serious mounting plates to take the pressure and flex at high speeds, and.........Frankenstein was birthed. This baby will not win any Miss America titles, but it really gets it done. And that is beauty in the eye of the beholder. When you go around LS all day in the advanced group, and nobody passes you, or even challenges all day long, and you are running with Ferrari 360 Challenge, Porsche GT3, ZO6, Evo VIII, Subie STI, and other hot cars, who just see you coming and put out the pass signal, you know you have some stuff working right.

 

Hey Ed, my pleasure. Michael A. asked me before he borrowed it and asked to put it on a G35. I figured if I wasn't using it, maybe some else could get some good use from it. He didn't tell me it was for YOUR car though - I would have said H*LL YES instead of just yes!

People have asked me if the rear wing really makes a difference, and if you can actually feel the difference with the rear wing. I think you have proven that the answer is YES. At full angle of attack, you can feel it at speeds as low as about 60-70mph. I really feel that it adds an extra measure of stability to my car, even on the straights.

The only other aero mod that I have is a full blown rear diffuser. I think that works just as well as the rear wing, if not better.

So now you know the value of aero. Maybe now the only other car/driver that can catch you is ME or another VRT car.

 

How much speed to you think you all lose at the end of the backstraight with all your downforce?

 

That is a good question. By having upgraded to the larger 700 units at the same time as installing the aero, I just don't accurately know. The 700's with the aero are still faster down the straight than the 530's were without aero.
But I think you have to assume that the drag associated with the aero is material. Nevertheless, 5-8mph higher corner exit speed is very valuable. On a more radical race car capable of very high speeds the sacrifice might be questionable, but on our cars, it is not as much an issue. It will really depend on the track, the types of turns and straights, how you set the angle on the wing and the amount of down force you dial in. A track like LS has some very high speed turns followed by long straights or uphill climbs, so more downforce to power hard through and up those sections is valuable. A track with more slow speed turns and long straights would be better with less downforce, as the slow turns do not benefit from it and the straights therefore should have less as well.

 

good stuff, very clean looking. Glad to see the benefits. I always love hearing track stories when things go well.

 

I ask because I don't have ridiculous amounts of power, but "battled" often with IP E36 M3s that are 300lbs lighter and have front and rear downforce options (they can run almost about 2-3 seconds faster than a T2 350Z at VIR). I really don't plan on going turbo, but I could definitely use some assistance where applicable in the turns. I'm just trying to do some analysis as to whether or not the drag from the added aero on my car will be outweighed by the aerodynamic grip through high-speed turns.

J, who can turn some fast laps with his "slow" NA Z...

 

very nice, I actually really like the looks of the splitter. So the 700's are worth it? I have been thinking of upgrading, but haven't yet had the chance to ride in someones car that has them. Maybe when I take a trip to GTM.

 

Talking with several drivers who are much better than I am (ok, I know, that is a pretty large universe, but humor me) including a couple of pro circuit guys that have driven in several series, the feeling they had after driving a couple of Mike A's TT cars at Buttonwillow, was that aero would be good for "at least" 2-3 seconds per lap, whether the car was NA or boosted. After experiencing it myself for the first time at Laguna Seca, and acknowledging that it will depend on which track you are running, I would agree.

An important key to lap times is how fast we can go in the turns. We do things to the suspension and wheels to help the car get the best out of the tires as we can. And we work on our skills to safely take the car to the edge of adhesion of the tires. And then...that is what it can do...you are pretty much at the limits when your skills are up to the task of extracting everything the car can do with the tires you have.

With all other factors equal, a boosted car will give you better acceleration than an NA car, and thus a higher top speed in each segment of straight section of track (duh!), but it has no advantage in a turn unless you have a situation where on turn exit and following straight the NA car cannot get up to the maximum corner entry speed that the car/tires could handle at the next turn. It is very unlikely that you will be in a turn where having lots more power from a boosted set up will be an advantage over an NA car because the limits of adhesion from the tires are the determining factor. Some sweepers perhaps, some uphill curves perhaps, but in general the power advantage is limited to the point in time beginning when the WOT at track out for the NA car no longer exceeds the lateral adhesion of the tire, and then all the way down the straight to the next time one has to apply braking for the ensuing turn. That is a lot of advantage, but it is not in the turns.

So, then we ask, is there much advantage in the turns to be gained?

That advantage of speed in turns is no more ably demonstrated than the example of a Spec Miata car. Those little mites are in the category of "momentum" race cars, where smooth technique and finesse are critical. With light weight and a decent power to weight ratio, they carve through turns fabulously and extract superb traction returns from their tires because there is less inertial momentum to redirect, so more velocity can be carried into higher corner entry, mid turn speed, and especially corner exit speed. This type of car can routinely best many high horsepower cars whose weight, and thus higher lateral inertial force that the tire has to work to redirect in the turn, requires the brutes to slow down. Exiting turns 5,8, even 10mph or more slower than the Miata puts the high hp car at a handicap coming out of every turn. That is a lot of speed advantage. And at the end of the straight the high hp car is on the brakes harder, slowing the car from a possibly higher speed to a lower corner entry speed....so it is working HARD to go faster. At almost every HPDE event you hear the lecture about the high hp guys needing to recognize that pulling away from the Miatas on the straight, then having him all over your tail two turns later means that the Miata is faster, so let him by!! And breathe throttle on a straight to help him if that is where you let him pass.

The aero downforce increases the grip of the tires, by pressing the car down against the pavement, and thus the speed the car can go through a turn before losing adhesion is increased, assuming that the car still has the power to push faster through the turn than the tires can grip. Whether the motor is boosted or not, it is the case for almost all turns on a racetrack circuit that the VQ35DE motor will in NA have the power to do that. (You will not see many Miatas with aero wings etc because the added drag would outmatch any increased cornering speeds...they are often WOT in several turns on a circuit without any braking before turn in as it is).

The art of the downforce game is "how much wing"? You need to adjust it for each car, and for each track, based on the speeds and straights, to get the ideal combination. But if the bottom line here is whether aero on our cars in NA will help on the track, I would say most definitely it will. Two to three seconds per lap is..........HUGE gains. But, if you are not driving at the limits of what the car can deliver, then you probably do not need to go through the process. I would work at driving the car until you feel you are getting about as fast as you can and it is not you that is the big factor in lap times...in other words....there is not two or three seconds left in the car just based on YOU as driver. Then do the aero.

How much is the straight line speed sacrifice? If the net is a gain of 2-3 seconds, who cares? There is some sacrifice in top speed, no question, but given the higher corner exit speed you carry with you all the way down the straight, and the higher corner entry speed you throw into the next turn, it is in most situations way better to have the aero than not have it.

In conclusion, if you have a big ole wing on the back of that car, you better be fast with it brother. Because otherwise, you don't need it. And getting passed by another guy in the same type car without the aero is about as embarassing as it is going to get!!!!!!!!

 

Perfect as usual....that is so true...in so many ways.

 

Can't wait to see just who's aero parts work and the added speed if any at some upcoming track days, and the Time Attack coming up. Using some of my (seemingly useless) aerospace engineering background and my driving experience, I have formed my own conclusion about aero for these Z's and G's. Sometimes modifications work because people really want them to work, you know. So they will push a little harder, or try a little more, like the plasibo effect but with cars, Hahaha. I would be more likely to give any added credit in a decreased lap time (especially 2-3 plus seconds) to improved conditions, driver improvement, or a increase in a HP mods, etc. rather than aero. On a 1500 pound indy car going 200+ MPH aero is VERY useful and important. These are in fact 34-3800 LB. cars (with driver) and they are only averaging about 90-110 MPH. the effect on aero for these cars is pretty minimum, maybe about 1-2 seconds maximum for a 1.30.00 to a 2.10.00 min. lap time. I am pretty sure that the aero parts I have experience with do in fact add some help in some of the 100 mph. turns, but no help at all in low speed turns, and the added aero downforce will then hurt top speed.

Yes aero can, and is helpful on these cars for our purposes, but I am referring to "well thought out", light weight aero mods, and probably not as big as a difference as some would think, especially unless you are a very advanced driver that can feel the slightest difference in his/her car (like a couple of LBS in air pressure change in the tires, etc.) Not many on this message board (if any) are going to actually be able to pin-point these subtle changes,

In my conclusion...... I do feel aero can, and does make a positive difference, just a mild one, and it must be well designed and thought out with some kind of wind tunnel type testing. Either way, I would rather have the cars aero mods on it than off of it. (they look cool, and work a little bit)

At my next track day with the time attack car (sincityZ's) I will run the car with, and without the aero parts (without any other changes made) to see just what the times are compared to each other. I am sure the difference will be interesting.

I hope the aero parts are good for 5 seconds, I am just well aware of the reality of it.

 

Scott: That Kognition unit on Mike B's car is very nice looking indeed. I will be very interested to hear your experience with the aero on and off on the next run at the track you take with it. I would not expect 5 full seconds difference either. But certainly at least 2 to 3 sec. Given how slow I am ......a difference of even 1 to 2 seconds is a big deal!

See you soon!

Ed

 

Nice. If you weren't a real track driver I was gonna call rice

 

Nice write up as usual Eagle1. if you dont mind me asking what type of times were you running at LS. the best run and average run. as far as the splitter is concerned that is a hot looking pice.

Hammad

 

Ed, looking at your front splitter after a while, what are your thoughts on the effect of the three vertical gussets in regards to aerodynamics? Do you think they can have a negative effect on airflow by creating some sort of turbulance? Also, after running the car at LS you said that it has a little to much rear downforce if I remember correctly. Do you think thats because of having your OEM rear spoiler on along with your APR wing? Do you plan on lessening the downfore in the rear or adding more downforce to the front via canards or something else?