THSCC Forums

Wait, why are the Euro motors "rare compared to production motors" when they are production motors?

For 3.2L engines something like 22,000 S52 USA motors were built while about 15,000 Euro S50B32 motors were built.

See the BMW Mregistry FAQ for more detail. Here's the link to the section on 3.2L M3:
http://www.bmwmregistry.com/model_faq.php?id=15

Perhaps you're just meaning "rare" here in the US which of course is true.

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Current stable:
2019 BMW M2 Competition slicktop 6MT
2011 BMW M3 sedan slicktop 6MT
2007 BMW 328i wagon (slushbox for now)
1975 CanAm 125MX2

Uh, you sure about those numbers? You mean they had 12.5 gallon dump cans and two dudes big enough to haul them around and got it done in under a minute? It almost had to be a smaller cell and less in each can for it to happen in under a minute.

We have a Grand Am fuel rig. It's a big tank mounted with the top at 6' high on a big stand. It has a 2" hose (I think...either way it goes to the same size dry break that the NASCAR dump can would use and the hose is at least that big) coming off of it and goes straight into a dry break in the back of the car. It takes us about 50 seconds to fill 25 gallons. It can be improved with a two hose system so that the vent is bigger, but I'm skeptical as to how much. But a dump can system should have the same vent on their cell that we have now, which makes it hard to go any faster. Plus those dump cans won't have the gravity advantage that our tank will.

But we're quibbling over a few seconds here. And it's not JUST about fast driver changes. It's about being able to get out safely and quickly. I prefer something with a bigger door for that. *shrug* Yeah, I still drive my SM and probably will for a while, but I don't like that part. Not one bit. So I don't want to do it all over, particularly if it's going to be annoying for the driver changes.

But yeah, 25 gallons is the max under the rules. You're also only allowed to have 25 gallons of fuel in the pits at any one time, too. So every time you fuel the car you have to use something to go OUT of the pits to another fuel source and bring fuel INTO the pits to refill whatever fueling rig you use.

Note that many classes don't allow a dry break, though, such as Spec Miata. With those you still have to use a funnel.

As for fuel mileage, I'm just quoting numbers I've found people have posted from their cars. I can't imagine short shifting a little getting you 2-3 more MPG when we're talking numbers this low already. As for a 911, well, I'm just not that interested in paying for a Porsche. If I were, I'd build a Cayman instead. Better balance but the same as a 911 otherwise. No way I'm doing a Lotus anything. I barely fit a stock Elise with no cage. There's no way with get the big fella in one without a shoe-horn and some butter.


--Donnie

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Nascar Sprint Cup fuel cells are just under 18 gallons. The dump cans are 12 gallons. A pit stop is maybe about 15 seconds assuming 4 tires. That means a can and a half including changing cans in less than 15 seconds. Of course, the cans weigh about 80 lbs.

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Dick Rasmussen

FS 50 2018 Mustang GT

I am pretty sure they didn't put a full 25 gallons in the cell. I know with the ITA car we have a 23 gallon cell but we do fuel stops every 2 hours 20 minutes to be on the safe side and always have about 2 gallons left in the cell after running under green in dry conditions. We just use two 12 gallon dump cans no dry break setup, just a hose off the end that goes into the gutted filler nozzle. We do have a large vent out the top of the cell though. Either way I lug the cans around (I am the lucky guy who plays fuel man for the team) and we dump 21-22 gallons out of those in about 90 seconds.

Either way you are correct we are quibbling over a few seconds here. I don't see picking up many MPG's by short shifting a V8. I can agree that a 4 or 6 cylinder is the way to go for what you are looking for though.

Or you could buy an ex-TDI cup car and run it in ITE on better tires. Think of the mileage you would get with one of them.

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2010 Honda Fit Sport
Couple of bicycles

yeah but that's fwd. what you need is a rwd diesel car: http://raleigh.craigslist.org/cto/1451509465.html

Holy crud. I never knew there was a Chevette diesel. Now you can wear your mullet and be eco-friendly at the same time.


--Donnie

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Somebody's gonna buy that thing and run it on WVO.

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Karl S.
2014 Baby, 2014 House, 2013 Ford Focus ST, 2013 BMW 328i, 1994 Mercedes E320
(Insert passive aggressive signature line here)

On the 4-6-8 mileage question: Under racing conditions is the cylinder count really the issue versus the size/weight/drag of the car and the total amount of energy it takes to move the car around the track? Is a race tuned 4 or 6 significantly more efficient than a more mildly tuned 8 under racing conditions assuming fuel injection which shuts off flow on decel?

Is a Vette with a mild version of today's very fuel efficient V-8's really going to need more energy to push around the track than a BMW sedan with a highly tuned 6?

This assumes the 8's aren't required to carry more weight since I'm assuming that the tire/wheels sizes/weights would be similar and the Vette might actually be lighter and have less drag than a sedan based car unless the rules say otherwise.

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Dick Rasmussen

FS 50 2018 Mustang GT

modern v-8s can return good highway fuel efficiency because they turn very low revs in top gear. wind them out and kiss economy goodbye. this is true even on smaller engines - my nsx would get high 20s on the open road but only 6-7 mpg on the track thanks to an 8000 rpm redline. pumping and frictional losses are significant as the revs climb, short shifting a big v8 might yield better mileage than most people think. also note that at full throttle many fuel injection systems go into open-loop mode and run full rich to prevent detonation, it'd be interesting to see if a throttle stop at say 80% improves track mileage without a giant power sacrifice.

I have a request for E36 owners still following this. Can you measure the height of your car for me? And also post what wheel/tire package you're running as well as suspension mods (if any). Just trying to make absolutely sure one of these will fit in my trailer. I have 53" of height on the upper shelf. An E46 will not fit.


--Donnie

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52.5"
255/40/17
AST SA Coilovers

Note my car is not aggressively lowered. Probably 1-1.5"

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Mike Whitney
whit32@gmail.com, 919-454-5445
V10, V8, V8t, I6, I6, V6, F4t, I4, I4, I4, I4, I2, 1, 1

52.25"

235/40/17

TC Kline DA Coilovers

corner weighted, no idea on how much drop over stock height

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BenchWarmer Motorsports

another one of those damn LeMons heads

just another Chump

we are an Autocross Club Dammit............

Thanks. I had measured a random E36 race car at VIR a few days ago and it looked like about 52", but it was parked on the sand gravel and I just wanted to be sure there was no issue here.


--Donnie

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this will fit, likely turn 2:09 as well

A CSR is a sports racer and would not be legal for the 13.


--Donnie

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