Author Topic: A few more mph from my Pilot?  (Read 1728 times)

raceinsnake

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A few more mph from my Pilot?
« on: August 03, 2009, 03:54:31 AM »
Hello All!

I'm new on here and although I've had my Pilot for 3 years now I still haven't done any mods to it. Entered my second competition at the weekend there and won my class even though I was up against a couple of crazy fast rage and other types of buggy.

They seemed such a handfull on the tight tracks where the Pilot was effortless.

I have a 2 day event in 3 weeks time where the track is a bit more open and I wondered if there are any tips on squeezing another 10 or 15 mph out of my Pilot. I think it barely does 45 mph at the moment and I'll get slaughtered by these others on the day with the speeds they're capable of. Any tips on how to gear it up a little?

Adnoh

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A few more mph from my Pilot?
« Reply #1 on: August 06, 2009, 10:12:20 AM »
MAN, If it was only that easy. As you now the pilot has a cvt trans and belt. The transmission has fixed gears. There is to my knowledge no gears availble to change out in the trans. Your options are limited to what effects MPH.

The options are: #1 Rpm, #2 Tire size, #3 CVT ( belt) run out.

Lets talk accerlaction for a minute not MPH. Some times MPH is not what you need but quicker accerlation or slower accerlation. SInce you race you should know what I mean. If you over gear you will slow down you cornor to cornor. The best set up is the average power to accerlation curve for the track.  Remember were talking accerlation. Tourge gets you there and Horese Power keps you there.

Stcok bike = stock motro CVT and shocks. You start messing with one you change the rest in the way they work together.

If your afraid there going to out run you down the straight which is usally just on or two straight would you be better off increasing the  time lost in the straights in the cornering and turns where most of the racing takes place. Driving skills will equal and lot of speed. If you cornor right and set up your bike for the best speed thu the greater section of track the faster your overall time will be. Most MX races are not dragstips. Getting the most from your acceleration is why better than straight line speed.

One thing I learned setting up pilots ( motor,cvt and shocks) is they must work in unasone or the extra power is wasted. 75 Hp is no good without a butt load of torgue. It will actually slow you down while your waiting for the CVT to upshift I'am already up shifted to ran out. See how accerlation is key to MPH. It's not when you get there but how quick.

Once your change the gear ratio to a taller gear you now need to get it to accelrate at the same rate or your change will have negitive effects. So increase in torgue is needed to get it there while HP holds it.

So how do increase torgue. Two simple ways. One is to increase displacment( bigger bore). The other is to increse CR (Compression Ratrio) or increase your static compression levele which effect your CR.  

What this effect will do is get the taller gear moving quicker. Think about leverage. longer the handle or more weight applied the eisier it is to move. Since the handle is like stroke and unchanged more force is applied acting like weight on th eend of the handle making the heiver object easier to move AKA taller gear. For every action there is equal or greater reaction. I do believe this is a basic law of physics.

While on the subject of torgue and the cvt The torgue curve can be minuplated by RPM . This to say were it comes on and crosses over to HP.

The basic rule here is 5250 rpm. So one will need to find where it come on then set up there cvt to operate in this range. If set to low it will not accelerate at peak untill a time it reaches the rpm required to accelerate to the HP cross over which maintaines the MPH. If the CVT rpm is to high you are not making the best of the torgue and accerlation and are already in the HP curve which only holds you there. I call this a lazy motor and most say it acts like its no ton the pipe. This is a slower accerlating bike. I like to think about it like bolting up paddles to a stock fourwheeler. You will find it takes longer between shift. You now have added additional load to which the motor must over come. The simple thing to do change your gearing. This will not only let it accerlate quicker but achieve a higher top speed related to the pramiters of the motor efecting leverage. Most refer this as rotating mass to which I like to refer to as efficiency.

The torgue and Hp curve are based off of time and area ( cylinder porting). If these are changed it effects the way the related parts move and the leverage or force placed on them. If one was to increae RPM to raise the MPH a change in the curve is necessary or the motor just make noise. You will need to up the curve of both which effectes the CVT and rate of CVT upshift. Now you have chnged that rate you must allow the engine to get in to its band width or it fall flat . An expanison chamber is alos need to take advantage of this change. The time and area ( cylinder porting) is usally done to the expanion chamber to take advantage of it changes tuned lenghts as it reactes to the pressure changes  of the motor.
There is many option for this depending on riding conditions.

Now for the quick ansawer. Clutch, pipe ,carb,intake mods,porting and rev delete cdi. How and which way to go depends on you and your engine builder.

No I did not forget about shocks. WIth most engine mods you will quickly over power your suspenion which negates the motor mods. A good shock package is worth about a 30% increase in power. Another thing to consider is weight as related to rotating mass effecting efficiency. If you cant hold a cornor you must slow down to regain control or if it cant turni n becuse of loss of traction your entry speed must be reuced. The quicker it takes set the quicker you canget back on the gas and accerlate.   If you have to slow down thu the woops MPH does you no good. Go talk to some other racers about cornor speed nd the important role it playes. I will quote  race driver that published book  on speed secertets that said " most race are won in the cornors".  

The only way to do any better is to do a sled motor and driven conversion which increases the whloe pramiters and will hall butt.

raceinsnake

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A few more mph from my Pilot?
« Reply #2 on: August 07, 2009, 04:25:19 AM »
Thanks for taking the time to reply in so much detail. You've certainly given me plenty to think about!

I did fancy doing the sled conversion but that will have to wait until the winter at least. Thanks again mate I'll let you know what I decide to do

raceinsnake

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A few more mph from my Pilot?
« Reply #3 on: August 07, 2009, 04:34:28 AM »
I should say that most of the events we enter are on grass fields and usually end up wet. The surface can be really greasy and the high powered buggys struggle for grip on acceleration. I think there is a chance that I could lose out on a little bit of torque to gain some extra top speed in this type of situation. I'm tempted to try a larger tyre size because I could alays easily change back depending on the conditions on the day etc. I've had a look around the net for replacement tyres / wheels and can't seem to find any direct fitting options but maybe someone here could advise? I'm guessing the wheel should be 12" or so or is there a higher profile grasstracking tyre available for the exisiting rim? Sorry to lean on everyone again for this type of advice but I havent found anywhere to get advice in the UK yet.

Adnoh

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A few more mph from my Pilot?
« Reply #4 on: August 07, 2009, 09:07:27 AM »
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Adnoh

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A few more mph from my Pilot?
« Reply #5 on: August 07, 2009, 09:12:41 AM »
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