Time for Stage I
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MotoGP
Joined: Apr 2005
Posts: 5,631
From: Montreal
I wrapped the headers all the way back to the link pipes as it helps to reduce the heat radiating off front pipe and heating up the oil sump. As for the rear pipe, it helps keep heat away from the shock. Take it for what it`s worth of course. I am looking into getting my new Akra system ceramic coated (for the saem reasons, as well as aesthetics and longevity, and of course better scavenging from the hotter pipe)
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
Two suggestions:
Feed the vent lines into the bottom of the airbox (use a T fed through a grommet, hook up the line from underneath and have it sense air pressure from the sides of the T located in the box), this will allow the system to stay in equilibrium (note: most carbureted snowmobile engines run this type of set-up, helps prevent teh possibility of pressure differentials developping))
Feed the vent lines into the bottom of the airbox (use a T fed through a grommet, hook up the line from underneath and have it sense air pressure from the sides of the T located in the box), this will allow the system to stay in equilibrium (note: most carbureted snowmobile engines run this type of set-up, helps prevent teh possibility of pressure differentials developping))
I'm sure there's a way to make it work.
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MotoGP
Joined: Apr 2005
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From: Montreal
It works on thousands and thousands of carbureted snowmobiles. Having everything reading the same pressure at the same time is the only way to ensure the fueling stays consistant regardless of speed, cross-winds,.... In fact, the Flo-Commander uses a central air feed located inside the airbox.
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SuperSport
Joined: Jun 2008
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From: San Diego
F3 were the ones that had this
They also had a small port that went directly to the carb float bowls in addition to the ram air ports.
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SuperBike
Joined: Dec 2005
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From: South Lake Tahoe, CA, USA
All I'm sying is, there's more to it than cut 'n'' slash.
Maybe it's a matter of tube size. I dno't know. But there are engineers with lots of test equipment and money to back them up, figuring out what works.
I know for sure they aren't trying to figure out how to derease power output.
Maybe it's a matter of tube size. I dno't know. But there are engineers with lots of test equipment and money to back them up, figuring out what works.
I know for sure they aren't trying to figure out how to derease power output.
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SuperBike
Joined: Aug 2005
Posts: 1,864
From: Fort Wayne, IN
That's logical.... until you realize that many of the Engineers are working on ways to satisfy the Government regulations and human factors (harshess, vibration, etc). In fact, their efforts often result in less performance. That's handy for the aftermarket suppliers that produce exhaust, air filters, and the various other parts we spend thousands of dollars on!
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SuperSport
Joined: Dec 2005
Posts: 963
From: Sunshine Coast, Australia
My suspicion is the same as RCVTR. It is not the jetting that is affected by airbox mods, it is the vacuum control of the slides. I tried a few combos of the slide holes (drilling extar and filling them in etc) to see what effect they had, but no luck. They next trick was to try differnet springs in the slides to see what that did, but I got the ***** with it and gave up on it. I decided to go to EFI instead (not done yet, but most of it worked out), so never persisted with the carb mods.
My airbox was not like yours either, I left the lid on. I added two small intakes beside the snorkel, and fitted a much larger airfilter than standard, maybe 50% bigger in surface area. Made a big differnce to the jets I needed, but no way could I get rid of that mid range flat spot. Be great for the track though, as it was great at WOT.
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SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
Who knows it may be fine. I was running 205 mains and 50 pilots in mine with my modded airbox and WOT was great. But I could not dial out the flat spot in the midrange at about 5000rpm. Nothing fixed it, except closing up the airbox again. I even tried some HRC needles, which are a LOT richer than standard or Dynojet etc.
My suspicion is the same as RCVTR. It is not the jetting that is affected by airbox mods, it is the vacuum control of the slides. I tried a few combos of the slide holes (drilling extar and filling them in etc) to see what effect they had, but no luck. They next trick was to try differnet springs in the slides to see what that did, but I got the ***** with it and gave up on it. I decided to go to EFI instead (not done yet, but most of it worked out), so never persisted with the carb mods.
My airbox was not like yours either, I left the lid on. I added two small intakes beside the snorkel, and fitted a much larger airfilter than standard, maybe 50% bigger in surface area. Made a big differnce to the jets I needed, but no way could I get rid of that mid range flat spot. Be great for the track though, as it was great at WOT.
My suspicion is the same as RCVTR. It is not the jetting that is affected by airbox mods, it is the vacuum control of the slides. I tried a few combos of the slide holes (drilling extar and filling them in etc) to see what effect they had, but no luck. They next trick was to try differnet springs in the slides to see what that did, but I got the ***** with it and gave up on it. I decided to go to EFI instead (not done yet, but most of it worked out), so never persisted with the carb mods.
My airbox was not like yours either, I left the lid on. I added two small intakes beside the snorkel, and fitted a much larger airfilter than standard, maybe 50% bigger in surface area. Made a big differnce to the jets I needed, but no way could I get rid of that mid range flat spot. Be great for the track though, as it was great at WOT.
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
That's logical.... until you realize that many of the Engineers are working on ways to satisfy the Government regulations and human factors (harshess, vibration, etc). In fact, their efforts often result in less performance. That's handy for the aftermarket suppliers that produce exhaust, air filters, and the various other parts we spend thousands of dollars on!
Emissions standards play a big role in stock jetting. They test at ~7k RPM, I believe. Therefore, the stock jetting is lean there.
But in any case, it is a tuned system.
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MotoGP
Joined: Aug 2007
Posts: 5,942
From: Lake View Terrace, CA
HRC also used different lift hole configuration depending if you run a long or short Velo. stack....... so with stock stacks you end up with two different slide set ups........ just something else to consider.....
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SuperSport
Joined: Dec 2005
Posts: 963
From: Sunshine Coast, Australia
I had a friend with a HRC jet kit, which he loaned to me to experiment with as, he did not have it fitted to his bike any more. But it didn't work out. I did not try blocking off the air jets as HRC do though, so perhaps that was the key.
My friend removed it from his bike as he found it was not as streetable as he wanted. He eventually fitted Keihin FCR 41mm flatslides instead, which run with pod filters no worries. No vacuum slides to worry about with those babies. If anyone is serious about increasing the intake of the VTR, I believe flatslide carbs are the best option. EFI is THE best option of course, but will be too expensive for most people.
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SuperBike
Joined: Aug 2005
Posts: 1,864
From: Fort Wayne, IN
If you can do some fabrication work, a Megqsquirt EFI setup would be quite a bit cheaper than those flatsides. Especially if you use some RC51 parts. I'm kind of surprised that I don't hear about more people swapping over the RC51 EFI systems to the VTR. I'd think for well less than $1000 you could make that happen.
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
The only thing I see wrong with that is the size of the RC51 thottle bodies.
IMO they are too big on a stock RC51 engine as well, but are sized for a Superbike engine to meet homologation rules.
I found the part throttle response to be quite abrupt, bit I'm running a 1/6 turn throttle. I'm going to see about softening up the part throttle response when I get it mapped.
SP1 throttle bodies are the ones to get, if you want to experiment with RC51 EFI, because they are smaller than the SP2 throttle bodies, but make just as much HP. I think the hardest thing would be getting it mapped for a different Baro sensor location. On an RC51, the Baro sensor is mounted in a quiet zone above the ram air intake. Maybe right where the VTR float vents are? It seems like the ECU would pretty well plug and play. There is no cam angle sensor, so the EFI probable does a half squirt every crank revolution.
I've wanted to experiment with developing a Megasquirt system for a car or bike. It would help you develop a very good understanding of fuel injection. Not sure I could find the time at this point. Maybe some day.
IMO they are too big on a stock RC51 engine as well, but are sized for a Superbike engine to meet homologation rules.
I found the part throttle response to be quite abrupt, bit I'm running a 1/6 turn throttle. I'm going to see about softening up the part throttle response when I get it mapped.
SP1 throttle bodies are the ones to get, if you want to experiment with RC51 EFI, because they are smaller than the SP2 throttle bodies, but make just as much HP. I think the hardest thing would be getting it mapped for a different Baro sensor location. On an RC51, the Baro sensor is mounted in a quiet zone above the ram air intake. Maybe right where the VTR float vents are? It seems like the ECU would pretty well plug and play. There is no cam angle sensor, so the EFI probable does a half squirt every crank revolution.
I've wanted to experiment with developing a Megasquirt system for a car or bike. It would help you develop a very good understanding of fuel injection. Not sure I could find the time at this point. Maybe some day.
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SuperSport
Joined: Dec 2005
Posts: 963
From: Sunshine Coast, Australia
I have done some work on an EFI set up already and have most of it worked out. Here is a thread that I have on Ozfirestorm that lists my progress.
http://ozfirestorm.proboards.com/ind...ad=8281&page=1
I chose the SP1 bodies over SP2 due to their size. 54mm is about right I reckon, when you compare it to bikes such as Suzuki's SV1000 which runs 52mm throttle bodies.
I did look at the Megasquirt and a lot of other ECU's, however I think that the key to a really good EFI system is the ECU. The better it is the better the throttle control will be. Because of this, I am looking for an ECU that has the ability to run different fuel and ignition maps for each cylinder (which I think a twin needs due to the configuration of airbox and exhaust, as well as cooling differences) and can run using a wide band lambda sensor etc etc. In short, I want the best ECU I can get. That costs big bucks, but it is the only option for me. One thing in my favour is that Australia is one of the best ECU manufacturers in the world so we have good selection and price is good too. Most stuff we get here is twice the price you guys pay for it, but ECU's are different.
Back on topic for a minute, and back to the airbox. I did some experiments on a fuel injected VFR800 along the same lines. I opened up the top of the airbox and fitted a grill in there. I cut about half of it out I suppose. I did it after speaking to a reputable mechanic that does a lot of dyno stuff, and has a good rep in drag racing circles. He said that injection is not subject to the same things as carbs, so we could do that no worries, and then use a Power Commander to remap the fuel. I had a full exhaust on the bike, removed the PAIR, and factory oxygen sensors, so it should all have worked well.
But that open airbox did not work and I had to replace it with a stocker (with just the snorkel removed and another vacuum controlled flap taken out - common VFR mod). With the modified lid, the bike was really flat up until 3000rpm. It was ok after that, but until then it was like riding a two stroke. It just stuffed it. My theory is that it reduced the airspeed too much at low RPM.
I will need a modified airbox to fit to my EFI set-up, and I think I will use a flow bench to design it. Otherwise it is just guesswork, and I don't reckon that is good enough unless you get real lucky.
http://ozfirestorm.proboards.com/ind...ad=8281&page=1
I chose the SP1 bodies over SP2 due to their size. 54mm is about right I reckon, when you compare it to bikes such as Suzuki's SV1000 which runs 52mm throttle bodies.
I did look at the Megasquirt and a lot of other ECU's, however I think that the key to a really good EFI system is the ECU. The better it is the better the throttle control will be. Because of this, I am looking for an ECU that has the ability to run different fuel and ignition maps for each cylinder (which I think a twin needs due to the configuration of airbox and exhaust, as well as cooling differences) and can run using a wide band lambda sensor etc etc. In short, I want the best ECU I can get. That costs big bucks, but it is the only option for me. One thing in my favour is that Australia is one of the best ECU manufacturers in the world so we have good selection and price is good too. Most stuff we get here is twice the price you guys pay for it, but ECU's are different.
Back on topic for a minute, and back to the airbox. I did some experiments on a fuel injected VFR800 along the same lines. I opened up the top of the airbox and fitted a grill in there. I cut about half of it out I suppose. I did it after speaking to a reputable mechanic that does a lot of dyno stuff, and has a good rep in drag racing circles. He said that injection is not subject to the same things as carbs, so we could do that no worries, and then use a Power Commander to remap the fuel. I had a full exhaust on the bike, removed the PAIR, and factory oxygen sensors, so it should all have worked well.
But that open airbox did not work and I had to replace it with a stocker (with just the snorkel removed and another vacuum controlled flap taken out - common VFR mod). With the modified lid, the bike was really flat up until 3000rpm. It was ok after that, but until then it was like riding a two stroke. It just stuffed it. My theory is that it reduced the airspeed too much at low RPM.
I will need a modified airbox to fit to my EFI set-up, and I think I will use a flow bench to design it. Otherwise it is just guesswork, and I don't reckon that is good enough unless you get real lucky.
Last edited by shayne; Jun 12, 2009 at 04:05 PM.
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
Again, I think the key is matching the actual airflow to what the fueling system "thinks" the airflow is. I don't believe it is so much a velocity issue as a calibration issue.
The calibration can't be sensitive to vehicle speed. It has to work the same way all the time. Pressure measurements are the key.
shayne, why are you not considering an RC51 ECU, with a Power Commander? The most obvious reason is that you don't get ignition timing control with the RC51 version of the PC. Carmo seems to be the common aftermarket race ECU for the RC51.
The calibration can't be sensitive to vehicle speed. It has to work the same way all the time. Pressure measurements are the key.
shayne, why are you not considering an RC51 ECU, with a Power Commander? The most obvious reason is that you don't get ignition timing control with the RC51 version of the PC. Carmo seems to be the common aftermarket race ECU for the RC51.
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SuperSport
Joined: Dec 2005
Posts: 963
From: Sunshine Coast, Australia
I haven't looked at a RC51 wiring loom swap. I just assumed it would be too nasty, as the bikes are completely different. Also, as you mention, there is the issue of the ignition control.
I dunno. Just as a guess, I reckon it would be more trouble than it is worth. Whilst the aftermarket ECU is the most expensive option, it will also give the best result.
Have you looked at the two looms? Are there any similarities?
I dunno. Just as a guess, I reckon it would be more trouble than it is worth. Whilst the aftermarket ECU is the most expensive option, it will also give the best result.
Have you looked at the two looms? Are there any similarities?
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
I'm more familiar with the RC51 wiring diagram than I ever wanted to be. Still have not gotten to the bottom of my fuel pump enable problem with the HRC harness.
I misstated something about the RC51 EFI. There is a cam pulse generator. Something the Super Hawk does not have - but needs for EFI to work, unless you want to use the half-squirt method.
Most of the pins on the RC51 ECU are related to the EFI system. You would need to wire in the TPS and be sure the resistance ranges are the same. I would imagine ignition timing are similar, since they have similar redlines. The RC51 cams should have similar timing to VTR stage 1 cams.
Use an RC51 instrument cluster and the hard part is done. Fuel mapping can be handled with a Power Commander. Seems like it would be pretty straightforward.
This has to be the best thread jack in history!
I misstated something about the RC51 EFI. There is a cam pulse generator. Something the Super Hawk does not have - but needs for EFI to work, unless you want to use the half-squirt method.
Most of the pins on the RC51 ECU are related to the EFI system. You would need to wire in the TPS and be sure the resistance ranges are the same. I would imagine ignition timing are similar, since they have similar redlines. The RC51 cams should have similar timing to VTR stage 1 cams.
Use an RC51 instrument cluster and the hard part is done. Fuel mapping can be handled with a Power Commander. Seems like it would be pretty straightforward.
This has to be the best thread jack in history!
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SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
I'm more familiar with the RC51 wiring diagram than I ever wanted to be. Still have not gotten to the bottom of my fuel pump enable problem with the HRC harness.
I misstated something about the RC51 EFI. There is a cam pulse generator. Something the Super Hawk does not have - but needs for EFI to work, unless you want to use the half-squirt method.
Most of the pins on the RC51 ECU are related to the EFI system. You would need to wire in the TPS and be sure the resistance ranges are the same. I would imagine ignition timing are similar, since they have similar redlines. The RC51 cams should have similar timing to VTR stage 1 cams.
Use an RC51 instrument cluster and the hard part is done. Fuel mapping can be handled with a Power Commander. Seems like it would be pretty straightforward.
This has to be the best thread jack in history!
I misstated something about the RC51 EFI. There is a cam pulse generator. Something the Super Hawk does not have - but needs for EFI to work, unless you want to use the half-squirt method.
Most of the pins on the RC51 ECU are related to the EFI system. You would need to wire in the TPS and be sure the resistance ranges are the same. I would imagine ignition timing are similar, since they have similar redlines. The RC51 cams should have similar timing to VTR stage 1 cams.
Use an RC51 instrument cluster and the hard part is done. Fuel mapping can be handled with a Power Commander. Seems like it would be pretty straightforward.
This has to be the best thread jack in history!
RC
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SuperBike
Joined: Dec 2005
Posts: 1,689
From: South Lake Tahoe, CA, USA
Just to finish this up...
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
*edit* Also need the reg/rectifier and converter unit. And a wiring diagram. And a Power commander. And rewiring all the light connectors. Easy...
Rick, how's the engine coming along. Is it done already?!
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
*edit* Also need the reg/rectifier and converter unit. And a wiring diagram. And a Power commander. And rewiring all the light connectors. Easy...
Rick, how's the engine coming along. Is it done already?!
Last edited by RCVTR; Jul 1, 2009 at 07:44 AM.
Thread Starter
Fastest Color
SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
Just to finish this up...
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
Rick, how's the engine coming along. Is it done already?!
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
Rick, how's the engine coming along. Is it done already?!
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Fastest Color
SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
Update: The parts are all in and the flywheel is lighter and the block bored and heads buttoned, but I'm waiting on my mechanic/dyno tunner to put her back together for me so I know it's done right...I'm not pushing him to get it done cuz it's the rainy season here...
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SuperSport
Joined: Dec 2005
Posts: 963
From: Sunshine Coast, Australia
Just to finish this up...
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
*edit* Also need the reg/rectifier and converter unit. And a wiring diagram. And a Power commander. And rewiring all the light connectors. Easy...
Rick, how's the engine coming along. Is it done already?!
If you are thinking of trying an RC51 EFI system, you will need the wiring harness, ECU, bank angle sensor (can be wired around, but why?), bank angle sensor relay, fuel pump relay and a fuel pump. I guess you can make ony of several instrument clusters work. Don't know anything about that.
*edit* Also need the reg/rectifier and converter unit. And a wiring diagram. And a Power commander. And rewiring all the light connectors. Easy...
Rick, how's the engine coming along. Is it done already?!
Back to Ricks engine, have you thought about doing it yourself? I did my own assembly, and it was an enjoyable part of the project for me. First time I had done a four stroke rebuild, but it is not rocket science.
It also give you the opportunity to detail and paint things as you go. As your time is free, you can spend as much of it as you like to get the job just right.
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SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
Back to Ricks engine, have you thought about doing it yourself? I did my own assembly, and it was an enjoyable part of the project for me. First time I had done a four stroke rebuild, but it is not rocket science.
It also give you the opportunity to detail and paint things as you go. As your time is free, you can spend as much of it as you like to get the job just right.
It also give you the opportunity to detail and paint things as you go. As your time is free, you can spend as much of it as you like to get the job just right.
Thread Starter
Fastest Color
SuperBike
Joined: Jul 2007
Posts: 2,091
From: Lithia, FL
