big bore kit dyno

[TNT]

Quote: Originally Posted by Blizzard24

Terry, I am not sure about these motors but when you stroke a motor, usually it is much more reliable than trying to get the same displacement through over boring. I may be wrong and if I am somebody please correct me. But engine builders that I have talked to always prefer stroking a motor over boring it.

The longer stroke produces more piston/ring wear a high maintenance item. When I talked to Falicon he said stoking the big bore really wakes it up on some motors. If I remember right the $1100 was for a rod and crank. The big piston can also put more wear on the rod and crank, but this motor looked strong to us. Think it be interesting if you stroked the 495 what port would work. You’d really be asking for more volume and velocity so would wonder if expoxing down the intake port in this case to gain more velocity less volume is the answer. I’d think you need a 52 maybe bigger TB. A flow bench would tell but as far as I know your can’t flow check the combustion chamber and fuel atomization. I would think in this case the largest injector BRP makes is a must so that the EFI can handle within range since the injector’s durations is based on air and if the injector is limited in size it will not deliver. I would also wonder how close in upper air flow capacity we getting to the MAP sensor. Why be nice if BRP would allow programming of their ECU.

To compete in AMA Open A MX against KTM’s, SUKS, w/60+ whp/37+_ tq this is the only way(stroke/bore) starting @ 39whp stock I know of anyway or with a very unreliable 450 pro quad…Then again does no good to have a bunch of power you can’t deleiver to the ground so being in national pro shape is a must otherwise why waste the $. We came close 10 in open A/ LL with this engine on a blown head gasket; bet it we were not overheating and shutting down due to lack of throttle and power we’d seen the podium that day @ 50hp, 35_tq. Unless your drag racing it’s not always how much power or big dyno numbers you got that & keeping the quad running half the battle, other half is the racer.

Like all the cartoons on this site lol:

[ds450power]

Quote: Originally Posted by TNT

Heres a list of our mods, we run a 495 w/about 50hp and 35 ft-lbs of smooth TQ excellent throttle response.

whats a stock ds450 put down on this dyno?

[TNT]

Quote: Originally Posted by ds450power

Quote: Originally Posted by TNT

Heres a list of our mods, we run a 495 w/about 50hp and 35 ft-lbs of smooth TQ excellent throttle response.

whats a stock ds450 put down on this dyno?

One thing we wanted to check but never found the time. I was looking at this last night since I'm amazed at how some of the dyno #s I see vary leaps and bounds, I think some people claim numbers that are unreal. This motor is not easy to get reliable power out of especially 20+ hp and 450. You'll see big gaps between some of the big DS engine builders even.

What LTR posted on this site is believable although I could not find his correction factor or load. Also load dyno's can be misleading we use a 10% load on a brand new Dynojet so if you use none the #s may be higher. Load dyno's like LTR's and ours that operate under eddy current load are the best for tuning accuracy. Another misleading factor when comparing to other quads is weight and weight-to-power, DS is light not needing as much hp/tq to compare.

Heres what Rossier got: Dynamometers: Tips & Tricks

Our quad competes real well with KTM450 my son at a race in TX couple months ago 2nd in the TQRA pro class only one quad length behind a KTM Pro Champ that's faster then him by a little as a racer, he blows KTM trannies all the time.

[ds450power]

i understand the differences in one dyno to another, so you have to use the same dyno to see what you actually gained from your previous baseline. i could say i dynoed at 60hp but if a stock bike puts down 56hp on that particular dyno thats not a good gain lol....

[TNT]

All stock quads should baseline the same about 39-40hp. What I find interesting about Rossier results is he only gains 2hp from a $500 port on their “Super Flow Bench”. http://www.rossiereng.com/products.php?product=1192137435

Our BB does not epoxy down the ports like the 450’s and I might take the xtra head I got and do it and see what happens……It’s not really a rocket science all your doing is trying to cone-taper down to gain velocity a low pressure area at the port for more vacuum pressure to the intake and atomizing……Guy that does my motors I’ll have him do it with some Devcon. I don't see the benefit of the head only flow bench w/efi.

But if you look at LTR mild build he has close to the same 48-49 ish without a port but has a HC piston. Rossier does not show his TQ but I bet it’s around the same 32 or so.

So what have you decided are you going to stroke and bore?

Be about a month before we swap over to a 450 I’ll have some pics then or JSR Performance sells the 495 kit 316-706-3658. Ask for John tell him Terry sent you.

[fast507]

Wouldn't the increased cfm demend from the BBK serve to do the same thing, all variables being equal? It seems like the head port profile on the DS is to big for the std bore and that being the case wouldn't it lend itself to a BBK application. I would be interested to see numbers from a build with a fresh, stock head, (maybe just clean up the ports as needed) on the big bore motor with a throttle body mod and a "green" or "blue" injector and decent cams.

[TNT]

Thats basically what we got.......We did our big bore back in the beginning of 09, first one. Back then we we all experimenting, the 450 power was unreliable in the 08's so we BBK. We got decent power back then, 50hp, 36.5 tq, PC3, etc....today they came a long way with the 450's and are beating those #'s by a bit with reliable motors.

The BBK REALLY wakes up with a stroker like Falicon, but I'd question reliability like pushing the 450 too far...I have yet to hear of DS that has done this.

The DS big air head and heavy large valves came from a BRP 1000 motor I think it was, done quote me on that. This fat air flow has always posed a low end torque prob since velocity is low, CFM high, so the race teams found epoxy down the port to create a venturi effect solved this. Our BBK solved the low end tq prob too by pushing more CFM over that area of the RPM curve, not that I'd choose this path today rather a 450 now that we understand them better.

495 CC
13:1 CP
50MM TB (BRP)
Web Cams
Ti Retainers ( BRP)
Port
Oversize Injector (BRP green)
FCI/Large K$N(prototype)
Rossier Pipe(full)
Race ECU
PC5
CV4 fuel tank boot(prototype)
PEP(PD1) Shocks
Race Team Louvers
ECU protector
Custom Race Team graphics by SSI
Dom 2 Axle
BCS Battery Box
E-85 fuel
Gearing: 14/39, Rethanol chains
Precision Stabilizer.
Tires: Maxis Razor X Front 20x6x10, MR MX Rear: 18x10x8...(orange compound)
Oil: Motorex
BCS cooling and race harness.

[CANAMracerdad]

our stock 08 , came out at 33 HP and 27 ft lbs of torque
WE wound up with just below 48 hp and 32 ft lbs of torque ..... A 50% increase in hp and @ 25 % increase in torque ....
WE have just freshened it up, made some changes, and will repost the new numbers next week. hoping for 50 and 36 on 110 octane

some of our bikes outrun the ones that claim they pull 60 rwhp
our dyno is 2008 dynojet dyno w/o load braking . WE have taken bikes that claim 60 rwhp and they go 52-53 on our dyno

we are also building a 3 rd engine with all new porting and expect to hit 55, and 37 on 110 race fuel ... but that will be on another dyno .... long story

we canot go big bore ... we have a 450 rule in pro-am class