tinkerbell

it has been suggested rather commonly that you should swap the B20B water pump for a VTEC type pump.

the B20 pump having a 19 tooth pinion and the VTEC pump being 22 tooth.

both pumps have a 7 blade impeller.

the laws of physics regarding belt drive reduction means that the 22 tooth pump would spin the impeller LESS than a 19 tooth pump for any given RPM.

conversely, a 22 tooth pump would take less effort to turn than a 19 tooth pump for any given RPM.

so, the B20 pump flows more coolant but creates a higher engine load,

and the VTEC pump flows less coolant and creates a lower engine load.

the reason for the differences?

it is simple - the VTEC pumps are for higher RPM engines and that means that there is a possibility that it can be spinning to fast, hence the need to slow its maximum flow down.

the B20 pumps are designed with lower RPM engines in mind, which will need higher coolant flows as they dont get reved as high as a VTEC engine.

anyways,

not sure what this means for the B20VTEC, but if anyone has any thoughts on this please share them...

should i use the B20 pump or the VTEC pump?

t..

Kamin

depends
how often to you plan to take it to 8000?

Mikey3000

maybe it's not the diameter size of the pump that matters but the design of the impellers. maybe the VTEC water pump incorporates a better impeller design which outflows the non-vtec one.

C-speed

If i'm not mistaken, you are assuming the rotation speeds between the two pumps based on the fact that there are the same number of teeth on the VTEC timing belt vs the non-VTEC timing belt.

If this were the case, then yes, the b20 pump would spin faster than the GSR pump. However, you must remember that you have to match the timing belt to the water pump you choose to use. Thus, the B20 pump requires you use an LS timing belt and a GSR pump requires that you use the GSR timing belt.

Both timing belts have different number of teeth.

HTH

tinkerbell

Well, yes it does depend on how often you goto 8000rpm, but that is more of a general issue…

Both water pumps have the same design impeller.

Number of teeth or length of belt is irrelevant when the belts have same sized teeth.

It is the diameter of the pinion relative to the diameter of the drive gear that determines speed of rotation. Not the length of the drive belt.

The crank pinion is 17 teeth, so for every rotation of the crank, there are 19/17 or 22/17 rotations of the water pump or 89% or 77% of a full impeller rotation.

<u>As I said above, there is a perfectly good reason for having a slower spinning pump on a high revving engine. And a faster spinning pump on a lower revving engine.</u>

So the coolant goes around at a speed that is, on average, unlikely to be too fast or too slow.

This is assuming that it is understood that coolant has an optimum flow rate within an engine/radiator system to ensure that the system does not overheat (recall a system without a thermostat? or a cooling fan?)

anyways,

So, the real point is that people swapping the 19-tooth pump for the 22-tooth pump because it is “better” without knowing WHY it is better…

It is only useful to ensure that the speed of coolant flow does not go PAST a certain optimum velocity.

t..

C-speed

No. you are missing the point.

The LS timing belt and the GSR timing belt are different. They have different number of teeth. I don't know off hand how many teeth each one has, but follow me here.


You need to be aware of how many teeth are on the belt because this will determine how many revolutions the waterpump makes PER COMEPLETE REVOLUTION OF THE ENGINE.

For example, if the LS belt has 50 teeth on the timing belt and the GSR belt has 55 teeth, then the fact that the water pumps have more/less teeth will be offset because on each engine revolution, both water pumps will have made the same RPMs as well.

(the 50 teeth and 55 teeth are just random numbers picked from the top of my head)

Follow me now?

tinkerbell

so your point is that the length of the belt determines how fast the water pump spins?

OK,

the 17 tooth crank pinion has 17 teeth per complete revolution

if the belt that passes the 17-tooth pinion then passes a 19-tooth pinion, the 19 tooth one doesn’t make one full revolution. neither does a 22 tooth pinion - in fact it makes less of a complete revolution than the 19-tooth pinion.

it doesn’t matter how long the belt is, it could be 500 tooths long, it still passes each toothed pinion in direct correlation to the amount of teeth eg 17/19 or 17/22.

the length of the belt is irrelevant to how fast the pumps spin

OK, let me present this to you differently:

the cam gears have exactly 34 teeth and run directly off the crank pinion which has 17 teeth, so it is a 2:1 ratio (17/34 = 50%)

the crank spins once, the camshafts spin twice. (Which is required in a OHC internal combustion 4-stroke engine)

Now, you should be able to see how the belt length is irrelevant to this discussion and the teeth count of the pinion gears is what matters.

and i would like to hear some comments on whether or not this concept has any implications for cooling of a B20VTEC engine.

t..


[Modified by tinkerbell, 2:34 PM 7/29/2002]

C-speed

Again, i did NOT say the LENGTH of the belts are different, i said the NUMBER OF TEETH on the belts are different.

Think about it. If that didn't matter, then why would you have to match the timing belt to the type of water pump you get? If you don't take this into consideration, the belt will keep skipping teeth even though it is tensioned correctly.

daver

If the two belts have a different number of teeth AND the teeth are all the same size then the belts WILL be different lengths. If the two water pump pullies have a different number of teeth AND the teeth are the same size, then the pulleys will have different diameters. All else being equal on the two engines, the belts will HAVE to be different lengths to match their different water pump pullies.

Tinkerbell is right, you could put 4 more pullies in there and use a longer belt and the pump will turn just as fast at any given engine rpm.

Did i get that right there?

Is the deck height the same on the gsr and ls engine? Is the belt routing configuration the same?

What about the oil pump?

d

tinkerbell

the teeth are the same size so different amount of teeth means different belt lenght.

that's easy.

yes, this is true.

but it doesnt mean the 19 tooth water pump spins LESS than the 22 tooth water pump.

all i am saying that the B20 water pump would flow more coolant than the VTEC water pump.

t..

C-speed

Dave, I guess you're right.. if the teeth are different, then the length is also different. Like i said earlier, I don't know exactly how many teeth each belt has, however I'm pretty sure they are different. Thus the lengths must also be different.

My point wasn't that they would spin at different speeds (the waterpump). My point is that although the b20/ls pump have different teeth than the GSR pump, they still spin the same rpm because the timing belts are different.

And no, the LS/b20 oil pumps are the same as the GSR pumps, and both blocks have the same deck height. Routing of the belt is also the same.

Again, i don't have actual numbers for both timing belts, as I've never actually physically measured both belts and counted the teeth on each - who would?

tinkerbell

[QUOTE]
My point wasn't that they would spin at different speeds (the waterpump). My point is that although the b20/ls pump have different teeth than the GSR pump, they still spin the same rpm because the timing belts are different.
[QUOTE]

this is the bit that i disagree on.

the 19 tooth B20 pump takes less teeth to do one revolution than the 22 tooth VTEC pump,

so therefore would spin faster at any given RPM when compared to the VTEC pump.

because the pump has less teeth.

it is rather simple physics.

do you get the point about the 34 tooth cam gears and 17 tooth crankshaft pinion?

it is a ratio thing - the amount of times they spin around is related to the amount of teeth, not the size of the belt.

so for every one revolution of the crankshaft:

the camshafts rotate 50% of 360 degrees,
the B20 pump rotates 89% of 360 degrees,
the VTEC pump rotates 77% of 360 degrees.

so these are set ratios which cannot be changed at all.

belt length is not important to the rotational speed of the water pump.

t..

daver

and if you throw on a bigger water pump pulley, then you need a bigger timing belt so it will FIT. Or if you throw on the smaller pump pulley, then you need a smaller belt so the tensioner can be effective in taking the slack out of it. Thats the reason for the belt/water pump match-ups.

I think g3teg is stuck on the thoughts of needing the cam pulleys and the crank to be in sinc, and being off a tooth will throw it out (or having extra teeth or less teeth?...nope). Two different things here and in this case, as long as the number of belt teeth on the front of the engine (between the front cam sprocket and the crank sprocket) remain the same (correct) number, the number of teeth on the back side can be infinity (as long as the slack is taken out )

did i get that right? its late...

tinkerbell

yeah, i think you got it right

but what water pump are you going to use?

im sticking with the B20 one, so i can use the B20 belt and also because it will flow a bit faster than the VTEC one.

not that i expect cooling to be an issue for the B20VTEC...

it was just a thought that occured to me when i was playing with my B20 the other day...

t..

daver

gonna use the pump that came with it and i already put a new ls belt on.

...and it fits perfect

goodnight

owen_the_soyboy

WHOOOOOOO HAHAHHAHAHAAAAAAAAAA

this thread is hilarious!

EE_Chris

If all else remains equal [cam teeth & crank pinion teeth] and the water pump pinion has gone smaller in tooth count....it HAS to rotate faster per any given RPM vs the higher tooth count of the VTEC pumps. Belt length has nothing to do with it....it has everything to do with the ratio of the tooth count.

Look at a 10-speed...chain length plays no part in it....its there to connect the sprockets together. Chain length also stayed the same, ehh. Well, why would it be different for the timing belt. Yeah sure, the water pump has fewer teeth on it....but so does the 10th gear on my bike....just had to have some way of taking up the slack.

Perhaps whats tripping you up is the fact that the belt lengths are the same, but the tooth count is different [I have to take that at face value, as I don't know whats different].

Lets look at some pulleys with NO teeth. I've got a pulley with a 1ft circumference. The second pulley also has a 1ft circumference. 1 turn = 1 turn. Now lets change one of them so its only 1/2 ft. 1 turn = 2 turns. Well, when I went to the smaller pulley, one of two things HAD to happen: either the belt changed length or the pulleys distance was changed. Either way, belt slack had to be accounted for.

Hope that was clear.

Ehron

What about the Mezier electric water pump? Anyone use that? Excuse me if it is not relevant. My brain has been dazzled by all the tooth talk...

Charlie Moua

iTrader: (3)

haha this thread is sweet. Lots of good info. Not everyone will need to know this extensive info but it's nice to see ideas/theorys out there.

BTW does anyone know:
*****how many teeth are in a GSR/ITR timing belt compared to a LS timing belt?

any thoughts on this?
....search is my friend