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Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1014427 times)

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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1110 on: March 17, 2013, 11:52:08 AM »
Triumph Performance has the standard 0.043 inch thick head gaskets giving an 11.5 to 1 static comp ratio.  That is what I will use for the race build.  The street build will use a 0.063 gasket giving around a 10.7 to 1 ratio.  A pair were ordered from Cometic today.  I would lower the CR down even more but these are overhead cam engines with a chain.  Typically there is enough slop in the chain to accommodate a small increase in gasket thickness.  Using a thicker gasket advances the cams a small amount.  This is not enough to cause problems and it will be a benefit on the street by helping the low rpm power.

A pair of OEM Triumph cams for the 790 cc engine are on order.  They will be in the street build.  The cylinder head is in California while the shim-under-bucket kit is being fitted.  I asked the machinist to see if there was a way to use lighter springs on the street and I could switch to the heavier ones for racing.

The plan is to set engine up in race tune, haul it up to Cascade Moto Classics, and jet it for Bonneville.  Then, I will drain the tank and put in some race gas equivalent to the "event gas" in AUS.  I found a source here for Sunoco where I can by it by the gallon and I do not need to purchase a big can.  Is there anywhere where I can get the specs for the event gas that is available at Gairdner?

I did not hear the piston slap from the badly worn engine I am rebuilding.  Maybe I am deaf in those frequencies and I also cannot hear detonation?  I asked for information from a supplier about those Knock Link detonation sensor lights.  They glow red when the engine pings and I hope to see any problems on the on the light before I blow up the motor.

 

Offline Jon

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1111 on: March 18, 2013, 06:54:17 AM »
There's no fuel available at Lake Gairdner Bo, there's not much of anything there actually.
If you need something it has to be in your van on the way in.
Plenty of Salt, Sand and flies though

jon
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1112 on: March 18, 2013, 10:37:57 PM »
The fellow that designed the motor parts I am using, Matt Capri, says 110 octane leaded is the best fuel for the setup I have.   Some internet research shows I can get VP, Sunoco, and ERC race gas here and in AUS.  These fuels look like they might work:  ERC 110K, Sunoco Standard 110 octane leaded, and VP C12 108 octane leaded.  Some basic questions.

AUS is a big country and I am not sure where we will be based, it is either Adelaide or Victoria.  Which of these brands has the widest distribution in the South Australia/Victoria area?

The fuel spec sheets are sort of a mystery to me.  It looks like these fuels have different properties.  Am I correct to say that if I jet the bike for one of them I had better use it when I get to AUS?

Can I jet for one of these fuels and be fairly certain the jet choice will be too rich for the other two if I use them?

Are all of these legal for an attempt at the 150mph club?  I think they are based on reading the DLRA the rule book, but I am not 100% sure.

These are a lot of questions.  Any help is appreciated.       

 

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1113 on: March 20, 2013, 12:19:03 AM »
Jon, are they biting flies, regular house flies, or those little brine flies?

Today did some thinking.  The density altitude at Bonneville is pretty high and that reduces the bike's compression ratios.  That explains why the engine runs well on all sorts of different gasolines.  Gairdner is only 111 feet above sea level and fuel choice will be more critical.  The various compression ratios will be higher.  In addition, the air will be thicker and I will be pushing against more aerodynamic drag.  All of this adds up to more combustion pressure and heat than I am used to.  The situation is made worse by the new engine configuration.  The old motor was an 865cc twin with 10.5 to 1 compression and the new one will be 994 cc with 11.5 to 1 comp.

A hot burning oxygenated gas might not work good in this air cooled motor.  What do I look for on the gasoline spec sheet to tell me what a good fuel would be?  It needs to be forgiving.


Offline Jon

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1114 on: March 20, 2013, 12:37:45 AM »
They are exploratory flies Bo, they will just wander over and into you.

I think most fuels are available, if you have a specific fuel I can track some down and meet you at the lake with it if you want.

jon
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Offline fredvance

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1115 on: March 20, 2013, 08:50:53 AM »
I think VP mr12 would work great for you. I run 13-1 comp and it gives me 6-8 HP over ERC mul-b.
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1116 on: March 20, 2013, 11:33:36 PM »
Fred, this year I am going to go for a record at B'ville and I need all of the help I can get.  Some highly oxygenated leaded gas will be perfect.  How do you set the jetting for that stuff besides renting dyno time in SLC?

Offline tauruck

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1117 on: March 21, 2013, 12:31:05 AM »
Bo, why don't you blend your own "jungle juice"?. Toluene and Xylene added to gas makes HP. :-)

Offline fredvance

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1118 on: March 21, 2013, 10:25:43 AM »
I haven't messed with jetting in 30 years. My ecu compensates for the altitude, some. This year we are going to put the bike on Scott Horners dyno in SLC. I highly recommend you use MR12 and put it on Scotts dyno.
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1119 on: March 21, 2013, 11:00:41 PM »
Jon, it seems that a person needs to belong to certain race clubs or organizations to get leaded gas and not all race groups can get all brands of fuel.  The oxygenated leaded fuel Fred is recommending is not sold in AUS.  Sunoco EXO2 is an oxygenated leaded with 10% oxygen by weight.  I can get it here and in AUS.  Can a DLRA guy, which I will be the year I am in AUS, get leaded Sunoco?

It looks like this Sunoco EX02 is some radical stuff and I will need to jet the bike richer for it.  I can do that on the dyno.  Has anyone used this gas?  It will put me into the fuel classes at BUB.

Mike, I am not confident enough to make my own fuel.  I do have xylene, toluene, acetone, etc on my paint shelf. 

Offline Jon

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1120 on: March 22, 2013, 02:50:34 AM »
Bo
If you choose a fuel I'll look around for it, if your fuel is oxygenated your in fuel for DLRA as well.
What altitude are you at there for Dyno?
I would be tempted to get your bike dynoed and jet it and set your timing curve over there at close to sea level so that any issues can be dealt with in civilisation.
jon
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1121 on: March 22, 2013, 08:45:09 PM »
The dyno I use is almost exactly the same elevation as Gairdner.  We do not use the oxygen sensor to jet with leaded gas.  The procedure is to increase the jet sizes one at a time until power peaks and then drops.  Then, the jets that make the most power are reinstalled.  Next I try different advance curves until I find the best one.  Then I recheck the jet sizes.  It is a time consuming way to go.  It sure works, though.  That is why I do not switch fuels very often.  The Sunoco EXO2 is what I will use.  It will put me into the fuel class on a 1000cc APS-F running against Brett DeStoop's 240 mph record.  He does not have anything to worry about.  Thanks for the offer to bring some fuel.  It is 2015 when we are there and a lot can happen between now and then.  Who knows, leaded gas might be banned.

We have a city near here named Bend where I used to live.  It is near the same elev as B'ville.  I might do the jetting there for Utah.  We do not have the FIM rules yet so I am not sure they will have a fuel class.  I need to run event gas in the gas class.

Thanks for the ideas about jetting and oxygenated leaded.  The engine is built with "can tipping" in mind, and specifically nitropropane.  It is plenty strong and it should handle the stress if I get the timing and jetting right.       

Offline Seldom Seen Slim

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1122 on: March 23, 2013, 10:28:26 AM »
Bo, FIM doesn't care about fuel.  Run pump gas or race gas or spray with nitrous or use 99% nitro or bug juice or anything -- they only move you based on displacement and whether or not you've got forced induction.  I think. . .
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Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1123 on: March 24, 2013, 12:18:59 AM »
Slim, we are both interpreting the regulations the same way.  I ordered a can today.

The intake tuning I am doing needs some background information.  The standard Triumph air box has a little snorkel for an intake.  It is replaced by this aluminum bell mouth to increase the flow.  The standard Triumph paper filter is plenty large and it does not restrict air flow enough to reduce power.  The oiled foam filter I am using in the air box does not restrict the flow enough to cause problems, either.  The air box is divided into two chambers.  One is the filter chamber.  The other is a plenum chamber.  The pistol shaped plate divides the two.  The view in the photo is the plate from the plenum side.  The plenum is tuned using Helmholtz principles to aid performance.  The plate needs to be in the box for this to work.  The rubber intake trunks between the air box and the carb ends are tuned to produce peak power at the third harmonic between 6,000 and 7,000 rpm.  That is just right for a street motor.  The air box is a good thing.   

Offline wobblywalrus

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Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1124 on: March 24, 2013, 12:42:50 AM »
Unfortunately for me, I will be switching back and forth between street and racing carbs yearly.  It is a pain in the tail to change out the air box.  Pod filters will be used on the Triumph OEM carbs for the street.  This way, it is no problem to switch to the racing carbs.

A popular modification is to connect the pod filters directly onto the carb ends.  A disadvantage to this is the air tumbles into the carb ends from the filters and it is swirling and turbulent at the vacuum slide orifices and the jet orifices on the carb intake bells.  This confuses the carbs and they do not work correctly.  Also, this is the incorrect tuned length.

A pair of inlet runners are made up with the same tuned length as rubber trunks that go to the OEM air box.  Copper plumbing pipe and fittings are used.  The little ears are connection points for zip ties that help to hold the runners on to the carbs.  This added length helps to organize the air flow and when it reaches the carb it will be less turbulent.  These street carbs will work much better than they would with the filters directly attached.  The correct tuned length helps performance, too.

In summary, the OEM air box is the best setup for the street.  Pod filters with runners are next best, and the worst are pods attached directly to the carbs.