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Learning how to build Lotus Seven replicas...together!
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PostPosted: Wed Jun 03, 2009 4:28 pm 
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Justin - with 1.5 points added to the modification factor over a non-aero modded 7, you either need to make the car a good bit heavier or make much less power.
At least from the racetracks in the region here, I think you'll have a seriously hard time justifying it.

Fred, why not Donkervoort D8 RS06 :wink: ?

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PostPosted: Wed Jun 03, 2009 4:37 pm 
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Yup the Donkervoort is another cool version,

I think it's cool that you could build a STR2 Se7en, if one was willing to put in the effort... A K24 or an S2000 engine would be perfect in there... or a small turbocharged engine could also be a possibility. Having sidepods would enable to improve the cooling options of the Se7en design.

Long live the Se7en :D

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PostPosted: Wed Jun 03, 2009 4:47 pm 
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Blackbird wrote:
Justin - with 1.5 points added to the modification factor over a non-aero modded 7, you either need to make the car a good bit heavier or make much less power. At least from the racetracks in the region here, I think you'll have a seriously hard time justifying it.
True I usually think about courses like Road America, since that's what's closest to me. On a 1160lb BEC with driver, I get that as going from 145whp to 125whp...Or on a 145whp car going from 1160lbs to 1360lbs with driver. Given those numbers I can see how the advantage could probably go to the non-aero locost on slower/tighter courses, but quite possibly to the aero locost on the faster/open courses.

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PostPosted: Wed Jun 03, 2009 4:49 pm 
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Jawfish wrote:
I think it's cool that you could build a STR2 Se7en, if one was willing to put in the effort... A K24 or an S2000 engine would be perfect in there... or a small turbocharged engine could also be a possibility.

Be careful that you don't get yourself into STR1 or SU with that kind of power.

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PostPosted: Wed Jun 03, 2009 7:00 pm 
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Driven5 wrote:
Jawfish wrote:
I think it's cool that you could build a STR2 Se7en, if one was willing to put in the effort... A K24 or an S2000 engine would be perfect in there... or a small turbocharged engine could also be a possibility.

Be careful that you don't get yourself into STR1 or SU with that kind of power.


Agreed... just need to keep it in STR2... Then again a Brick or D8 RS06 type car could play with the much bigger and powerfull cars...


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PostPosted: Wed Jun 03, 2009 7:58 pm 
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It surely can, but the cost to build is going to be massively higher.

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PostPosted: Wed Jun 03, 2009 8:34 pm 
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Blackbird wrote:
It surely can, but the cost to build is going to be massively higher.

Moti


Yup, combined with longer build time... just the bodywork is going to take a while, unless you get some little helpers :mrgreen:


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PostPosted: Wed Jun 03, 2009 8:40 pm 
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Come to think of it, the Donkervoort D8 RS06 type sidepod type aero package (and roof?) could pretty easily be added as a completely modular/bolt-on affair along with a strategically placed and removable ~200lbs for ST2. That way not only would it be possible to do back testing be done on numerous tracks, but the car could then be setup in whichever configuration is faster on any given track...If only money grew on trees. :oops:

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PostPosted: Fri Jun 05, 2009 12:38 am 
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Quoting myself from the recent "differential thread" in the BEC section:
erioshi wrote:
With approximately 1450 lbs (car + driver) my ST1 (or STR1) cap would be about 216 whp and my ST2 (or STR2) cap would be about 146 whp (assuming only listed penalties). At 216 whp my top speed should end up very roughly around 154 mph and with 146 whp my top speed (again, very roughly) would be around 135 mph. Those are ideal numbers, on a real track I think I'd need better gearing to actually hit them in a reasonable time. A possible way to fix things a bit might be a turbo BEC. A small turbo could be sized to deliver lots of extra torque in the lower RPMs but provide less additional power up top. With good engine management I expect staying within spec would be manageable.

Where I will be playing there are 2 tracks with huge straights & I'm hoping to use a full body with fairly slippy aero (reasonable replica of an existing coupe). While I'm not worried about acceleration under 80 mph or so, my fear with a BEC is that when drag really takes over the scales will tilt heavily in favor of heavier, big HP cars. I did some time to speed & time to distance calculations and it looks like a BEC get slaughtered even against a stock C5 Corvette at higher speeds.

Does anyone have some real world experience you can share here? My largest concern is the big tracks; I can always use lower gearing on the shorter tracks but how does a BEC fair on tracks like Road America or full VIR with room to really put your foot down?

I guess you could say I'm locked in analysis paralysis trying to sort out whether I build a BEC or deliberately build heavier just to get the needed HP for high speed tracks, lol. It feels wrong to want more weight but it also feels like the rules strongly favor heavier cars.

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PostPosted: Fri Jun 05, 2009 2:08 am 
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I arrived at the same conclusion a while ago, but the majority of the tracks that I'll be playing at offer a fair shot for the BEC.
The tighter things get the more the BEC shines.
If you're planning on being competitive in your region you need to do a reality check for the BEC, building a Locost with an SR20DET and ballast will work better for some tracks...

Moti

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PostPosted: Sun Jun 14, 2009 2:07 am 
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Driven5 wrote:
Come to think of it, the Donkervoort D8 RS06 type sidepod type aero package (and roof?) could pretty easily be added as a completely modular/bolt-on affair along with a strategically placed and removable ~200lbs for ST2. That way not only would it be possible to do back testing be done on numerous tracks, but the car could then be setup in whichever configuration is faster on any given track...If only money grew on trees. :oops:


If money grew on trees, you'd just have two cars. :lol: 8)

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PostPosted: Tue Dec 01, 2009 3:09 am 
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The new NASA ST/STR/SU rules for 2010 are out & available here: http://www.nasaproracing.com/rules/Super-Touring.pdf

The NASA Forum link for the relevant classes is here: http://www.nasaforums.com/viewforum.php?f=18

Highlights include a 50% reduction in the power to weight penalty for very low weight cars (from -1.8 to -0.9) and some info on NASA's plan to move forward with in-car GPS monitoring as a method to combat the new generation of "hidden" in-car instant ECU map switching.

Here's a link to the relevant thread on the NASA Forums: http://www.nasaforums.com/viewtopic.php?f=18&t=31821

The meat of the GPS from stuff the rule book is:
NASA ST Rules v4.1 Nov 20, 2009 wrote:
NASA is actively conducting research on the use of in-car GPS monitoring units as an alternate
method of compliance testing of horsepower output. It is possible that GPS monitoring will be
used at the 2010 NASA Championships, and that vehicles found to be out of compliance will be
penalized without Dyno testing, based on the results of the GPS on-track monitoring. If NASA
elects to begin compliance testing with GPS units, competitors will be given adequate notice
prior to their use, including details of the units to be used, so that they may do their own testing if
desired.

There is also a small change to tire width bonuses for slicks. While that section became more defined, it also became more confusing. It basically looks like slicks get their bonuses reduced about 5mm of tread width earlier than last year when both slicks & DOT tires used the same width schedule for bonuses.

And classing is still just HP to Weight instead of the average of TQ & HP to Weight which I think would be a better overall method. This might be a good year to race a diesel ;)

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PostPosted: Tue Dec 01, 2009 12:40 pm 
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Thanks for the rules posting notification and summary of some key changes. :cheers:

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PostPosted: Wed Aug 18, 2010 4:41 pm 
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Wow, I'm surprised I didn't post the latest change in NASA's STR rules earlier; guess I've been away for a while:
http://www.nasaproracing.com/rules/Super-Touring.pdf

As of 7/1/2010 (Version 4.2 of the rules) there was a change specifically aimed "Sports Racer" type cars:

For STR cars only (not ST/SU cars) the penalty for weighing under 1850 lbs (with driver at race weight) is now a factor of -2.7.

For a 1450 lb car (example from my post above) it looks my potential max RWHP would be 131 for STR2 and 185 for STR1 once factors for tires, gears, etc. are also added in. For a 1355 lb car, my actual target weight, the power levels drop to 123 whp for STR 2 and 173 whp for STR1 .. ouch, lol. That pretty much kills any chance of my "mini-LMP" type car being even remotely competitive unless I bulk it up over 1850 lbs and go for serious power.

Those looking to race a "Caterham or Lotus 7" or "Brunton Stalker" should be unaffected; They are still approved for ST competition under section 8 of the rules, ST1 & ST2 Approved Non-Production & Tube-Frame Vehicles and are still at the same +0.75 no aero / -0.75 with aero factors.

For comparison, a non-aero locost at 1355 lbs (using my same mod factors for tires, gears, etc.) would be allowed 160 whp in ST2 and 258 whp in ST1. A locost with aero mods would be allowed 136 whp in ST2 and 200 whp in ST1.

At this rate I may end up building a locost just to go racing...

OT:

I have also looking again at the SCCA rules. Unfortunately I can't see any way of getting anywhere near the minimum weight (or even regionally competitive) for an SCCA DSR build without spending cubic money on a build. Or just buying a used West or Sthor and running regionally or upgrading for national competition.

/OT

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PostPosted: Wed Aug 18, 2010 8:14 pm 
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Two quick notes about other rule changes in NASA:

The specification for roll cage steel has been changed to "CDS or DOM" in section 15.6.18 Roll Cage Tubing Sizes of the CCR. CDS = Cold Drawn Seamless and DOM = Drawn Over Mandrel from the usual list of Internet steel suppliers.

It looks like TTU and TTS are now essentially fully compatible with ST1 and ST2 respectively, allowing ST1/2 prepped race cars to also compete in Time Trials without modifications. At least that's how it looks based on my initial scan of the rules. If so, this makes it easier for one driver to buy twice the track time (and consumables ;)) or share a car between two drivers for a weekend.

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