Hi my 2 questions are. I was just curious if i know toyota has been winning a lot of races here recently and nascar has been doing dyno tests on the car - engine i was just curious if nascar plans on taking away anymore horsepower from them.

I know they took engines from all 3 of the top series at bristol.

Even though they lowered - took away 10 horsepower from the toyota's it still seems like the joe gibbs cars have a horsepower adavantage in the nationwide series

I was just curious if nascar plans to do what the alms sportscar series sometimes do when a car gets a big advantage like a couple of times in sportscar a couple of cars the viper and the corvette had a really big advantage so they kept adding weight and taking away power from them to try and equal things up.

I was just curious if nascar plans on doing that.

Also did nascar do anymore dynotests after the race last night?

My other question about when a car runs out of gas is i've seen a few cars run out of gas and stall on pit road and have seen the teams have trouble refiring them someone was telling me that 1 way to refire a car that has ran out of gas and stalled is to hold the throttle wide open up until it refire's i was just curious if that's true and that's how the engine refires or restarts.

I'll take the second question and say that you can't just hold a throttle open and wait for the engine to start. Sometimes they'll spray ether into the air cleaner to force combustion. Ether is a volatile substance so if that can ignite it would hopefully cause a chain reaction that forces the gasoline to ignite.

Restarting an race engine that stalls is always hard because the batteries have to be small to save weight, but if the engine stalls, it'll take more power to restart it. As the temperature of a metal increases, it's resistance increases, so the (already small) battery cables can't handle the amperage to restart the engine.

mustang6172 - 31 August 2008 08:55 PM

I'll take the second question and say that you can't just hold a throttle open and wait for the engine to start. Sometimes they'll spray ether into the air cleaner to force combustion. Ether is a volatile substance so if that can ignite it would hopefully cause a chain reaction that forces the gasoline to ignite.

Restarting an race engine that stalls is always hard because the batteries have to be small to save weight, but if the engine stalls, it'll take more power to restart it. As the temperature of a metal increases, it's resistance increases, so the (already small) battery cables can't handle the amperage to restart the engine.

Just to expand a bit:

The ether is used to temporarily 'start' the engine, meaning that it will run for an instant, and in doing so will turn much faster than the starter will turn it, which results in new fuel being pumped into the carb much faster than if the starter were doing the turning of the engine.

As to the second part, the resistance is caused by the expansion of the engine components, making the assembly's clearances tighter and thus making the energy required to turn the crankshaft much greater, which in turn requires much more amperage from the battery to be drawn by the starter motor.

As to the 'evening of the playing field': Nascar needs to tread lightly in this area; ALMS, IMSA and other sports car series', when assigning weights and/or air inlet restrictors to even things up, are usually dealing with different chassis/engine combinations and different engine types and sizes (4, 6 and 8 cylinders, turbo and normally aspirated, etc.). The changes to the 'restrictor' on the Toyotas in the Nationwide series is the first time I can remember Nascar ever changing anything but aerodynamic items (spoiler height, air dam height, etc.) in an effort to 'even things up'.

Everyone starts out with the same restrictions on engines as far as size, type and other parameters go, and Nascar would be wise not to penalize those that do a better job within those parameters too much, the others' whining not withstanding. If they go too far down that road, it will, IMO, remove the primary reason they have for NOT allowing different engine types, i.e. overhead cam 4 valve engines, which would then require Nascar to do exactly what they're doing now, adjust inlet airflow to even out the different types of engines.

Just my two cents.

Holding the throttle WIDE OPEN only means you are holding the butterfly's open, it doesn't cause the fuel pump to deliver fuel from the tank to the empty fuel bowls in the carb any faster. It won't hurt anything either.

Turning over a HIGH compression, HIGH HP engine, HOT, takes a POWERFUL starter, and with empty fuel bowls more time then many of the batteries have left in them.

When ALMS and SCCA "adjust weight" for a particular model within a class, they are doing it based on results of races, NOT DYNO NUMBERS. They are not trying to equalize HP, they are trying to get LAP times closer. Sometimes it works, sometimes it doesn't. They are attempting to equalize lap times, this allows very different types to COMPETE with each other.

As was said already, NASCAR is putting itself in a box it may not like once it gets in there. AA JMHO

Bill

I'm not sure about nascar, but I believe in F1 they HEAT the engine prior to starting it, because if it's cold, it won't start, the necessay clearances only COME with the temp rise.

I'll try to find it back somewhere, but it's to do with pistons and cylinders: which way does a cylinder expand? outwards of inwards? Probably outwards.

speedy_bob - 02 September 2008 09:35 AM

I'm not sure about nascar, but I believe in F1 they HEAT the engine prior to starting it, because if it's cold, it won't start, the necessay clearances only COME with the temp rise.

I'll try to find it back somewhere, but it's to do with pistons and cylinders: which way does a cylinder expand? outwards of inwards? Probably outwards.

They expand in ALL directions, but so then do the pistons and rings. Clearances tend to be looser when cold, because the sleeves are typically steel and the pistons aluminum. Steel doesn't expand as much, so the pistons expand farther to tighten up the clearances.

Bill

speedy_bob - 02 September 2008 09:35 AM

I'm not sure about nascar, but I believe in F1 they HEAT the engine prior to starting it, because if it's cold, it won't start, the necessay clearances only COME with the temp rise.

I'll try to find it back somewhere, but it's to do with pistons and cylinders: which way does a cylinder expand? outwards of inwards? Probably outwards.

It would most likely start; more likely is they heat the engine and the engine oil so it will flow and lubricate properly-even with street engines it is said that the majority of engine wear happens in the seconds right after startup; the GTP team I worked with never started an engine without heating the oil first.

Good. Glad they're engine dynoing these instead of just the chassis dyno, that way, if a team knows how to reduce driveline loss, they won't be penalized by using results just from the chassis dyno.

Here is the new engine dyno at Nascar's Tech Center, installed a month or so ago. It is to be used for Nascar & Grand Am comparative-testing and measures elapsed time rather than torque/HP. (Just like a race track.) I've seen (and heard) this dyno run and it sounds exactly like an engine at the track. It accelerates, decelerates, tests at part throttle, wide open throttle, coasts, etc. The results are measured in milliseconds and can be converted to torque and hp.

No more: Toyota made 840 hp, RO7 made 836 hp, etc. This thing verifies how the engine operates from the lowest rpm to the highest rpm. Nascar will know how an engine operates at every rpm point now.

Do you know if at-track chassis dynamometer testing will continue? This is as good as or better than what the teams use, but not very convenient for after race comparisons for obvious reasons. Here's a link to view the thing at work:

http://www.revolutiondyno.com/index.php

Bryan Blanton - 31 August 2008 11:14 AM

Hi my 2 questions are. I was just curious if i know toyota has been winning a lot of races here recently and nascar has been doing dyno tests on the car - engine i was just curious if nascar plans on taking away anymore horsepower from them.

I know they took engines from all 3 of the top series at bristol.

Even though they lowered - took away 10 horsepower from the toyota's it still seems like the joe gibbs cars have a horsepower adavantage in the nationwide series

I was just curious if nascar plans to do what the alms sportscar series sometimes do when a car gets a big advantage like a couple of times in sportscar a couple of cars the viper and the corvette had a really big advantage so they kept adding weight and taking away power from them to try and equal things up.

I was just curious if nascar plans on doing that.

Also did nascar do anymore dynotests after the race last night?

My other question about when a car runs out of gas is i've seen a few cars run out of gas and stall on pit road and have seen the teams have trouble refiring them someone was telling me that 1 way to refire a car that has ran out of gas and stalled is to hold the throttle wide open up until it refire's i was just curious if that's true and that's how the engine refires or restarts.

1. Since NASCAR is going down the road of equal performance and not just equal rules I think they should leave the engine rules open and just limit dyno performance. They could give a certain torque and horsepower range that you cannot outperform. Simple. You would need to need to have a rule for engine (physical)size, weight and placement in the car but that's it.

Another idea is that NASCAR owns and dynos all the engines and the teams need to rent them. Anyone who thinks they got a dud could have it dynoed at the track (for a fee). Nascar could make $$ on this one.

2. NASCAR rules do not allow an electric fuel pump so the only way to pump fuel is to turn over the engine. The starter does this but not well enough to start a car that was run out of fuel. When they spray ether into the carb the engine fires for a short time but that short time pumps "a lot" of gas from the cell towards the engine.

Holding it wide open works when the engine is flooded and/or hot. This may happen when it was running at race speed and stopped suddenly like when a car spins and the driver locks up the brakes. This floods the engine with fuel and to get it running you hold the throttle open to allow maximum air and avoid pumping more fuel.

Cold engines need a richer mixture to run (that's why we choke a cold engine). Hot engines need a leaneer mixture to start and being flooded doesn't work well. After they spin and you see that big flame come from the exhaust it's all the fuel from the flooded engine being pumped into the headers where it finds enough oxygen to ignight.

Don't confuse what I said with an engine that overheats / blows up because it was too lean. That's the other end of the spectrum.