How much faster can they go?
Discussion
Been looking at the NHRA. How about Hagan running 322mph and two topfuel dragsters running 327mph @ 1000ft. Makes me wonder how much faster they will go. Do they still run rev limiters over 1000ft?
Until recently I wouldnt believe a Funnycar running close to 320 let alone over 320mph.
Until recently I wouldnt believe a Funnycar running close to 320 let alone over 320mph.
Yes, when I started 10 years ago we used a couple of air pistons on the mag drive to handle the timing advance/retards during the run (not that accurate, but better than totally static timing!). Then we all went onto the MSD six-shooter systems, which involved locked the mags physically in the drive and the retard was applied by the electronic box based on the retard chips you put in and when you set your controlling timer box. 6 stage, but you could stack up to three shooter boxes I think if you really wanted that much timing control!! Now we all have to run the MSD Pro-Mag controller system, which is basically an ECU to handle the timing control. It's programmed via an LCD screen programmer where you can make a nice timing graph over the whole run and also set things like ramp rates for when a driver pedals the car. It also includes a rev limiter per NHRA regs, and power is supplied to it via the Electrimotion safety shut-off box.
The big speeds to 1000' you're now seeing is not really to do with timing advance/retard control. The timing control on a fuel car is mostly there to help you calm the car down just after the launch. Your aim is to get the tyre wound up and turning just a small amount on the surface, but once the front end comes back down and it comes back off the wheelie bar, you need to stop the tyre unwinding and unloading and either going into shake or spin. So you pull timing out at that point to take some power out, finesse the car through the transition, then pile the timing back in again as quickly as you dare/can. From then on, the timing is pretty much flat to the finish.
The big mph and times to 1000' are really just coming from an ability to get the clutch (and fuel) in as quick as possible. The US tracks are so awesome in the first eight now, they really whack the clutch in there quickly and it's very apparent when we look at the data from a US run and compare with what we can get away with here in Europe! Look at the incremental times and you'll see that, plus particularly the mid-track speed trap. They don't make much speed from mid track to the finish! And this is also why fuel pump rates have gone over the 100gpm rate, because when you get the clutch in that quick and hard and really load the motor, you need a LOT of fuel. And once the clutch is locked up, then you need a nice big BDK (fuel pressure regulator) to cut in and take a bunch of that fuel flow rate back out again (because once the clutch is locked up, the load drops dramatically so you can't burn the fuel and you'd go very rich).
Just think what they could have done with the 60-amp mags that MSD developed but NHRA said "no" to....! Fuel burn-o-rama!! Very soon the NHRA will be back in a tricky place with the fuel cars and the tyre technology. The speeds are once again approaching tyre design/safety limits, and in many ways it's even harder on the tyre now over 1000' with the way the cars are accelerating.
The big speeds to 1000' you're now seeing is not really to do with timing advance/retard control. The timing control on a fuel car is mostly there to help you calm the car down just after the launch. Your aim is to get the tyre wound up and turning just a small amount on the surface, but once the front end comes back down and it comes back off the wheelie bar, you need to stop the tyre unwinding and unloading and either going into shake or spin. So you pull timing out at that point to take some power out, finesse the car through the transition, then pile the timing back in again as quickly as you dare/can. From then on, the timing is pretty much flat to the finish.
The big mph and times to 1000' are really just coming from an ability to get the clutch (and fuel) in as quick as possible. The US tracks are so awesome in the first eight now, they really whack the clutch in there quickly and it's very apparent when we look at the data from a US run and compare with what we can get away with here in Europe! Look at the incremental times and you'll see that, plus particularly the mid-track speed trap. They don't make much speed from mid track to the finish! And this is also why fuel pump rates have gone over the 100gpm rate, because when you get the clutch in that quick and hard and really load the motor, you need a LOT of fuel. And once the clutch is locked up, then you need a nice big BDK (fuel pressure regulator) to cut in and take a bunch of that fuel flow rate back out again (because once the clutch is locked up, the load drops dramatically so you can't burn the fuel and you'd go very rich).
Just think what they could have done with the 60-amp mags that MSD developed but NHRA said "no" to....! Fuel burn-o-rama!! Very soon the NHRA will be back in a tricky place with the fuel cars and the tyre technology. The speeds are once again approaching tyre design/safety limits, and in many ways it's even harder on the tyre now over 1000' with the way the cars are accelerating.
MotorPsycho said:
Massive insight into how a fuel setup works Rob, thanks! Useful things for the brain bank and general drag racing geekery 
so far detached from running any other kind of motor.
Good that was the intention. Fuel motors are really simple beasts, but hugely difficult to tame!! But that's what I like about it I guess. So many people have come through from other classes and disciplines and struggled, and that's why. Like F1, you need great parts, great people, and great knowledge to run a fuel car well. This is why the Andersens have been a step ahead for so many years now. so far detached from running any other kind of motor.
RobKarloff said:
Yes, when I started 10 years ago we used a couple of air pistons on the mag drive to handle the timing advance/retards during the run (not that accurate, but better than totally static timing!). Then we all went onto the MSD six-shooter systems, which involved locked the mags physically in the drive and the retard was applied by the electronic box based on the retard chips you put in and when you set your controlling timer box. 6 stage, but you could stack up to three shooter boxes I think if you really wanted that much timing control!! Now we all have to run the MSD Pro-Mag controller system, which is basically an ECU to handle the timing control. It's programmed via an LCD screen programmer where you can make a nice timing graph over the whole run and also set things like ramp rates for when a driver pedals the car. It also includes a rev limiter per NHRA regs, and power is supplied to it via the Electrimotion safety shut-off box.
The big speeds to 1000' you're now seeing is not really to do with timing advance/retard control. The timing control on a fuel car is mostly there to help you calm the car down just after the launch. Your aim is to get the tyre wound up and turning just a small amount on the surface, but once the front end comes back down and it comes back off the wheelie bar, you need to stop the tyre unwinding and unloading and either going into shake or spin. So you pull timing out at that point to take some power out, finesse the car through the transition, then pile the timing back in again as quickly as you dare/can. From then on, the timing is pretty much flat to the finish.
The big mph and times to 1000' are really just coming from an ability to get the clutch (and fuel) in as quick as possible. The US tracks are so awesome in the first eight now, they really whack the clutch in there quickly and it's very apparent when we look at the data from a US run and compare with what we can get away with here in Europe! Look at the incremental times and you'll see that, plus particularly the mid-track speed trap. They don't make much speed from mid track to the finish! And this is also why fuel pump rates have gone over the 100gpm rate, because when you get the clutch in that quick and hard and really load the motor, you need a LOT of fuel. And once the clutch is locked up, then you need a nice big BDK (fuel pressure regulator) to cut in and take a bunch of that fuel flow rate back out again (because once the clutch is locked up, the load drops dramatically so you can't burn the fuel and you'd go very rich).
Just think what they could have done with the 60-amp mags that MSD developed but NHRA said "no" to....! Fuel burn-o-rama!! Very soon the NHRA will be back in a tricky place with the fuel cars and the tyre technology. The speeds are once again approaching tyre design/safety limits, and in many ways it's even harder on the tyre now over 1000' with the way the cars are accelerating.
So interesting. Thanks. I was wondering the same thing as you mentioned on the last paragraph.The big speeds to 1000' you're now seeing is not really to do with timing advance/retard control. The timing control on a fuel car is mostly there to help you calm the car down just after the launch. Your aim is to get the tyre wound up and turning just a small amount on the surface, but once the front end comes back down and it comes back off the wheelie bar, you need to stop the tyre unwinding and unloading and either going into shake or spin. So you pull timing out at that point to take some power out, finesse the car through the transition, then pile the timing back in again as quickly as you dare/can. From then on, the timing is pretty much flat to the finish.
The big mph and times to 1000' are really just coming from an ability to get the clutch (and fuel) in as quick as possible. The US tracks are so awesome in the first eight now, they really whack the clutch in there quickly and it's very apparent when we look at the data from a US run and compare with what we can get away with here in Europe! Look at the incremental times and you'll see that, plus particularly the mid-track speed trap. They don't make much speed from mid track to the finish! And this is also why fuel pump rates have gone over the 100gpm rate, because when you get the clutch in that quick and hard and really load the motor, you need a LOT of fuel. And once the clutch is locked up, then you need a nice big BDK (fuel pressure regulator) to cut in and take a bunch of that fuel flow rate back out again (because once the clutch is locked up, the load drops dramatically so you can't burn the fuel and you'd go very rich).
Just think what they could have done with the 60-amp mags that MSD developed but NHRA said "no" to....! Fuel burn-o-rama!! Very soon the NHRA will be back in a tricky place with the fuel cars and the tyre technology. The speeds are once again approaching tyre design/safety limits, and in many ways it's even harder on the tyre now over 1000' with the way the cars are accelerating.
RobKarloff said:
They don't make much speed from mid track to the finish! And this is also why fuel pump rates have gone over the 100gpm rate, because when you get the clutch in that quick and hard and really load the motor, you need a LOT of fuel. And once the clutch is locked up, then you need a nice big BDK (fuel pressure regulator) to cut in and take a bunch of that fuel flow rate back out again (because once the clutch is locked up, the load drops dramatically so you can't burn the fuel and you'd go very rich).
Can you please explain how the load drops once the clutch is locked up?Or is it that the "load" comes from the rate of acceleration rather than what the clutch is doing and the clutch is locking up at a point when there is a lower rate of acceleration.
Burndown said:
Can you please explain how the load drops once the clutch is locked up?
Or is it that the "load" comes from the rate of acceleration rather than what the clutch is doing and the clutch is locking up at a point when there is a lower rate of acceleration.
Yes, the rate of acceleration you can apply by increasingly locking up the clutch is greatly more than you can achieve post-lockup. Hence why the cars really don't pick up that much speed through the back half of the track. That's also why the funny cars have a much better back half than the dragsters, more aerodynamic drag and downforce to create more load on the motor, burn more fuel and make more power!Or is it that the "load" comes from the rate of acceleration rather than what the clutch is doing and the clutch is locking up at a point when there is a lower rate of acceleration.
Think of it like this, you're trying to keep the motor up near max rpm the whole way. You do this by making as much power as you can for the weather conditions and corrected altitude, without going too far whereby you can't harness it all due to traction conditions on-track and then instead "blow through" the clutch and likely over-rev (and break) the motor. The clutch is essentially just a big brake on the engine, and if you can't apply enough "braking" via the clutch because the track won't take it, then you blow through the clutch and can't keep hold of the motor and will over-rev it. On the other hand, if you make the motor tune too weak, then when you pile the clutch in you will likely pull the motor down too far which is very hard on the parts, and you also run the risk of tyre shake because you can't keep the tyre turning hard enough.
Ideally you want to hit just over 8000rpm at the hit of the pedal, and probably go no lower than 6800rpm mid-track as you pile on the load with the clutch. Once the clutch locks up (driveshaft rpm meets engine rpm), then you have around 1300rpm to keep accelerating back up to 8000-8100rpm through the finish line. So that's where you pull a bunch of fuel volume back out the engine and actually try and run it a little lean for maximum power. Ever read about top fuel drivers like Prudhomme using the "high speed lean-out" to nip a race near the finish line in their rear engined dragsters?? That's what they were doing, leaning out the engine to push it to the limit in the last few hundred feet, but at the risk of it going bang!
The Enthusiast said:
Has the recent development of the goodyear tyres helped achieve the speeds they are doing or is that just a safety thing? I maybe wrong but the walls seem to be shaped slightly differently than before. Was the tyre models a 1020 and 2040 tyre? I cant remember.
Nah not really. NHRA and Goodyear continue to be worried about the safety of the tyres, so they're not doing anything to make them allow the cars to go even faster. They're really just trying to stop them coming apart and causing disasters! The sidewall construction is where it's all happening, in that they want to make the tyre more durable but without making it behave too differently.The mind boggles 
before all the extra restriction came in Doug Herbert went 4.42, and that was still with the mandated rev-limiter pulling timing from (I think?) 3.8 seconds. Surely without that we would have seen fuellers deep into the 4.3s approaching 345mph? The limiter must cause a head-ache when setting the timers before a run, or is it just something else you learn to work with?
The loading of fuel motors is always something thats interested me, watching from the top end as close to head on as you can get you can almost see when the clutch goes 1:1, the shape and dynamics of the car totally changes, more noticeabley with the dragsters whereas (due to the aero) funny cars appear to stay more planted. Nice to get more of an understanding of the processes behind it all.
Do I remember reading somewhere that in the early 90s GoodYear were looking at making a 38" tyre? Which NHRA banned before it went any further. How would that affect the launch, surely more difficult to get the required slip to prevent shake, but maybe a bigger window to opperate in further down track. Also a larger rotating mass, higher centrifugal forces and possibley more chance of chucking itself apart.
Chuck into the mix streamliners..............Swamp Rat 30 and the Mono-wing car and Gary Ormsby's Castrol car the only ones that really achieved much success, but without rules preventing them, how much would streamlining help?
Enclosing wheels is a given, massive reduction is drag, what about the cockpit having a canopy. I'm a massive believer in the narrow rear end and mono wing design, stability, reduction is frontal area and a rudder effect can't be a bad thing for stability. Biggest issue is adding weight, but with carbon fibre/aramid/honeycomb it should be achieveable now.
before all the extra restriction came in Doug Herbert went 4.42, and that was still with the mandated rev-limiter pulling timing from (I think?) 3.8 seconds. Surely without that we would have seen fuellers deep into the 4.3s approaching 345mph? The limiter must cause a head-ache when setting the timers before a run, or is it just something else you learn to work with?The loading of fuel motors is always something thats interested me, watching from the top end as close to head on as you can get you can almost see when the clutch goes 1:1, the shape and dynamics of the car totally changes, more noticeabley with the dragsters whereas (due to the aero) funny cars appear to stay more planted. Nice to get more of an understanding of the processes behind it all.
Do I remember reading somewhere that in the early 90s GoodYear were looking at making a 38" tyre? Which NHRA banned before it went any further. How would that affect the launch, surely more difficult to get the required slip to prevent shake, but maybe a bigger window to opperate in further down track. Also a larger rotating mass, higher centrifugal forces and possibley more chance of chucking itself apart.
Chuck into the mix streamliners..............Swamp Rat 30 and the Mono-wing car and Gary Ormsby's Castrol car the only ones that really achieved much success, but without rules preventing them, how much would streamlining help?
Enclosing wheels is a given, massive reduction is drag, what about the cockpit having a canopy. I'm a massive believer in the narrow rear end and mono wing design, stability, reduction is frontal area and a rudder effect can't be a bad thing for stability. Biggest issue is adding weight, but with carbon fibre/aramid/honeycomb it should be achieveable now.
Edited by MotorPsycho on Tuesday 20th September 10:47
RobKarloff said:
Yes, the rate of acceleration you can apply by increasingly locking up the clutch is greatly more than you can achieve post-lockup.
This is what I don't understand. If in the NHRA they are locking the clutch up sooner then they would be running more of the track at this lower ROA.I was trying to find out if the biggest load on the engine was accelerating the mass of the car plus drag at "lower" speeds or maintaining that car with the increased drag at say 310mph.
MotorPsycho said:
The mind boggles before all the extra restriction came in Doug Herbert went 4.42, and that was still with the mandated rev-limiter pulling timing from (I think?) 3.8 seconds. Surely without that we would have seen fuellers deep into the 4.3s approaching 345mph? The limiter must cause a head-ache when setting the timers before a run, or is it just something else you learn to work with?
The loading of fuel motors is always something thats interested me, watching from the top end as close to head on as you can get you can almost see when the clutch goes 1:1, the shape and dynamics of the car totally changes, more noticeabley with the dragsters whereas (due to the aero) funny cars appear to stay more planted. Nice to get more of an understanding of the processes behind it all.
Do I remember reading somewhere that in the early 90s GoodYear were looking at making a 38" tyre? Which NHRA banned before it went any further. How would that affect the launch, surely more difficult to get the required slip to prevent shake, but maybe a bigger window to opperate in further down track. Also a larger rotating mass, higher centrifugal forces and possibley more chance of chucking itself apart.
Chuck into the mix streamliners..............Swamp Rat 30 and the Mono-wing car and Gary Ormsby's Castrol car the only ones that really achieved much success, but without rules preventing them, how much would streamlining help?
Enclosing wheels is a given, massive reduction is drag, what about the cockpit having a canopy. I'm a massive believer in the narrow rear end and mono wing design, stability, reduction is frontal area and a rudder effect can't be a bad thing for stability. Biggest issue is adding weight, but with carbon fibre/aramid/honeycomb it should be achieveable now.
Didn't car owner say no to the bigger tyre's cus they would of had to have new chassis's before all the extra restriction came in Doug Herbert went 4.42, and that was still with the mandated rev-limiter pulling timing from (I think?) 3.8 seconds. Surely without that we would have seen fuellers deep into the 4.3s approaching 345mph? The limiter must cause a head-ache when setting the timers before a run, or is it just something else you learn to work with?The loading of fuel motors is always something thats interested me, watching from the top end as close to head on as you can get you can almost see when the clutch goes 1:1, the shape and dynamics of the car totally changes, more noticeabley with the dragsters whereas (due to the aero) funny cars appear to stay more planted. Nice to get more of an understanding of the processes behind it all.
Do I remember reading somewhere that in the early 90s GoodYear were looking at making a 38" tyre? Which NHRA banned before it went any further. How would that affect the launch, surely more difficult to get the required slip to prevent shake, but maybe a bigger window to opperate in further down track. Also a larger rotating mass, higher centrifugal forces and possibley more chance of chucking itself apart.
Chuck into the mix streamliners..............Swamp Rat 30 and the Mono-wing car and Gary Ormsby's Castrol car the only ones that really achieved much success, but without rules preventing them, how much would streamlining help?
Enclosing wheels is a given, massive reduction is drag, what about the cockpit having a canopy. I'm a massive believer in the narrow rear end and mono wing design, stability, reduction is frontal area and a rudder effect can't be a bad thing for stability. Biggest issue is adding weight, but with carbon fibre/aramid/honeycomb it should be achieveable now.
Edited by MotorPsycho on Tuesday 20th September 10:47
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