Rode a Vipec HM Turbo last night...
- Thread starter Scott
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B
bighole1818
Member
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Vi-PEC Powersports
Well-known member
the "lazy" bottom end of a turbo 2 stroke application comes from the fact that, while off boost, the restricted air intake/pipes makes the engine suffering from a restriction in air delivery therefore making less hp( an hm turbo kit installed with charge tube off create only 105-110 hp vs 131 hp stock system naturaly aspirated).....therefore creating a lazy bottom end, but with the vi-pec ECU, you can tweak timing/fuel/dwell time(spark duration/intensity) so the bottom end is suffering only minor performance lost.....remember off boost is only a few hundreds rpm...i realy would like to understand how the boost-it injector driver can somehow make the lazy bottom end of a turbo application better than a fully adjustable ECU?? the timming/fueling/dwell on a stock sled is optimal for a NON TURBO apllication with original air intake system.... and when boost show up from 0.5 psi(4500rpm) up to whatever psi ( as soon as 4500rpm ) how can you run same timing/dwell and get more performance than any kind of standalone ECU ?? not saying it is not running ok, but more power,more adjustability,more bottom end?? no way.
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jsandgren10
Well-known member
Then mine must be a watered down milkshake Haha cause it flows just fine for my conditions.
Two strokes need more air flow then four strokes, that's why yours works well.
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jsandgren10
Well-known member
My Silber is a 2860 on my Pro, and like I said seems to flow and work just fine. But here in California we don't get that bottomless powder with huge loads to bring the charge temps up so high.
I agree if you are riding different deep conditions all the time the 2871 would be a better choice but here in California its not needed.
My mistake, I thought you were referring to the apex in your signature.
Good write up Scott...
My take...
Fuel choice DOES play a big role... and it does Not boil down to JUST the octane numbers... the thermal properties and other characteristics in the Fuel blend greatly affect how the fuel will perform and what the throttle response is... Especially in rapid throttle cycle situations that two stroke sleds, when ridden in technical terrain, present.
The transition from vacuum to boost is the key for the Tree riders out there... with laminar flow through the charge circuit and intake volume to draw from, when off boost, playing major roles... but that is a double edged sword... high volume box can give spongy on-boost character in rapid on/off throttle cycles... low volume sacrifices throttle response in negative charge pressures (vacuum). I'd like to see some of the old-school tricks of a reed-valve bypass being used in these sub 12 lb boost, smaller turbo, all-around use sleds.... Maybe not for the hill Chuter... but may give some benefits in this segment which, to me, represents a larger portion of potential turbo users.
The more these "stand alone" systems get used... the more will be learned in the mapping for the different applications... This unit looks very nice, some of the best builders on here are really excited about it.... the hardware is only as good as the programming put into it... the more of these that are out there in peoples hands... the better it will be for us as consumers.
Good to see stand alone options out there that can give the tuners and Aftermarket-package developers out there more flexibility in their design without the limitations that "Piggy-backing" off a the factory ECU can bring. With the inherent protective systems for Consumer and production considerations that the factory must program into the systems to meet reliability in abusive situations with bad fuel, owner neglect and other situations... It is hard to work around and give a seamless integration into a factory system...
On a closing note... For the average consumer... It is my OPINION that a stand alone system, unless it comes with a tried/trued map for your particular application (like the mapping offered in Shanes, Curts and Brads mods) , will pose more challenges than it is worth... you will still need to know how to program the system and have the time, patience and technical background to pull it off.
MY 2 cents.
Keep on trucking people... can't wait to see what this brings in the near future.
.
My take...
Fuel choice DOES play a big role... and it does Not boil down to JUST the octane numbers... the thermal properties and other characteristics in the Fuel blend greatly affect how the fuel will perform and what the throttle response is... Especially in rapid throttle cycle situations that two stroke sleds, when ridden in technical terrain, present.
The transition from vacuum to boost is the key for the Tree riders out there... with laminar flow through the charge circuit and intake volume to draw from, when off boost, playing major roles... but that is a double edged sword... high volume box can give spongy on-boost character in rapid on/off throttle cycles... low volume sacrifices throttle response in negative charge pressures (vacuum). I'd like to see some of the old-school tricks of a reed-valve bypass being used in these sub 12 lb boost, smaller turbo, all-around use sleds.... Maybe not for the hill Chuter... but may give some benefits in this segment which, to me, represents a larger portion of potential turbo users.
The more these "stand alone" systems get used... the more will be learned in the mapping for the different applications... This unit looks very nice, some of the best builders on here are really excited about it.... the hardware is only as good as the programming put into it... the more of these that are out there in peoples hands... the better it will be for us as consumers.
Good to see stand alone options out there that can give the tuners and Aftermarket-package developers out there more flexibility in their design without the limitations that "Piggy-backing" off a the factory ECU can bring. With the inherent protective systems for Consumer and production considerations that the factory must program into the systems to meet reliability in abusive situations with bad fuel, owner neglect and other situations... It is hard to work around and give a seamless integration into a factory system...
On a closing note... For the average consumer... It is my OPINION that a stand alone system, unless it comes with a tried/trued map for your particular application (like the mapping offered in Shanes, Curts and Brads mods) , will pose more challenges than it is worth... you will still need to know how to program the system and have the time, patience and technical background to pull it off.
MY 2 cents.
Keep on trucking people... can't wait to see what this brings in the near future.
.
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That being said... I think that there could be some improvements made with a custom fuel blend just for these "Tree Riding" everyday turbos on lower boost that work at a high load (like sleds do) IMO... a big diff.
Something like a TRUE 96-98 MON non leaded fuel, with good RVP and 90% evap numbers... Not really seeing something that would be Ideal for turbo sleds yet in the way of "race gas".
The typical 110 or 112 octane race fuels are not tailored for the cold weather an fast throttle transition cycles that we see here...
Something like a TRUE 96-98 MON non leaded fuel, with good RVP and 90% evap numbers... Not really seeing something that would be Ideal for turbo sleds yet in the way of "race gas".
The typical 110 or 112 octane race fuels are not tailored for the cold weather an fast throttle transition cycles that we see here...
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sledstew
Well-known member
Good to see you took it for a spin Scott, are you sold on it?
Guys just to clear some things up a little.
The pump gas setup on 7 or just over 7 in the trees is awesome and you actually dont need any more than this it gets to be uncontrollable especially with a 163" track.
Avgas setup has a slight and I mean very slightly slower burn to it but nothing to worry about for the high boost application. Ive run both apps and very small differences in throttle response. The timing control helps this tremendously.
I've helped all the guys above to get them going with the Vipec and have to say by the way it looks next season is going to provide alot of options for high performance applications.
Guys just to clear some things up a little.
The pump gas setup on 7 or just over 7 in the trees is awesome and you actually dont need any more than this it gets to be uncontrollable especially with a 163" track.
Avgas setup has a slight and I mean very slightly slower burn to it but nothing to worry about for the high boost application. Ive run both apps and very small differences in throttle response. The timing control helps this tremendously.
I've helped all the guys above to get them going with the Vipec and have to say by the way it looks next season is going to provide alot of options for high performance applications.
I have not ridden a boosted sled much but i have driven boosted cars. One of the tricks rally and road racers use is to ride the brakes and apply the throttle so boost is built before you need it. Then when you release the brakes you have instant throttle response. Has anyone used this technique sledding? I rode Chris Brown's boosted Yami and I had to use the brakes to control the after run or surge when I chopped the throttle. The sled would keep pushing for a second after you cut the throttle and when it was tight it was giving me track speed I didn't want, lol. Not sure you can ever get rid of some of the turbo lag so you might have to just ride around it.
Good to see you took it for a spin Scott, are you sold on it?
Guys just to clear some things up a little.
The pump gas setup on 7 or just over 7 in the trees is awesome and you actually dont need any more than this it gets to be uncontrollable especially with a 163" track.
Avgas setup has a slight and I mean very slightly slower burn to it but nothing to worry about for the high boost application. Ive run both apps and very small differences in throttle response. The timing control helps this tremendously.
I've helped all the guys above to get them going with the Vipec and have to say by the way it looks next season is going to provide alot of options for high performance applications.
Yes, it was fun. I do like it. I got used to the throttle, and after about 15-20 minutes I was much better at boondocking it.
So to counteract that bottom end feeling, can you run more timing down there?
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sledstew
Well-known member
The thing to remember is that the snow right now is not normal conditions and when you ride it in the powder it will feel way different because there is alot more load on the engine and in turn the turbo will spool alot faster. Timing is pretty much set to where we feel its very safe, the bottom end has alot to do with clutching and if it was off a bit that will make a huge huge difference with the vipec. It runs so clean you can pick up on flaws where as the other kits seem to bobble and gloat a bit even when they are running at their peak making it somewhat unoticeable.
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sledstew
Well-known member
Absolutely Correct!!!! Thats why we are shying from the 110 and going to AVGAS for high boost, very good analogy.With timing control and Avgas for us its a perfect combo.
Here is a video of a HM Pro running the Boost It fuelbox.
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Vi-PEC Powersports
Well-known member
V
Vi-PEC Powersports
Well-known member
ok Dave, never mind, we are all stupid.....do you really believe we're not seeing/understanding what you are doing?? talk back to you in august(taking a summer brake), just a tiny bit before haydays(hope you are coming to visit , our boot is just beside arctic cat USA and i will PERSONALlY entertain yourself about our new plugin ECU for the 800cc 2 stroke arctic cat and 1100 turbo 4 stroke)....we never know,we may become the best of friend
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