SPF with 550HP 1/4 mile times?

[PHM]

I have a so called freind that is a chevy lover and drag races and we were arguing about what the 1/4 mile time will be on the SPF i am waiting for. I wanted to ask the guys out there what kind of times and MPH's they are seeing with stock tires.

[Clois Harlan]

Similar Hp in by B&B. I have a 427 with 585 hp Toploader/3.50 gears and POSItrac fand I ran 11.78 but I could have gone faster because I was spinning my tires all the way through the lights. I would think with a decent set of slicks and average RT I could do 11.50 in the quarter.

Clois

[Thieleng]

Stock tires, good luck getting under the low 12's, problem is hooking up to get traction through the 1/4. ET I had was at 12.1+, which was the best run and I spun the tires through the first three gears. SPF, Roush 427IR, 564 HP

[mpanten]

I know greg schroeder has gotten into the tens on drag radials with a similar set up. 10.7 i believe.

[D-CEL]

PHM,

He called it, drag radials, lower gear and a good tune, and you can run easy low 11's maybe 10.8-10.9

[greg schroeder]

I love this topic!

In reality the engine HP is just a number. It's the wheel HP or usable HP that will have the most influence on performance. There is variation. From what I've noticed on and about the forum a 550 HP engine in a Cobra seems to range around 330 to 480 wheel HP depending on carb, tuning, exhaust, fuel delivery and stuff. My Roush 427R had 561 corrected engine HP in a Superformance. As dealer prepped it produced a little over 400 corrected wheel HP. After I looked into obvious power restrictions and changed things I ended up with 475 at the wheels. This seems about were a 561HP engine should be.

Actual wheel HP comes out really close to 1/4 mile trap speed if you use a racing calculator. In other words trap speed doesn't lie. It's very consistent if you can shift through the gears.

Time for the 1/4 mile is very dependant on how well you start. Each .1 second variation in 60ft time is about .2 seconds at the end.

Here's a drag race calculator. The trap speed portion is really accurate.
http://www.prosystemsracing.com/calculate.html

The lower the DA, density altitude, the more power an engine will make. Here's a sea level correction calculator with a DA calculator built in. Using this calculator you can compare performance of the same car on diffrent days or two diffrent cars in diffrent locations. It's really cool to compare apples to apples.
http://www.modulardepot.com/density.php

Sea level corrected, a 2550lb race weight Cobra with a real 475HP at the wheels should produce a 1/4 mile trap speed of around 131 to 132 mph and with a 1.7 60ft time should be about a 10.5 or 10.6 ET. With a 1.5 60ft the time would be around 10.3 or 10.4. A 1.9 60ft time would be about a 11.1. Trap speed would remain real consistent unless you totally screwed up the pass.

The pass in the video in my signature is starting from idle and only a 1.7xx 60ft time. I had my normal daily drive Mickey Thompson ET Street drag radials in a 275/60 15 with 20 psi. A 1.7 60ft time isn't all that great.

[SPF1061]

I have a SPF with a Roush 427R. Engine is stock except for an AED "Super Mod" carb that was custom built and dyno tuned for my motor. Suspension has Olthoff custom Bilsteins and Olthoff heavy sway bars. TKO 600 transmission. Torsen Type2, 3:27 rear. Avon CR6ZZ rubber.
Car runs 11:30s on a good day, 11:50s on an average day, 11:70s on a bad day. Top speed just under 125.
Not bad for a car that is geared and set up for road racing.