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Author Topic: street roadster in wind tunnel  (Read 9916 times)

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Offline promachine

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street roadster in wind tunnel
« on: February 17, 2006, 05:51:06 PM »
Check out the April 2006 isue of Hot Rod. The Thacker and Shine street
roadster is in the wind tunnel. Vary interesting.
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Offline SPDRACR

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Street Roadster in wind tunnel
« Reply #1 on: February 17, 2006, 06:54:36 PM »
What is the drag coefficient of a barn door any way? To think I though the way to make a roadster go fast was lead and lots of horse power.
t
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Offline promachine

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street roadster in wind tunnel
« Reply #2 on: February 17, 2006, 07:30:35 PM »
You are right and you can take the article for what it is, but I am allways
looking for clues. Never heard of a roadster in a wind tunnel before.
 They had load cells under the tires to see how the changes effected
the weight , nothing suprising, just interesting thats all.
Well maybe the test with the moon tank in fronte of the grill shell was
suprising.
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Offline NaCI

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Street roadster in wind tunnel.
« Reply #3 on: February 18, 2006, 07:05:34 AM »
The same, or a similar, article appeared in a UK magazine in October 05, interesting but yes take it for what it is......... not sure how the reduction in drag/hp at 200mph (from 551 hp down to 504) would equate to real life changes on the salt, perhaps Speed Week 06 will tell.
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Offline Stan Back

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street roadster in wind tunnel
« Reply #4 on: February 20, 2006, 01:33:34 PM »
Will aero changes be enough to pick up the 40+ miles per hour they're off the record?
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Offline promachine

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street roadster in wind tunnel
« Reply #5 on: February 20, 2006, 03:30:48 PM »
I don`t think so, not with that engine. And I don`t think that is the point.
But the car is streetable (Street roadster) and was driven to B-ville a
couple of years ago only to go 192 mph backwards threw the lights.
It is pretty arodynamic backwards!
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Offline Sumner

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street roadster in wind tunnel
« Reply #6 on: February 20, 2006, 03:47:14 PM »
Quote from: Stan Back
Will aero changes be enough to pick up the 40+ miles per hour they're off the record?


Theoretically their new found 47 HP should move them from 202 MPH to 208 MPH.

I think the earlier
Quote
What is the drag coefficient of a barn door any way? To think I though the way to make a roadster go fast was lead and lots of horse power.
tells it all with a roadster.  They are going to need lots more HP to pick up 40 mph.  I calculate about 890 HP needed to get to where the current record is.  

I liked the article though and it is good to see this type of thing get more press.  If they could get the driver lower in the car and some of the cage more out of the wind I think that would help along with the new tonneau cover.

c ya, Sum
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Offline promachine

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street roadster in wind tunnel
« Reply #7 on: February 20, 2006, 05:03:44 PM »
Interestingly enough the engine had about 746 hp down hear on the
dyno. But our dyno sweeps only last about 15 seconds.
Running to the 5 mi. mark takes alote longer and the blower builds
up lots of heat . That is why alote of the blown gas classes are dominated
by turbos or screw blowers.
My d/bgr record was run at 214 mph with 860 hp with a 871 and a
intercooler but the e-c-b records are way up there and are turbo engines.
I picked up 12 mph when I put the cooler on, and I also shut it down
at the three mile marker.
This year I put a 550 c.i. whipple on the little d engine and am making
1180 hp on gas. We will see how she does at the 5 mi.
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Offline Sumner

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street roadster in wind tunnel
« Reply #8 on: February 20, 2006, 07:47:56 PM »
   

That is interesting information and I agree with you on the heat building.  I worry a lot about that with Hooley's new motor.  Last year we were never able to run over 30% throttle, so we don't know the full extent of that.

Gary Hart (picture above) has ditched the roots and gone with twin turbos using a Megasquirt to control the fuel injection.  He got to do a test run at the Texas Mile last year.  I think this car is going to run real strong this next year.  There is another picture ( HERE ) .  

One thing about that article is they mention 500 HP to run the 200 with the aero changes.  That is probably rear wheel hp and a degree of theory mixed in.  The car was probably making more like the HP you got on the dyno at the crank on the salt.  Like you said to drive a car to the salt and then run 200 is impressive in anyone's book.  They don't need to break the record to impress me.

Good luck with your new motor.  How much less heat does the whipple build vs. a roots?  Looks like you are really making some big numbers.

c ya, Sum
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Offline promachine

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street roadster in wind tunnel
« Reply #9 on: February 20, 2006, 09:35:52 PM »
You know I wish I had heat sensors in the intake, but didn`t. The biggest
thing I was able to do with the whipple was give it more boost.
 With the roots 871 @ 6% back on the drive I got 24 lbs. and if I tryed to
overdrive the little D anymore it just didn`t like it.
 With the big Whipple @ 6% back I get 36 lbs. and no signs yet of dry
runners or detonation. I havn`t seen the need yet to try more boost
but I think I can get 40 to 50 lbs. no prob.
Allmost as efficient as a turbo but not quiet.
Also it is not as sudden as most of the turbos I have run, should be easy
to drive. I guess we will see, everybody told me I coudnt`t put that
big ass blower on the little engine so I did it anyway. I have seen 1400
hp with a D on gas with turbos and I am sure other folks have made more
but like I said , this should be easyer to put to the ground.
                       Nice Stude- See ya on the salt
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Offline Ro Yale

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street roadster in wind tunnel
« Reply #10 on: February 22, 2006, 04:17:10 PM »
8) Great article, I've really been impressed with Hot Rod mag the last few years. It's cool again. I've subscribed and it's one mag that I always look forward to checking out.
Later,Ro
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Offline RaceDeck

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Good Stuff
« Reply #11 on: February 23, 2006, 12:31:58 PM »
Good Stuff in that article- It will be interesting to see what we can do to get a few more MPH out of our roadster. The fastest pass I have had on it was around 213 mph ( then the engine hand granaded :twisted: ). We have made a few more improvements in the new motor ( 2.4 L turbo 4 cyl F Class).
htpp://www.racedeckracing.com
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Offline Stan Back

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street roadster in wind tunnel
« Reply #12 on: February 23, 2006, 03:23:13 PM »
Jorgen -- As I remember you ran your roadster as a street roadster, altered roadster and maybe even a modified roadster with the same (?) engine set-up at one meet.  Can you tell us what leaving off the fenders and headlights accomplished (if any) and was the motor the same?
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Offline promachine

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street roadster in wind tunnel
« Reply #13 on: February 23, 2006, 05:52:01 PM »
Altered roadster?
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Offline Rex Schimmer

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Comment on the state of HOT ROD mag:
« Reply #14 on: February 23, 2006, 10:41:52 PM »
Ro Yale made a comment about HOT ROD being "cool again". There is only one reason and that is DAVE FREIBURGER!!! He is a great guy, smart, an absolutely down and dirty racing dog  and a hard worker. He has brought Marlin Davis back, the best tech guy period!, runs at the "Big white dyno" and sets a record, blows motors up in race cars and dynos and is a real all round hot rodder!
 
Regretfully this may be his down fall and possibly the return of HOT ROD to its former ways. If you happen to read Dave's editorial he is being put in charge of a pile of other Primedia car mags that they want him to dig out of the dirt like he did HOT ROD. It's the "Peter Principle"! he is being promoted to his highest level of incompetence. He is a great rodder but is he a great administrator? Personally and very selfishly I don't want to find out ! I would just like to see him continue doing great things with HOT ROD, build great projects, go fast at the Bonneville.

Rex
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