How many mph does an NA car usually gain from the 1/8th to 1/4?. My 1/8th mph is 91.5 mph but my 1/4 is 113 ish. Does that sound right?

 

on average my car picks up 22-22.5 mph n/a,stock heads/cam.

 

On my 94Z I would do 86 in the 1/8th and 110 in the qtr. That was N/A. Average for me was 24 mph. A friend of mine"big dave" also averages 24 mph.

 

Mine does 80.x in the 1/8 and 102.xish in the quarter, with minimal bolt ons and A4.

 

My '97 Vette would only hit about 88 in the 1/8th but would hit 119 in the 1/4. Traction was a bit factor with that car. My 2002 Z06 was at about 90 in the 1/8th and 115 in the quarter. Hope this helps.

 

When I had my 6 speed I would go 90-91 in the 1/8 and 116-117mph in the quarter depending on track and weather. Now with the auto I go 92-94 depending on the weather and track and 116-118. With that much RWHP you should be trapping 119-120.

Later
Matt

 

The "rule of thumb" is that you pick up 25% of your 1/8-mile MPH. 25% of 91.5 = 22.9mph. 91.5 + 22.9 = 114.4. Sounds like you are a little low, but that's just a very rough approximation. You can do the same with ET, where you multiply 1/8-mile ET by 1.56 to get 1/4-mile ET.

 

I personally look at two things. How much you pick up total and how long it takes you to pick it up.

Take my Z28 in my old combo with time in the sig.

Gained 24.49 MPH in 4.251 seconds averaging 5.76 MPH per second.

Then take my old Charger which had a much better top end charge. It gained 26.43 MPH in 4.011 seconds averaging 6.59 MPH per second.

Looking at 1/8-1/4 MPH gains, you could think that my Charger pulled a little harder with a little under 2 MPH more, but when you take the 4.011 X what my Z28 gaines per second average, your looking at a 3.33 MPH, which is a lot.

 

So it looks like its about right. My best MPH of the day was 115.23 but that was with a 1.8 60'. The 113 trap came on a 1.7 60'.

I know I should be in the 119-120 range. The plugs were going in the car half way through the night as I started to get "used" to the car. The air was also really crappy, the DA was 2200 or so if I remember correctly.

 

I've found that if I spin I pick up more between the 1/8 and the 1/4. On a good run I'll gain 21-22 mph (84/106). On a crap launch I'll gain more, like 80-81 at the 1/8 and then 105-106 at the 1/4.

 

you know you want to let me test drive your car matt

i some 11 second experience/good luck i can bring to it for ya

 

Im gaining about 24 mph NA 89 at 1/8 and 113 at 1/4.

 

Bolt-ons - 21.49mph (26.7% gain)
Small cam with stock heads - 24.63mph (28.7% gain)
Big cam with ported heads - 25.10mph (27.6% gain)

All those runs were made at the same track over the years

 

My biggest gain was 26 mph, but I averaged about 23-24.

 

29.2 mph 108.2 1/8 -137.4 1/4