What is faster if hp/tq is the same?

[thematrixhazune]

3.55 gears are a great gear for a turbo car.

If you have a turbo you do not want the same gears as with a s/c (too tall of a gear). Then again it goes back to its dependency on your combo (tranny, turbo size ect.)
Pick the right gear for the most minimal lag/ but not sacrificing take off.

3.55 is good and so is my stock 3.08's but 4.11's can hurt you.

 

[Stopsign32v]

If you have a turbo you do not want the same gears as with a s/c (too tall of a gear). Then again it goes back to its dependency on your combo (tranny, turbo size ect.)
Pick the right gear for the most minimal lag/ but not sacrificing take off.

3.55 is good and so is my stock 3.08's but 4.11's can hurt you.

It depends on your motor. A car that has no torque will not like a set of 3.08 gears. A 5.0 would be fine with 3.27 gears and a turbo but a 4v motor would more than likely be better with 3.55 gears. That is why you see 4 cylinder turbo cars with gears in the 4.XX range.

 

[thematrixhazune]

It depends on your motor. A car that has no torque will not like a set of 3.08 gears. A 5.0 would be fine with 3.27 gears and a turbo but a 4v motor would more than likely be better with 3.55 gears. That is why you see 4 cylinder turbo cars with gears in the 4.XX range.

Yes true but I was just pertaining to v8's in this case.

 

[98Snake03]

:nonono: And back to the point...how does launching in boost have anything to do with how much power the turbo takes from the motor?

No, no, no...that isn't what I was commenting on...sorry, I should have quoted.

I was referring to what HotRodK said to BadGT04 as far as AOD's not making power. All I said was that off the line with a stock AOD w/ a turbo vs a stock AOD w/ a screw- that the screw would probably be quicker because of the instant boost. I went on to say that if the AOD car with the turbo had a stall, it would be a good race.

sorry my bad.

As far as me asking you to elaborate on your flowmaster vs. turbo comment, I was just wondering where you came up with that analogy.

 

[HotRodK]

Im glad you reitterated, because you lost me too. One last question. If twin screws are better, then WHY dont ANY of the Pro 5.0 cars run them?? Its all Turbo/Centrifugal/N2O.
Not ONE twin screw. :shrug: :shrug:

 

[longrodLX]

its not legal.......and as far as an auto goes with turbos what about brake boosting?

 

[98Snake03]

its not legal.......and as far as an auto goes with turbos what about brake boosting?

yeah...most turbos boost up at 2500-3000 though, correct?

I didn't think stock converters had that much slip?

 

[HotRodK]

A stall rating is based on power output at that rpm. If the turbo starts to spool up and is making 3-5psi when on the footbrake, then the power output is higher, and the stall speed can/will go up.

Why are roots/screw blowers illegal in Pro 5.0? I never knew that. :??:

 

[69gt4speed]

I'm going to say too hard to tell, the twin screw at 700rwhp cause of low end torque may have traction issues, whereas a turbo works like a progressive nitrous controller so on the street the turbo could come out on top, may be a lil easier to launch more rpm range to play with. in theory you could set up a boost curve like a progressive controller with a turbo, no way for a twin screw to do that. Sometimes less low end power is better.

 

[mlccar]

Twin Screw

If both make 700 hp MAX then the twin screw will win. Why? Because the ET's are based on the area under the torque vs. rpm curve. A twin screw has a flat torque curve and a linear hp vs. rpm curve. The centrifugal or turbo torque curve will vary from a low to high value. The high value at the high rpm corresponds to the max Hp. Since Hp=Torque*RPM (with some constant conversions), ther will be more area under the torque curve for a posi.

Why are posi's not used in the drags? They simlply cannot generate as much boost as a centri or turbo at top rpm. So eventually, the centr or turbo will be a better drag car (but probably not a very mannered street car).

 

[Stopsign32v]

As far as me asking you to elaborate on your flowmaster vs. turbo comment, I was just wondering where you came up with that analogy.

He argued with me because I said turbos do not take power to make power by arguing that they are a restriction to your exhaust. So I came back and said that a turbo is only as restrictive as a flowmaster muffler. In short....turbos don't take power to make power.

 

[98Snake03]

He argued with me because I said turbos do not take power to make power by arguing that they are a restriction to your exhaust. So I came back and said that a turbo is only as restrictive as a flowmaster muffler. In short....turbos don't take power to make power.

that's cool...I just never thought of it that way.

 

[longrodLX]

If both make 700 hp MAX then the twin screw will win. Why? Because the ET's are based on the area under the torque vs. rpm curve. A twin screw has a flat torque curve and a linear hp vs. rpm curve. The centrifugal or turbo torque curve will vary from a low to high value. The high value at the high rpm corresponds to the max Hp. Since Hp=Torque*RPM (with some constant conversions), ther will be more area under the torque curve for a posi.

Why are posi's not used in the drags? They simlply cannot generate as much boost as a centri or turbo at top rpm. So eventually, the centr or turbo will be a better drag car (but probably not a very mannered street car).

we will see. watch for tim of MPH next year. hes gonna put a whoopin on all the centri guys

 

[mlccar]

Whoopin

we will see. watch for tim of MPH next year. hes gonna put a whoopin on all the centri guys

I am sure he cold. My point was that with a flat torque curve, you get the same boost at 2000 rpm as at 6000 rpm so that the car has a broad flat torque curve and feels like a big block engine. For the drags a Turbo or Centri will cetainly generate more boost at higher rpms, hence more torque and horsepower. I do not think anybody is arguing that a 2.2 L Kenne Bell is going to get to 800-1000 hp.

 

[longrodLX]

with my turbos i am seeing full boost at 3k rom or less and its stays that way to redline

 

[Blown02]

Im picking my car up tommorow!!!

 

[aoe_viruz]

If both make 700 hp MAX then the twin screw will win. Why? Because the ET's are based on the area under the torque vs. rpm curve. A twin screw has a flat torque curve and a linear hp vs. rpm curve. The centrifugal or turbo torque curve will vary from a low to high value. The high value at the high rpm corresponds to the max Hp. Since Hp=Torque*RPM (with some constant conversions), ther will be more area under the torque curve for a posi.

Why are posi's not used in the drags? They simlply cannot generate as much boost as a centri or turbo at top rpm. So eventually, the centr or turbo will be a better drag car (but probably not a very mannered street car).

Top Fuel cars make 40-50psi of boost at 10k rpm.

 

[HotRodK]

They also use 250hp to turn those blowers. Not exactly apples to apples. ;-)

 

[mlccar]

Drags

Yes. Since I was 12 years old in the 60's I have known that Top fuels used massive roots blowers. I guess my point was more directed at stock or modified stock. In this category I believe the fastest cars are using centrifugal blowers with ICED intercoolers. I would guess this is because of high rpm boost?

 

[05 Roush]

It depends on the turbo configuration. If you run smaller twins instead of one single, you will produce boost down low.

It may be a toss up between the blower and a TT configuration, especially if the N/A application has sufficient torque already.