1/8th to 1/4 conv - SRT Forums

Dragvan · 11-02-2009, 02:26 PM

To convert from 1/8th to 1/4 mile ive been using a rwd simple calc. multiply 1.55 by time 8.141 = 12.61. for mph mutiply 1.24 by mph 88.964 = 110.32

Does this sound right for our cars?

bene · 11-02-2009, 03:47 PM

no, we pick up more in the backhalf than that.

someone that runs 8.0 or lower usually runs 11's

everything is mod depending though

ATaylorRacing · 11-02-2009, 04:11 PM

It all depends on the individual car and set up.
My SRT4 when bone stock, stock boost ran 8.8 at 78, 13.80 at 101.
On stage 2 with stock turbo, 22 psi boost ran 8.6 at 81, 13.30 at 108.
Change to FM E1 turbo, 19 psi boost ran 8.4 at 89, 12.99 at 107.
Change to FM stage 3 turbo, 15 psi boost ran 8.2 at 90, 12.87 at only 106
Alll passes on pump gas and decent short times with DOTs....no spark knock and playing it safe on launches and tune. Exhaust is okay, not great.

On my carb low hp 84 Horizon it runs 10.75 at 64 in 1/8th and 17.20 at 75 in 1/4. Your formula would have it run 16.66....mine has 2.2 short times and no hp....lots of converter and decent drag gear.

Oh yeah, my 3 banger 1 liter Geo Metro runs 12.7 at 57 in 1/8th and a paint peeling mid 19.9s at 65 when bracket racing....

Kason23 · 11-02-2009, 04:11 PM

Quote: Originally Posted by bene

no, we pick up more in the backhalf than that.

someone that runs 8.0 or lower usually runs 11's

everything is mod depending though

I wish lol..that means im almost in the 11's on street tires

. Its that damn 2nd/3nd gear and traction ugh.

ATaylorRacing · 11-02-2009, 04:12 PM

The 110 on my sig came with slicks on the SRT4.

bene · 11-02-2009, 05:24 PM

Quote: Originally Posted by Kason23

I wish lol..that means im almost in the 11's on street tires

. Its that damn 2nd/3nd gear and traction ugh.

ya. we run theoretical 11's

BDCarrillo · 11-02-2009, 06:01 PM

Quote: Originally Posted by Dragvan

To convert from 1/8th to 1/4 mile ive been using a rwd simple calc. multiply 1.55 by time 8.141 = 12.61. for mph mutiply 1.24 by mph 88.964 = 110.32

Does this sound right for our cars?

8.195@88.21 equals 12.64@113.94 straight off a time slip. That formula you're using doesn't seem to quite fit the SRT4 fwd wimpy 60' real world results

On a random sample of 20 runs (throughout the modding lifetime, from stock to current) from my timeslip spreadsheet I came up with the following coefficients:

ET: 1.5-1.54 1.522 avg
MPH: 1.25-1.36 1.2875 avg

Running your 1/8 time through my average numbers gets you:
12.39@114.54

12.2115-12.53714 range for ET
111.205-120.99104 range for trap

I'd favor more towards a 12.5x at 113-115 as the "theoretical 1/4" for your original 1/8th numbers

Dragvan · 11-03-2009, 09:44 AM

Quote: Originally Posted by BDCarrillo

8.195@88.21 equals 12.64@113.94 straight off a time slip. That formula you're using doesn't seem to quite fit the SRT4 fwd wimpy 60' real world results

On a random sample of 20 runs (throughout the modding lifetime, from stock to current) from my timeslip spreadsheet I came up with the following coefficients:

ET: 1.5-1.54 1.522 avg
MPH: 1.25-1.36 1.2875 avg

Running your 1/8 time through my average numbers gets you:
12.39@114.54

12.2115-12.53714 range for ET
111.205-120.99104 range for trap

I'd favor more towards a 12.5x at 113-115 as the "theoretical 1/4" for your original 1/8th numbers

I thought the mph was low at 110. From just looking at other time slips seemed that 1.27 was a better fit for mph and 1.53 for et just to get a idea where it would run. I just need a 1/4 mile to find out lol. All we have around here is 1/8th.

dsmfan95 · 11-06-2009, 01:38 PM

Quote: Originally Posted by bene

no, we pick up more in the backhalf than that.

someone that runs 8.0 or lower usually runs 11's

everything is mod depending though

Not with 88mph. 8.0 on a stock turbo setup is good for mid 12s.

turbojonsrt4 · 11-06-2009, 02:17 PM

Quote: Originally Posted by dsmfan95

Not with 88mph. 8.0 on a stock turbo setup is good for mid 12s.

Truth.

My 8.02 @ 97 run 2 years ago would have just been borderline high 11's. 88 mph in the 1/8th wouldn't be enough mph to carry the car to 11's in the 1/4.

The few stock turbo cars that run high 11's normally go 7.5-7.7 in the 1/8th.

dodgezdad · 11-07-2009, 06:58 AM

My old conversion chart shows an 8.08 that you ran would be a 12.45. To reach a high 11 you would need a 7.7.

turbojonsrt4 · 11-07-2009, 09:37 AM

Quote: Originally Posted by dodgezdad

My old conversion chart shows an 8.08 that you ran would be a 12.45. To reach a high 11 you would need a 7.7.

Calculators don't factor in mph. 97 mph in the 1/8th would have been around 126-127ish in the 1/4. More than likely that would be enough mph to get in the 11's, regardless of the 8.02 1/8th et.

Real world > Calculators

dsmfan95 · 11-11-2009, 02:26 AM

Quote: Originally Posted by turbojonsrt4

Calculators don't factor in mph. 97 mph in the 1/8th would have been around 126-127ish in the 1/4. More than likely that would be enough mph to get in the 11's, regardless of the 8.02 1/8th et.

Real world > Calculators

I think 127 is a bit optimistic. I would guess 123-124 or so, but at this point we're just bench racing.

turbojonsrt4 · 11-11-2009, 05:25 AM

Quote: Originally Posted by dsmfan95

I think 127 is a bit optimistic. I would guess 123-124 or so, but at this point we're just bench racing.

A decently tuned big turbo car will pick up 28-30mph in the back half. Some pick up a few more than that. I was being optimistic. But you're right, it doesn't matter. That was 2 years ago.