Curb Weight Correction

[vinman]

After being somewhat stunned by the variety and inaccurate weights listed for all models of classic Austin Minis, I went to two sources to check my recollection.

 

Both my owner's manual and the Haynes Repair Manual list the car as 715kg. Haynes specifies this weight for ALL saloon models regardless of engine. There wouldn't be but about 20lbs difference between different models (Cooper, Cooper S, and non-Cooper). The engine displacement would not affect curb weight in any tangible way as they ALL used the same block - if anything, the smaller displacement cars would be a tiny bit heavier due to less mass being removed when building the block.

 

715kg = 1576.31lbs

 

If you used the numbers in the newest rules to figure p/w ratio, you're pretty far off from an accurate number.

 

The only time you'll ever find a Mini under 1500lbs is a GTLite prepped Mini or perhaps a custom space frame creation.

 

Please look back over these numbers and let me know what you think, as you have my car (Mini Cooper 55hp) incorrectly weighing 1288lbs - that's a full 290lbs LIGHTER than it actually is.

 

Thanks,

Vince Pack

[kbrew8991]

or you can go "shhh nevermind", claim alternate weight reduction method, hack the 300lbs+ off (account for driver weight, gear, etc) and get it to 1200lbs points-free

[JCraven]

yes, but the car is classed as a base at TTG** with the incorrect weight since the lighter cars have gotten heavily penalized. If the weight gets corrected, car will probably drop to TTG and then he can increase the motor size, build it to a 1275 with some enhancements and class out lower than the Mini Cooper S model even with more power. I'll share that upgrade mod in another thread which also works for VWs.

Edited December 10, 2006 by Guest

[subrew]

Hello,

 

IMO, your weight is as off as the NASA weight. And no offense, but an owners manual and Haynes manual shouldn't be the gospel on vehicle weights. Some quick searching online, including many Mini specific tech sites show weights in the 617kg to 670kg range. Specifically, the 55hp model are shown as 636kg on numerous tech sites.

 

Here is one particular site, pulled from factory manuals:

 

http://www.dataphone.se/~fixer/info.htm

 

I've run into similar issues with my Fiat 128. I can find weights anywhere from 1730lbs to 1850lbs, looking in manuals, road tests etc. But...the 1730lbs is from the factory service manual, so that is the one I recommended NASA use.

 

Chris H.

'72 Fiat 128

[vinman]

Chris, that website sure has a lot of information. Some is accurate, and some isn't. For example, there are several models listed with leading drum brakes that actually had disks. The weights are all over the place. I'll be glad to have my car weighed. I don't remember exactly what the result was when I had corner weights done, but it was pretty close to the published 1580ish lbs. The other thing to try and bear in mind here is that I didn't just happen to see one of these cars in IWANNA, and go buy it. I have spent the past 30 years of my life around Minis. The weight of the car didn't fluctuate even 100lbs over the entire 40 years they were in production. I'd be curious to know what tech manual that site was pulled from, as they don't have any relevant info on Minis produced after 1992ish. Those particular Minis (the injected models) especially the last couple of years in production, were some of the most consistently built and reliable Minis built during the entire history of the car. The rub was that they are notoriously difficult to pull more power from - the result of computer controlled multi point fuel injection. That last model mentioned NEVER has produced 90bhp on a dyno. There have been volumes written on this very subject. In fact, John Cooper himself designed an aftermarket mod kit for MPi cars that he claimed to produce 90bhp. Those didn't either. They all dyno'd at roughly 78-82bhp.

 

subrew,

Regarding building my motor to be more powerful than the "S" spec, that's unlikely without incurring WAY too many penalty points. The 1275 S motors had a crank made of a different alloy than the standard 1275 (and smaller) cranks. It was both lighter weight and exhibited less flex at high rpm. It was also equipped with an additional cap and bearing (a center main) to add to the overall ability the engine had to rev higher than the standard spec motors. Additionally, with a different cam profile, slightly different lifting height (1.38:1 vs 1.3:1), a slightly worked head, and a higher compression ratio, well, you can see that the standard A Series motor is a very different animal than the "S" spec motor. The bodies were IDENTICAL in every way to every other Mini being produced. There was no tangible weight difference.

 

Besides, other than a few standard bolt-on engine mods, I've used a bunch of points on my suspension. If memory serves correctly, I have 25-27 points total. Only about 6 of those are related to engine mods. I should also state that my primary interest in NASA is NASA-X - not TT. I've done track days in my car, and frankly it's just too hard on a 32 year old car that I can't buy parts for on every corner. I know these aren't going to be the end all/be all rules for NASA-X, but from what I hear, is the basic skeleton from which they will be built. Essentially, with the mods already done to my car under the previous rules, I was still in G with a few points left to play with. Now, I'm either WAY up in F or possibly even in E without turning a wrench or buying a part. Trust me, my car was just made completely obsolete if these rules remain as they are now.

 

Vince

[vinman]

Oh, jcraven, I missed an obvious point you made that should be clarified. The Mini Cooper (55hp) IS a 1275. Not all 1275 motors were created equal, as referenced in my above comments.

 

It should be interesting to note that the 1071S motor listed in one of the models is actually BY FAR the most highly sought after motor ever made for the Mini. That motor did everything right. It's rarity and potential for power/torque has even made the (until recently) throw away 998 motors shoot up in value because that's how the 1071 capacity was derived - boring out a 998 block and putting in some very special components. Due to the available piston sizes and rod lengths, there is no mathematic way to build a 1275 from any block other than the original 1275 block. You CAN take a 998 motor, offset bore, and actually come out with a 1420. You can turn a 1275 into a 1435, but the walls are literally paper thin, and only a few have been built. The most common overbore for the 1275 is a 1380. That's a nice little torque monster, but would be WAY too costly in mod points for competitive use. The next size up for me is, fortunately, within the tolerance spelled out here - 18 over (or 1293cc).

[JCraven]

Yes, I actually know very little about the Minis except I have wanted one for years. I have many books and shop manuals that I bought at a garage sale and I need to read them one day. I've seen some modified Minis driven on the track and they were amazingly quick. The Minis are also superb racecars which have been won in Production racing. Saying all that, I think that the Minis in the new rules are classed higher than ideal since they are lightweight so penalized more than the VWs.

 

Let me use the VW example since I am more familiar with it. This example will attempt to build a 150+hp VW PT racecar. I will start with 2 cars, VW Rabbit 1.7 and VW Rabbit 1.8

 

TTG Rabbit 1.7

- bore motor to 1.8 which increases displacement +4

- non-oem cam +6

- port/polish/big valves in head +6

- non-oem intake +1

- non-oem carbs +2

- header +2

- remove cat +1

- non-oem exhaust +2

- increase tire size to 205 +4

- reduce weight 94lbs +6

---------------------------------

Total Points 34 points - new class - TTF

 

TTF Rabbit 1.8

- displacement is 1.8 +0

- non-oem cam +6

- port/polish/big valves in head +6

- non-oem intake +1

- non-oem carbs +2

- header +2

- remove cat +1

- non-oem exhaust +2

- 205 tire size +0

------------------------------------

Total Points 20 points - new class - TTE

 

We have 2 cars which are identical in power, aerodynamics, tires, car geometry, weight etc. One is in TTF and the other is in TTE.

 

Similarly, one can start with the VW Rabbit 1.6 in TTH**

 

 

 

Oh, jcraven, I missed an obvious point you made that should be clarified. The Mini Cooper (55hp) IS a 1275. Not all 1275 motors were created equal, as referenced in my above comments.

 

It should be interesting to note that the 1071S motor listed in one of the models is actually BY FAR the most highly sought after motor ever made for the Mini. That motor did everything right. It's rarity and potential for power/torque has even made the (until recently) throw away 998 motors shoot up in value because that's how the 1071 capacity was derived - boring out a 998 block and putting in some very special components. Due to the available piston sizes and rod lengths, there is no mathematic way to build a 1275 from any block other than the original 1275 block. You CAN take a 998 motor, offset bore, and actually come out with a 1420. You can turn a 1275 into a 1435, but the walls are literally paper thin, and only a few have been built. The most common overbore for the 1275 is a 1380. That's a nice little torque monster, but would be WAY too costly in mod points for competitive use. The next size up for me is, fortunately, within the tolerance spelled out here - 18 over (or 1293cc).

[vinman]

jcraven, I see what you're getting at. Unfortunately, even though the A series blocks all start from the same blank, you can't make a silk purse out of a sow's ear in this case. The assumption is incorrectly made in this case that displacement (along with a little misinformation) means the car is faster. What is not being taken into account is the ridiculous number of final drive variations and gear ratios the Mini was delivered with over the course of its production history. A good example is the 1071S mentioned earlier. That motor, with its factory spec, shouldn't really be a faster engine than the 1275S, but it is. Call it a Harry Potter spell, or what have you, it simply produces more power - or I guess more accurately, a more usable power curve.

 

Another thing I noticed in your example is you have quite an accumulation of points and yet haven't touched the suspension. Just out of curiosity, did the factory 1.6, 1.7, and 1.8 liter cars come from the factory with the same suspensions, or were there incremental improvements? I just wonder if that may account for the 1.8 being in a higher base class.

 

I guess another thing that puzzles me a little is this (directed at Greg); are there other Minis running NASA-TT or NASA-X around the country? I wonder what prompted all the scrutiny on this paricular car, and why the drastic class shifting. It appears that a few assumptions were made when this car came up for review, and several appear to be incorrect. Just curious as this is going to basically put me out of any sort of viable competition, and having built my car specifically within NASAs framework for autocross, seems a little extreme. I'm not trying to sound critical here, sorry if it's coming off that way. I'm having to stave off a panic attack as I've just watched the car I love driving forced out of racing competitively when it was so carefully built to remain in class G (it started in H).

 

Vince

[Tom A]

Another thing I noticed in your example is you have quite an accumulation of points and yet haven't touched the suspension. Just out of curiosity, did the factory 1.6, 1.7, and 1.8 liter cars come from the factory with the same suspensions, or were there incremental improvements? I just wonder if that may account for the 1.8 being in a higher base class.

I am guessing he didn't touch the suspension simply beacuse this is just an example. Even so, adding coliovers, and sway bars to the above wouldn't change the outcome.

 

The only difference between the GTI and the base rabbit I can think of is sway bars and brakes. The GTI has pencil-thin sways front and rear, and uses vented rotors in front, instead of the solid disks of the base rabbit. This would end up as a free upgrade to the base rabbit though, as the calipers are the same, all you need to do is replace the rotors, which are no points now. Both cars have drums in back.

 

On Edit: I forgot the GTI also comes with a decent relatively close ratio 5 speed tranny.

[JCraven]

On Edit: I forgot the GTI also comes with a decent relatively close ratio 5 speed tranny.

 

Yes, transmission is different but if that is an issue, one can purchase a full on race straight cut gear close ratio Quaife type box and add +3 points. This transmission will be more efficient and transfer more power to the ground and also making that cool gear whine of the pro race cars.

 

jcraven, I see what you're getting at. Unfortunately, even though the A series blocks all start from the same blank, you can't make a silk purse out of a sow's ear in this case. The assumption is incorrectly made in this case that displacement (along with a little misinformation) means the car is faster.

 

How big is your pocket book? This is racing, and it isn't entirely clear yet what we can do to fix manufacturer shortcomings and improve reliability and performance. For example, modifying the head is +6 . Any head mod is +6, so one can change the combustion chambers by changing their size, welding them up and machining if beneficial. Install bigger valves, move the ports. It might even be possible to change the siamese ports and even change them to cross flow with 4 full ports. I'm pretty sure this is a legal area since you will be starting with the OEM head, even if it looks completely different once the work is complete. Of course, you will need a custom intake to take advantage of the new intake port locations which is only a +1. The Sow's Ears in PT have the most opportunity for performance improvement.

 

You mentioned the lower end issues where I am unclear what is legal to modify. Pistons can be forged, rods replaced. Crank might be legal to replace with a custom forging with some extra stroke. Block might be able to be fixed too.

[vinman]

Pocket book. Definitely opens up a few interesting options with an adequate budget. You mentioned the exotic porting/intakes. There are a few companies building 8 port intake systems (Arden is probably the most famous). There are also 16 valve conversions available. The former is a $5000 upgrade while the latter runs $12-15,000. There's also forced intake systems of all varieties and even a Honda motor swap option. The thing is, I want to keep my car competitive with like vehicles. I love going to an event and racing guys in Midgets and Sprites and Spitfires. With the new classing, I'll be racing Miatas and cars which the classic Mini (even modified like mine) can't successfully race against.

 

Again, my concerns lie totally in the autocross arena, so maybe the weight issue will be corrected and the ax rules will be different enough that the classic Mini won't get phased out - not that there are a bunch of them running around to begin with. Either way, I'm looking forward to an official response so I can figure out which direction to go in...

[JCraven]

Vinman, I just reviewed the rules and if those manufacturers start with the correct oem head and don't increase the number of cams, then they are perfectly legal to install and use on your car.

 

Hmmm, what will a 1275 16V Mini motor put out with dual sidedraft carbs?

 

Sounds like fun!

[vinman]

Vinman, I just reviewed the rules and if those manufacturers start with the correct oem head and don't increase the number of cams, then they are perfectly legal to install and use on your car.

 

Hmmm, what will a 1275 16V Mini motor put out with dual sidedraft carbs?

 

Sounds like fun!

 

If set up properly, about 130hp

 

The problem with the Mini is that really after you top about 100hp, you start having enough traction issues. My brother did Honda VTec conversions for a while with Minis, and I've driven all variations - up a 230hp R series tuned motor. It's fun in a white knuckle, ear to ear grin sort of way, but the power isn't usable in any practical way - especially in autocross. You can make the wheels spin at will, at any rpm, in the first three gears with a LSD fitted and R compound tires.

 

Guess I'm gonna have to give up on the Mini and get an Elise

Seriously, where's Greg? I was hoping to at least get a preliminary response by now...

 

Vince

[Greg G.]

jcraven, I see what you're getting at. Unfortunately, even though the A series blocks all start from the same blank, you can't make a silk purse out of a sow's ear in this case. The assumption is incorrectly made in this case that displacement (along with a little misinformation) means the car is faster. What is not being taken into account is the ridiculous number of final drive variations and gear ratios the Mini was delivered with over the course of its production history. A good example is the 1071S mentioned earlier. That motor, with its factory spec, shouldn't really be a faster engine than the 1275S, but it is. Call it a Harry Potter spell, or what have you, it simply produces more power - or I guess more accurately, a more usable power curve.

 

Another thing I noticed in your example is you have quite an accumulation of points and yet haven't touched the suspension. Just out of curiosity, did the factory 1.6, 1.7, and 1.8 liter cars come from the factory with the same suspensions, or were there incremental improvements? I just wonder if that may account for the 1.8 being in a higher base class.

 

I guess another thing that puzzles me a little is this (directed at Greg); are there other Minis running NASA-TT or NASA-X around the country? I wonder what prompted all the scrutiny on this paricular car, and why the drastic class shifting. It appears that a few assumptions were made when this car came up for review, and several appear to be incorrect. Just curious as this is going to basically put me out of any sort of viable competition, and having built my car specifically within NASAs framework for autocross, seems a little extreme. I'm not trying to sound critical here, sorry if it's coming off that way. I'm having to stave off a panic attack as I've just watched the car I love driving forced out of racing competitively when it was so carefully built to remain in class G (it started in H).

 

Vince

Vince, we aren't even competing in G--Autocross may be different, though. There was no specific scrutiny of the Minis. In fact, it took less of a hit than would have been dictated by their very light weight. All classing was done objectively. So, if your lightweight cars moved up, then so did Joe's.

[Greg G.]

Nice Joe. Here you guys are complaining about a car moving up 2-3 asterix levels, and you have already figured out ways to get the car up to be very competitive in a higher level class. I wish that everyone would quit worrying, and start thinking--Joe's apparently at work already. Now, what if Joe had a Mini, and the Mini's were still classed in H, and you did those mods and had 100-130 hp? Gee, that would be fair to have a car with a 12:1 wt/hp ratio, weighing only 1500 pounds in TTG or TTF.

[vinman]

Greg, back to the original post in a thread gone somewhat askew. The curb weight NASA has listed for the Austin Mini (basically all models) is incorrect. The particular model that I drive you have listed at 290lbs lighter than it actually is. That's almost 20% off. At this weight, that is a significant error. The main point was to make you aware of this fact and hopefully get it changed to the factory spec.

 

Now, you made a comment that begs an explanation. "we aren't even competing in G" - in TT? Just out of curiosity, why? I seriously hope there isn't a consideration to remove G and H from NASA-X...

[vinman]

Greg, just saw your post regarding emailing curb weight discrepencies. Email sent.

Vince

[Greg G.]

Greg, back to the original post in a thread gone somewhat askew. The curb weight NASA has listed for the Austin Mini (basically all models) is incorrect. The particular model that I drive you have listed at 290lbs lighter than it actually is. That's almost 20% off. At this weight, that is a significant error. The main point was to make you aware of this fact and hopefully get it changed to the factory spec.

 

Now, you made a comment that begs an explanation. "we aren't even competing in G" - in TT? Just out of curiosity, why? I seriously hope there isn't a consideration to remove G and H from NASA-X...

 

If there are enough cars, then there will be no reason to remove them from NASA-X. We saw about 6 TTG cars across the country last year, and maybe 2 PTG cars that were legal. The G cars are pretty slow on the road course, and closing speeds become a bigger safety issue with them out there.

[vinman]

that makes sense in the context of TT. In fact Ken has mentioned his concern regarding my light, slow car in TT in the context of safety.

 

Autocross, however...

We have about six guys driving consistently in G in our club, alone.

 

What do you think about the weight discrepancy?

 

Vince

[Greg G.]

It will probably be changed, but I need more time to check on it. I'm still working on "larger issues" that effect everyone.

[vinman]

Thanks Greg. Just wanted to make sure it was being considered for review.

Vince