77 replies to this topic

[Bruce Wilson]

.77 is a BIG DEAL just like a hundredth of a second or one inch is a BIG DEAL. It could mean the difference between winning and losing. Weight penaly is needed. Front runners will overbore, and that just puts the rest of the field that much farther behind. It CAN be teched just as well as most of the rest of the rules we have, i.e. doesn't happen much, but it can be done.

-bw

[wheel]

I have a perfect block, except it needs a slight bore to clean it up. I vote yes, with no weight. And, .77 hp is almost unmeasurable, and certainly would not show up on the track. Mine might move from 118.1 to 118.87 damn, I love the power.

wheel

[Alberto]

My comments from the other thread on the topic:

My initial reaction is > fudge No.

My reasons:

1. I can get a 1.6 for $500 off craigslist or a JDM importer (Atarco for example).
2. I have seen absolutely no evidence of lack of 1.6 motors or parts. Prove it if you can.
3. $3,500 for a crate motor ain't bad and I'm sure the quality is excellent. In my brief time in SM, I've seen and read of more than a few "PRO" motors blow up w/ not much use.
4. I suspect that building the motor would cost about as much as a crate motor. I remember reading ad nauseum on the old site about how building a motor was much more expensive than buying a crate.


If they want to make engine rules changes, they should switch to a spec sealed engine package like other spec series IMO. IT is a builder's class. SM is a Spec class.

[Danny Steyn]

My comments from the other thread on the topic:

Alberto

I am missing the logic train on the argument you are putting forth. I don't see how any of your four bullet points affect the question at hand (allowing overboring)

A sealed Spec Miata engine is a completely different consideration, and one that I beleive we should seriously be considering before the cost of the arms war destroys the popularity of the class.

Just my $0.02

[davew]

Most used engines will require out at 0.006 oversize hone just to get the bores straight. So the 0.010 overbore can be achieved by simply rough honing the extra 0.004. So there should be no additional charge from the machine shop for overbore, when doing a rebuild.

Standard vs +10 pistons and rings are available from Mazda at the same price.

So when rebuilding an engine, there will be no price difference. In the long run, this will be a cost savings, because many blocks are worn beyond the rebuild tolerances allowed. This will save money for the budget racer who does not want to search for a usable block from craiglist or a JDM importer or a junkyard (sorry, automotive recycler)

A no extra charge hone plus same price pistons plus same price rings = No Additonal cost. Versus Alberto's claim of $500 from craigsliest.

Yes, some people will exploit the 0.77 potential horsepower increase. But these are the same people who rebuild their engines twice a year. And buy tires everyweekend. And have data......etc, etc etc

I do not feel this is an issue of rules creep or a cost increase concern.

I am 100% in favor with no weight penalty.

Allowing the 1.6 to go 30 over is a totally seperate issue and is not currently being discussed, to my knowledge.

Dave

[Jim Drago]

My comments from the other thread on the topic:

Alberto...

I'll give the reasoning behind it if I can under each of your bullets.

My reasons:

1. I can get a 1.6 for $500 off craigslist or a JDM importer (Atarco for example).

What do you do when the bore on your supposed 30k Japanese engine or salvage or street car engine that you just bought for $500.00 is too large for a decent rebuild That is the case in 75% of all the 1.6 blocks over 100k. I would bet 95% are over 100k at this point, despite what they "say" they are. get a car fax and match vin plate on oil pan and see for yourself.




2. I have seen absolutely no evidence of lack of 1.6 motors or parts. Prove it if you can.

Ask most of the engine builders, I know we see as many Miatas, probably more than anyone in the country and rarely do we get 1.6 engines in less than 125k. The problem is not as bad i the 1.8 or 99's, but it is absolutely problem with the oldest cars that happen to be 1.6's




3. $3,500 for a crate motor ain't bad and I'm sure the quality is excellent. In my brief time in SM, I've seen and read of more than a few "PRO" motors blow up w/ not much use.


Do a little research on crate motors, you will find many of them blow up as well. All these engines can and will blow up, we stress the heck out of them. More often than not it is a tuning or assembly issue.

4. I suspect that building the motor would cost about as much as a crate motor. I remember reading ad nauseum on the old site about how building a motor was much more expensive than buying a crate.

It is.





If they want to make engine rules changes, they should switch to a spec sealed engine package like other spec series IMO. IT is a builder's class. SM is a Spec class.

Sm is spec, not sealed. take a look at the SF thread on sealed engines from a month ago where one car had like 8-10 hp on the field and no one knew how or why. In a sealed engine class ( which the ship has long sailed in SM by the way) Those who prep cars will have the same advantage or more IMO. This has been discussed for years as well


Jim

[Ron Alan]

Lets not lose site of the thought process here. Potential cost savings for the majority who join this class and the ability to reuse a perfectly good block(not $3500 for a crate) that may have minor issues. Times are a little tight with smaller budgets all around...I'm all for any little things that have the potential to keep people involved.

Will some throw more money at another potential HP gain...of course. But I see the benefit far out weighing the downside. We have a great head on our car with a stock bottom end...when we are ready to have the bottom end worked on it will be great to know with almost 100% certainty that we wont have to spend the extra money to find another block assuming there are no holes in the side of ours

As for weight...just doesn't seem realistic to enforce.

For those opposed, how about this...since its no secret that a lot of the big dollars is being thrown at the NB cars, make this only legal for NA cars

[pat slattery]

Lets not lose site of the thought process here. Potential cost savings for the majority who join this class and the ability to reuse a perfectly good block(not $3500 for a crate) that may have minor issues. Times are a little tight with smaller budgets all around...I'm all for any little things that have the potential to keep people involved.

Will some throw more money at another potential HP gain...of course. But I see the benefit far out weighing the downside. We have a great head on our car with a stock bottom end...when we are ready to have the bottom end worked on it will be great to know with almost 100% certainty that we wont have to spend the extra money to find another block assuming there are no holes in the side of ours

As for weight...just doesn't seem realistic to enforce.

For those opposed, how about this...since its no secret that a lot of the big dollars is being thrown at the NB cars, make this only legal for NA cars

Not a chance

Pat

[Caveman-kwebb99]

Whats the big deal? My engine builder just sent me one of these! There was no shortage as far as I can tell.

[Steve D]

A 10 thou bore is nothing. Let's say .77 hp.

I keep seeing that number tossed around but I don't where it comes from. Can anyone help me there?

Here's my question from the other thread. It is a genuine question. I am under the ASSumption that there is less than a 1:1 relationship between increased displacement and increased power if everything else is kept the same. Right? Wrong?

I'll expose my ignorance here, but the weight penalty seems to be just that - a penalty.

All other things being equal, displacement and the resulting power produced is not a 1:1 equation, is it? If the displacement increases by 0.65% (if my maths are correct), the power gain would be ~0.5% just based on volumetric increase? What about the offset of larger (just barely heavier?) pistons?

I'd hate for this allowance to be made in an effort to help the budget guys, then have them legitimately complain about a 20 lb (~0.08%) weight penalty.

[Jim Drago]

I keep seeing that number tossed around but I don't where it comes from. Can anyone help me there?

Here's my question from the other thread. It is a genuine question. I am under the ASSumption that there is less than a 1:1 relationship between increased displacement and increased power if everything else is kept the same. Right? Wrong?

Steve
I did the math on 130 hp, it was .77 by volume. No idea if it is a 1:1, it is a best guess, feel very confident it would be very hard to gain anything measurable. By volume, it would be less gain in a 1.6 making 123. ( You see we are trying to slow the 1.6 down by legally giving the 99 another 1/4 HP)

[dstevens]

I keep seeing that number tossed around but I don't where it comes from. Can anyone help me there?

Here's my question from the other thread. It is a genuine question. I am under the ASSumption that there is less than a 1:1 relationship between increased displacement and increased power if everything else is kept the same. Right? Wrong?

The number came from dyno pulls from Drago. And I'd reckon that was under a high state of tune, under the best possible circumstances. IOW, like all the top runners do but not like the rank and file do. Knowing that HP is a product of torque, and increased displacement can achieve a performance advantage. However, if one increases the displacement without a companion increase or offset in static compression ratio there may not be that great of a performance advantage, if any.

[Jim Drago]

As for weight...just doesn't seem realistic to enforce.

For those opposed, how about this...since its no secret that a lot of the big dollars is being thrown at the NB cars, make this only legal for NA cars

Ron
How do you enforce over bores now? How about illegal rings? pistons? illegal valves and valve jobs? lightened cranks? There are a lot cheaper and easier ways to cheat if that is someones motive. There is a rule, if you break it you are illegal, At most races it will NEVER be checked. So why not just go .040 over and 11:1 if that is the mentality? I still believe that MOST want to abide by the rules, push them maybe, but not cheat. Running the overbore without the weight is intentionally cheating!


As for being a 1.6 only. This is primarily to benefit the 1.6 owners, eventually the 1.8 cars as well. But if it were a 1.6 only change, it would be perceived as a comp adjustment WHICH IT IS NOT and the 100 flaming posts would read, Why does the 1.6 guy always have to spend the money, why not just put a restrictor plate on the other cars. How it was presented was well thought out before putting it out for input.
We wanted to insure their was no performance advantage,no implied necessity to change, no way it could be interpreted as a comp adjustment and lastly it was a way to contain costs.
Jim

[Steve D]

The number came from dyno pulls from Drago.

I did the math on 130 hp, it was .77 by volume.

[Tom Hampton]

Busted like Benjamin bunny.

[dmathias]

Benjamin bunny? Who the f is that?

[Jim Drago]

Also guys as usual, if you are for or against this you need to send a letter in. The debate here means nothing... CRBSCCA.com


Jim

[Jim Drago]

I would guess 1+1=2 in this case I took highest legal numbers I have heard and that's what I used to do math.

[Steve D]

We wanted to insure their was no performance advantage,no implied necessity to change, no way it could be interpreted as a comp adjustment and lastly it was a way to contain costs.

That makes complete sense. By the same token, I'd like to have a better feel for whether there is a performance DISadvantage due to the weight penalty.

Are 0.010-over pistons the exact same weight as standard? Logic tells me they would be 0.6% heavier since they fit a hole 0.6% bigger. If that's true, how much of the gain in displacement is offset by losses in reciprocating mass?

Granted, the estimated 0.77 hp gain is well within the 'noise' but it will become the standard for the pointy end. The flip side, IMHO, is if we put a weight penalty on it to discourage that practice, it doesn't help the parity wars. Besides, what a nightmare for tech. 2 chassis, three displacements, five generations of ECU/engine combo... Then we have to have 2 different weights for each?

For simple minds like mine, this gets confusing!

[Weekend Warrior]

You see we are trying to slow the 1.6 down by legally giving the 99 another 1/4 HP)

I knew it!