Laugh. I dont need to ask injuneer because I know this myself. Your giving out BAD information. The higher stall will ALWAYS help in such a case. HP is a FUNCTION of torque. Regardless of your torque, if you shift into more horsepower, you will be faster at the track, EVEN IF torque at that particular RPM is lower, which is usually the case when your shift extension isnt but 7 or 800 rpm, as opposed to 2500rpm with a stock stall. Your continuing to preach misinformation, and you ought to get out of the thread before you make a bigger fool of yourself then you already have.

 

Any ideas on what kind of HP numbers you would make on a setup like this?

 

YOu are confusing shifting into more horsepower (I.e. delayed shift) with increasing rpm in a static gear beyond the torque band via a looser stall. They are different things. You're talking to a guy who achieved the top 0.1% in the physics section of the (14 on the standard curve) of the physical sciences portion of the MCAT. I know my physics and I dont preach misinformation.

As I already explained, shifting into peak horsepower band results in greatest possible rwtq and acceleration. Increasing the stall to run from 4000 to 5000 rpm in a given gear will NOT increase rwtq unless the engine torque is greater at 5000, which is rarely the case in an lt1. In the latter case, the engine cranks more HP (flywheel has wame tq, but more speed), but RWHP remains the same, because rwtq is the same, and speed is SAME with the higher stall and lower stall. This means more energy is being wasted, and thats why higher stalls dyno less to the wheels.

 

Hey reject, funny you brought up torque multiplication. Do you understand the STR rating on the converters. Seems to me if what you said was true (and I have my serious doubts because I am in physics and we didnt learn anything about high performance torque converters through high torque applications, and I doubt you did either), but the gain in torque mult. would more then offset the torque diff. And if it is torque that accels the rear wheels then that would be a win for converters, since they loose hp but gain torque, esp with a high str.

-James

 

by torque multiplication, i was referring to the transmission and rear and gears, multiplying the flywheel torque. I do not know of different stall torque converters increasing torque at the flywheel itself at any given engine rpm. YOu may not have learned about torque converters in uni, im sure you have a solid grasp of the relationship between torque, velocity, HP and acceleration. Thats all you need to understand what I am saying.

 

Blah blah blah MCAT this, MCAT that, you failed the practical portion of drag racing tech. At a given TQ, your motor will make more power at 5000rpm then it will at 4000. Suppose you make 6% less TQ at 5000 rpm then you do at 4000, your still coming out well ahead in HP (which is what matters here) when you shift into the next gear.


Which car is faster, the one that spends it time accelerating between 340 and 350 horsepower, average 330 torque for 10 seconds (big stall, low shift extension)

Or the one that spends it time accelerating between 270 and 350 horsepower, averaging 340 torque for 10 seconds. (stock stall, HUGE shift extension)




I rest my case, everything you say is contradictory to the basic fact that more hp at the wheels over a given amount of time = you get from point a to point b faster. Preach wasted power this, torque that, okay sure, but the fact remains. 10% more average power gets you there faster, even if you do have a 1% efficiency loss (which mind you, isnt always the case)

 

would it kinda be a good thing to have a lil less grunt bottom end maybe it will help you to keep a lil better traction and youll get up into those high rpm's quick and after that your gone

 

Nah the most power you can have is better, but yes with traction like you mentioned. Traction is one of the key factors in good performance. You can have all the power in the world but if you can't hook up, it's useless. An underpowered car might have an edge from a dig because it can grip, but an underpowered car is still underpowered....it's not an advantage. I've kicked the crap out of a few cars outta the hole that seriously overpowered me. That was the only reason was I was able to retain traction and they were not. Once they finally hooked....it was bye bye for me....all I saw were tailights.

 

if you want to prove your point, do it with equations, explain where I am making a mistake. For simplicity, lets assume a gear that results in a 1:1 ratio between engine rpm and rear wheel rpm.

rwtq = torque produced by engine x drivetrain efficiency (eg. 0.8)
rwtq is also proportional to acceleration of the car.

rwhp = rwtq x rotational velocity of rear wheels
engine HP = torque produced by engine x rpm.

We all agree on this. Depending on units used, you'll have a constant as well.

Increased rpm = increased engine HP if torque is maintained.
If increased rpm CORRESPONDS to increased rear wheel velocity, while maintaining rwtq, then you get increased rwhp.

We all agree on this too?

If you increase rpm with a looser converter, and maintain the same torque, you still get increased engine HP.

We agree on this.

to increase rwhp, you MUST increase either the rw velocity or the rwtq.

What is rwtq at 4000rpm stock stall vs. higher rpm aftermarket stall?
It is torque produced by engine x drivetrain efficiency. If engine torque at 4000rpm = engine torque at 5000rpm, rear wheel torque will NOT change between these rpms. It remains the same.

Will a looser stall allowing the motor to run at 5000rpm at a given speed increase rw velocity? Well by definition, we have the same rear wheel velocity with a higher engine rpm.

You have the same rear wheel velocity and the same rwtq with a stock stall at 4000 vs. aftermarket stall at 5000 (or any higher rpm). So even though the engine HP is higher as per the equation, the rwhp is NOT higher with the higher stall.

to increase rwhp, you MUST increase either the rw velocity or the rwtq. Beyond the motor's torque peak, a higher stall will NOT achieve EITHER at any given rear wheel speed.

If you maintain a given gear, on the same stall, higher engine rpm results in higher rear wheel velocity. In this case, you get BOTH increase in engine HP and rwhp if the torque is maintained.

 

stock stall vs aftermarket stall does not change the rpms the car makes the most power at. The car does not make any more hp or tq before or after. It just multiplies it more efficiently and just all around better. What I mean is. if your giving 3/4 throttle and it results in 4k rpms on a stock stall, it will not automatically result in 5k rpms with an aftermarket(using your example rpms). It will result in the same rpm. The only way more throttle effort is required(of course resulting in more rpm) is below the stall speed. In my situation 3k or lower....but actually a little less. My car still rolls off the line like it always used to when stock. Now though instead of it requiring hardly any throttle to move forward to above 3k rpms, it requires atleast 1/4 or so. Once above that 3k though I can back right off and accelerate with the same rate I did(and same pedal effort) before the stall. Take away marginal pedal effort and go WOT. Given the same traction the car with the stall will come out of the hole harder and quicker. It's just like launching an M6 at 1800rpms vs launching the same M6 at 3000rpms. Again all things including traction being equal which one will come out first? It's obvious. On top of all that crap. Dropping a vehicle out of it's "powerband" inhibits acceleration, which is exactly what happens on a stock car. It may not be physically noticable but it does happen. Of course, keeping a car in it's "powerband" at all times(with a stall) is going to result in harder acceleration. If my car makes it's best power at 4k rpms or higher, if it stays at or above that at all times it's going to accelerate faster than dropping down to 2k rpms and then climbing back up to 4k and then passing it(this would be at each gear shift). Even if you take the percentage of hp lost through the slippage of the converter and add it to the equasion. The torque multiplication of that same converter more than makes up for it. Whew...I've been drinking forgive me for talking forever.

 

Its nice to read a post that is not so emotional

i was talking about WOT, not part throttle. The higher stall does not multiply the torque, it allows the engine to rev higher at a given speed in a given gear at full throttle. The engine will still produce the same flywheel torque at a given rpm with either stall converter, assuming the same efficiency.

If a stall was meant to keep the car in the peak powerband at all times, then a 6000 stall would be the best for a big cam like cc-306 or gm847. Intuition alone shows this would be disasterous. My basic point was, high stall is best to keep the motor out of the low rpms where it produces less torque, and best shift point is that which keeps the car in peak horsepower band. Hence you shift at very high rpm, but you stall at mid rpms.

 

Will a looser stall allowing the motor to run at 5000rpm at a given speed increase rw velocity? Well by definition, we have the same rear wheel velocity with a higher engine rpm.

You have the same rear wheel velocity and the same rwtq with a stock stall at 4000 vs. aftermarket stall at 5000 (or any higher rpm). So even though the engine HP is higher as per the equation, the rwhp is NOT higher with the higher stall.

But the motor is putting more power to the ground a GIVEN SPEED because it's turning more rpms and is farther into the powerband then a stock stall would be. You just proved my point, go home troll.

 

power to the ground is measured by rear wheel velocity and rear wheel torque. Its not measured at the engine. What you measure at the engine is ENgine HP, and that is done by rpm x engine torque. Engine can be producing 1000HP but the rwhp is still determined by rwtq x velocity ALONE.

I'll go home if you go to school. Deal??

 

Lloyd claims 340-360 rwp with the correct tune & should mass emissions. But this is with: headers, 52mm TB, 3" exhaust.

 

You dont have a clue what your talking about.