technonovice

The method:

You need a flat straight away preferably one that would allow you to run it both directions so you can average the times to account for wind.

Start by maintaining a steady 35mph in 3rd gear. Floor it!
At 40 mph hit the timer...a stopwatch is fine.
Keep it floored and in 3rd gear.
Stop the timer at 70 mph.
Repeat as neccasary...careful it gets addictivley fun.

I've seen times range from 4.5 secs to 5.5 secs depending on mods and state of tune.

I'd be curious to see what mods do compared to stock times.

The Why:
We should'nt use 1/4 mi times as a gauge when talking about mods. The 40-70 mph in 3rd gear test is awesome for gathering test numbers.

It is easy to do and gets rid of launching and shifting vaiables. You can time your car, then do a mod or tune, and retest.

What is wrong with a dyno?
1. I don't have one.
2. This test is free and can be done nearly any time.
3. A dyno can't tell you what weight reduction has done. I get signifigant variance from a full tank and a 1/4 tank.

I think the 40-70 in 3rd gear gives us a cheap ...make that free, simple, and pretty reliable way to compare.

Happy testing.

The last time I tested my Touring it was 5.15 secs...stock no mods with about 1/2 full tank and 65 degrees F.

This list will make no sense unless your mods are listed.

JoeD

i would love to see different times with different modifications.

it would be cool of this was stickyed, but i dont know if the mods see this wrothy of stickying.

cash money

i bet if people who have dynoed their car do this and list their mods(not as important for calculating) and their 40-70 times, someone could come up with some sort of formula for guess-timating hp using your own 40-70 time. but i dunno

Dr Wankel

Damn I wish I had saw this tread earlier. I just left my car at home for the week while I'm at school. I'll give it a try next weekend though.

technonovice

Ugh....come on guys. Lets get some times here. You do it. Get your friends to do it. Get your friends' friends to do it. Do it in your other performance cars. Do it in your daily beater.

Dr Wankel

My daily beater won't hit 70.

technonovice

This is from RX-7 Digest: Thanks Jim!

I like the 40-70 mph in 3rd gear test myself. I've
been trying to compile numbers without much luck however.

I use this test to verify that everything's working right on my car.

I can repeatedly do the test in 3.7 seconds when it is.

My car is a '94 Touring with mods equivalent to M2 Stage 3. (N-Tech Intake, N-Tech Downpipe, RS*R cat back, M2 Medium Intercooler, M2 modded ECU, wastegate pill set to limit boost to about 12.5 lbs.) On a fourth gear dyno run, it pulled 284 rwhp (uncorrected) which equates to roughly 335 flywheel horsepower. I love it when it's working right!

Jim White
Vintage Red '94 Touring/R2/R1/efini
http://www.NorthstarRotaries.com

evot23

iTrader: (17)

there has got to be more guys with 40-70 times...I'll post mine tomorrow.

evot23

iTrader: (17)

Here are my 40-70 times. 10 - 10.5 psi boost

5.4
5.4
5.2
5.0
5.3
5.0
5.1
5.3
5.4
5.4
avg is 5.25

Me timing at the wheel, 5 runs one way, 5 the other.

MODS

Apexi Power FC
Pettit LSMIC
N-tech DP
N-tech hi flo cat
Apexi N1 dual catback
M2 CF air intake
air pump gone
battery in the back
greddy bov
greddy profec b

kwikrx7

Hey evot23 - not to be a turd but aren't those numbers close to what a stock FD will do (I think I did mine at 5.5 secs when stock) Get that boost up to 12! You have the mods to handle it.

capt. bill1

Best 40-70 time so far, 3.6-3.8 sec., 12 psi of boost. And that was with the car going flat at 6000 rpm. Fixing that and too lean an A/F ratio at full throttle now.

M2 high flow ball bearing turbos
M2 stage 3 ECU
M2 large intercooler
M2 cold air box
Wrapped DP
High flow cat
Cat back
Pulley kit
Removed secondary throttle plates
High pressure fuel pump
Jacob's ignition
Aluminum flywheel
GReddy ProFec B
J&S knock sensor(which seems to be source of 6000 and over rpm problem)

Dyno pull at 12 psi with 6000 and over rpm problem 276 RWHP

evot23

iTrader: (17)

ok,ok so i did a wussy 40-70 run. I'll give you the runs at 12 psi tomorrow.

JoeD

i wonder how single turbo FDs would do in this test.

i posted this exact same question in the Single Turbo forum about three months ago, but ony one person replied, and that was in a single turbo first gen.

neevosh

I tried it today. The conditions were far from perfect and I only got to try it once. I counted out loud by one one-thousand...and so on. I just said five and I was already at almost 80mph and some ******* pulled out in front of me. So I would guess around 5 sec. Maybe a little less. And this is on a non-sequential setup.
Mods-
DP
Apexi GT CB
intake
RX7 Fashion intercooler
upgraded ECU
ACT clutch/11# flywheel
AVC-R- 11psi
full boost around 4200 RPM's

girl7

See if you can at least borrow someone's sports watch that has a stop watch.

evot23

iTrader: (17)

4.9
4.7
4.6
4.7
4.9
4.9
4.9
4.8
4.6
4.7

Avg: 4.77

12 psi...does that look a little better?

FD Seeker

I'm having a little trouble believing that the same car will vary by .4 seconds going in the same direction. I'm assuming that using a handheld stopwatch makes for a lot of error. Since some people will be optimistic while others will be pessimistic, we could have cars of equal (actual) times differing by 1/2 a second or more!!

I'm going to try this on my VERY stock FD while video taping my instruments. I'll check the ACTUAL timing while reviewing the footage on my computer. I'll even post them for those who care to see a slow stocker's 40-70.

technonovice

Either a slight breeze or incline can slow you in one direction and help speed you in the other. Theorizing only .2 sec variance in each direction is pretty reasonable.

evot23

iTrader: (17)

There is definitely room for error, especially if you are driving and timing at the same time. It's not like our gauges are marked for every individual mile.

I suppose getting someone else to time would make it better and/or even making more runs and getting another average.

It's not perfect but if you are consistent with your own car, it may be a good measure.

technonovice

Thanks for those of you that have posted. I wished we could collect more times. Seems that you get more involvement if your posts include body kits and shooting flames.

Encourage folks to put some runs on. I don't have enough numbers to really work with.

evot23

iTrader: (17)

I'll try to drum up some interest with the local guys.

nocab72

hehe, I haven't picked up my FD yet, but I can get you some 40 - 70 numbers from my BMW X5 4.4 tomorrow...

K

technonovice

I'd be interested in the X5 number too! I am SO disapponted in the pathetic lack of participation. I guess folks either don't have their cars running or are scared to do it.

evot23

iTrader: (17)

Yeah, where is everyone?

FD Seeker

Okay, I finally got a chance to do the 40-70 test. The average time for my bone stock 93 Touring RX-7 is 4.75 seconds.

For more details and video of the test (guages), check out:
http://cerebralmedia.com/rx7/40-70/