Filling in the current rear cutout area is costly in both time and money. It also seems likely that we'll need at least a 2-inch cutout to accommodate a GEN3 muffler. So, here's a thought...

For GEN3 keep the current tail configuration options legal until 2017, with the exception of the 2-inch muffler cutout.

At 2017, require that all cars go to a rear cutout that is the same dimension as the current cutout (cutting is cheaper than filling) and remove the left side scoop (provide a fill panel for this to make it easier to fill in).

It may be that this change will increase rear downforce to the point that generates a push in high speed corners. It's probably something that will need testing to determine if chassis set-up alterations can mitigate or eliminate understeer at certain speeds.

Or it could be that it balances the car better in fast corners. In which case, whooopeee!

We already have plenty of "test cases" given the mix of drivers running both the "Ford" and "Renault" configuration. I haven't run a scientific comparison but my expectation is that the Ford has higher drag, but that neither contributes significant downforce (if any.) We've experimented with a long tail configuration with a wicker bill and the difference is definitely "seat of the pants" measurable in high speed corners (+100mph) in back-to-back comparison to a standard tail with measurable downforce (or at least less lift).

With the Enduro nose that had tunnels, the downforce on the front was so strong that the car was scary loose as speed increased and the wicker bill on the updated enduro tail did not generate enough downforce to overcome the addition stick on the front. Adding a wing on the back with a modest angle made a huge difference. The balance of the car was immensely better, especially in high speed corners where extra downforce on the rear is probably a desirable effect for most drivers. The one caveat is that we ran on "properly sized" tires (185 front/205 rears) as the current one-size-fits-all-corners Goodyears are not as balanced as the R888's. On the test day we had last weekend I was able to get the Gen3 down to 2:01's without overdriving the car at Thunderhill (the same tires that did 25 hours+ on the front tires and about 10 hours on the rears.)

The one area we also explored with the Enduro car was spring rates. The Renault had much smaller springs and with the Ford conversion it became clear that the extra weight was creating a severe imbalance. What ended up happening was we moved the rear springs to the front, and put in stiffer rear springs to compensate. In testing the Enduro with the Gen 3 we went further and moved the Ford rears to the front and went with stiffer springs on the rear that were closer in spring rate to the fronts than the delta between the Ford springs. Our initial thought was to go softer to compensate for the high front downforce, but the stiffer rear springs actually felt much better (again, on different tires, though.)

That leads me to the final thought is whether the current spring rates are right for the car with the reduced rear weight? There's probably sufficient sway bar adjustment to compensate (right now we're pretty maxed out on the fronts and rears to compensate for the Goodyears), so the lighter weight may offer some additional adjustment range beyond the "full soft" setting in the rears today. The one thing that I liked about the increased spring rate was the car felt more responsive with less roll. The downside is that rough spots on the track are much more noticeable (and our tracks up here are generally on the smooth side.) We'll know more once we test the Gen 3 in the spec configuration.

Final New Year's wish (perhaps for next year) are properly sized, radial R-compound tires that are competitive for more than 8-12 sessions.

Looks like plenty of good data from a variety of body configurations, Bob.

The configuration I'm talking about is specifically the current spec open tail with no left side scoop that forces in air to raise the pressure, and lower downforce, beneath the tail.

Not sure I understand the distinction you're making. The only noticeable aero difference should be on air flow over the top of the nose. The cutout in the back should not make much of a difference as airflow below the car is pretty disturbed air and I expect there's really no difference in efficiency/drag if the tail section is closed (Renault) or open (Ford.), though I'll leave that to the aerodynamicists.

The only reason for the scoop and cutout on the Ford was to fix the overheating issue with the exhaust pipe and front-facing header. Frankly, I'd prefer to have the full Ford cutout on the back with the Renault tail just to lose the weight on the rear of the card.

We ran the Gen 3 with the muffler in the enduro, which is pretty large, so I expect it's going to take more than 2" of trimming. Since we can in a modified trim because of the wing in the enduro car we did not run in a standard muffler configuration (muffler was connected to the wing mount in the center; once we run in a spec configuration we should have more data both on the fit of the muffler and whether it will make the sound window. My first impression is that, while it's definitely much quieter than an unmuffled Ford (ran back-to-back last weekend) it may still need some work to get to an acceptable db level at Laguna. Hopefully we'll have a test day a Laguna sometime this year to get better data. Hopefully we don't end up with too many mufflers (as it is, we now have two with the "Portland" muffler that barely does any "muffling" and the big Laguna muffler that's over-kill for most tracks. Frankly, I prefer running the Gen 3 with the muffler just to save what's left of my hearing (and it still sounds pretty cool!)

breton wrote:Not sure I understand the distinction you're making. The only noticeable aero difference should be on air flow over the top of the nose. The cutout in the back should not make much of a difference as airflow below the car is pretty disturbed air and I expect there's really no difference in efficiency/drag if the tail section is closed (Renault) or open (Ford.), though I'll leave that to the aerodynamicists.

The only reason for the scoop and cutout on the Ford was to fix the overheating issue with the exhaust pipe and front-facing header. Frankly, I'd prefer to have the full Ford cutout on the back with the Renault tail just to lose the weight on the rear of the card.

The rear cutout 'glass weighs a bit under two pounds. (I was anal enough to weigh it once.)

Anyway, Bob, it seems we agree on going with no scoop, and having the large rear cutout. And you're likely correct about the aero. It could be that evacuating more air from under the tail might create more downforce, but it's probably not much given the dirty entrance points for the air.

Looks like I will be retrofitting alot of tails eliminating the scoop in the next few years, including both of mine! I still hope Mike D. will leave the back cutout on the "scooped" tails alone in the rules as that could be more work than its worth.

Well, I'm late to the dance on this one but I'll toss in my two cents anyway. Assuming there is room for it I prefer as much of the no-scoop tail as can be preserved. Just as the rear wheel cutouts improved the look of the cars over the Renault style, the full untrimmed tail looks better than the cutout/scooped version. I have both and every time I put the version with the cut out back on the cat and look at it from the back, quite frankly the car looks unfinished. (Ugly!)

How about we get a car that is faster, handles better, sounds awesome and also looks good from all angles?

In terms of having the air scoop or not having it, so long as the air box draws air from the midsection scoop, power will not be a factor. So having it would do nothing more than create unnecessary drag. Get rid of that too.

I agree with you Jim. Those of you who have the full tail configuration can cut what is needed for the Gen 3 layout based on whatever the rules state. But those of us who have tails cut out already, filling in part or more of the back is going to be difficult, again, if a mold isn't handy. Adder or filler pieces glassed from the inside will add more weight than the full tail to begin with partly cutout for the Gen 3. I am resigned to see the scoop phased out and hope that Mike D. will allow a period of time for that, given there is no advantage. Would be nice to survey who has what kind of tail out there. Can someone set that up for us? More participation would help determine what we should do. It is our class...

Mark, I think we agree , but not completely. FYI, about 8 or 9 years ago when my Stack system was actually working properly I experimented with both styles of tails on the same day; the scooped and cut out verses the original design. I was convinved from the data that the original design was/is one and a half miles per hour faster than the scooped version on a long track like Road America. (I am sure someone will pipe in with contrary information, but that is what I found.)

I am sure you, like me, have had professional photographers sell you action shots and in some where the car was coming straight at the camers I have always been shocked at how big that scoop is and how it's out there in the breeze in a big way. So, I believe the scoop is slower. Whether the cut out happens in the back, to squeeze out every MPH we can from our $12,000 investment I am hoping the scoop goes away in the Gen 3.

Meanwhile, I am jacked up about getting the kit. Those who have driven it make it sound like fun!

Hey everyone, this is what I need...people having a conversation about parts of the kit or GEN3 in general. Please people chime in.

I think everyone knows, one of our goals with the GEN3 was to raise the performance a little as economically as possible and gain back some of the class appeal. All while making the drivetrain less field tunable. So far so good on that goal.

It’s also nice to have current engine technology and a little manufacture support to help maintain supply and stability for the future. At this point 1.6 engine reliability/durability is exhalent. We all know the 1.9 was pretty long in the tooth.

Another goal, bring the cars back to as close to the same as possible. We are “Spec” Racer Ford” one of the biggest reasons we love to compete in the class. It’s tuff, fare and satisfying !

Financial security is a big one, what other race car in general can you buy, race 5 or 10 years, keep it well maintained and in most cases break even or make a little money on your original purchase price.

Safety is high on most peoples list, I don’t know of many people that have been seriously hurt in a SRF crash…I know it’s not a perfect record, but SRF is very safe as race cars go !

We are working on GEN3 details everyday, I’ve said it before, I want this to be the best “Spec” Racer ever !