Is it worth the expense and hassle of a turbo to run 4-6 lbs boost? I keep hearing about good running N/A mods keeping up with or beating them?
So are pump gas turbos kind of a waste?
- Thread starter Interceptor
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mod03rmk800
Well-known member
For racing, probably.
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maxwellzx
Active member
depends. most run 5-6 lbs and are making deecent power. not near 200 like claimed at elevation anyways. maybe 170ish.
and they seem to be around par with the big bore kits.. the 860s.
as far as my opinion i wouldnt do a pump gas kit just because of the cost.
5000 for a turbo kit or 2000 for a big bore. not to mention your adding 100 more things to go wrong with a turbo system so if you are going to do it might as well be race gas as far as im concerned.
however as far as i know you can always upgrade and run race fuel in the future just by changing a couple things..not sure what...
so i guess slapping one on and riding it with the option of upgrading far beyond the power of a big bore is an option.
there is a whole debate on this in this forum
and they seem to be around par with the big bore kits.. the 860s.
as far as my opinion i wouldnt do a pump gas kit just because of the cost.
5000 for a turbo kit or 2000 for a big bore. not to mention your adding 100 more things to go wrong with a turbo system so if you are going to do it might as well be race gas as far as im concerned.
however as far as i know you can always upgrade and run race fuel in the future just by changing a couple things..not sure what...
so i guess slapping one on and riding it with the option of upgrading far beyond the power of a big bore is an option.
there is a whole debate on this in this forum
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mtn_extreme
Well-known member
Oh boy
I'll give my thoughts. I bought a 2005 m7 with a bigbore 800 kit that had porting , high com heads , twin jaws pipes, etc. in 2005. This sled flat azz ripped and when the m1000 came out a lot of owners were pizzed because my little sled was beating them out of the hole and highmark on the hill.
I have since put a turbo on that sled, although you do have to reduce compression, drop twin pipes, etc.
To answer your question - My turbo is a race gas kit and as far as I am concerned, a turbo at low boost (pump gas) would be a waste standing alone. What would I do today. Stock sled with a race gas turbo that would run on pump gas. The 2500.00 for the bigbore kits goes along way towards incredible power that you won't see (unless a turbo) as you will be maxed out and wanting more.
Cheaper to do it this way than like me and do it twice.
my .02
I'll give my thoughts. I bought a 2005 m7 with a bigbore 800 kit that had porting , high com heads , twin jaws pipes, etc. in 2005. This sled flat azz ripped and when the m1000 came out a lot of owners were pizzed because my little sled was beating them out of the hole and highmark on the hill.
I have since put a turbo on that sled, although you do have to reduce compression, drop twin pipes, etc.
To answer your question - My turbo is a race gas kit and as far as I am concerned, a turbo at low boost (pump gas) would be a waste standing alone. What would I do today. Stock sled with a race gas turbo that would run on pump gas. The 2500.00 for the bigbore kits goes along way towards incredible power that you won't see (unless a turbo) as you will be maxed out and wanting more.
Cheaper to do it this way than like me and do it twice.
my .02
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You can run more than 4-6lbs of boost with pump gas if it's set up right.
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cpatts2000
Well-known member
I run my pump gas dragon 800 at 7-9 lbs on av gas and it will spank my 1200 at elevation, at 6 lbs it will run side by side. I like the pump gas kit because if I want to run strait 110 I can turn it up higher, and it was quit a bit cheaper than a race gas kit.
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Spaarky
Well-known member
chit disturber..... are you bored?????
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NITROSKIDUDE
Well-known member
Not on my T-Pex at 12 pounds WOOOHOOO!!!!!
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Bigbore or Turbo, I personally have had many of both and have leaned to the boost side of things. PG turbos are a lot of fun and can be turned up a bit safely, I have a 4 stroke Nytro PG turbo and a 2 stroke M12 PG turbo both of which I can run at higher boost levels.
I'm running 18lbs of boost on my RXP motor project on 91 octane. Glad I don't have to pay for race gas!
How is 7 psi at elevation different than sea level?
I've been sort of sitting back and evaluating the low boost turbo's all season and have come to one conclusion. AN 8LB. TDRAGON IS ONE HECK OF A MACHINE!!!. It will pull my UBR900 on nitrous, it is not finicky in any way shape or form. It will submarine all day long without a hiccup. When everybody else is having breathing issues in 3' of powder the TDragon just effortlessly floats and kicks azz to say the least. I can't really speak for the 4 to 6 lbs. sleds but from what I've seen the 7.5 to 8 lbs. sleds are far superior to any big bore (1,000cc or less) that I've been around. I'm one of the few old school big bore holdouts left and will probably run them for as long as I can keep them alive, but I'm not going to sit here and tell you how superior my big bore is, because it would be a lie. I will say I love my big bore on bright sunny days, but put my big bore in 3' or 4' of fluffy powder and it sucks big time compared to the two stroke low boost turbos I've seen. The best thing about them is they don't seem to be condition sensitive at all. When I run my big bore into a 100% humidity fog bank at 10,000' it's game over, or tuning time. The TDragon runs is these conditions without any hiccups at all.
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SSWIM
Well-known member
Density is simply the number of molecules of the ideal gas in a certain volume.
In order to achieve a certain psi you need x amount of molecules in a certain volume.
7 psi at altitude = 7 psi at sea level when it comes to the amount of molecules.
The difference is your starting point. At sea level you have 14.7 psi and at 9000 feet you may only have 10.29...So your turbo may have to flow more to get your 7 psi of boost. But you still need the same amount of molecules to achieve 7 psi...sea level or at altitude.
I guess my point is be carefull when running a turbo...just because you go up in altitude doesn't mean you can go down in octane.
Well this is the way I see it anyway...please correct me if I am wrong.
In order to achieve a certain psi you need x amount of molecules in a certain volume.
7 psi at altitude = 7 psi at sea level when it comes to the amount of molecules.
The difference is your starting point. At sea level you have 14.7 psi and at 9000 feet you may only have 10.29...So your turbo may have to flow more to get your 7 psi of boost. But you still need the same amount of molecules to achieve 7 psi...sea level or at altitude.
I guess my point is be carefull when running a turbo...just because you go up in altitude doesn't mean you can go down in octane.
Well this is the way I see it anyway...please correct me if I am wrong.
And would it be safe to say that if the density of oxygen is less at altitude, you will loose X amount of power. Yes, 7 psi is 7 psi, but the number of oxygen molecules in that 7 psi will be less at altitude.
Not sure the conversion, but may need to run 9 psi at 10,000' to be equivalent to 7 psi at Sea Level.
Octane is a function of air density, right??
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Octane rating is a measurement of the fuel's ability to resist engine knocking
So maybe...
So I guess the question would be if the ratio of oxygen changes as you go up in altitude. If the ratio is constant then 7 psi sea level does = 7 psi at altitude.
Hold on here, this is getting messy
Octane has nothing to do with density, but density affects how much oxygen there is in a litre of air. This in turn affects how the fuel is burned in the engine, so high air density will lean out your fuel mixture.
14,7 psi of air at sealevel + 7 psi of boost = 21,7 at sealevel. 10,3 psi at altitude + 7 psi of boost gives you 17,3 total. So you can either turn up boost to compensate, or safely go down in octane (faster burn) without damage.
But DONT ask me for numbers!! Dont have any.
Living where I do, this is somewhat a mute point as the highest I can go is maybe 5000'. Got a 1000 triple big-bore now and might up that to 1300-1500 someday. With my low altitude I believe the power will suffice
If not, there's always NOS...
RS
Maybe I said that wrong. Does Octane have to be increased or decreased based on air density and barometric pressure??
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