MG Motorsports Forum

Welcome! Sign In Register

Please Sign In or Register to Search

"so, what’s a reasonable gain? "

Posted by Gofanu

Want to advertise your business in this space? Click here for more information!

Page 1 of 2 12

Topic List Forum List Newer Older Start New Topic

"so, what’s a reasonable gain? " #1
Gofanu Fletcher Millmore Titusville PA, USA	Posted: June 20, 2012 09:29PM Registered: 6 years ago Posts: 610

0.1sec per lap x 10 laps = 1 sec
consider that 100mph = about 150ft/sec
If the flagstand is at a 100mph point on the straight,
that is 12 MGB nose to tail, or 24 if they are two wide.
At 200mph. it is 300ft, or the entire 43 car field of a Nascar race.
On a half mile dirt track, that could be the top ten in a high level sprint car race.

How many exciting races have you seen that don't have 3 or more cars in the 150ft? The REALLY good ones have three cars in the first 15 ft, or 0.1sec, half that at Nascar, F1, Indy.

I once saw Doug Wolfgang and Bobby Allen (I think) finish a Sharon Nationals Sprint feature so close that nobody could tell who won. Nobody really cared WHO won, but SOMEBODY DID, and they (REAL Racers) told the track to quit being slackers and figure it out. They refused to accept a draw unless it could be proven, so everybody sat happily in the stands and waited more than an hour while fans' films were rushed off and developed in real time to decide the race. It was decided by an estimated 1.25". At the 120mph= 180ft/sec lap speeds they run, that is around 0.0008sec, in what was likely a 35 lap race.

So, can your driver maintain the speed the builder put in, or compensate for what he left in the shop?

FRM

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: "so, what’s a reasonable gain? " #2
Steve64B Steve Opitz Phoenix, AZ, USA 1966 MG MGB	Posted: June 20, 2012 11:53PM Registered: 6 years ago Posts: 8,339

Ultimately that's always the question... Isn't it?

No doubt if you had offered the loser of the Wolfgang/Allen match a modification that was good for 0.009 over 30 laps he would have thought it a good idea.

Reply Quote

Re: "so, what’s a reasonable gain? " #3
Gofanu Fletcher Millmore Titusville PA, USA	Posted: June 21, 2012 01:02AM Registered: 6 years ago Posts: 610

Was your question,
and your suggestion is off/excessive by one decimal place, or one order of magnitude.

Details!

FRM

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: "so, what’s a reasonable gain? " #4
dcharnet Donald Charnetski Grinnell, Iowa, USA 1963 MG MGB	Posted: June 21, 2012 06:40AM Registered: 2 years ago Posts: 945

This is all so subjective and relative to your degree of innate competitiveness---no "right or wrong."

Reply Quote

Re: "so, what’s a reasonable gain? " #5
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: June 21, 2012 06:50AM Registered: 7 years ago Posts: 20,317

I think the tigthest racing we see in our SCCA/Vintage racing is probably Spec Miata and Formula Vee, they alway have close finishes, in our production classes a close race that last between two cars for the entire race is far and few between, there is just so much variaction between car prep and driver talent, on longer courses, even in F1 close finishes for the win are far and few between, of course with those cars it's hard for them to race nose to tail, because the rear car gets robbed of front downforce, but this is the price of a ground effects car.

I always tell people road racing is decided by seconds, short track racing is decided by tenths of seconds. I think alot of road racer don't much care for round track racing, I've done it and it's harder than road racing, it all about tenths and set up, I have the ultimate respect for what these guys. In few weeks we'll meet up with fFed at Bowman Gray Stadium for Sheetz Night of Racing, and we'll get treat as always, watching the ultr-trick Nascar Modifieds race on the 1/4 track, they always put on great show. Persoanlly I love wathcing a good short track race.

Flecther, I watched Bobby "the Shark" Allen win a sprint car race down this way after getting into the main from the last chance qualifier, from the rear of the field in the main, all the guys in the pits had big rigs and tons of crew, Bobby was pulling his sprint car with a station wagon on a open trailer, borrowing parts from Donny Shotz, only to go out and beat him in the main smiling smiley

Hap Waldrop
MGexperience Supporting Vendor
Make Sure to check our promotions/product offerings in the Vendor Deals Forum here.

Edited 1 time(s). Last edit at 06/21/2012 07:02AM by Speedracer.

How to advertise on this website

Acme Speed Shop – Greenville, SC USA VTO Wheels 866-855-3473 Acme Speed Shop (864) 370-3000

Reply Quote

Re: "so, what’s a reasonable gain? " #6
fast-MG.com Dave Headley Cortez, 4 corners, Colorado, USA	Posted: June 21, 2012 08:28AM Registered: 4 years ago Posts: 3,227

Fletcher,

Any reasonable gain from air flow management is worthwhile unless that gain is off set in some other way by the added weight and complexity/reduced ease of maintenance of those same efforts done to achieve it. confused smiley

The hard part for the weekend racer is the ability to measure those gains and losses.

Hence my use of K.I.S.S.! smileys with beer

FWIW, I've never been beaten on the track by another MGB since the early '70s. devil smiley

How to advertise on this website

Fast-MG.com Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.

Reply Quote

Re: "so, what’s a reasonable gain? " #7
geezer charles durning Magee, MS, USA 1958 MG Magnette ZB "Chick Magnette"	Posted: June 21, 2012 08:39AM Registered: 2 years ago Posts: 400

I like Bobby Allen's style. He doesn't paint his cars cuz paint weighs too much and he doesn't upholster his seat for the same reason.

Sponsored Links. You can hide this ad & support this site by upgrading to a Gold Membership ~ click here for more info.

Reply Quote

Re: "so, what’s a reasonable gain? " #8
refisk Rick Fisk Frankenmuth, Michigan, USA 1959 Austin-Healey Sprite 1961 Austin-Healey Sprite 1979 MG Midget 1500 "Party Midget"	Posted: June 21, 2012 03:16PM Registered: 1 year ago Posts: 2,242

I get a kick out of the guys that spend big bucks for super trick light weight parts to cut a few pounds and then have two cheeseburgers for lunch when they really only need one. smiling smiley

Rick

Reply Quote

Re: "so, what’s a reasonable gain? " #9
geezer charles durning Magee, MS, USA 1958 MG Magnette ZB "Chick Magnette"	Posted: June 21, 2012 03:31PM Registered: 2 years ago Posts: 400

That sounds like Bobby Allen. Cut back on the car weight so he can enjoy 2 cheese burgers if he wants to.

Reply Quote

Re: "so, what’s a reasonable gain? " #10
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: June 21, 2012 04:33PM Registered: 7 years ago Posts: 20,317

Our kinda of racing is just not that close, not that attention to detail doesn't matter. I had a friend that raced in SCCA national HP races, always brought up the rear of the pack, but always spent big money on engines, suspension and so on, none of it never matter, he was always at the back, I once told him, if he had a V8 GT1 car in HP, I thought he still couldn't win the runoffs.

Look at Steve Sargis, a Spitfire is far from the car to have in FP, or HP, but he won the runoffs in both classes with a Spifire. People don't want to admit it, but the greatest advantage in our level of racing, is the driver's talent.

Hap Waldrop
MGexperience Supporting Vendor
Make Sure to check our promotions/product offerings in the Vendor Deals Forum here.

How to advertise on this website

Acme Speed Shop – Greenville, SC USA VTO Wheels 866-855-3473 Acme Speed Shop (864) 370-3000

Reply Quote

Re: "so, what’s a reasonable gain? " #11
Steve64B Steve Opitz Phoenix, AZ, USA 1966 MG MGB	Posted: June 21, 2012 04:37PM Registered: 6 years ago Posts: 8,339

In reply to # 2099559 by fast-MG.com Fletcher,

Any reasonable gain from air flow management is worthwhile unless that gain is off set in some other way by the added weight and complexity/reduced ease of maintenance of those same efforts done to achieve it. confused smiley

The hard part for the weekend racer is the ability to measure those gains and losses.

Hence my use of K.I.S.S.! smileys with beer

FWIW, I've never been beaten on the track by another MGB since the early '70s. devil smiley

Aero is the ultimate K.I.S.S. the only moving part... is the air.

Reply Quote

Re: "so, what’s a reasonable gain? " #12
Gofanu Fletcher Millmore Titusville PA, USA	Posted: June 21, 2012 04:39PM Registered: 6 years ago Posts: 610

Agree completely with Dave - if you don't understand it don't do it, if you can't keep up with it don't do it. You only gotta be faster than your buddy, the bear will take care of the backmarkers.

And with Rick, as long as the spec weight does not include driver.

Allen built his own cars. I once heard him admit that the weight vs paint thing was a good side benefit of running out of time building the new car. And to do upholstery he would have had to buy a sewing machine - not happenin', nor paying for seat covers.
Now his grandson Logan Schuchart is lighting up Williams Grove and other area tracks, proving that racing talent really is genetic.

FRM

Reply Quote

Re: "so, what’s a reasonable gain? " #13
fast-MG.com Dave Headley Cortez, 4 corners, Colorado, USA	Posted: June 21, 2012 06:39PM Registered: 4 years ago Posts: 3,227

Steve, achieving gains in Aero is anything but K.I.S.S.! thumbs up smiley

How to advertise on this website

Fast-MG.com Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.

Reply Quote

Re: "so, what’s a reasonable gain? " #14
Steve64B Steve Opitz Phoenix, AZ, USA 1966 MG MGB	Posted: June 21, 2012 07:52PM Registered: 6 years ago Posts: 8,339

Dave... we might be playing with semantics. Innovating and developing aero is difficult and hyper expensive. The total 2011 F1 budget for Ferrari is believed to be $600 million, of which an estimated 25-30% is spent on aero development.

But in application, on a race car at speed… the only moving part in aero is the air. It’s about as simple as you can get.

I think the key is to take the work of F1, Indy and NASCAR engineers and adopt it.

The latest F1 cars are using vortices to gain significant advantages. The low pressure area is at the center of the vortex, they are less sensitive to flow disruption and intrusion from flow outside the vortex. With votices you can gain the benefits of lower local pressure under the chassis and not run afoul of the rules regarding conventional ground effects by means of belly pans.

The thread a while back about grill openings grew out of a story I was reading about all the crazy little things NASCAR guys do for Daytona and Talladega. When they race at a track like Martinsville they have horsepower to burn and can go with max wings and openings all over the front of the car for cooling. They are neither HP or aero restricted at a short track. But at the high speed tracks they can’t make enough power to make a difference at 190MPH+. Any advantage has to be with aero.

I was thinking that small bore race cars are a lot like NASCARs at Talladega. They’re HP limited. Take two equally prepared cars, but make aero improvements in one… and it will always be faster.

Reply Quote

Re: "so, what’s a reasonable gain? " #15
dcharnet Donald Charnetski Grinnell, Iowa, USA 1963 MG MGB	Posted: June 21, 2012 10:50PM Registered: 2 years ago Posts: 945

So let's synthesize.

Deep valence is generally good--less air under the car.

Too much, as in SCCA air dam, might move the center of pressure too far to the rear for the tools and devices available to us to balance at both ends.

I like management of air flow behind the valance by panels, to speed and smooth the flow of air under the car. I don't see that as upsetting dynamic balance. Fast flow benefits both ends, unless air is trapped in the rear (see below).

I like dumping air from behind the rad by carefully placed hood vents which create the least drag and laminar flow disruption possible. This cools the motor and reduces reversion.

The optimal ratio between grill area and rad area is debatable, but can be easily experimented with by racer's tape and sealed chambers. It may be less than 1:1.

The Great Unknown is how to reduce lift at the rear to maintain dynamic high speed balance. The only thing I can think of is holes in the lower rear valance to relieve pressure back there and speed airflow systemically. The Ungodly Fast Sprite which finished first in VSCDA Group 2 at Blackhawk last weekend had something like that. I will ask questions at Grattan.

There are about 5 of us who believe in this. We are like the Chess Club or Serbian Relations Club at Beverly Hills High School--passionate, lonely, outliers. But we may eventually rule the country.

Anything else to say about this?

Edited 3 time(s). Last edit at 06/22/2012 07:36AM by dcharnet.

Reply Quote

Re: "so, what’s a reasonable gain? " #16
JohnP John Prater Alabama, USA	Posted: June 22, 2012 01:44PM Registered: 7 years ago Posts: 156

Has anyone tried a tonneau? Soft ones are legal in some vintage groups but I have not seen many run with one.

Reply Quote

Re: "so, what’s a reasonable gain? " #17
Speedracer Hap Waldrop Greenville, SC, USA 1967 MG MGB "The Biscuit"	Posted: June 22, 2012 02:31PM Registered: 7 years ago Posts: 20,317

In reply to # 2100731 by JohnP Has anyone tried a tonneau? Soft ones are legal in some vintage groups but I have not seen many run with one.

Yeah, Rick Starkweather,and those guys had one on the yellow MGB they race, I remember seeing some incar video of them with one in use.

Hap Waldrop
MGexperience Supporting Vendor
Make Sure to check our promotions/product offerings in the Vendor Deals Forum here.

How to advertise on this website

Acme Speed Shop – Greenville, SC USA VTO Wheels 866-855-3473 Acme Speed Shop (864) 370-3000

Reply Quote

Re: "so, what’s a reasonable gain? " #18
Bandit Racing Donald Dickey Illinois, USA 1963 MG MGB Racecar "#99 BRG Vintage Racecar" 1965 MG MGB Racecar "#10 Huffaiker/ British Leyland"	Posted: June 22, 2012 02:35PM Registered: 8 years ago Posts: 269

If you want aero get a crew cut and take the bobble heads off the dash.

Reply Quote

Re: "so, what’s a reasonable gain? " #19
fast-MG.com Dave Headley Cortez, 4 corners, Colorado, USA	Posted: June 22, 2012 02:59PM Registered: 4 years ago Posts: 3,227

Raise the rear of the car a little. It helps air passing under the front valance/spoiler to get out. You can also trim a little from the bottom of the rear valance.

How to advertise on this website

Fast-MG.com Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.

Reply Quote

Re: "so, what’s a reasonable gain? " #20
JP12 Joe Phillips Bristol, United Kingdom	Posted: June 22, 2012 03:37PM Registered: 4 years ago Posts: 166

In reply to # 2100781 by fast-MG.com Raise the rear of the car a little. It helps air passing under the front valance/spoiler to get out. You can also trim a little from the bottom of the rear valance.

The aerobytes features in Race Car Engineering would generally support Dave's view, hence why my car runs with a bit of rake and has as much of the rear valance cut away as is legally possible.

Reply Quote

Page 1 of 2 12

Topic List Forum List Newer Older Start New Topic

RSS

Add your reply here, or post your own questions!

Members Sign In if you've already registered, or
Register a New Account
Registration is free and takes less than a minute

MGB & GT · MG Midget · Buy, Sell & Trade · Vendor & Group Buy · MG Engine Swaps · Original MG · MGA · MGC · MG Magnette · 1100 & 1300 · T-Series & Prewar · Modern MGs · MG Motorsports · MG-2013 Event · Member Meetup · Other Vehicles · Off Topic · Clubs

Having trouble posting or changing forum settings?
Check the Forum Help File (FAQ) or contact the webmaster.
View the archived version of this thread.
Built using Phorum Open Source Software

The MG Experience

www.mgexp.com

MG Motorsports Forum

"so, what’s a reasonable gain? "

Add your reply here, or post your own questions!Members Sign In if you've already registered, orRegister a New AccountRegistration is free and takes less than a minute

Join Our Club

MGExp Menu

—

Adjust Text Size

More to Explore

Add your reply here, or post your own questions!

Members Sign In if you've already registered, or
Register a New Account
Registration is free and takes less than a minute