Automatics On Dynos?

[kmaster]

never seen auto's on dyno. Why? Is there a tech reason?

[Ruffels]

you mustn't have seen many cars on dynos then

[Rj34GTT]

never seen auto's on dyno. Why? Is there a tech reason?

<{POST_SNAPBACK}>

I've got an Automatic (tiptronic) Skyline and set it on the dyno. No drama's about it

p.s only got auto cos it was hard to find manual with the 4 door R34

dont think they exist..

[Gav]

In actual fact they are fully automatic - you set the various parameters and the dyno program automatically runs according to the ramp up speed.

[Duncan]

Auto drivers are just too soft to put their cars on dynos

[R33S2]

most performance cars are manual except the high HP drag cars, I wanted an auto but they are rare and nobody wants em.

[kmaster]

Yeah..... I havent seen many dyno runs 4 real but is there any disadvantages to an auto for making big power figures? Can you have a fast quarter car (auto) and a high HP dyno car without the heavy clutch etc. issues?

[R33S2]

Most/all of the fastest 1/4 mile cars are auto the only restriction is $$$.

[rob82]

Ever seen a 2000hp drag car on the dyno - they usually make about 3/4 of that value. To much trans slip to give accurate readings not to mention changes in auto trans fluid temps(varying viscosity etc etc) not good for dyno comps or tuning at high levels of horsepower.

[paulr33]

we had an auto r33 at the sau vic dyno day yesterday. was ran in 2nd gear as the auto juggles the power rating all over the place apparently when left in drive. the manuals are done in 4th gear so what power rating the auto gets i would say add %15 more power cos of the 2nd gear ratio? does that seem reasonable ?

[rob82]

You can run a car in any gear and it should give comparable horsepower readings. ie a manual R33 should give about the same power readings in 3 as it would in 4th within about 1-2% depending on the dyno operator. You must remember that dynos measure the rate of acceleration under a specified load and Horse power is a function of Torque and RPM so while lower gears will give a higher torque than a taller gear the RPM of the rollers is less in the lower gears than the higher gears.

Now dyno dynamics specify that their dyno's are accurate between about 80 -140km/hr. So the aim of the dyno operator is to choose a gear that will rev between these points.

[FATAZZ]

my auto was dyno'd in 3rd gear,plus most auto's dont get thrashed by the Jap owners as much as the manuals.

well on the read-out sheet it says 3rd gear

Edited October 30, 2005 by RSTME

[kmaster]

Thanx 4 the replys everyone, very useful, Im asking really what i would have to do to get a high HP street car (auto) to be efficient on a dyno as well. Is there options for making an auto box perform well on the dyno? Shift kits etc. Any ideas?

[rob82]

Lots and lots of line pressure uprated clutches etc etc you would have to talk to an auto guru. Usually the higher the hp the higher the stall (the greater the slip). Simply answer no.

[heartbrkr]

dunno how you lock an auto in 3rd.

mine was in 2nd gear, so speed topped out at 110kph, by which point the power output had plateud.

123.4, altho im told 125 is about average for stocky.

[Kaido_RR]

plus most auto's dont get thrashed by the Jap owners as much as the manuals.

<{POST_SNAPBACK}>

rofl thats wat u think

[J_R32]

take off overdrive and it will stay in third gear in a auto. am i right??

[Angry]

nope. coz as soon as they ramp the power up it kicks back to 2nd anyways..unless u have it manualized.. they'll always do it in 2nd gear for the autos. .... and they seem to strap them down harder than teh manual cars.. coz apparently the auto (car itself) can jump on the dyno from time to time.

autos are the ghey... too much drivetrain loss thru slippage. .. thats just my personal opinion but.

[Miller the hoon]

My auto blows 250 hp at rw

all they need is shift kit and oil cooler to start with then a rebuild

autos r good in a straight line

[AMS]

My Stagea is an Auto, I dont mind it. We will have to see how she goes on the dyno