Cammed S197 > Ported Terminator
10-29-2009, 11:57 AM
#84
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
FWIW.
I raced a C5 vette, stock, auto. He beat me on R/T by a little under 2 tenths. I beat him on 60' by about a tenth.
He ran a 13.8 @ 103. I ran a 13.9 @ 100. When we went over the line he was around a car length in front of me.
The vette has tall gears but has 350@the crank and less weight. Isn't that about what I should expect given my car's modifications? Dyno considerations aside.
I raced a C5 vette, stock, auto. He beat me on R/T by a little under 2 tenths. I beat him on 60' by about a tenth.
He ran a 13.8 @ 103. I ran a 13.9 @ 100. When we went over the line he was around a car length in front of me.
The vette has tall gears but has 350@the crank and less weight. Isn't that about what I should expect given my car's modifications? Dyno considerations aside.
10-29-2009, 01:23 PM
#85
6th Gear Member
Join Date: Feb 2007
Location: North Carolina
Posts: 11,302
FWIW.
I raced a C5 vette, stock, auto. He beat me on R/T by a little under 2 tenths. I beat him on 60' by about a tenth.
He ran a 13.8 @ 103. I ran a 13.9 @ 100. When we went over the line he was around a car length in front of me.
The vette has tall gears but has 350@the crank and less weight. Isn't that about what I should expect given my car's modifications? Dyno considerations aside.
I raced a C5 vette, stock, auto. He beat me on R/T by a little under 2 tenths. I beat him on 60' by about a tenth.
He ran a 13.8 @ 103. I ran a 13.9 @ 100. When we went over the line he was around a car length in front of me.
The vette has tall gears but has 350@the crank and less weight. Isn't that about what I should expect given my car's modifications? Dyno considerations aside.
10-29-2009, 01:25 PM
#86
6th Gear Member
Join Date: Nov 2007
Location: Montaner
Posts: 6,193
And yet somehow those dyno numbers usually end up in our sigs. 
When I told Mishri about that race against the C5 he was upset that he wasn't there. That way he could come back here and brag about beating an LS1. lulz
When I told Mishri about that race against the C5 he was upset that he wasn't there. That way he could come back here and brag about beating an LS1. lulz
Last edited by Riptide; 10-29-2009 at 01:27 PM.
10-29-2009, 10:17 PM
#87
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
Dyno numbers don't really mean jack. They can be manipulated, or inadvertently screwed up and come out wrong. Like it was said before, they're a tuning aide for setting baseline, and nothing more.
What really moves a vehicle down the road is torque at the wheels...horsepower is just a way of measuring torque at a certain rpm, though it is important(without going into tremendous detail). Torque output at the engine is multiplied by the transmission then multiplied again by the differential, so that in first gear you're producing thousands of lb-ft of torque at the rear wheels, but dynos don't take that into account. That's why 2 cars that have the exact same power and weight might run differently, the one with more gear will accelerate faster.
And even dyno tuning isn't the end of it. 90% of cars tuned on a dyno will find a bit more USABLE power with track tuning. What a car puts down on a dyno and how it runs in the real world can sometimes be RADICALLY different, this is especially true of carbureted cars that are very sensitive to how the engine is being loaded....they load differently on a dyno than in the real world. A dyno is great to baseline the car, so you have a starting point to make changes from when tuning at the track. Most street EFI cars though won't find enough extra power track tuning for it to make much of a difference(which is why dyno tuning is a powerful aide for EFI cars). 2-3rwhp on a production street vehicle that is 3,500lb won't make enough difference to justify data logging and tuning changes and the costs and trouble involved.
But carb'd cars provide a good example. I've seen guys get a carb tuned on a dyno with a nice AFR(anywhere from 12.5-13:1), only to go down the track so lean that it barely runs, or go down the track pig rich and the intake never cleans out and it sputters the whole way.
Dynos are just an aide, and in the end the numbers they produce just give you a reference point for both AFR and power...the power rating lets you try to measure any power CHANGES that occur as a result of engine changes....but that doesn't mean the # it gives you is correct. What matters more is if it went up or down, not really by how much.
What really moves a vehicle down the road is torque at the wheels...horsepower is just a way of measuring torque at a certain rpm, though it is important(without going into tremendous detail). Torque output at the engine is multiplied by the transmission then multiplied again by the differential, so that in first gear you're producing thousands of lb-ft of torque at the rear wheels, but dynos don't take that into account. That's why 2 cars that have the exact same power and weight might run differently, the one with more gear will accelerate faster.
And even dyno tuning isn't the end of it. 90% of cars tuned on a dyno will find a bit more USABLE power with track tuning. What a car puts down on a dyno and how it runs in the real world can sometimes be RADICALLY different, this is especially true of carbureted cars that are very sensitive to how the engine is being loaded....they load differently on a dyno than in the real world. A dyno is great to baseline the car, so you have a starting point to make changes from when tuning at the track. Most street EFI cars though won't find enough extra power track tuning for it to make much of a difference(which is why dyno tuning is a powerful aide for EFI cars). 2-3rwhp on a production street vehicle that is 3,500lb won't make enough difference to justify data logging and tuning changes and the costs and trouble involved.
But carb'd cars provide a good example. I've seen guys get a carb tuned on a dyno with a nice AFR(anywhere from 12.5-13:1), only to go down the track so lean that it barely runs, or go down the track pig rich and the intake never cleans out and it sputters the whole way.
Dynos are just an aide, and in the end the numbers they produce just give you a reference point for both AFR and power...the power rating lets you try to measure any power CHANGES that occur as a result of engine changes....but that doesn't mean the # it gives you is correct. What matters more is if it went up or down, not really by how much.
12-15-2009, 09:25 PM
#88
Banned
Join Date: Nov 2009
Location: MS
Posts: 723
sorry to bring up a old thread but since its about me i will add my 2 cents...
i am by far no 3vnutswinger i know my place and there are many eaton only cobras that would hand me my ***...i never said my car went low 12s on street tires... i went 12.5 with a 1.9 60ft and the cobra went 12.1 with a 1.9 60ft the same week he made 465/500 on the dyno and is full weight i should make 350-360 range and weight 3400 with driver... we had 2 runs 10-110 i got the jump he pulled even and missed 4th.. dig-120 he was a little late on the horn and at 120 i had half a car we never went to 130 like posted by grabber half the **** he said was false
i am by far no 3vnutswinger i know my place and there are many eaton only cobras that would hand me my ***...i never said my car went low 12s on street tires... i went 12.5 with a 1.9 60ft and the cobra went 12.1 with a 1.9 60ft the same week he made 465/500 on the dyno and is full weight i should make 350-360 range and weight 3400 with driver... we had 2 runs 10-110 i got the jump he pulled even and missed 4th.. dig-120 he was a little late on the horn and at 120 i had half a car we never went to 130 like posted by grabber half the **** he said was false
