If you have a view and would like it heard, you should email AORCom at: offroad@cams.com.au

936 wrote:

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How do we voice our view?  

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Good question.  Cant say Ive ever voiced my view, but I have viewed my voice.  Early morning after too many bourbons and a kebab.

Im here to tell you that the noise BARRVERREFEBVDSGDE(*##*($#@&*@ has carrots in it.

We're laughing on the inside.

If we are going to talk numbers how about we look at the classes which seem to be left out of this topic. This is class 4,5,7,8. At Hyden they had a combined entry of 33 competitors giving them 50% of the total field. Finke they had 24 combind entries giving them well over 25% of the field. Race days wood look fairly sad without them. So lets not forget about them. 

Wrangler wrote:

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If we are going to talk numbers how about we look at the classes which seem to be left out of this topic. ..... Race days wood look fairly sad without them. So lets not forget about them. 

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Fair enough, its just that Ive got a buggy in my shed, so its what Im most interested in discussing.  Whats your suggestion for tin tops?

There as been more comments/suggestions bouncing about in the shed for buggies, namely this one:

State (at least in NSW) - leave it as is.
National - combine 1 & 9 then split by:

Pro: up to 6Ltr NA or > 1600cc Forced
Pro Lite: up to 4Ltr NA, up to 1600cc Forced
Remaining classes stay as they are.

Not one I personally agree with (I still prefer the original proposal) but a couple of people have discussed it.  I do like the idea of turbo 1600 in with NA 4Ltr though, and the SR20's etc into pro class. More food for thought. 

Also, most important... are we going to rename classes?  Personally I think challenger class sounds like its a division for special people.  Any comments there Azteck? 

 

Wolf wrote:

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Wolf wrote:  Hey OBR, were Hyden numbers similar?

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Hyden---

17 class 1s  27%

9 class 2s   14%

13 class 4s  20%

9 class 5s  14%

4 class 7s   6%

6 class 8s   9%

5 class 9s    8%

2% lost in decimal points.

 

 

 

Regarding turbos.......

Have a look at this formula. There is no way our x 1.7 rule is fair.

run some numbers through the formula and you can see the amount of cfm of air required for both types of engine. CFM is a direct proportion to the power that is to be made considering that O2 is the volatile gas we are trying to get to the cylinder to burn carbon in the fuel......
 
From the examples below you can see that at 15 psi a turbed 3L engine induces more air than a 5.7L engine(therefore a 3.3 induces more than a 6l, therefore a 3.5 is going to induce more again) . Don't let the carb fool you....it is just a way of quantifying the cfm and the same runs over to a throttle bodied engine. So much for the 1.7 equivalence.........
 
 
 
 

 Formula == Equivalent capacity of turboed or supercharged engine when comparing it to a naturally aspirated engine.




To solve the CFM air flow requirements of an engine for carburettor sizing.
OR
How big is an induction boosted engine when compared to a normally aspirated engine?

The below formula is for 4 stroke only.

(CID * RPM) / (1728 * 2) * (% boost pressure + 1)

Example:
Atmosphere is 14.7 PSI
A boost of 9 PSI would be (9 / 14.7) or 0.612 or 61% of 1 atmosphere

Lets try an example engine:
Engine = 3 litre or 183 cubic inches
RPM =  7,000

183 * 7,000          = 1,281,000 CIM
1,281,000 / 1728  =  741.3 CFM
741.3 / 2               =  370.65 CFM [for 4 stroke]
370.65 * 1.61       =  596.74 CFM

The correct carby for this engine would be a 600 CFM carby in draw through mode.

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As above but with 15 PSI boost:
15/14.7  =  1.02
+ 1         =  2.02

from above 370.65 * 2.02 = 748.7

A 750 CFM carby is needed.

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To size a carby for normally aspirated 350 Chevy @ 7,000 RPM

(350 *  7,000)  /  (1,728 * 2)
2,450,000 / 3,456  =  708.9 CFM

A 709 CFM carby is needed.

WOW! Friday afternoon, trying to wind down, shouldn't have read last 2 posts, now Ive got a sore brain, have to go home & have drinkies.

Maybe if OBR184 had done those calculations and read the rules properly for class 1 in the first place he would not have chosen the engine configuration he has as the moment!

what about running class 1a turbo and class 1b non turbo and when the numbers are too low combine them

the problem with class changes is that national rounds are completely different to state and club rounds, there is no solution to solve all problems

Stingray 2212 wrote:

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Just a message to obr, it's not "our 1.7 rule". The 1.7 forced induction multiplication factor is an international formula. The engine in my car is 930cc & was specifically designed by the nissan factory to compete in a 1600cc rally class. 

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with controlled boost...?

I have no idea if the boost is controlled, I would assume so. I was only using my engine to illistrate that the formula of 1.7 is used in other countries. It's not our formula.

Renegade wrote:

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... proposed 4 Litre Class as it is not really any cheaper than the current Class 1. With that size motor, you still need the fully uprated drivetrain, suspension and chassis to make it handle ...

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Hey Renegade - welcome to hte forum.

I have to disagree with the above - I know as Im in the midst of building one.

Compared to the costs of any of the top 10 cars at finke, ours is 4.0Ltr being built at a fraction of the cost.

Renault gearbox, stock 4.0Ltr, Fox shocks with bypass on the rear only etc etc.  Its quite a big car chassis wise - we're hoping to be able to be comparable with brakes, handling and reliability, but we dont have anything like the horsepower.  Its a mig'ed cold drawn chassis and we're making as much stuff ourselves as possible as were still running to a budget.

*EDIT* - The suggestion has been made around the sheds that I frequent that the 4.0ltr proposal would work better if restricted to an OEM manufactured case - IE Renault, Porsche, Audi with a h-pattern shift etc and pass on the Albins, Mendiola's, fortins etc. This would keep someone from building a gun 4.0ltr with a full albins seq box and running away with the class due to more money.

Im all for it as I think it would work, and because its whats in my garage. (just being honest!) and the NA cars up to 4.0Ltr are already like that anyway... bit I doubt if Albins would agree... *EDIT ENDS*

Renegade wrote:

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Just seems to be adding a class for those that want the power but not have to prove themselves aganst the big boys.

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I'd love to prove myself against the big boys!  But we wont have the power to try to prove ourselves. Nevertheless, even if 4.0 doesnt go through, we're still going to go with it as class 1, just like the other normally aspirated cars being put together at the moment.

Of the Lexus engined buggies at Finke (3 of them) none of them challenged the leaders - they were all built to the price of an albins box plus a years maintanence.

This class already exists - its just bigger buggies without budget that constantly (in nationals anyway!) get their but kicked.

State is a completely different story - dont know what suggestions might work for that conundrum.  In NSW the current classes are very evenly distributed - so there's arguments against as well.

 

Now that the serious stuff is done - *HIJACKHIJACKHIJACK* 

I love Zaphod - He is one hoopy frood who knows where his towel is.

"Are you really the Zaphod Beebelbrox?"  "Count hte heads baby!"  I really would like a night of pan galactic gargle blasters with him and Ford.

Although my fav character has got to the ravenous bugblatter beast of traal - an animal so stupendously stupid that it assumes that if you cant see it - it cant see you.  hahaha!!!  Gonna have to go dig out my trilogy in 4 parts.  :)

-- Edited by Wolf at 19:29, 2006-06-27

Stingray 2212 wrote:

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I hope that I am way off the mark with this but I will run it by everyone. After reading wolfs most recent post it became obvious that the most logical engine for the new proposed class two would be the Toyota V8.

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Yeah - I think the 1UZ would be the most popular...  to start with - I know of 2 buggies with honda 3.5's recently finished, plus another one being put together.  These motors (though I hate to admit it!) have more factory tq and hp than the lexus engine, though Im not sure how they respond to (or require) to performance bits. I also know of a couple of 3.8ltr holden motors being put into cars, one buggy one truggy.  

I'd guess that it would probably end up with similar percentages as 20valves in class 2 or suzuki's in class 3.   Unless the VTec engine started whooping butt which is possible.

Mind you, I think the lexus motor is def the cheapest option for the class - ours was $900 from the importer and we're about to buy another long block for 300 as a spare.  Not sure how that compares with honda or holden V6 options.

Im afraid that as Im just some schmo club/state racer the rest of the post is all abit between the lines for me! 

 

 

-- Edited by Wolf at 11:05, 2006-06-28

Hey Wolf.

Who ever it was that you got that email from needs to get a few facts straight.

According to Patto the idea of the new class restructure is not about evening out the number of cars in the classes. It is called class rationalisation and what that means is lowering the total number of classes. If you remember Patto's spin  on the reason for lowering the total number of classes it was because it is apparently too confusing for people to understand 9 levels of race cars. It is funny though because if that is the case then the yanks must be heaps smarter than us Aussies because they don't seem to have too much trouble understanding their 10 or more. And what's even funnier still is that the sponsors in the good old US of A don't seem to have too much trouble with it either and come to think of it the spectators over there dont seem too stressed about it either.

So it would seem that it is only CAMS, Aussie spectators and Aussie sponsors or televisors that only have 7 fingers and would struggle without removing a shoe and sock to understand our current class structure. That then being the case, even if we had enough different cars to make up 10 classes of 50 cars per class we Aussies unfortunatley would blow some kind of a circut breaker trying to cope with it.

Remember it's class rationalisation not class restructure!