What top speed with what hp?
#46
Rennlist Member
BTW, I spoke to Dfastest at lengths and was a big supporter of Chris Cervelli for his rebuild . In my eyes, he is the best out there.
Raj
#47
Drifting
I'm running 285/30/18's out back (24.7" diameter). Stock motor with a Cat-Back. At 3200rpm in 5th gear, I'm at exactly 80mph. Thus means at 6400rpm in 5th gear, I should be capable of 160mph. If I could wrap my motor to 8000rpm (as well as have a crap load of power), I should be able to hit 200mph.
In these cars, that have been modded...top speed is only limited by how fast your motor is spinning. Not how much power you make. Some guys here have the power to hit 180mph, as well as ST...however, ST has the power to absolutely demolish them TO 180mph.
#48
Drifting
Stop it already. I've given you tire sizes for the speeds achieved. NONE OF US RUNNING THIS POWER HAVE STOCK TIRES AND WHEELS.
Sorry,
Sorry,
#49
Drifting
Your car looks great. You have one of my favorite cars. I just couldn't swallow the $$$pill to build one. Hats off to you.
Looks like there will be two bad 3.0 cars running in NY soon! Did you purchase that last 968TS transmission that was available last year from Porsche?
PM me, as this is too OT.
#50
Rennlist Member
I have a 88 turbo s with everything stock except the chips in the DME and KLR. I know I hit 130MPH pretty quick and this is usually still in 4th. I think I could go over 160MPH if I had the room to do it. People need to stop with the math, because they are soo many factor that you can't account for with the math.
#51
Instructor
Just to put some math to this debate. Let's assume George D's vehicle making 400 RWHP (let's call it 465 crank HP for this argument) Here are the inputs (some assumed)...
Inputs
Weight: 3000.00 Pounds (assumed weight including driver)
Drag coefficient: 0.370 (conservative)
Frontal area: 18.000 Square feet (rough ballpark)
Tire pressure: 36.00 PSI
Gear ratio: 0.829 :1 (5th)
Differential ratio: 3.375 :1 (1989 AOR)
Tire diameter: 25.861 Inches (Includes 0.2" tire growth allowance)
Power: 465.000 HP (est. crank HP, assuming 400 RWHP)
Redline: 6500 RPM
Altitude: 1000.00 Feet
Road grade: 0.00 %
Head wind: 0 MPH
--------------------------------------------------------------------------------
Outputs
Speed at redline: 179 MPH, 288 KPH
Total power required: 330.0 HP, 246.1 KW
Power is sufficient to reach redline
Weight/power ratio: 9.1 lbs/HP, 5.5 KG/KW
Final drive ratio: 2.798:1
Hope this helps clear a few points. Assuming some margin of speedometer error, George was spot on with his claim of 180 MPH.
Hope this helps.
Inputs
Weight: 3000.00 Pounds (assumed weight including driver)
Drag coefficient: 0.370 (conservative)
Frontal area: 18.000 Square feet (rough ballpark)
Tire pressure: 36.00 PSI
Gear ratio: 0.829 :1 (5th)
Differential ratio: 3.375 :1 (1989 AOR)
Tire diameter: 25.861 Inches (Includes 0.2" tire growth allowance)
Power: 465.000 HP (est. crank HP, assuming 400 RWHP)
Redline: 6500 RPM
Altitude: 1000.00 Feet
Road grade: 0.00 %
Head wind: 0 MPH
--------------------------------------------------------------------------------
Outputs
Speed at redline: 179 MPH, 288 KPH
Total power required: 330.0 HP, 246.1 KW
Power is sufficient to reach redline
Weight/power ratio: 9.1 lbs/HP, 5.5 KG/KW
Final drive ratio: 2.798:1
Hope this helps clear a few points. Assuming some margin of speedometer error, George was spot on with his claim of 180 MPH.
Hope this helps.
#52
Three Wheelin'
I like what you are trying to do - However my experience at bonneville would indicate the power/mph ratio is low.
My mods were typical - max chips, tial38 (1bar spring), EBC, 3" fabspeed (no cat), 3bar fpr, all else in excellent working order. I did not dyno car. I recall seeing few dynos with equivelent mods in the 230-240whp range.... though I can't seem to find them.. my search must not be quite right... anybody recall these - think there were two or three people.
There is significant elevation and perhaps that played a role, but my car even tweaked (taped, mirrors removed, etc) with a light tailwind would not break 160 (real, not speedo) in 3 miles.
EDIT:
I should clarify this with 26/6 turbo
My mods were typical - max chips, tial38 (1bar spring), EBC, 3" fabspeed (no cat), 3bar fpr, all else in excellent working order. I did not dyno car. I recall seeing few dynos with equivelent mods in the 230-240whp range.... though I can't seem to find them.. my search must not be quite right... anybody recall these - think there were two or three people.
There is significant elevation and perhaps that played a role, but my car even tweaked (taped, mirrors removed, etc) with a light tailwind would not break 160 (real, not speedo) in 3 miles.
EDIT:
I should clarify this with 26/6 turbo
I think the answer is the K26-6. On all the dyno sheets I have seen for a K26-6, the boost starts to drop off at high rpm. I know mine did, even with a Tial and test pipe. As a result, the HP peak moves lower in the rpm range, typically 5600 rpm or even lower. The torque and power drop quickly above about 5800 rpm, and you would need about 6100 rpm to make 160 mph. Any wheel slippage on the salt would only make it worse. Still, I think that if you had a K26-8 or larger turbo you would have broken 160.
None of this applies to the guys who have the magic K26-6s that hold 17 psi to the red line with only a shimmed wastegate and dyno at 300-320 rwhp, of course.
#53
Instructor
Also, it is worth noting that my vehicle's tuning at the time had a 7,500 RPM soft redline, BFG R1's 275/40/17, sea level elevation.
Here's some supporting data:
Inputs
Weight: 2675.00 Pounds (car plus myself)
Drag coefficient: 0.370 (rough estimate)
Frontal area: 18.000 Square feet (ballpark)
Tire pressure: 36.00 PSI
Gear ratio: 0.829 :1 (5th)
Differential ratio: 3.375 :1 (stock 1986 Turbo transaxle w/cooler)
Tire diameter: 25.861 Inches (includes 0.2" tire growth)
Redline: 7500 RPM
Altitude: 50.00 Feet
Road grade: 0.00 %
Head wind: 0 MPH
--------------------------------------------------------------------------------
Outputs
Speed at redline: 206.8 MPH, 332 KPH (radar indicated 207)
Total power required: 490.7 HP, 365.9 KW
Power is sufficient to reach redline
Weight/power ratio: 5.5 lbs/HP, 3.3 KG/KW
Final drive ratio: 2.798:1
Thanks for reading...
Here's some supporting data:
Inputs
Weight: 2675.00 Pounds (car plus myself)
Drag coefficient: 0.370 (rough estimate)
Frontal area: 18.000 Square feet (ballpark)
Tire pressure: 36.00 PSI
Gear ratio: 0.829 :1 (5th)
Differential ratio: 3.375 :1 (stock 1986 Turbo transaxle w/cooler)
Tire diameter: 25.861 Inches (includes 0.2" tire growth)
Redline: 7500 RPM
Altitude: 50.00 Feet
Road grade: 0.00 %
Head wind: 0 MPH
--------------------------------------------------------------------------------
Outputs
Speed at redline: 206.8 MPH, 332 KPH (radar indicated 207)
Total power required: 490.7 HP, 365.9 KW
Power is sufficient to reach redline
Weight/power ratio: 5.5 lbs/HP, 3.3 KG/KW
Final drive ratio: 2.798:1
Thanks for reading...
#54
Rennlist Member
I thought our CD was more like .32?
#55
Just as a *** packet comparison with another car in stock trim - A 997 turbo is kicking out 450 fwhp and a hell of alot more torque than a 944turbo, and is more efficient aerodynamically and they are just shy of 200bhp. Therefore it is reasonable to assume you would need at least 450fwhp to even be approaching 200mph in our cars so that should give you an idea as to what is required.
Remember drag increases at the square of speed, so to go a little faster you generate a hell of alot more drag and therefore need a hell of alot more HP (I think the HP requirements increase with the cube of speed or something like that - i'd need to dig up my old college notes to check). I would think with a 944 with stock transmission you need to be knocking on the door of 500 fwhp to stand half a chance to be sure. With a tail wind and a downhill gradient you might be able to get away with less.
Just to put things into context - a 997 turbo needs 450fwhp to just get shy of 200mph, a Bugatti Veyron needs 1000fwhp to get to 250mph. So that extra 50mph will cost you another 550bhp.
Remember drag increases at the square of speed, so to go a little faster you generate a hell of alot more drag and therefore need a hell of alot more HP (I think the HP requirements increase with the cube of speed or something like that - i'd need to dig up my old college notes to check). I would think with a 944 with stock transmission you need to be knocking on the door of 500 fwhp to stand half a chance to be sure. With a tail wind and a downhill gradient you might be able to get away with less.
Just to put things into context - a 997 turbo needs 450fwhp to just get shy of 200mph, a Bugatti Veyron needs 1000fwhp to get to 250mph. So that extra 50mph will cost you another 550bhp.
#56
Rennlist Member
ER translation for our US friends. A *** packet in UK lingo is a Cigarette packet...not something else...not that there's anything......yada yada yada........................
#57
Thanks for clarifying that for me Patrick. Please bear that in mind for future reference especially if I or any of my fellow countrymen forget and refer to 'smoking ****'.
#58
Drifting
Thanks for sharing this little piece with us. I had NO IDEA what a *** packet was. I was going to ask him to send a pic....LOL
#59
Drifting
[QUOTE=sawood12;4847597]Just as a *** packet comparison with another car in stock trim - A 997 turbo is kicking out 450 fwhp and a hell of alot more torque than a 944turbo, and is more efficient aerodynamically and they are just shy of 200bhp. Therefore it is reasonable to assume you would need at least 450fwhp to even be approaching 200mph in our cars so that should give you an idea as to what is required.
When I did this with my old motor, it hit 430hp and 350tq at the wheels. The T4turbo would hold 20psi boost till redline easily. That turbo would have held 35psi to redline if I set it that way. The car would have easily hit the rev limiter in 5th at 7K. It was pulling through 6500rpm when I lifted.
Again, we are NOT talking about stock motors here. I expect my new motor to hit over 500whp and 500wt at 20psi.
When I did this with my old motor, it hit 430hp and 350tq at the wheels. The T4turbo would hold 20psi boost till redline easily. That turbo would have held 35psi to redline if I set it that way. The car would have easily hit the rev limiter in 5th at 7K. It was pulling through 6500rpm when I lifted.
Again, we are NOT talking about stock motors here. I expect my new motor to hit over 500whp and 500wt at 20psi.
#60
I remember reading about this and being puzzled. I agree, with those aerodynamic improvements I certainly expected you to easily break 160. With your mods, I would expect that you would have at least 240 rwhp, maybe as high as 260.
I think the answer is the K26-6. On all the dyno sheets I have seen for a K26-6, the boost starts to drop off at high rpm. I know mine did, even with a Tial and test pipe. As a result, the HP peak moves lower in the rpm range, typically 5600 rpm or even lower. The torque and power drop quickly above about 5800 rpm, and you would need about 6100 rpm to make 160 mph. Any wheel slippage on the salt would only make it worse. Still, I think that if you had a K26-8 or larger turbo you would have broken 160.
None of this applies to the guys who have the magic K26-6s that hold 17 psi to the red line with only a shimmed wastegate and dyno at 300-320 rwhp, of course.
I think the answer is the K26-6. On all the dyno sheets I have seen for a K26-6, the boost starts to drop off at high rpm. I know mine did, even with a Tial and test pipe. As a result, the HP peak moves lower in the rpm range, typically 5600 rpm or even lower. The torque and power drop quickly above about 5800 rpm, and you would need about 6100 rpm to make 160 mph. Any wheel slippage on the salt would only make it worse. Still, I think that if you had a K26-8 or larger turbo you would have broken 160.
None of this applies to the guys who have the magic K26-6s that hold 17 psi to the red line with only a shimmed wastegate and dyno at 300-320 rwhp, of course.
I always thought my 26/6 would hold 15 to redline... and it just might in 4th. But in 5th 12.5psi was all it could do at the top of 5th No matter the EBC settings