HomeFeatures & ColumnsDragbike.com Analysis: New NHRA Pro Stock Motorcycle Rules

Dragbike.com Analysis: New NHRA Pro Stock Motorcycle Rules

At the conclusion of the 2006 Pro Stock Motorcycle season, the NHRA made changes to the PSM rules that promise to change the face of the class as significantly as the 2002 rule changes that allowed purpose-built V-Twin engines to compete.

NHRA Pro Stock Motorcycle Rules

Inline four cylinder metric bikes can now have four valves per cylinders with the maximum allowable displacement, run plain-bearing cranks, all-billet construction and electronic fuel injection.  These new rules catapult the class into modern times.  Formerly PSM was the only pro class in NHRA POWERade drag racing that still used production engine “cases” with roller-bearing cranks.

Four valves per cylinder have been allowed for years but always as a significantly smaller displacement then their two-valve counterparts.  Now 4-valve engines can have everything the 2-valves do.

At the beginning of the 2006 season NHRA allowed in-line four-cylinder, 2-valve metric bikes to increase displacement to 1500 cc to 1655 cc and more significantly, allowed the bike to run EFI.  EFI was first allowed in the class with V-Twins and now that it is opened up to all makes.  Now Pro Stock Motorcycle in some sense leads the way for technological advances as Pro Stock, traditionally a “gas and carburetors” class, moves into the 21st century.

EFI has not yet been effectively been used in the current metric engines.  Those in the know feel it will be the standard, but more development time is needed.

Perhaps the most significant part of the rules is that while purpose-built billet engines can be developed and run in the competition, all parts must have an OEM part number.  Anything can be built – within NHRA guidelines – as long as a motorcycle manufacturer is willing to put a part number on it.  This ensures factory involvement in the class.

The upside is a utopian racing fantasy:  to have multiple motorcycle OEMs battling it out with the most current technology.  Racing events where American V-Twins go head-to-head with Japanese inline fours on a level playing field.

The downside is, it is thought, that the cost will inevitably escalate to the point where die-hard independents that have ran the class for years will be financially forced to the sidelines, thinning the field.

The task for the NHRA is nothing short of monumental:  To retain parity among racing vehicles of radically different engine geometry.

While each side of the argument postures that the other side has an unfair advantage, the NHRA has to be commended as their rules tweaking over the last few years has produced legitimate parity between purpose-built V-Twins that were non-existent in the year 2000, and Suzuki GS-based engines which last saw US showrooms in the mid 1980s.

The numbers bear this out:  While Harley-Davidson rider Andrew Hines took his third straight championship in 2006, he was hardly dominant.  His last championship wasn’t decided until the final event in Pomona when Hines was able to edge out the Army Suzuki of Antron Brown by a mere 23 points.  A V-Twin (Chip Ellis on the Drag Specialties Buell) has the all-time quickest pass ever at 6.911 but a Suzuki (Angelle Sampy on the Army Suzuki) holds the backed-up national elapsed time record at 6.939 seconds.  The top ten in 2006 were evenly split with five V-twins and five Suzuki’s.

Also, multiple racers have had a legitimate shot of winning.  For the second year in a row eight different riders scored wins on the 15-event circuit with no single rider winning more than three events.  A total of 14 riders made the finals in 2006 – a much different scene from 1998 when Matt Hines won 10 events with a total of three riders winning races the entire season.

So why mess with success?  While the GS motor is at the end of his development life, the new V-twins have yet to show their true potential.  These new rules allow both configurations to remain competitive in the years to come.

What do the leaders of the sport feel about the new rules?  We spoke with four of the top engine builders, team owners and crew chiefs in the class to find out.

Byron Hines is a true legend in the sport.  Vance & Hines is one of the best-known names in the motorcycle aftermarket.  The Harley-Davidson V-Rod Pro Stock Motorcycle engine designed and built by Hines has won the last three NHRA PSM championships.  In fact, including the Suzuki powered bikes of Matt Hines and Geno Scali, a Vance & Hines engine has won seven of the last 10 POWERade championships.

“The NHRA thinks they need the playing field more level than it is currently,” said Hines.  “They keep moving the goalposts.”

“They asked us what our opinions were but I don‘t think they are paying much attention to us.  We are the targets and until we get smoked they are just going to keep making changes. Everything they have done over the last few years – whether it is right or wrong – was to slow our bike down or speed it up.  Everything they have changed has been directly related to our bike.”

“The new rules have their good points and they have their bad points,” he continued.  “They are trying to make a place for a future for more modern technology closer to what the factories actually produce, more closely aligned with what is on the production floor. There was speculation that the parts for the GS motor would be drying up.  They have been out of production for five years.  Parts you need to build an engine will not be available down the road.”

“Unfortunately it puts a lot of guys in a predicament where they have a lot of money invested in what they are racing now – spare engines or whatever,” continued Hines. “It is going to be an effort for the aftermarket to pick up the slack.  It’s a huge investment to build the engine to what the NHRA spec is because there is nothing currently available that matches that spec.”

George Bryce is a motorcycle drag racing legend in his own right.  He has garnered six NHRA championships with riders John Myers and Angelle Sampey.  Seeing the advantages of the V-Twin design allowed by NHRA in 2002, he teamed with George Smith and S&S Cycle to develop, market and sell the G-Squared Buells ridden by four of the top 10 riders in the POWERade points.
“What the NHRA are doing is the same ‘open book’ policy that they gave the Vance & Hines Harley Davidson deal to get the V-Twins in the sport,” said Bryce.  “In order to get the new ZX14 and Hayabusa engines in the sport they have to give them an open checkbook so to speak, to let them build what they want.  It is not an open checkbook in the sense that anything goes but they are giving them a lot.”

“I think it was the right thing to do because no one was going to build one until they gave them Carte Blanche,” continued Bryce. “I wouldn’t do it.  Kawasaki wouldn’t be interested in spending all that time and money to build a little 4-valve that maybe would go out and run good.  Suzuki wouldn’t be interested.  They were more interested in getting a fair shake.”

Army crew chief Steve Tartaglia has had the most impressive results currently with the long-standing 2-valve Suzuki GS motors.  His riders, Antron Brown and Angelle Sampy placed 2nd and 3rd respectively in the NHRA points in 2006 and Sampy holds the elapsed time record for the class.

“I think the new rules will be as monumental to the class as the V-Rod was,” said Tartaglia, “but it will positively affect more people. The V-rods have purpose-built engines now we can have them as well.”

“I like the fact that it is a new motor and the factory can get involved. You can’t buy a [production] bike with two valves and carburetors.  The only thing I don’t like about it is that they came out too soon. They should have made it effective in 2008.”

Finally Rob Muzzy has been at the absolute peak of motorcycle racing capturing numerous World Superbike road racing championships in the 1990’s as the leader of the Kawasaki factory team.  A motorcycle drag racer himself in the 1960s Muzzy came back into the sport running various classes (and winning championships) in the AMA/Prostar series.  He entered the NHRA Pro Stock wars four years ago with a Kawasaki ZX-12 with rider Ryan Schnitz but was not able to qualify the bike.  The team switched to a V-Twin Buell in 2005 and Schnitz won events and placed in the top ten in points two years in a row.

“I am pleased to see they have taken into consideration the modern engines and made changes that should allow them to be competitive,” said Muzzy.  “I am a little disappointed at the all-billet engine deal.  I think it opens up the opportunity for the person with the resources and the funds to make an engine that would dominate – like what happened with the twins.”

“In the case of the twins it would have not been competitive if it wasn’t a billet engine a purpose-built engine,” Muzzy continued.  “I don’t believe that to be true for the inline fours.  I believe there are production engines available, specifically the ZX14 and the Hayabusa, that can be modified to win. Therefore I don’t think there is a need for a billet engine.”

Current Status

Muzzy and the Kawasaki Trim-Tex team seem to be the closest to fielding a bike that utilizes the new rules.  The plan is for a ZX-14 case with widened cylinder bore centers and a billet 4-valve head.  It should hit the track in the first quarter of the season.

Muzzy selected a production engine case as the platform for his race engine due primarily to his sponsorship arrangement from Kawasaki. “Kawasaki is not interested in advertising accomplishments made with a billet, non-production engine,” stated Muzzy.  “The Japanese corporate heads have to feel like it is their product to brag about it.”

Muzzy also feels that his approach will keep costs in line. “I think you may be able to build a ZX-14 engine like we are going to run for less money than you would have to give Byron Hines for a competitive 2-valve engine,” said Muzzy. “It won’t be more money and it might be less. A lot can come from our success.  Not just for us but to drag the other guys in.”

Vance & Hines currently has the largest numbers of engines running in the class.  But their staple 2-Valve GS power plant has limited life considering the new rules.

“Our customers have a tremendous investment in what they race now,” stated Hines. “We are going to continue forward with our two-valve program.  We have big stake in it, we have castings and molds and stuff that it would be all obsolete if we just abandoned it. For other aftermarket suppliers like Falicon and MTC this is a staple of their pro category.”

“We are not going to abandon it but at the same time we need to look to the future and see if we can come up with,” continued Hines. “We don’t want to take on the whole engineering and design of our own engine that is a big expense for multiple suppliers in the aftermarket because only one is going to survive.”

For George Bryce, he is quite happy with his rampaging V-twins, thank you very much.  As far as a new 4-valve in-line four in his future: “I am not interested in designing one, building one or getting involved with that right now,” he stated.  “But when they do become available and it is a reasonable product with a reasonable performance then I might be interested.”

“I am glad that Suzuki and Kawasaki are getting involved hiring people to build engines for them,” Bryce said.  “Good for them.”

“When we put the S&S deal together we worked on it hard behind the scenes to get a piece that would work,” he said. “When we finally put in on the track it was competitive and for sale right away. That is a tribute to the S&S guys and team that George Smith and I put together.  I hope that is the goal for Suzuki and Kawasaki because if it is, it will make our sport continue to grow at the rate it has.”

“I am working on a 1655 2-valve,” continued Bryce.  “We will have one leg on each side of the fence. I am going to be with Karl Klement and his team.  I will be based out of their truck.  I will be an advisor to the G2 team.”

By far, the team with plans to most leverage the new rules is the Army/Don Shumacher Racing team.  DSR is currently in negotiation with Suzuki to build a full-billet, purpose-built engine.  They are working to identify a company (word is they have it down to two) to build the prototype which will then be produced by the DSR team.  Tartaglia will oversee the effort.

“That is the plan,” said Tartaglia.  “We don’t have a contract yet.  It could happen any day.  If we get the contract today I can see us possibly testing by the end of the 2007 season.”

“We are going to take advantage of everything that is available,” said Tartaglia of the new engine project. “It will have a plain bearing crank which will take away a huge headache.  Changing cranks will be easier, it will be just like any other racing motor.  We are also planning on making the engine scalable where bore size changes are more easily accomplished. The motor will be designed for EFI. A carburetor will not go near it.”

Will the Suzuki Pro Stock engine be available to other competitors?  Absolutely says Tartaglia.  “Suzuki wants them on display at the races with a price tag on them,” he said.

Until the new engines are running and competitive the Army team will run a pair of their current 2-valve power plants inside a new Roo-Man chassis and TL bodywork.

The Issues 

The main concern of conventional wisdom is how the NHRA is going to maintain parity once the potential of the new engines become apparent.

The four valves are going to dominate, if you ask Bryce.  “If you go outside of America and go out of drag racing and go to any of the engine design corporation companies and ask them what would they rather have a 1655 3-valve or a 1655 4-valve Nobody will vote for the 2-valve,” he said. “The only people that will tell you a 2-valve is just as good as a 4-valve – and there are people out there they I respect that say that – they are either covering their bases, protecting their own interests, have their own personal agenda or they don’t know what they are talking about.”

“Allowing big 4-valves is the right thing to do as long as they understand that as soon as [the new bikes] start out-running the old antiquated dinosaur 1655 2-valves they will probably have to change the rules. Same thing as they did with us.  As soon as the V-Twins started running good they changed the open checkbook to a penny-pinching bank with a 40 pound weight addition. It knocked the V-Twins backward.  Of course not enough to keep Andrew from getting three championships in a row.”

Hines is concerned that the new engines will also dominate and that changing the rules to keep parity will be essential.  But will it be effective?

“It’s an interesting situation,” said Hines.  “I think you will see the 4-valve motors get competitive pretty quick. You could take a ZX14 or Hayabusa and modify it to go racing. I think NHRA had their eye on the Suzuki so they didn’t realize what Kawasaki potentially could do.  The engine has the right layout with a few special pieces.  It doesn’t have to as big as they made it.  1500 cc would be right in the ball park.”

“I think they assumed that if they allowed this to happen this year the bikes would be ready for 2008,” continued Hines.  “These new 4 valve engines don’t need much development on them.  They will make the power if you get them big enough.  Ryan Schnitz will be a good indicator of the potential.”

“The NHRA people say they can invoke the parity rule.  The problem is how long does it take to do that and it the championship out of reach by then?  With the way they have the new points structure laid out someone could hold back and just pick everybody off at the end of the year. It is a tough call. I would not want to be in their shoes.”

Muzzy says that the real problem with the new engine design is not only engine size or valve per cylinder, but allowable geometry.

“I had lobbied for limiting the bore spacing on the billet motors so somebody couldn’t make a very over-square, high-revving Fourmula-1 type engine,” said Muzzy.  “They should limit the bore to where you couldn’t run a modern engine that had any more RPM capabilities than a current 2-valve engine has.”

“No matter how you look at it, when it comes down to the bottom line, engine size and RPM dictates the horsepower” he explained. “Ultimately want really limits the RPM is piston speed. Piston speed is directly related to the stroke.  The longer the stroke the greater the piston speed at the same RPM.  They should have limited the bore spacing to 93 mm which means you can only do 89 mm bore.  This way 2 valve and 4 valve motors would have the same stroke. They would therefore have the same RPM limit.  So there shouldn’t be a huge difference in performance between the 2 valve and the 4 valve.”

“If you can take a 1655 motor and turn it at 15,000 RPM instead of 14,000 RPM it will make more horsepower. Period.  That bothers me.  I am opposed to that. I think it was a mistake. I think it will cause them, in time, to have to review the rules.  In the meantime somebody spends half a million dollars to build an engine and the later find out the rules change.”

“I think Shumacher Racing can do the exact same thing with a Hayabusa that I can do with a ZX14,” continued Muzzy.  “I don’t think they need to build a billet engine to be competitive under today’s rules. And I believe if they do build a billet engine they are going to screw up the works because then everything else is going to be behind.”

The Future

Beyond all the talk of specific issues, the rules, as they are currently written, open up the possibility for a “generic” engine that could bring all of the manufacturers into the NHRA fray.  As Hines notes, this has been in discussed before.

“Years ago there was talk about having one engine,” said Hines.  “It is going that way. You could go to Yamaha with an engine for them to put a part number on and it could be the same engine Honda had their part number on. I think it is possible at some point in the future that you can have a generic engine modeled with the technology that they currently sell that could potentially bring in Honda and Yamaha at the NHRA level.  But I think that is still a ways off.”

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