So are pump gas turbos kind of a waste?

[Wheel House Motorsports]

I will start this right now and maybe finish it tonight or tommorow, just dont want to spend 20 minutes typing.... here goes


PV=nRT that is the ideal gas constant, that way you can find the number of moles of oxygen per unit of volume of air. This way you can account for the air temp, and altitude, and see just HOW much oxygen there is, the only hiccup is finding the exact pressure for altitude and barometric pressure, based on weather. Now, say you brought A barometer, a pen and paper with you into the hills, you could find out just how much oxygen is present in the air around you. As I dont know how much octane is required for X amount of oxygen to run safely, this is somewhat useless, BUT, if someone were to calculate, how much they were able to run with X amount of oxygen it could be a very useful data composition, and if enough people provided there info It would be a great resource, this would just take a lot more effort for not much that sledders dont want to try.

as for random thoughts on boost at elevation, I bought a boost gauge that was zero'd by a guy who rode in california. I looked at it at 6000 ft where I live in MT and it reads 2 psi of vaccum ~ at the time I looked at it, meaning there was approximately 12.7 psi air pressure assuming it was zeroed for 14.7psi.

If all boost gauges were zero's at 14.7 then the loss for elevation combined with the boost being run would actually be a VERY usefull number, although your gauge may only read say 7psi of boost on your motor, you could be running 10 because you are high in elevation. This number would be VERY useful as to what kind of fuels could be run.




CC as for octane, barometric pressure directly affects air density, as pressure decreases so do density, therefor less pressure = less octane as there are less oxygen molecules per unit of volume to burn.

this was defniately a little jumbled, I will come back to it later and add what info I can.

 

[Wheel House Motorsports]

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?

And to answer this question, If your setup to ONLY run pump fuel, meaning the fueling ant turbo setup are maxed out running pump fuel, then NO, I would say its not worth it. If you have a setup that can run higher boost with nothing more than clutching adjustments and better fuel then go for it. Now when you have some money to waste, throw some 110 in the thing, turn the knob and try not to flip over. We all know power is addicting, with a bigbore, thats all you get, it may be a tad better than low boost turbo but more compression and way better fuel wont get you what you want, another few PSI of boost and better fuel will.

if you only want a little more power, stay with bigbore, if you ever think you may want to get crazy, go turbo.

 

[SSWIM]

This is really interesting how many are saying the PG turbos are not worth it. I am not bashing anyone. It is hard to believe so many feel this way. Maybe it is because we ride at such high elevations (10k-13k), but the little PGM8 I just picked up is very, very impressive at these elevations. It gives up very, very little to my TAPEX running 13PSI. Granted, I am running 8PSI in the M8. Yes the TAPEX is much heavier, but for the M8 to even stay close to the TAPEX is way more than we could have expected.

Anyway, these have been my findings, and I have been having an absolute blast on the M8.

Sam

 

[hatchers]

7 psi at altitude = 7 psi at sea level when it comes to the amount of molecules.

Well, yes and no. Boost is simply a difference pressure measurement across the compressor….so 10 psi of boost at sea level is not the same as 10psi at 10K elevation…understand PSI drops when temps decrease and elevation
goes up….actually temps are a much bigger factor vs elevation

and the bigger picture is a fixed compressor stage compresses whatever gas “air” it gets in at the suction side…the discharge side will have more flow and pressure as the suction side gets colder and of less elevation

 

[mtn_extreme]

This is really interesting how many are saying the PG turbos are not worth it. I am not bashing anyone. It is hard to believe so many feel this way. Maybe it is because we ride at such high elevations (10k-13k), but the little PGM8 I just picked up is very, very impressive at these elevations. It gives up very, very little to my TAPEX running 13PSI. Granted, I am running 8PSI in the M8. Yes the TAPEX is much heavier, but for the M8 to even stay close to the TAPEX is way more than we could have expected.

Anyway, these have been my findings, and I have been having an absolute blast on the M8.

Sam

Have you had the opportunity to run a stock m8 (or m9bb)against the tapex. I would think at only 13 lbs boost would just make up for the weight difference. 13 isn't alot of boost for a 4 stroker.

The m8 is impressive just in stock form

 

[4strokesnewbie]

Have you had the opportunity to run a stock m8 (or m9bb)against the tapex. I would think at only 13 lbs boost would just make up for the weight difference. 13 isn't alot of boost for a 4 stroker.

The m8 is impressive just in stock form

This should be interesting. Most wouldn't even bother running their Tapex at 13lbs against a stock sled-any of them. It would be a joke.

 

[mtn_extreme]

Fair enough, I don't know about the apex's on 13 lbs. Was just asking a question. Would a big bore 900 or a well tuned m1000 run with it?

 

[drinkwyo]

I agree 100%. Pump gas 12lbs on the Nitro or Apex is worth every penny

I agree too. except I run 17-18 lbs on pump

 

[SSWIM]

Have you had the opportunity to run a stock m8 (or m9bb)against the tapex. I would think at only 13 lbs boost would just make up for the weight difference. 13 isn't alot of boost for a 4 stroker.

The m8 is impressive just in stock form

The TAPEX has a 2860 Turbo on it. 13-14PSI was what the boost was at when comparing them. It works well.
The 09 PGM8 pulls the stock 09 Sno Pro M8s with 162" track very decisively.

Sam

 

[4strokesnewbie]

Fair enough, I don't know about the apex's on 13 lbs. Was just asking a question. Would a big bore 900 or a well tuned m1000 run with it?

The short answer is No. They have their advantages, like being lighter, but they will not run with a Apex on 13lbs. That's about 270ish horsepower or more at elevation.

 

[fnengineer]

If all boost gauges were zero's at 14.7 then the loss for elevation combined with the boost being run would actually be a VERY usefull number, although your gauge may only read say 7psi of boost on your motor, you could be running 10 because you are high in elevation. This number would be VERY useful as to what kind of fuels could be run.

My bad I should have stated PSIG.

 

[mtn_extreme]

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.

Ok, so here I have a pump gas dragon spanking a 1200 bb. How will this dragon compare to a tapex at 13lbs? Trying to get a feel for power output on these other turbo's

 

[joker2]

I am running a boondocker pgm8 and with 8 lbs boost at about 6000 ft, it will hold about the same track speed up a hill climb as my last sled( apex with 12 lbs boost). the big difference is the m8 does not have the bottom end torque to get to the top speed as fast. m8 is way more fun to ride as it is 100 lbs lighter.

 

[mtn_extreme]

joker2,

Good info! It gives me an idea as I can turn mine down to 8 lbs, so I know what it feels like. What track speed are you talking approx (I know there are a ton of variables)? Guess the assumption that I and alot of others were making is that a pump gas turbo was only good for about 6 lbs boost max. Six pounds hardly gets my spool going good

 

[FTXMOTORSPORTS]

Bingo! done correctly, 8-10 psi is VERY do able on pump gas and WELL worth doing. pump gas kits that won't live beyond 6-7 psi are struggling with poor intake design and ineffective (if not non existent) intercooling, both of which create dangerous detonation scenarios from excess charge temps.

curt

 

[ridgeclimber]

08 d8 turboed

I have a 08 turboed 800 dragon. The turbo kit is a pump gas kit from boondocker. At low elevation with the boost controller turned down to about 5 psi I have to run straight race gas for it to run good. Once I get up to 3500 ft to 4000 ft I run a couple of gallons of race gas to a tank of premium pump gas, just to be safe. I have turned it up to 8 1/2 psi boost. All I can say is wow, it is worth the money. I can stay beside a buddies m1000 with a 1200 kit accross the lake. And when climbing, it is unstoppable. You can not wipe the smile off my face. As far as turbo lag or tuneablity proplems there is none. I keep opening the hood on the hill or check it over good when I get home. I take the spark plugs out and look it side the bore with a flex light, it looks all good. There hasn't been a problem yet. Turbo it as soon as you can afford it.

 

[m8matt]

I'm Having a blast with my pump gas M8. I do have the ability to turn mine up. ( I think to ten pounds with out extra injectors) . I haven't turned it up yet. I can only assume that once I turn it up I probably won't go back. Would I do a pump gas kit again? Probably on a M1000 not on an M8.

 

[kraftymike]

Ya pump gas turbos are junk! Run a big bore so I have more time to destroy the POW while you guys turn wrenches.

 

[JSCC]

I am running a boondocker pgm8 and with 8 lbs boost at about 6000 ft, it will hold about the same track speed up a hill climb as my last sled( apex with 12 lbs boost). the big difference is the m8 does not have the bottom end torque to get to the top speed as fast. m8 is way more fun to ride as it is 100 lbs lighter.

At 12 lbs of boost my Apex turns 70-80 mph track speed. If you can make that PGM8 turn them kind of speeds at 8lbs you need to get in the business of selling kits.
There is absolutley no way equally tuned sleds that the M8 will run the the Apex with that boost spread. Equal boost for boost and you would have a decent race, but the M8 will lay down on the top whereas the Apex will keep pulling.
Been there done that. Go to Fairview for your own viewings.....

 

[Best Place Boost]

Boosted 09 M8

I have not seen an 860 that has been ahead of my m8 pump gas turbo in either a drag race or on the hill. I wanted a reliable sled and this one has been.
I run around 8 to 9 lbs of boost. Yes I run 30 to 50 percent 114 octane with my premium unleaded to keep things safe as was the plan since I built the sled. The cat has been a pleasure so far this year.
The 860's run well but my experience has been they do not carry the speed on the last half of the hill the m8bdt does. I am running 85 grams of weight and turning around 8400 rpm. I am continuing to add weight to the primary as the season goes on, I started at 82 grams.