Forum: HoseHeads Sprint Car General Forum (go)
Moderators: dirtonly  /  dmantx  /  hosehead

Could a compression limit make 410 & 360 motors last longer, lower the H.P. a bit, and make it a little easier on the owner's wallet? I know that folks freak about anything being limited in racing.
Aren't sprints already limited? Limited to 410 cubic inches maximum displacement. Limited to 5X5 maximum top wing. Limited to 1300# (or whatever) minimum weight. What could be the downside to a compression limit?

It would make things last longer, that much is correct. It seems it would be difficult to police however. How would you measure it without pulling the head? With head gaskets going for 150+ a set, I wouldn't be real happy pulling a head very often.

They used to "pump" the cylinders all of the time - at least one cylinder. In fact - in the old days of restriction (possibly the modifieds) some guys would make one cylinder legal (the one that was always pumped to check) and the others would be bored &/or stroked.

On the lighter side - back in the 70's a friend was in a shop where a dirt car engine was being built. He commented something about the bore and stroke is how you figure the displacement (cubic inches) of the motor. The guy building the motor said "it might be that way on those little sporty cars you fool with but it isn't that way with a Chevy."

A compression limit would save too much money and is too easy to check. Top race teams need a way to throw stacks of hundreds in the fireplace to be able to keep their foot on top of everyone else. They'll never let it happen, either will engine builders.

 
 
 
They don't even know how to spell sprint car 
much less chromoly...http://www.ycmco.com

Cubicdollars you are 100% correct. But here's something even cheaper to do and easier to police.

How about something as simple as a stack diameter or header diameter. Everybody could use what they already have as far as engines and for a couple hundred bucks everyone could conform. The BIG engines can't put out the big horsepower if they can't breathe big amounts of air or expel all the exhaust gasses.

www.harleytrikes.com

2009 Knoxville Raceway 410 Rulebook: (We are considering a 2 5/8ths injector stack rule for 2010.. Your input is requested.)

 
 
 
They don't even know how to spell sprint car 
much less chromoly...http://www.ycmco.com

Staying home and watching football on grammy's black and white TV is also more affordable.  You are exactly right, the 410 stuff is already so limited.  We need a new true OUTLAW sprint class.  Spending a fortune and going the same speed as 10 years ago is silly.

Luna's Ford engine style that won 2 WoO titles and 3 
Kings Royals before a weight rule against the best EVER
in their prime and now DOMINATES super dirt late model
racing is no longer allowed/wanted in a WoO sprint
car.... Was Luna a miracle worker?

Lets make sprint car racing as awfull as NASCAR. Why not a a 1/4 inch injector stack or a carb off a 5 horse Briggs. Now that would save some big bucks.

Luna's Ford engine style that won 2 WoO titles and 3 
Kings Royals before a weight rule against the best EVER
in their prime and now DOMINATES super dirt late model
racing is no longer allowed/wanted in a WoO sprint
car.... Was Luna a miracle worker?

Compression limits are simple to police. The thing is, you'd have to find a way to unhook the cars or everybody would be running wide open all the way around and they'd be no passing. It would probably take 4 x 4 wings without the offset side boards and smaller tires.

The problem is the vocal minority of fans. They want to see cars that are as God-awful expensive and fast as humanly possible or they won't be able to get the same drunken enjoyment out of the races as now.

for those that don't want limitations.. I wish you well in the future watching 5 cars in the feature...

Bottom line...engine costs v's $$$ won is way outa hand !

The only two options would be .. increase the admission price to $30 for a regular show, to add more to the purse ( then no-one would go and racing is in a worse position than now) or limit the costs of the engines...( more teams could afford to race. more races, and cost them less money..)

Pretty simple really !

How is compression checked without removing a head to cc and measure everything? I haven't been in a situation where compression had to be checked so I have never seen it done. I am familiar with getting a motor pumped, but that was for displacement.

Whistler Gauge... http://www.katechengines.com/corporate_services/whistler.php

 
 
 
They don't even know how to spell sprint car 
much less chromoly...http://www.ycmco.com

Letting things go until the 410's are gone seems to be working just fine doncha think?

Isn't it the compression that makes them grenades?

That and turning an engine 8500-9000 rpm's on lightweight parts that weren't meant to be turned that hard!

There's a guy who could tell us. What effect does compression have on horsepower, logevity and cost of a motor?

The higher the compression,the closer the piston comes to the valves.When a piston hits a valve,it's bye bye motor.

The valve train is what gives up under normal conditions, due to the aggresive inverted ramp style cams and the 8500-9000rpm. The other thing that grenades these engines is the tune, the fuel system is leaned out to try an increase fuel mileage and h.p. the end result is often a burnt piston. The compression ratio is not an issue as engines have had 15-15.5:1cr for a long time, the compression is cheap horsepower, the heads and valve train, aswell as lightweight parts is expensive horsepower.

There's a couple of variables, but to give you kind of an idea an ASCS engine is around 14:1 on compression. Most of our guys freshen their ASCS engines on average around 18-22 shows. We are able to re-use the pistons over again for another 18-22 ($1,100 a set) shows due to the fact that they aren't abused as hard.

A 410 is generally around 15:5 -16:1 (maybe higher with other people) and they (WoO) guys send theirs in after 8-10 shows. Atleast when we had 3-4 cars on the Outlaws that was the schedule, maybe it's changed since then but I doubt it.

Hope that helps a little.

Engines are the easiest to cheat and hardest to check. If there were better tire and wing rules that wouldn't allow the high $$ engines to make that big of a difference.