How to dyno auto Camry?

[94CoupeV6]

I kind of feel like a noob asking this question, but I have never gotten a good answer out of people and every response is different. Question is, how do you dyno an automatic car?! When you mash the pedal to WOT, it would just kick down in lower gear. Someone told me that it has to be computer controlled, and someone else said a simple disconnect of our vaccuum line will disable downshifting?

I know this is a good question for General Discussion, but the reason I asked it here is because I want to know exactly how to dyno my car, not some other automatic. I'm going to have some free dyno time and I need to get my SAFC tuned, but I just don't understand how to dyno my car. Is there a trick to it on the Gen3 V6 that I should know about? And also what gear would give me a 1:1 ratio for the dyno?

[RedPhoenix]

Ah

you turn off OD. then the person who is dyno'ing basically tricks the car into not downshifting. there is a certain point in the rpm band where it wont downshift. Doing so will make you stay in 3rd til it redlines.

On the 5sfe its somewhere around 3-3.5k rpms



edit: wow you can really see where the ct26 craps out!

[Stonegrave]

when we went to dyno the dude had the same problem, and if he let me drive i told him i could find the point where it wont downshift, because it pisses me off when it wont on the street so i kinda have a feel for it. what we found out after our little dyno sessions, is(not sure if yours is the same) but theres a electrical connection on the top of the trans, that if you un-plug it, the car stays in 3rd. im not sure if this is for sure, we havnt had another dyno time to try it, but while we were leaving we met some dude that started the 3rd gen supra forums(on some other site) and he gave us a tip. i dont know if you want to try it, but i definately am next them i go.


A540E =-

A540E

2.810

1.549

1.000

0.734

according to this, third gear is perfect 1:1.

[terrastrife]

3rd is perfect 1:1 to get an accurate torque at wheels reading but its much easier to do the power run in 2nd, as you find the kickdown point is probably a bit lower then in 3rd, so you get a bigger band readout. pretty much you arent at WOT until a certain point...at this point you can tell because the a/f ratio just gets killed under WOT on that graph pictured you can see they stomped it at about 4200rpm

dynos arnet hard, the shop wouldve done hundreds of autos beforehand and wont have any trouble.

[Toysrme]

Doesn't matter aslong as you program it correctly.
Keep in mind you have a different actual road torque output regardless of the gearing simply because it's more than jsut the transmission gearing. You have torque converter gearing, final drive, and tire size.

You can't disconnect anything to keep it in gear. What you can do is make yourself a transmission controller like I have previously posted on so that you can hold whatever gear you want. You can also lock the torque converter if you want, but I wouldn't.
1) The stock ones are not being enough to like it
2) You'd never do it anyways, so it's not indicative of the power you actually transfer


And if you give the car gas under 2400rpm (+/- 150rpm, you're going to have the torque converter slipping & giving torque multiplication at a 1.9:1 ratio. So where your 1mz-fe makes a paltry 70bhp @ 2000rpm. It would show up as you making 1.9 times whatever you actually make until the rpm hit say 2650rpm. (Numbers for the purpose of this dicussion only.)
















If you can't control the transmission, you get what you can get. You have to roll into the throttle as hard as possible, without incurring a gear shift & hope it pulls a good amount on the top end without shifting.





If you dont' want the trouble of a real controller. You can put a switch on the solenoid wires so that No1 power is cut & then feed No2 10-12v so it energizes. At which point you magically get 3rd gear.

[Toysrme]

Don't unplug the connection on any OBD-II transmission. The valve body pressure is not regulated completely mechanically with a throttle valve. Early versions retained a throttlevalve, but have a solenoid that controls the pressure. later controls just have the solenoid.



Too much of a possibility to slip.



And if you unplug the solenoids ontop of the transmission. You get 4th, not 3rd.



Tada





Aslong as they record the correct ratio into the machine, it will re-compute it. If you don't. You're just going to have a dyno run that is about 25-30% lower than it should be.

[Axel Kain]

what about disconnecting the trans kick down cable from the throttle body?

[terrastrife]

Originally Posted by Axel Kain

what about disconnecting the trans kick down cable from the throttle body?

all that does is set vavle pressure.

[Toysrme]

Then the transmission will probably be slipping by the higher rpm ranges even tho the dyno isn't very stressfull. And if it wasn't outright slipping like a tranny low on fluid. I bet there's a good chance it would be slipping to some extent, letting power go by.


Try it & see, but I wouldn't be caught dead doing it. Too easy to jsut manipulate the pair of solenoids.

[94CoupeV6]

Thanks a lot for the responses guys. Kind of a noobish question but I just have never understood how to dyno automatic cars, especially mine. I know people at a dyno place would know how to do it, but I'm using my schools dyno, so there wont be any pro's, and I know that we have many pro's here on TN..

[94CoupeV6]

Does anyone have dynographs of a 1MZFE? Modded or stock is cool.

[Toysrme]

Normally you just give it about 80% throttle until you hit 4500-5000rpm so that it doesn't shift back down.

[terrastrife]

i cant belive i lost my dyno print out... hahaha

[mzfe5speed]

http://www.cardomain.com/member_page...06_42_full.jpg
here is mine. the dyno was screwing up the torque readings though, so all i got for numbers is the hp.

[Toysrme]

God damn you're rich boy.

You need to fix that LMAO.