The 40th Mitty at Road Atlanta

VW underneath a classic Italian body design.

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The 40th Mitty at Road Atlanta

Post by FJCamper » Mon May 01, 2017 4:13 pm

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Above: We love our Ghias, and like Walter himself in the classic 1939 short story The Secret Life of Walter Mitty, daydream about really racing. We took our Ghia to the 40th Mitty at Road Atlanta, where we were tossed in with what the elite call the "real" racers. This is what happened.

40th Mitty at Road Atlanta

20Apr17; Thr. We arrive at the track and locate a place to paddock the Ghia down in the swamp, an isolated glade in the trees flanked by a stream, off the hot paddock asphalt. Great place to camp if you can tolerate the wildlife.

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Above: Road Atlanta is a serious track. It opened in 1969, and I began racing there in 1974. It's most infamous feature is the long, fast, steep, downhill run from under the bridge. There are concrete walls on both sides at the bottom. Barret could take it flat out, without lifting.

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21Apr17; Friday. The Historic Sportscar Racing 40th Mitty at Road Atlanta is officially underway. The day is clear and warm, with a projected high of 80F+. We have the Ghia at Tech at 0730 hrs, get our logbook updated. We're scheduled to be on track by 0915 hrs for Group 2 practice and qualifying. We are VP5 (Vintage Production class 5), the small-engine crowd. Our Ghia has a stock 85.5 bore but a 74mm stroke to show solidarity with the 356's, our venerable cousins. At just 9:1 compression, our engine is not highly stressed, and is not going to be competitive with the 356's in this event.

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Above: Barret wipes the dew off the Ghia. We differentiate between the LeMons races with its Mad Max cars we run and the HSR series, as the HSR cars are the ones you have to wax.

Our Weber 40 IDF (Chinese copies) configuration is:

36mm venturis
135 main jets
.50 idles
200 airs
F11 emulsions

By the last race, the mains will be 155's.

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Above: Group 2 bunches up at Turn 1. In that melee it is the golden age of sports cars again, cars with curves, small but fierce engines, and carbs you can tinker with. This is where the Ghia belongs.

At 0800, Group 3, which has all or most of the 356's and 2-litre 911's and a smattering of Datsun 510's among other famous marques launches its qualifying session. Jamie and I walk up from the swamp to Turn 1, which is the uphill run off the front straight.

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Above: Datsun 510 at speed on Saturday.

One of the 510's suffers a stuck throttle coming down the straight, floors the brakes, and without ever attempting to turn, slides through the runoff gravel and hits the tire wall head-on at about 60 to 70 MPH. Jamie and I are about twenty feet away from the crash and I feel the impact in the soles of my feet. The driver was carried out on a stretcher, a neck support inflated under his chin. What a way to start the day.

Our VP5 competition is all British:

1959 MGA hardtop coupe 1676cc #42
1959 Austin Healey Sebring Sprite 1275cc #2
1966 MG Midget 1275cc #91
1968 Triumph Spitfire 1331cc #141

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The British racing green (BRG) MGA coupe posts the fastest VP5 qualifying time of 2:02.6, then us at 2:04.2, with the MG Midget following us at 2.21.3. The (also-BRG) Spitfire was towed in and received no time.

The Ghia's oil temp pegged at or near 300F, and our Falken H-rated street radials began losing grip toward the end of the session as they heated up. A plug check on the BP8ES (cold) NGK's show we are running danger-zone lean. Barret feels that our 24-26 tire pressures are too high and drops them to 22-24. I don't agree, but let it go for testing.

We rejet the mains to 140's and refit .55 idles for our .50's.

Our new crankcase ventilation system is working. We learned at Barber during our test and tune day that we needed more breathing capacity, so we designed our own high-temp plastic filter-ventilated 2-gallon tank, fed by a 1-inch ID vent hose off the alternator stand oil filler cap location.

On our first session we got a touch of smoke from the new system and discovered after the main vent line just needed a hose clamp, as the push-on barb system allowed seepage once the hose was hot.

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We are back out for a second qualifying at 1330 hrs. Barret experiences the same circumstances, 290F oil temp, and slippery handling as the tires heat up. But we are a little faster, posting a 2.03.4. The rejetting helped.

The Sebring Sprite also got faster, with a 1:59.0, the MGA turned 2:01.0, and the MG Midget posted behind us at 2:03.3. The Spitfire did not run.

The BP8ES NGK's are still bone white. We go up to 145 main jets.

We check the oil level in our 3-gallon dry sump tank. We're down almost a gallon due to the losses at Barber, so Jamie and Barret fill it up with our high-ZDDP Shell Rotella 10w40. I warn they may have left too little head space, but the square dry sump tank on the Blitzwagen that Jamie is familiar with reacts differently to tank volume and head space issues, and Barret isn't familiar with dry sump peculiarities at all.

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Above; Our oil cooling problems were two fold. Lean jetting, and even with a fan, poor airflow over the cooler itself, which is mounted flat in the original luggage area behind the jump seat area, blowing down and out of the body. We discover at speed we develop too much high pressure under the body, countering what the fan can do. At a certain point, Barret could feel the cabin fill with heat as the air flow reversed itself.

The upshot of this is in our next session the Ghia burps out almost a gallon once the oil is hot and expanding. The new tank catches it all.

22Apr17; Our 3rd qualifying session, and surprises are in order. We go out at 0945 hrs. The Spitfire turns an amazing 1:49, running up with the fast 356's and 6-cyl Corvair's. And the red Sebring Sprite also dropped his lap time to 1.57.

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Barret and the 145 main jets won the Ghia our best time yet, 2:01. He was able to stay ahead of the MGA the entire session; it's best time also a 2:01.

We are stricken by the 1:49 Spitfire times. He apparently has one very powerful 1331cc engine. After all, there are decades of racing development for the British engines. And we are in a social crowd that can afford the best. We jet up to 150 mains.

At 1615 hrs that afternoon we have our first race. Barret drives hard, but can't do more than 2:01, identical to his previous qualifying time. But this is racing, and not a competition for lap times.

The green MGA is ahead going down the hill under the bridge and takes the flag. Barret is right behind the red MG Midget, trying to pull out to the right to pass the Midget and take second but he got blocked on his right by the Spitfire.

LAST LAP VIDEO https://www.youtube.com/watch?v=FWImxKl795s

The MGA didn't get any faster, posting a best-lap of 2:01, same as Barret's time.

We have one more race. We jet up to 155 mains.

23Apr17; Sunday. Last day of the Mitty. We wake to steady rain, cool 60F ambient temp, and dark, churning clouds. Above us, the Valkyries are loose, ready to snatch souls for Valhalla.

The rain is so hard the race organizers consider calling off the event. We see teams packing up and towing out. Barret wipes RainX onto the Ghia's windshield outside, and anti-fog on the inside. We are hardcore and have no windshield wipers.

The echoing loudspeakers finally tell us the races will continue. We see only one other VR5 car has stayed, the fast Spitfire. In a race, especially in the rain, anything can happen. And if we're going to get beat, we're going down revving.

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At 1400 hrs the green flag dropped and a reduced field of Group 2 & 3 diehards and desperadoes floored it in the rain, tire-spray off the sheets of water on the road blinding the drivers. In a normal start, the sheer force of all cars at wide open throttle can make your eyes vibrate. But in this rain, the howls are irregular and uncertain as the drivers are on and off their throttles, avoiding collisions.

Some of the cars skate and dart as they aquaplane. Barret maneuvers to stay out of the packs that form as drivers slow down. That includes the Spitfire. In its open-car configuration, the driver is as much assaulted by water as a motorcyclist driving through a car wash. You wonder how he can breath, much less see. He slows down.

On the long back straight, Barret takes it to the limit. The 155 main jets let the Ghia reach 6700 RPM in 4th. With our 3.88 r&p and 24-inch diameter tires, we're close to 130 MPH. In a coupe with no wipers, that is fast.

With the 155 main jets and the rain, our oil temp stabilizes at 240F.

The laps tick off, each minute an eternity. Disaster haunts every wet corner. Road Atlanta's several normally exciting blind corners become heart-stopping roll of the dice, your car or your life affairs.

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Above: One fast Spitfire. Credit where credit is due.

The flying Ghia is gaining on the carefully driven Spitfire, but not fast enough. There are too few laps. On a dry track, the Spitfire with its 12 to 14-second best lap speed advantage could lap us, but in this torrent the best it can do is just stay far enough ahead as to be out of sight.

On the last lap, Barret saw his tach needle start to jump, and his power went away. It felt like he'd lost two cylinders. He mentally blamed the recently installed EMPI Accu-Fire mag-trigger ignition module.

So it was we finished an official second.

We get to do it all again in a few weeks, 20-21 May at the Barber Historics on our hometown track.

FJC

eericson
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Re: The 40th Mitty at Road Atlanta

Post by eericson » Fri May 05, 2017 8:26 pm

Great report, great pics. I think I've seen that Spitty at the PVGP and/or Lime Rock Historics.

Still running the centermount fan shroud? And if so, how did the head temps look with that?

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Re: The 40th Mitty at Road Atlanta

Post by FJCamper » Sat May 06, 2017 12:25 am

Hi Eericson,

This is a long, roundabout way to answer your question about how the center-mount blower housing insert performed.

We just fixed a cooling problem, relocating our coil cooler up front behind our airdam.

We were initially way too lean and running too hot and losing power just as our tires were fading out on us. The proper jetting fixed part of the overheating, and the proper oil cooling should take care of the rest. To be specific on the oil cooling, we had a 96-plate Mesa cooler (with 9-inch fan) mounted in the luggage compartment area, blowing down and out through a hole over the transaxle.

The luggage compartment area is boxed in and vented, forming a big cold air plenum which is our air source for the center-mount blower housing. We have a direct duct from the blower housing into the luggage compartment plenum.

The fan is moving 1600 CFM out of the plenum to the engine, and the oil cooling fan has to blow downwards against the higher pressure trapped air under the body. There was actually coming a moment late in each race where our driver said he could feel the cabin fill with heat. The hot air from the oil cooler was no longer blowing downward, but sideways with enough force to overpower a vent and escape into the cabin.

So, to come back to the performance of the blower housing insert, we feel it gave us enough safety margin to keep racing under compound cooling errors. At the Barber Historics we'll be better able to test without lean carbs and 270f to 300f oil temps.

FJC

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Re: The 40th Mitty at Road Atlanta

Post by Piledriver » Sat May 06, 2017 4:46 am

914s have the same sort of "updraft" pressure distribution issue at speed... I once tried to figure out a fan setup that sucked up, rather than blows down, and perhaps takes cool air in from intakes in the rockers. It was basically a horizontal T1 fan, big end up. IIRC it turned the wrong way so I gave up. A late Corvair fan would not care tho...

Larry Widmer once raced MGs or such in the SCCA and was making something north of 300 HP before the whole class was basically kickbanned. (think unlimited head and chamber mods)
I'm sure some of the tricks survived. (some great racing stories on his site)
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

VW&MGman
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Re: The 40th Mitty at Road Atlanta

Post by VW&MGman » Sat May 06, 2017 8:55 am

Hey FJC,

As usual great write up. It's always a pleasure to read your posts.

With your oil temps up around 300F, what type of oil pressure were you getting?

In regards to oil temps, take a look at this interesting article from Hot Rod Magazine, between 240F - 260F is fine.

http://www.hotrod.com/articles/engine-oil-temperature/


As for your tires, are you running the Falken 615's? Those are suppose to be a pretty good street/track tire.

Having raced against some of those MGs, and Spitfires, engine sizes are very deceptive. (The size is not always what they say they are :wink: ) Those cars are very light and don't have much wind resistance. Something that is kind of against us VW racers.

eericson
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Re: The 40th Mitty at Road Atlanta

Post by eericson » Sat May 06, 2017 10:27 am

Thanks for the update, Frank. You're living the dream.

VW&MGman: that hot oil piece is real food for thought in the air-cooled world, where a lot of guys shoot for running oil temps under 200 degrees F. As you probably know, the Gene Berg dispstick-warning device used to blink the oil light at a little over 220, and light it solid-on at 230. In my car, temps in the 220 range made for some very low pressure readings—as when we ran her, loaded-up, https://bridgetmgtd.wordpress.com/2013/ ... ttsburgh/ over the Alleganys to Pittsburgh in late July. Didn't seem to do the engine any harm though.

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Re: The 40th Mitty at Road Atlanta

Post by VW&MGman » Sat May 06, 2017 11:19 am

Hi Eericson,

I agree that us VW guys are paranoid of oil temps. At 260F and above you have ensure that the oil could take that type of temperature. In my vintage race Beetle and my MGA I run Valvoline 20w50 VR1, as it has the proper amount of zinc and could take oil temps to 285F. This is a mineral based oil, but in the synthetic version, the oil could take a lot more heat. I change my oil after every 2 race weekends. The max temp I've seen with the VW was 260F and the MGA 220F in a 20 minute sprint race.

I was speaking with a Formula Vee (FV) engine builder a while back, and they often see the oil temps in the 250F range. JBBugs, who races in the Chumpcar series with a Beetle mentioned he runs his Beetle at 240F - 250F for 20+ hour races without any harm to the engine.

https://www.thesamba.com/vw/forum/viewt ... c&start=40

The key is to ensure that there is adequate oil pressure. I shoot for 10 psi/1000 rpm. When coming in from the track after a session, I try to keep the revs up ensure good idle oil pressure. I don't want oil pressure light to come on. :D

Just a side note, I take my oil temp from the sump of the engines. Oil temps vary from different locations of the engine.

Regards

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Re: The 40th Mitty at Road Atlanta

Post by FJCamper » Sat May 06, 2017 11:53 am

Gentlemen,

Barret doesn't watch the instruments much in a race, even the tach, his excuses usually being "don't wanna blink, miss something, crash and burn."

He noticed no oil warning light flashes. We have two trailer side-marker lights exact center of the dash, red for oil and yellow for fan belt. And while we showed 300F at one point on the oil temp gauge (coming off the track to the paddock) we are taking our temp reading from the base of the oil pressure relief valve, and thereby mostly reading case temp ... and we have a dense aluminum heat sink "race case."

I'm rigging up a dry sump tank temp gauge to the Ghia for the Barber Historics.

I am very aware of the disproportionate amount of power the Brit engines can develop relative to their engine size. The 1959 MGA that won our first race has at least 140 hp. The Spit has something near that, but is lighter. Their engines are over stressed and die young, but they have power. A friend of mine used to race a Spridget that was so highly tuned you had to start it on one set of plugs and race it on another. He was an SVRA champion.

To be sporting, I'm really running an 85.5x74 engine, 9:1, and yes, we are on 185x15 Falken H-rated street radials. Good tires, but race tires are better.

I can't believe my sterile, unmarked ChiCom Weber 40 IDF's are performing like they are. 155 mains, and 36mm venturis for 1699cc.

To close, about the only controversial thing we're taking to Barber is our new nose-mounted oil cooler. We're using a smallish (wide but not tall) 24-plate Mesa, fed by 5/8-inch ID (-10AN) hose. I believe most of the cooling in a nose-mounted system is created by the trip to the front of the car and back. I had an old-school six-pass on my 1975-76 IMSA Bug right under the front bumper and had to tape it off sometimes.

The 24-plate MESA is just there to say we have a cooler.

FJC

Bruce.m
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The 40th Mitty at Road Atlanta

Post by Bruce.m » Fri May 12, 2017 5:33 pm

Saw this posted in insta by Goodwood Revival.

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eericson
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Re: The 40th Mitty at Road Atlanta

Post by eericson » Sun May 14, 2017 8:50 pm

HA! Nice.

r@lf
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Re: The 40th Mitty at Road Atlanta

Post by r@lf » Mon May 22, 2017 4:54 pm

drum roll..... :) update for BarberHistorics... i cant wait!

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