Turbo HP #'s
- Thread starter jaxondean
- Start date
M
mynewuseddoo
Well-known member
I think the "rule of thumb" on a two stroke is something like 7 hp per Lb of boost. A pump gas setup should have you running somewhere in the 190-210 range at elevation. My turbo is coming this summer but everyone I ride with runs a race gas turbo kit but only uses 8 LBS or less and runs pump or pump/av mix and their sleds are pretty horny! My one buddy runs 13 PSI on race gas and it is just rank! The M's love to run in the 6-8LB range and so far all the turbos I ride with are pull and go after they get them dialed in. Preventative maintanence goes a long way too. They do the reed pettals every 600 or 700 KM, routine checks and all that stuff, you know.
I am purchasing the cutler stage three kit this summer. I will be running it in the 6 PSI range on straight Chevron 94. This is what my buddy runs and his M is an animal! The stage three kit is nice to have because it gives you the option to splurge the odd day and run race gas if you want and crank the boost.
I am purchasing the cutler stage three kit this summer. I will be running it in the 6 PSI range on straight Chevron 94. This is what my buddy runs and his M is an animal! The stage three kit is nice to have because it gives you the option to splurge the odd day and run race gas if you want and crank the boost.
M
mynewuseddoo
Well-known member
(13 psi x 7 HP/psi = 91HP) + 150HP = 241HP. Remember 7 HP per LB of boost on a two stroke is just a rule of thumb, need a dyno to verify. At 13 psi his sled is as horny as a sex addict in a whore house though. Honestly at 6-8 psi it will get your heart pumping pretty good and your fuel costs won't be through the roof. AV gas is anywhere from about $1.35-$1.50 per liter as opposed to race gas at over $3 a liter. Maybe once in a while but it costs $100 to fill my diesel and I'm not willing to spend that on fuel for my sled per day. Especialy when I get in 40 + days riding per year it would add up pretty quick.
I hope this helps.
I hope this helps.
M
mynewuseddoo
Well-known member
Oh and I sold my doo this year too, couldn't be happier. The handling is night and day better than the XP. And the turbo's actualy work on the M's. I've been reading the XP turbo forums and they have got quite the mess going on over there LOL!!
Numbers are all over the place. Turbo size, intercooler, fueling, exhaust design, intake design, airbox design, fuel, altitude, temperature all have an effect, but then you'll find that the best improvement to any turbo sled is just clutching! Trying to get an HP number per lb of boost is a very general way of thinking about it, but 7 lbs is as good as any other assumption.
I personally have a dyno (little land and sea water brake type) I don't even deal with the HP numbers. I just use it for tuning and loading the engine up and see improvements in output. The HP numbers are just way too out there, and I don't want to go through all of the effort making sure my setup is calibrated correctly for every one.
Bottom line is that the stock fuel pump / injectors limit (on both M8 and m1000) out at around 210 horsepower. Doesn't matter what altitude, temp, whatever, you can regulate boost to always get somewhere around 210 assuming your running fuel that is good enough to avoid detonation.
The difference between kits is quality, reliability, fueling, throttle response, lag, bog, looks, and price. I don't think there is a turbo kit out there that doesn't provide enough power, but some are definitely better than others with respect to quality, reliability, fueling, throttle response, lag, bog, looks, and price.
I personally have a dyno (little land and sea water brake type) I don't even deal with the HP numbers. I just use it for tuning and loading the engine up and see improvements in output. The HP numbers are just way too out there, and I don't want to go through all of the effort making sure my setup is calibrated correctly for every one.
Bottom line is that the stock fuel pump / injectors limit (on both M8 and m1000) out at around 210 horsepower. Doesn't matter what altitude, temp, whatever, you can regulate boost to always get somewhere around 210 assuming your running fuel that is good enough to avoid detonation.
The difference between kits is quality, reliability, fueling, throttle response, lag, bog, looks, and price. I don't think there is a turbo kit out there that doesn't provide enough power, but some are definitely better than others with respect to quality, reliability, fueling, throttle response, lag, bog, looks, and price.
S
sweperformance
Member
202hp 120fpt, 8psi boost, pumpgas push turbo. But the pump gas in sweden is a little better that us pumpgas. sealevel
J
jaxondean
New member
Thanks for that - there is an overwhelming amount of choice it seems, in buying a turbo system. I would love to hear your thoughts jgw on what kind you are running. Also then clutching too.
Different kits go about this in different ways.
BD adds 2 more injectors, cutler adds a bigger pump, I prefer the cutler way, just seems simpler to me (and tuning has been VERY simple on the cutler).
I don't have enough experience on all the kits to say what I think of them all, I will describe what I built a little bit though and you can take it for what its worth.
Leave stock pipe completely alone (like cutler)
Mount turbo with intake facing forward, and rout exhaust under turbo and out stock exhaust location (kinda like push, but he has to cut the pipe to make it fit)
Use barrell style water air IC
2871 Turbo
Stock fuel pump and injectors, running avgas (10 lbs at 7000 feet is plenty for me)
Without worrying so much about having a short charge tube and being more concerned with efficient air flow and consistent air to the tbodies, routing charge tube and making airbox a split y-pipe type with pulse tuned lengths to take advantage of resonance. Doing this, I think I probably ended up with about 4" more intake tube volume, which a 2871 turbo can pressurize in less than a tenth of a second.
Use aluminum tube to suck clean fresh air from the nose of the machine, and not from hot underhood air. Also, use an efficient air-horn on the filter intake to reduce suction, lag, and all that good stuff.
Blow off valve is good, but not 100% necessary.
Use attitude fueling box
Electric oil pump
And running a turbo without an AEM wideband 02 sensor is like trying to play baseball without a bat. Just wont work very well.
My clutching is not perfect, but good enough. I'm running a purple / white primary spring, 79g DnD big dog weights, 35/47 helix (I think, gotta double check), and stock secondary spring. My shift out is good, RPMs are good, Backshift is perfect, but engagement RPM is a little low, and would be good to get rid of some of what I refer to as "clutch lag" which just means when on and off the throttle it takes a half second to get to the right RPM.
I should finish off by saying that I am no expert. I'm an engineering geek with a tig welder and I know what I like, and what makes sense to me. I think my machine runs great, but you can take it or leave it.
Leave stock pipe completely alone (like cutler)
Mount turbo with intake facing forward, and rout exhaust under turbo and out stock exhaust location (kinda like push, but he has to cut the pipe to make it fit)
Use barrell style water air IC
2871 Turbo
Stock fuel pump and injectors, running avgas (10 lbs at 7000 feet is plenty for me)
Without worrying so much about having a short charge tube and being more concerned with efficient air flow and consistent air to the tbodies, routing charge tube and making airbox a split y-pipe type with pulse tuned lengths to take advantage of resonance. Doing this, I think I probably ended up with about 4" more intake tube volume, which a 2871 turbo can pressurize in less than a tenth of a second.
Use aluminum tube to suck clean fresh air from the nose of the machine, and not from hot underhood air. Also, use an efficient air-horn on the filter intake to reduce suction, lag, and all that good stuff.
Blow off valve is good, but not 100% necessary.
Use attitude fueling box
Electric oil pump
And running a turbo without an AEM wideband 02 sensor is like trying to play baseball without a bat. Just wont work very well.
My clutching is not perfect, but good enough. I'm running a purple / white primary spring, 79g DnD big dog weights, 35/47 helix (I think, gotta double check), and stock secondary spring. My shift out is good, RPMs are good, Backshift is perfect, but engagement RPM is a little low, and would be good to get rid of some of what I refer to as "clutch lag" which just means when on and off the throttle it takes a half second to get to the right RPM.
I should finish off by saying that I am no expert. I'm an engineering geek with a tig welder and I know what I like, and what makes sense to me. I think my machine runs great, but you can take it or leave it.
Someday i'll take some pics and post them up. The thing you'll find with home brew kits is that they take a few "iterations" and every iteration makes compromizes on little fit and finish things.
Now that i've got mine dialed well, I could start from scratch and make a very nice looking kit with the same functionality, but for the time being, its pretty ugly. Thats the nice thing about buying a kit. You get all the right piece parts, the right hoses, clamps, etc for a clean install.
Now that i've got mine dialed well, I could start from scratch and make a very nice looking kit with the same functionality, but for the time being, its pretty ugly. Thats the nice thing about buying a kit. You get all the right piece parts, the right hoses, clamps, etc for a clean install.
