Top Fuel Blowovers
Discussion
I was watching a great documentary on Don Garlitts on YT and it reminded me of the the blowovers that seemed like a common occurrence in NHRA in the 90's but have seemed to go away in the most part
What suddenly happened to cause them and what changed to make them become largely a thing of the past ?
The recent wheelie that Clay Millican suffered at Dallas last month got me thinking about it
Just for fun here is the 1991 Russ Collins blowover - https://www.youtube.com/watch?v=59WtrQaXmn4&ab...
What suddenly happened to cause them and what changed to make them become largely a thing of the past ?
The recent wheelie that Clay Millican suffered at Dallas last month got me thinking about it
Just for fun here is the 1991 Russ Collins blowover - https://www.youtube.com/watch?v=59WtrQaXmn4&ab...
It's probably a multitude of things; front aero, a better understanding of weight distribution and engine placement. Crank centreline, distance and angle in relation to the rear pinion are all critical in preventing the desire for the driveline wanting to climb up the ring gear and wheelie. The same as most things in the sport, knowledge and experience cause things to evolve.
Rat Fink ( Andy?) : you have more knowledge than me, but some of your points I don´t understand :
weight distribution and engine placement - the basic formula has not changed, wheelbase, rear engine, tank in front,
or has the engine been placed further up front behind the rollcage ?
Crank centreline, distance and angle in relation to the rear pinion.....has the engine moved up or down ?
Since a fueler has an ultra short driveshaft, has the axle position moved up or down ?
Cannot move up too much, I guess, or the ground clearance would be under tech spec limits ?
As far as I remember, those old fuelers had no wheelie bars (coz we dont need them, car´s too long to wheelie ) ,
now they have the bars, are they mandatory ?
Still remember my first trip to the Pod, stood trackside for 15mins and watched Rico loop the loop,
not the "first euro 4" he wanted but still in the books as "first euro blowover", he had determination though,
in a photo series poster the butterflies were 100% open when the nose was already 5ft in the air.
weight distribution and engine placement - the basic formula has not changed, wheelbase, rear engine, tank in front,
or has the engine been placed further up front behind the rollcage ?
Crank centreline, distance and angle in relation to the rear pinion.....has the engine moved up or down ?
Since a fueler has an ultra short driveshaft, has the axle position moved up or down ?
Cannot move up too much, I guess, or the ground clearance would be under tech spec limits ?
As far as I remember, those old fuelers had no wheelie bars (coz we dont need them, car´s too long to wheelie ) ,
now they have the bars, are they mandatory ?
Still remember my first trip to the Pod, stood trackside for 15mins and watched Rico loop the loop,
not the "first euro 4" he wanted but still in the books as "first euro blowover", he had determination though,
in a photo series poster the butterflies were 100% open when the nose was already 5ft in the air.
Benni said:
Rat Fink ( Andy?) : you have more knowledge than me, but some of your points I don´t understand :
weight distribution and engine placement - the basic formula has not changed, wheelbase, rear engine, tank in front,
or has the engine been placed further up front behind the rollcage ?
Crank centreline, distance and angle in relation to the rear pinion.....has the engine moved up or down ?
Since a fueler has an ultra short driveshaft, has the axle position moved up or down ?
Cannot move up too much, I guess, or the ground clearance would be under tech spec limits ?
As far as I remember, those old fuelers had no wheelie bars (coz we dont need them, car´s too long to wheelie ) ,
now they have the bars, are they mandatory ?
Still remember my first trip to the Pod, stood trackside for 15mins and watched Rico loop the loop,
not the "first euro 4" he wanted but still in the books as "first euro blowover", he had determination though,
in a photo series poster the butterflies were 100% open when the nose was already 5ft in the air.
Hi Benni, weight distribution and engine placement - the basic formula has not changed, wheelbase, rear engine, tank in front,
or has the engine been placed further up front behind the rollcage ?
Crank centreline, distance and angle in relation to the rear pinion.....has the engine moved up or down ?
Since a fueler has an ultra short driveshaft, has the axle position moved up or down ?
Cannot move up too much, I guess, or the ground clearance would be under tech spec limits ?
As far as I remember, those old fuelers had no wheelie bars (coz we dont need them, car´s too long to wheelie ) ,
now they have the bars, are they mandatory ?
Still remember my first trip to the Pod, stood trackside for 15mins and watched Rico loop the loop,
not the "first euro 4" he wanted but still in the books as "first euro blowover", he had determination though,
in a photo series poster the butterflies were 100% open when the nose was already 5ft in the air.
No not Andy, but Lee.
The basic dragster chassis formula hasn't changed, very true. But where the engine sits in relation to the gap between the rear of the roll cage and the axle will have done. The height of the crank in comparison to the rear pinion, plus the angle of the engine and axle will have all evolved too.
Moving the engine forwards, backwards, up and down all have an effect on the car's centre of gravity, plus the "leverage" under acceleration. Engines now are further away from the axle, and mounted slightly lower down in the chassis compared to the 90s. We're only talking 2" to 3" movements, but they all have an effect.
Similarly the drivers compartment/seat location will adjust depending on the driver. Take yesterday's NHRA final, Leah Pruett would've been sitting in a very different location in relation to the wheelbase, in comparison to a big guy like Doug Kalitta! The "driver box" specs are very stringent, but where that compartment is in the chassis is unique to the person it was built for.
Knowing the exact locations, dimensions and angles etc though will be proprietary secrets of the teams, especially now most of the big players build their own chassis in house. A lot of it will be Crew Chief specific too I would've thought, but again, not common knowledge. A bit like asking a Pro Stock engine builder to hand out their cam spec or valve angles!
Another thing to consider is that there is a lot more understanding of "controlled flex" in the chassis too compared to 30 years ago. The placement of the triangulations, bar angles, plus the wall thickness of the tubing all influence flex, which in turn has an effect on weight transfer when the driver stamps on the noise pedal! There are also adjustable tubes you can add or remove pre-load in on some cars, around the driver's feet. When installed, these control the amount of twist in the chassis. Back in the 90s it was quite common to see a Top Fuel car lift one front wheel away from the line as the engine torque twisted the frame, you'll notice nowadays that's a lot less pronounced. The gap between the top and bottom frame rails also has an effect on stiffness too, if you notice, modern Top Fuel dragsters are a lot taller or deeper side-on than they were in the 90s too.
I haven't followed the class as much as I once did for a while now, but as far as I'm aware, the wheelie bars are a mandatory item now.
I too remember Rico's blowover, vividly! September '93, time flies!!
Edited by Rat_Fink_67 on Monday 13th November 19:31
Thank you, Lee, I realize that there is much more to see in the TF pits than flying wrenches between rounds.
Sometimes I think I am a crap announcer, but I constantly try to soak up bits of "how and why" in the pits,
and try to bring a bit of that knowledge over the fence to the grandstands.
Tough job sometimes, as some of them have forgotten more than I ever knew.
Sometimes I think I am a crap announcer, but I constantly try to soak up bits of "how and why" in the pits,
and try to bring a bit of that knowledge over the fence to the grandstands.
Tough job sometimes, as some of them have forgotten more than I ever knew.
You're far from a crap announcer Benni! As you say, there's a lot to take in. On the face of it, a dragster chassis is pretty basic, but there's a lot going on when you take a deep dive. Same with funny cars - their limited wheelbase makes weight placement even more critical, as you can't adjust the driving position. Too much nose weight and it'll react slowly, or even worse struggle with smoking the tyres. But too much on the rear and it'll want to stand up on the wheelie bar at 45 degrees! Everything is about that fine balance, like walking a tightrope. Much like the fuel and clutch management systems!
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