Japshow report, July 2015

The Japshow streetcar event is not the ideal surface for us to test on, but with prepared track time short of supply in the holiday months it was the best we could hope for. A very lazy off the line and massively rich 7.4 @ 181mph straight out of the van cheered us all.

Mark from Owen Developments was on hand to drive the laptop and dialled out 20% from the fuel map to help compensate for the larger injectors. This resulted in more power and wheelspin off the line on the second run. Another reduction in fuel (but still rich) was followed by our first encounter with tyre shake on the third run.

Mick had gathered some useful info on turbine speeds and with everything in one piece we retired to fight again another day.

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2015 rebuild report

It took us nearly a year to rebuild after the rod breakage in August 2014. The damage was extensive, almost sawing the crankcases into three pieces and damaging the block, liners and pistons. Luckily the head was not damaged as both rods broke on the downstroke, under power, not the upstroke due to overrevving. The frame of Storm is designed to withstand this scenario, and the dry sump prevented large quantities of oil from spilling under the rear tyre, so there was no fire or crash.

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The new crankcases took longer to make than expected, and even when they were ready in April 2015 additional work to them was needed. Top Fuel style alloy rods from BME were installed, along with larger Injector Dynamics 2000cc injectors, and the high pressure intercooler was removed as it had reached its flow limit.cases1 cases2 cases3 cases4 rods1 rods2 rods3

Mark Harrison from Owen Developments handled the wiring of the new injectors, and also installed a Motec channel expander, clutch pressure sensor, 10 bar boost sensor in place of the 5 bar one, and a G sensor. The small turbo was also upgraded by Owens with a larger compressor.

The loss of our good friend and Top Fuel legend Brian Johnson in April shook us all, but by July we were ready to test.

 

Open Sports Nationals August 2014 report

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Mike Burrowes photo.

Mick has identified that as overall boost increases the size requirements for compound turbos change. This would not be a problem on a diesel, but increasing from 30psi to 50psi for us now means that our sizing is off. For this meet we went up one size on the turbo housing as a temporary measure to bring the rpm of the small turbo down and will most likely change to a GT35 for next year.

On our first qualifying run the burnout was ineffective and the tyre spun at the end of first gear, and harder in second gear, with a wheel speed of 200mph, so the run was aborted. On the second run the bike crept through stage, caused by the temporary use of nitrous oxide in our CO2 bottle after the braided line from our main bottle failed. And on our third and final run the bike left hard, but unfortunately threw rods number 2 and 3 through the crankcases just before the eighth mile mark at around 150mph. The bike stopped safely, but scattered metal fragments and oil all over the track. The crankcases are holed front and back, along with the cylinder block, and we are yet to determine any other damage.

Most likely this will end our racing activity for this year, a rebuild over the winter with alloy rods is already being planned.

Mark Skinner photos:

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Video:

Summernationals June 2014 report

Prior to this event Mick found a broken wire from the boost controller to one of the control solenoids and reconnected it. We did not know how long the wire had been broken. In Q1 the bike exhibited some strange behaviour on anti-lag and the burnout was not as good as it could have been. A mediocre 60′ time of 1.19 was the result but the bike pulled well to a PB of 7.105 @ 197.97mph – one tenth off and 7mph up put us in #1 position and a full 30mph faster than the rest of the field. We couldn’t afford to be complacent though as Dale Leeks also ran a PB of 7.28.

It turned out that the boost controller wire must have been broken for some time. We had been going up and up on the boost settings for the small turbo over previous meetings without much effect. Reconnecting the wire made the small turbo suddenly tried to do all the work, revving to 170krpm and effectively sucking all the air from the big turbo, which was barely turning. So our PB run was done with the little GT30 turbo only! It has now gone back to Owens to be checked over to make sure it is ok.

After Q1 it rained and there were no more runs that day. Overnight Lorcan’s riding gear was stolen from his car outside his house (see previous post). We hurriedly borrowed gear from other racers (thanks Woody and Danny!) and Q2 resulted in more anti-lag problems and a 7.3 @ 194mph. Then more rain and the event was cancelled. We found out that the anti-lag problems were caused by the increased fuel pressure making the bike too rich to run while the anti-lag retarded the ignition and cured this with less fuel and slightly less retard for next time.

On both runs the bike was spinning the tyre and snaking all the way to the finish so next time out (August 9th RWYB) we’ll be concentrating on giving the bike more boost and revs and less clutch in an effort to get it to hook up off the line with a harder launch. Better weight transfer off the line should mean we can put more power in earlier and knock some tenths off our ET. And we’ll be using both turbos!

Q2 in borrowed riding gear.

Nigel Moore photo.

 

STOLEN

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STOLEN: Lorcan Parnell’s race leathers, helmet, gloves and boots were stolen from his car in King’s Lynn on Saturday night (28th June 2014). The helmet is a Simpson “Outlaw” Stig style helmet in very rare Corvette yellow with an ACU sticker (not standard) on the rear and an iridium visor. Probably the only one of this pale yellow colour in the UK, so very distinctive.

The custom-made Scott leathers are in red/white/black with “Parnell” and “turbo” on the back. Unique, and even if you tried to remove the lettering the stitching holes would still be visible. The Sidi boots have extra toe sliders glued on the inside of the foot for drag racing, as well as the outside as usual, and the gloves are red, black and silver. All were in a blue “Head” branded holdall.

Please share this page and tweet with all bikers especially in Norfolk/Cambs area. A reward is offered. Contact Lorcan on 07947 569920 or lorcan@750turbo.com or Police 101 or Crimestoppers with any information please.

2014 Spring update

It may not reflect in our ETs yet but plenty of hard work has been done by the team over the winter (despite Barry’s workshop being under water for 6 weeks) and progress is being made. After the bike pumped nearly all the oil out of the motor via the breathers at the Extreme Bike Weekend 2013 the Total Seal piston rings have been replaced with a more substantial alternative. Five runs of testing now show barely a drop of oil in the catch tanks. Good news for us, the Santa Pod track crew and other racers!

After some work on the wastegate springs we’ve now got a pretty good handle on getting the two turbos to do equal work, despite being different sizes. Turbo speed sensors from Owen Developments show that both are just about getting onto the bottom edge of their respective compressor maps at 38psi boost overall, with the big turbo coming in hard about half a second after the small one. This is fine as we can launch with the small one then use the big one to ramp the boost up, and they are only going to get more efficient at higher pressures, not less efficient as would be the case with a single turbocharger.

Angus has nearly completed the fairing and front wing and these will be fitted when the bike reaches 200mph in the quarter. We think this will make a big difference to speed and traction but want to be consistently quick before introducing them to see just how much of an effect they have.

The other issue we are still exploring is the clutch setup. We know we need the control of a SSB bike with the power transmitting capability of a Top Fuel bike, but we’re still finding out how much slip to build in and where.

We’ll be out again on 30th May.

Photo from Jez.

Thanks to Jez for the photo.

Steering a big tyre bike

We’re often asked about how bikes with a long wheelbase and wide tyre like Storm steer, and the answers can be somewhat surprising. Legendary chassis builder Jim “Puppet” DiTullio wrote the following piece a good while ago for the Stripbike.com website, but although the page no longer exists and Jim is no longer with us these words give a good description of what’s going on in a conventional Top Fuel / Funnybike design. I hope Gary of Stripbike doesn’t mind me reposting them. I’ll post our own thoughts on the matter later.

Puppet speaks:

This may sound like a weird topic but it has been my experience that not many people even some pros understand how a big tire bike works. This also applies to smaller tires to a lesser degree.

We have all seen a new rider going down the track on a big tire bike and the bike starts heading to the centerline, the rider shuts it off and starts leaning the bike over till sparks are coming off the frame but it is still heading for the cones. If he’s lucky he will not hit any but usually they take a few out…You have no idea how many lower spoilers I have made do to cone damage…

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In fig. 1…you will notice the tire is straight up and down and the contact patch is the full width of the tire. This is the way the tire works the best, as soon as you lean the bike ( fig-2)

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you are asking for big trouble. When the bike is leaned over a thing called reverse steer happens, in other words, when you lean the bike to the right, it wants to go to the left.

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In Fig-3.. I have drawn a top view of what happens when you lean a bike to the right. As you lean the bike over to the right, the contact patch moves out to the edge of the tire, driving the bike to the left…

I always tell the new riders to go and ride a one of those off road 3 wheelers because a big tire drag bike handles much the same way…You have to lean them to the right to make a left turn. When you make a left turn, What you are actually doing is pushing down with your right foot ( to load the right tire) and leaning your upper body to the left to control how high the left tire comes up. A big tire drag bike is like a three wheeler with narrow rear wheels…..

You actually steer a bike with your feet (If you use the footpegs)…When it is on the bar going down the track and you want it to go left, you apply pressure to the right footpeg which tips the chassis slightly to the right loading the right side of the tire which drives the bike to the left..A the same time you lean your upper body to the left so it doesn’t tip to far..

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This brings up the subject of footpeg location. If you mount the pegs high as in fig. 4,
not much happens when you push on the footpeg. the best place to mount the pegs is to mount them as low as possible as in fig. 5 then when you push on them it is easier to tip the chassis and move the bike around…Whether you use the pegs or not ( Harley riders) this is basically how a chassis works..

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In summary…It is best to ride a big tire bike under full power and on the bar, keep the chassis straight up and down and use the footpegs…If you want to experience how hard these bikes are to ride slow ask someone if you can ride it while being towed back to the pits…Sam Wills told me one time that these are not motorcycles, they are Uni cycles and he thought it would be easier to ride one if you had never ridden a bike before. That way you would have no bad habits (leaning the bike) to overcome…..

Pup.