True HP rating of the LS1
07-09-2018, 04:01 PM
#61
Le Mans Master
Having said that, I wonder if different styles of wheels would affect the rwhp? A heavier wheel/tire combo is going to absorb more horsepower before it gets to the dyno roller. Have to check that out sometime.
07-09-2018, 06:09 PM
#62
Drifting
Sure there is. The chassis dyno can only measure what's left after the drivetrain has been accelerated, that's why the wheel horsepower is lower. All drivetrains of the same type have the same rotational inertia, so they will absorb the same amount of horsepower.
Having said that, I wonder if different styles of wheels would affect the rwhp? A heavier wheel/tire combo is going to absorb more horsepower before it gets to the dyno roller. Have to check that out sometime.
Having said that, I wonder if different styles of wheels would affect the rwhp? A heavier wheel/tire combo is going to absorb more horsepower before it gets to the dyno roller. Have to check that out sometime.
If the drivetrain is exactly alike the inertia is the same, so a percent accross that driveline can be used. If the drivetrain is different, EVERYTHING will influence parasitic loss and inertia. Just a few examples, type of gears, type of carrier, weight of disc brakes, break drag, length / weight of stub shafts, length / weight of stub axles, length / width of driveshaft, driveshaft design (torque tube, double cardan, singe joint, double joints) weight of flywheel, type of converter, clutch, transmission, and just about anything else that the engine moves. And yes, weight and height of wheels and tires make a big difference.
Still intrigued that the stock C5 has approx. a 12 percent loss (probably manual).
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Capterics (08-03-2018)
07-09-2018, 07:13 PM
#63
Le Mans Master
If the drivetrain is exactly alike the inertia is the same, so a percent accross that driveline can be used. If the drivetrain is different, EVERYTHING will influence parasitic loss and inertia. Just a few examples, type of gears, type of carrier, weight of disc brakes, break drag, length / weight of stub shafts, length / weight of stub axles, length / width of driveshaft, driveshaft design (torque tube, double cardan, singe joint, double joints) weight of flywheel, type of converter, clutch, transmission, and just about anything else that the engine moves. And yes, weight and height of wheels and tires make a big difference.
Still intrigued that the stock C5 has approx. a 12 percent loss (probably manual).
Still intrigued that the stock C5 has approx. a 12 percent loss (probably manual).
In the mid 90's, we would have dyno days with sometimes up to 20 impala ss's. Bone stock, we would only see horsepower variances of maybe 4 horsepower across 15 impalas. Of course, they all had the exact same wheel and tire package, so that's why I was thinking the wheels are the most likely culprit for the horsepower variations. GM is usually spot on with their horsepower ratings.
07-09-2018, 07:25 PM
#64
Drifting
Exactly. Great minds think alike. In the mid 90's, we would have dyno days with sometimes up to 20 impala ss's. Bone stock, we would only see horsepower variances of maybe 4 horsepower across 15 impalas. Of course, they all had the exact same wheel and tire package, so that's why I was thinking the wheels are the most likely culprit for the horsepower variations. GM is usually spot on with their horsepower ratings.
In the mid 90's, we would have dyno days with sometimes up to 20 impala ss's. Bone stock, we would only see horsepower variances of maybe 4 horsepower across 15 impalas. Of course, they all had the exact same wheel and tire package, so that's why I was thinking the wheels are the most likely culprit for the horsepower variations. GM is usually spot on with their horsepower ratings.
As for the tires / wheels, I have another toy that is an LS powered Jeep. Running around town, it has some light wheels and light 33/12.5 tires, about 55 pounds. For the trails, it has heavy wheels and 35/12.5 Kevlar tires, about 90 pounds each. It is amazing how much more power it takes to turn those off road tires. Never had it on a dyno, but would guess 50 HP or more is siphoned off. Fuel mileage also drops about 30 percent as well.
08-03-2018, 09:53 PM
#65
Intermediate
That is correct; 2001 = 350hp and 360ft.lbs.(Auto) 370ft. lbs. (Man), torque. The difference in torque is due to the converter.
Last edited by Capterics; 08-03-2018 at 10:01 PM.
08-04-2018, 01:39 AM
#66
Le Mans Master
Yep!
As for the tires / wheels, I have another toy that is an LS powered Jeep. Running around town, it has some light wheels and light 33/12.5 tires, about 55 pounds. For the trails, it has heavy wheels and 35/12.5 Kevlar tires, about 90 pounds each. It is amazing how much more power it takes to turn those off road tires. Never had it on a dyno, but would guess 50 HP or more is siphoned off. Fuel mileage also drops about 30 percent as well.
As for the tires / wheels, I have another toy that is an LS powered Jeep. Running around town, it has some light wheels and light 33/12.5 tires, about 55 pounds. For the trails, it has heavy wheels and 35/12.5 Kevlar tires, about 90 pounds each. It is amazing how much more power it takes to turn those off road tires. Never had it on a dyno, but would guess 50 HP or more is siphoned off. Fuel mileage also drops about 30 percent as well.
3.42 gears for example would effectively be 3.22 gearing...
08-04-2018, 10:07 PM
#67
Racer
Exactly. Great minds think alike. In the mid 90's, we would have dyno days with sometimes up to 20 impala ss's. Bone stock, we would only see horsepower variances of maybe 4 horsepower across 15 impalas. Of course, they all had the exact same wheel and tire package, so that's why I was thinking the wheels are the most likely culprit for the horsepower variations. GM is usually spot on with their horsepower ratings.
In the mid 90's, we would have dyno days with sometimes up to 20 impala ss's. Bone stock, we would only see horsepower variances of maybe 4 horsepower across 15 impalas. Of course, they all had the exact same wheel and tire package, so that's why I was thinking the wheels are the most likely culprit for the horsepower variations. GM is usually spot on with their horsepower ratings.
08-04-2018, 11:35 PM
#68
Drifting
That is why 5.38's are fairly common in Jeeps. 4.10's are considered tall gears.
08-05-2018, 12:16 AM
#69
Le Mans Master
08-05-2018, 01:45 AM
#70
Safety Car
