DynoTech on the Poo 800-Some thoughts

[indydan]

Polaris cares

Just a couple of comments-
First the ECU for the 08 & 09 Dragons is the same-just the map is different. At least the PN hasn't changed 4011518. So the 08's can accept the 09 map?

Second the SB has been under test for some time now so longevity isn't a question for me. There have been 100's of T6's running some for 3-4 years & a few pushing 10000 miles. A fair number of T7's & T8's too. Carl's success (reliability) with the 688's played a large part in Poo's decision to rush the D7 to market (now starting it's 3rd season). 840's have completed a second season & 860's a full season. These sleds are being ridden by hard core sledders that ride the pee out of them. Will the SB cranks live is a moot point as far as I'm concerned.

Finally, anyone that thinks Poo isn't concerned about engine quality is dead wrong. I know better but concern doesn't always translate into results. It cost them dearly to stop production of the 07 900-done just as spring sales were in bloom. They field test more than any other mfct. They held shipping last year while they took a load of early run production sleds (D8's) to WY for a 500+ mile endurance run. They may never attain quality like the Yammies but Poo doesn't deserve all the bashing of late either. The 800 engine is smooth as silk-IMO. And by the way I like the new crank stub with the sleeve:
PS-Dan you might want to get more into the Doo 800R...they make the BB Poo look good & should be a good source of business for years to come.

Ron, I respect what your saying. And it does look like Polaris is trying to make a good motor with this new breed.

Tell me this..............Why, with all the the reseach invest in the 755/900
would they just throw it to the wolves ????

I am not trying to slam Polaris ( Their sleds are hands down the only sleds that intrest me ) I can tell you have Polaris running thru your veins. ( thats cool )

I just wanted to set people back on their heels alittle, Polaris has given plenty of reason to make us wonder.

If it is the wish of the Snowest forum members for me to shut my mouth when I want to say what i think, then i will. I stayed away from SW for a few years when it got alittle weird.

We all have opinions. I was just throwing out some food for thought. No big deal really.

 

[AKSNOWRIDER]

Indy, I can only speak for myself..but I enjoy your threads..they always bring relevance to the forum as well as a different point of veiw..your knowledge is unsurpassed.......

 

[MARV1]

Love your input Dan, brings alot of info and a reality check for real world riding and experiences.

 

[63nova]

Indy Dan drumming up business

Quote:

1998 600 XC BB - Little to no crank problems 68mm stroke
1998 700 XC BB - A few crank problems here & there but exceptable. 68mm stroke
2000 800 ---BB - Hundreds and hundreds of crank problems. 70mm stroke

1999 440/600 SB - Little no crank problems 64mm stroke
2007 700 SB - A few crank problems here & there but exceptable 68mm stroke
2008 800 SB - Very few built ( Not even 5% ) of the 800 BB 's built. 70mm stroke

So my Point being - IMO - The crank problems are coming like a train wreck. It an't the stroke thats kills them. Its more power & Polaris quality control.

Indy Dan drumming up business....................
...............worse than listening to an Obama campaign speech

 

[dynotechjim]

For comparison of engine performance from 1000 to 6500 ft, I have just shipped pipes tested on our Dragon 800 in my DTR article, fitted for backpressure readings, to Exxtreme dyno in Utah. They have an 800 dragon waiting for comparison test next week with these same pipes. Also the PowerCommander unit I used in the DTR article should be shipped to Exxtreme next week, so they can see how it works from 1000 ft (here) to 6500 ft (their dyno facility) then riding to 10,000 ft. plus.

 

[shortstop20]

I enjoy reading your posts Indy Dan, as I'm sure most of the forum does.

There's nothing wrong with expressing your opinion, it's better to have lots of opinions than 100's of blind sheep that will not admit there's anything wrong with X brand of sled.

Your posts are always blunt and to the point, nothing wrong with that. Some people just take things that they read too seriously.

I am not trying to slam Polaris ( Their sleds are hands down they only sleds that intrest me )

Even after saying those things he still says this, what does that tell you guys?

 

[indydan]

Quote:


Indy Dan drumming up business....................
...............worse than listening to an Obama campaign speech

Druming up business................Interesting.......

Never have been much on the druming thing.

I don't have a single thing to offer for crank parts for the 800 SB

So what the heck would I do if someone sent me one ????

The new 800 SB crank has a wide bearing ( big deal ) the bearing size was never a problem in the BB motor the wide bearing kit is just a feel good thing.

Isn't funny how over the years, just about every sled made had the exact smae size jackshaft bearing behind the driven clutch and it never fails unless it runs out of lube...............

The PTO bearings on the old BB crank are twice as big as the jackshaft
bearing and there is two of them ( they feel that exact same amount of torque ) yet the pto-end, rod pin & bearings all fail for some reason............

2 very simple reasons.

1 - No lock ring bearing
2 - Poor quality control on the case.

The new SB motor ( from what i am told ) does not have a lock ring bear on the outter PTO-side.

If thats the case............. then a non lock ring PTO -end with a poor case fit ( or one thats woren from use over time ) with a 70mm stroke, Over time it will jerk the pto-end out of tru and the pto-end will fail.

The wide bearing does nothing to prevent this. Never has and never will without a lock ring.

All the wide bearing can do without a lock ring, Is pro-long the failure a little while.

Thanks to the others, You know who you are. Cheers.

Dan

 

[wellfed777]

i don't like mine i don't care what the ladies say plus i kind of hurts a little

oh i thought you said **** ring never mind wrong forum

 

[Jay]

Anytime you have IndyDan and DynoJim sharing information on the same thread you should pay attention. Don't mean to slight any of the other contributors, obviously not dummies either, but come on guys we are all into sleds and these are two of the best brains in the buisness. I have to wade through hundreds of threads to find a gem like this one. I would love to see a Struthers 910 on either one of these guys dynos. The 910 has proven itself to be a benchmark engine, to see reliable H.P.#'s on it would eliminate alot of B.S. dyno sheets on other engines. Dan don't you go anywhere, this forum would be less without you.

 

[BuilderBob]

I think we all agree how much HP it makes is irrellevent. My question is at what rpm does it make the HP? Do I clutch for 7900rpm as per the DTR info or do I clutch to 8200 as per SLP??

 

[dynotechjim]

During our tests the center section temp was averaging 1000 degrees after 20 seconds at WOT. SLP was probably running a leaner early fuel map, and maybe for longer time at WOT, so their pipe center section temp was surely higher, maybe 1300 deg F, so HP peak was at higher revs. That info is very useful in clutching, knowing exactly what RPM your HP peaks at from cool (say 400 deg on takeoff)(maybe HP peaks at 7500) to smoking hot at the end of a three minute run on a lake or hill, enables you to nail the clutching perfectly.

Next time we dyno a Dragon 800 (end of the month) I will try to obtain that information--maybe find the HP peak every 200 degrees F) Then if you add an open element EGT like digatron to the center section next to the factory probe, you can match revs to pipe center section temp (Digatron will replay a long run so you can compare revs/ temp) It can't be any more precise that that.

 

[allblowdup]

But how does Carl’s keep the transfer port adequate sized on the 800-to-860 big bore kits that now ditch the monoblock and go with Crankshop seperate cast cyls in thier BB kits???

You are right they are adequate but not optimal. The BB engine does have the extra c to c going for it so the transfers seem to be ok up to around the 850 mark. Polaris is trying to get the same power in a smaller and lighter package so using a mono block works better to keep the transfers as large as they can. My .02

 

[MOB]

Anytime you have IndyDan and DynoJim sharing information on the same thread you should pay attention. ...these are two of the best brains in the buisness... Dan don't you go anywhere, this forum would be less without you.

seconded......one for each.

 

[indydan]

During our tests the center section temp was averaging 1000 degrees after 20 seconds at WOT. SLP was probably running a leaner early fuel map, and maybe for longer time at WOT, so their pipe center section temp was surely higher, maybe 1300 deg F, so HP peak was at higher revs. That info is very useful in clutching, knowing exactly what RPM your HP peaks at from cool (say 400 deg on takeoff)(maybe HP peaks at 7500) to smoking hot at the end of a three minute run on a lake or hill, enables you to nail the clutching perfectly.

Next time we dyno a Dragon 800 (end of the month) I will try to obtain that information--maybe find the HP peak every 200 degrees F) Then if you add an open element EGT like digatron to the center section next to the factory probe, you can match revs to pipe center section temp (Digatron will replay a long run so you can compare revs/ temp) It can't be any more precise that that.

Jim brings up a great point, Many times you hear of people saying..............
My sled pulls to X - rpm and sits there awhile and then starts to go into a
overwind many think their helix is to flat at the end..........or they start adding tip weight to their clutch weights............

all to lock the rpm at the exact heard dynoed MAX H.P. almost always a bad move. BUT for some reason thats what people search for....

Big twins with BIG diameter pipes ( almost all of them ) should be clutched to pull an average of 200 to 300 rpms under short pull dyno numbers. when the pipes get hot they should rev to max hp rpm.

 

[indydan]

800 sb verses 800 bb center to center

For those that are interested.

The Small block motor is about 1/2 inch shorter between centers then the old Big Block.

As I said, In a big bore situation, there is no way the SB can make as much the power as the big block if the Ign timing and BSFC are the exact same.

And I stand by my first statement, A 1997 700 RMK in stock form in the new chassis will run the guts out of the new motor.

Remember I said the 1997 RMK Motor !!!!! I dynoed one of these in stock form ( 135 hp the first pull ) But as I said, Dyno numbers are only relative to what ever you want them to be.

The 1997 RMK was a one of a kind package, No other domestic motor had the timing curve or BSFC numbers that this motor did. As a matter of fact Polaris sent out an update CDI box to tame this monster.

If you ever had a chance to drive one of these when they were new and set up right you know how hard this package ran.

They would NOT hold together at sea-level ( Well a few people got lucky )
Most of them at sea-level in really cold weatHer blew the pistons out the exhaust in a lava form.

08/09 800, Its just a motor in a really good chassis with a great track.

1/2 narrower between centers it can never make the power of the old motor in full mod form.

Stock or trail Mod, yes. Because of the Mono block they can hold the transfer size to good perspective.

 

[shortstop20]

Does anybody know at what temperature the t-stat opens on the 800 RMK's and the Assault? Dynotech Jim says that this motor needs to run cooler for the flatlanders for best performance. I figured maybe there might be two different thermostats and maybe the RMK t-stat would help or be the solution.

 

[Ron]

Does anybody know at what temperature the t-stat opens on the 800 RMK's and the Assault? Dynotech Jim says that this motor needs to run cooler for the flatlanders for best performance. I figured maybe there might be two different thermostats and maybe the RMK t-stat would help or be the solution.

The Dragon 8's use PN7052452 a 163 degree thermostat, most others use PN 7052433 155 degree.

 

[modsled]

For those that are interested.

The Small block motor is about 1/2 inch shorter between centers then the old big Block.


1/2 narrower between centers it can never make the power of the old motor in full mod form.


So this means that PSI knew what they were doing on the Genesis motors? They have an extra 3mm between there rods.

I am no Engine building guru I can make them go and that's about it. I would really like to here from some Known Polaris engine builders.
Rett

 

[63nova]

600bb?

For those that are interested.

The Small block motor is about 1/2 inch shorter between centers then the old Big Block.

As I said, In a big bore situation, there is no way the SB can make as much the power as the big block if the Ign timing and BSFC are the exact same.

And I stand by my first statement, A 1997 700 RMK in stock form in the new chassis will run the guts out of the new motor.

Remember I said the 1997 RMK Motor !!!!! I dynoed one of these in stock form ( 135 hp the first pull ) But as I said, Dyno numbers are only relative to what ever you want them to be.

The 1997 RMK was a one of a kind package, No other domestic motor had the timing curve or BSFC numbers that this motor did. As a matter of fact Polaris sent out an update CDI box to tame this monster.

If you ever had a chance to drive one of these when they were new and set up right you know how hard this package ran.

They would NOT hold together at sea-level ( Well a few people got lucky )
Most of them at sea-level in really cold weatHer blew the pistons out the exhaust in a lava form.

08/09 800, Its just a motor in a really good chassis with a great track.

1/2 narrower between centers it can never make the power of the old motor in full mod form.

Stock or trail Mod, yes. Because of the Mono block they can hold the transfer size to good perspective.

Please explain then the old 600 big block (98-2000) that had the extra half inch but only made 105 Hp vs 120ish for the current small block 600s.

 

[indydan]

So this means that PSI knew what they were doing on the Genesis motors? They have an extra 3mm between there rods.

I am no Engine building guru I can make them go and that's about it. I would really like to here from some Known Polaris engine builders.
Rett

Rett, You would be correct. Bruce at PSI is a brillant engine builder
And yes he knew there was power in transfer size. there is a delicate balance between - Case volume, Bore size & transfer port.

Some of his big motors were domed by things behond his control, And some were dome because of a lack of quality control. ( all though most of his recipes were good ones ) a good share of the problems of years past was the wiseco piston.

#1 -The expansion rate of a forged piston that big. ( which premotes fairly large cylinder to wall clearances )
#2 - The pistons are made to be very lite weight. ( result ) thin skirts )
#3 - Large cylinder to wall clearances, & thin skirts ( results in collapsing skirts and then the piston tips in the bore and the rings loose face angle and power fades )

PSI was confined to useing Wiseco forged piston because they are one the only companies that will make production runs in very low numbers. ( runs as small as 25 pieces )

If PSI went a Piston casting such as ART the run numbers would have to start 1000 pieces or even higher depending on many factors such as lead time.

Then when PSI ventured into crankcase design, Quality control and bearing bore accuracy was not evaluated as closely as was needed )

Rushing a product to market can come with devastating results.

Cast pistons, & better quality control on the crankcase would have resulted in some very awesome motors.

If the case & transfers are to big for the bore then you do not pull hard enough on the carb to get the required charge needed ( this is a very complex process ) Air speed in the transfers wether to slow or to fast can both be bad. And is not equal for all motors .

Example

#1 - 1000 Twin at 7600 RPM

#2 - 1000 Triple at 9200 RPM

Now imagin the CC number is divided by two in one motor and by three in the other motor.

Case size & and transfer size are very complex ( and piston speed plays a large part in this. )

Bore, stroke and crankshaft speed of these two motors is going to give you completely different results.

The twin will be a awesome Boondock Motor with gobs of low-end torque. Thats easy to tune ( if the builder does not try it make it something its not ) and the port timing is in balance with crankshaft speed. ( what its never going to be >>> A High RPM speedster. Should be built to run 7400 to 7800 RPM - It is what it is.

The triple will be a great lake racer or hill climber with gobs of track speed.
( if the builder does not try and make it something its not ) and the porting timing is in balance with crankshaft speed. What its never going to be >>> A stump pulling Boondocker. Should be built to run 8800 to 9200 RPM - It is what it is.

To many times I see Big Twins built & aimed at what they are not >>> 8000 to 8500 RPMs

And to many times I see Big triples built & aimed at what they are not. >>> 7800 to 8200 RPM.

If you spin a twin to high....... its most likely not going to last.

If you spin a triple to slow...... Its never going to be what it should have been.

The cast Piston is what made Engine Techs Motors so good. And he used a good quality Cat bottom-end on the big ones.

This could go one and one ( and this is a very basic example )

And yes, both the twin & the triple can be built to work ( OK ) at both - by sliding the parameters one way or the other.

It is important to build and buy to favor your own personal style.

1000 Twin can be great for one guy, And a piece of junk to another.

1000 triple can be great for one guy, And a piece of junk to another.

It is very important to be realist with yourself when you buy or build a sled motor.

Example - a 550 Liquid would make some people happy, But yet a 550 fan would make the same person miserable>>>>>>>>>>> whats the difference you ask...................

Crankshaft speed ----

Most fans spin 6800 to 7000 RPM

Most Liquids spin 7800 to 8000 RPM

Why ...... Port timing, ign timing and pipe design.