4bt big power?

Smokem said:
Pull an injector and give me the numbers on the nozzle itself, there are a few good options from Bosch.
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As soon as I get my new barn build and move my crap over from the old place I'll be working on it and I'll do that.
 
There is a stock 4x0.013" cylindrical blind-hole nozzle for the off road applications that is 155°, should work if you have the non I/C pistons.
 
Still a few options, just need to be sure what nozzles/pistons it has for sure.
 
DEZLFREK said:
does anyone have a 4bt p7100 for sale
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The last I checked they were as scarce as hens teeth and higher than the price of gold! LOL It's easier to find a complete engine with a p-pump than it is to find just the pump.
 
the 4cyl VW diesel VE's are makin huge rpm and power - like on the order of 6000 rpm and 350-450 hp, precisely because there is two less cylinders to fill, and two less ports on the rotor. They even have an electronic conversion for the VE if memory serves - and yes it is a Bosch model VE same as used o nthe cummins - just tweaked much better
 
seeker1056 said:
the 4cyl VW diesel VE's are makin huge rpm and power - like on the order of 6000 rpm and 350-450 hp, precisely because there is two less cylinders to fill, and two less ports on the rotor. They even have an electronic conversion for the VE if memory serves - and yes it is a Bosch model VE same as used o nthe cummins - just tweaked much better
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Why would less cylinders help?

Isn't that just determining how many times you divide the fuel flow? As in, 4 cylinders at 90mm^3 is the same as 6 cylinders at 60mm^3 right?

At the end of the day, both cases are injecting 360mm^3 every two revs. So for any given BSFC the power will be the same because the flow is. It's just divided differently.

I don't see why 4 cylinders will make more power on a given gpm fuel flow than 6 will.

What's the deal with that?
 
seeker1056 said:
the 4cyl VW diesel VE's are makin huge rpm and power - like on the order of 6000 rpm and 350-450 hp, precisely because there is two less cylinders to fill, and two less ports on the rotor. They even have an electronic conversion for the VE if memory serves - and yes it is a Bosch model VE same as used o nthe cummins - just tweaked much better
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Bigger cubes take more fuel...119cu.in. vs. 239cu.in.
 
seeker1056 said:
the 4cyl VW diesel VE's are makin huge rpm and power - like on the order of 6000 rpm and 350-450 hp, precisely because there is two less cylinders to fill, and two less ports on the rotor. They even have an electronic conversion for the VE if memory serves - and yes it is a Bosch model VE same as used o nthe cummins - just tweaked much better
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You are wasting your breath with these guys!!! LOL. Maybe one day i can build one to prove a point!!! I think you could go quicker with less fuel on a ve then you could with a Chit ton out of a p-pump. I do know you can not beat a P-Pump for overall power and fuel. But to get 450 with a VE and 4cly would not be that hard and it would have much better fuel then a 450hp p-pump.
 
There is a guy here in Tennessee that wants to build a 4BT powered rock crawler... what do you guys think about that??? Will it handle the low RPM low speed stuff well or does it need to be spinning faster???
 
a rotary pump cant refill 6 ports as well as 4 ports in the pump, and with a 14mm head/rotor assembly can make 450+ cc's of fuel from right off idle
by other calcs for hp vs cc's that would equate to about 700hp give or take

a rotary pump excells at off idle power, so rockcrawlin should be a breeze
 
seeker1056 said:
a rotary pump cant refill 6 ports as well as 4 ports in the pump, and with a 14mm head/rotor assembly can make 450+ cc's of fuel from right off idle
by other calcs for hp vs cc's that would equate to about 700hp give or take

a rotary pump excells at off idle power, so rockcrawlin should be a breeze
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I guess what I'm trying to figure out, is how not filling 6 barrels all the way isn't the same as filling 4 all the way up.

Seems like there is a set fuel flow capacity, and the more P&B assemblies you have you just divide that number up accordingly. So you just end up with 6 cylinders each getting less fuel but the power output still being the same because there are more of them doing less.

If I look at it percentage wise..... the total fuel being injected into the engine is the sum of all fuel injected to all cylinders. Whatever that value is, that's 100% of what you've got to work with from the pump. Well, if you've got a 4 cylinder then each cylinder gets 25% of that value. If you've got a 6 cylinder then each cylinder gets about 16.6% of that value instead. But since you've got two more of them at 16.6% you STILL GET 100% of the fuel burned every two revs, and if the BSFC for each cylinder is the same whether 4 or 6 cylinder then the power will be the same as well.

Why is this not the case?
 
we are talkin VE rotary where one rotor has to fill all 4 or 6 injection events not a P-pump with barrels that has one barrel per cylinder- very very different
 
seeker1056 said:
we are talkin VE rotary where one rotor has to fill all 4 or 6 injection events not a P-pump with barrels that has one barrel per cylinder- very very different
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I know what you're talking about. Is there not still a P&B involved? Because you all are under the impression that it will only fill to ___ % full when running ___ number of cylinders vs running ___ number of cylinders. Which makes sense. My point is simply that filling less cylinders with more fuel, or filling more cylinders with less fuel, the total fuel injected and burned remains the same. So as long as the individual cylinder BSFC is also the same the power output will remain the same.

As of yet exactly zero people have addressed the fact that 4 cylinders getting ~10% more fuel DON'T make more power than 6 getting ~10% less because while each may be getting less, there are two more of them.

The total fuel consumption for the engine would be the same. The example I gave to begin with was 90mm^3 into 4 cylinders or 60mm^3 into 6 cylinders is still 360mm^3 no matter how you want to slice it.

And for any given BSFC 360mm^3 is going to make exactly ____ hp any day, every day.


The only way less cylinders would matter would be if the increased injection quantity wasn't proportionate to the number of cylinders. Which isn't what you all are suggesting.


Are you suggesting that 360mm^3 would make more power split between 4 cylinders rather than 6, or are you suggesting that the 4 cylinder injects so much more per cylinder that even with a 2 cylinder handicap it still injects more fuel in total for every two revs?
 
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