5at Dyno Results
1 Attachment(s)
i took my new db touring (1250 miles) to the dyno today and here is what i came up with. all three pulls were done in 4th gear. all in all i was pretty happy with the results, considering i've seen some 6mts dyno around the same or worse.:D
|
1 Attachment(s)
here are the DIN numbers.
|
your torque #s are off. should be in the 220s according to the graph. i dont know why it started off so high.
|
no according to the graph it is correct. but theres no way its correct... way too high.
hp is about right for an auto tho, not bad at all. |
ajk4: got any mods on the car?? or just bone stock.??
|
the car is stock, and yeah i noticed that the torque numbers were off. anyone have an idea why? maybe the dyno needs to be recalibrated or something? it was a dynojet so im clueless as to why the numbers were so high.:confused:
|
The tq was high because you dyno'd in 4th. The the tq posted is what was measured at the wheel, and then corrected for the graph taking into account the ratio to also calculate hp against the known resistence of the rollers.
EDIT: forgot to mention that I don't know the ratios of the 5at, but I'm pretty sure 4th isn't 1:1, hence my theory on the numbers being so high, and also, no matter what gear used, the tq converter is going to add some ratio low in the rpm band. |
no gear ratio would add 40 or 50torque. but I guess the torque converter may have something to do with it. not sure how all that works on a dyno, but I thought autos could get proper numbers on dynos.
|
Originally posted by Resolute The tq was high because you dyno'd in 4th. The the tq posted is what was measured at the wheel, and then corrected for the graph taking into account the ratio to also calculate hp against the known resistence of the rollers. EDIT: forgot to mention that I don't know the ratios of the 5at, but I'm pretty sure 4th isn't 1:1, hence my theory on the numbers being so high, and also, no matter what gear used, the tq converter is going to add some ratio low in the rpm band. M/T A/T 1st-3.794 3.540 2nd-2.324 2.264 3rd-1.624 1.472 4th-1.271 1.000 5th-1.000 0.834 6th-0.794 N/A R- 3.446 2.370 so 4th is the right gear to dyno a 5at in. however, im still at a loss for why the tq numbers were so high, im gonna call them tomorrow and see if they have an idea why. |
anyone dyno a 5at and have problems with tq readings or get a normal reading? with the number of 5ats out there someone else has had to dyno theres.:confused:
|
actually..i think ur the first
|
ive been waiting for someone to do it....i would dyno mine..but it already has mods..plus there isnt a place near me
|
in this thread https://my350z.com/forum/showthread....threadid=49800 , it says that mr. twisted dynoed 230/230 (hp/tq) with intake and exhaust. so i dunno what the problem was with the tq reading, so i'm thinking it was their dyno. but if thats the case then the hp reading should be off also.
|
Doesnt acosta racing do dynos in wallington nj?
|
This is messed up somehow. Torque numbers are wackey!
|
Originally posted by ares no gear ratio would add 40 or 50torque. but I guess the torque converter may have something to do with it. not sure how all that works on a dyno, but I thought autos could get proper numbers on dynos. |
your jibba jabba totally confused me. i dynoed in manumatic or e-shift mode so i shifted all the way from 1st-4th then punched it, so as nissan states that while in 4th gear the ratio would be 1.00 (which would be closest to the ideal 1:1 ratio) so i dont see how it would select a different ratio for the torque converter? of course my understanding of torque converters is very limited so i dunno.:confused:
|
here's the result of my Touring 5AT.
http://www.zyal8ter.50megs.com/Dyno1/7.JPG http://www.zyal8ter.50megs.com/Dyno1/8.JPG |
Ive dynoed ten runs now over 3 days and all the last runs are in the 237.4 hp 240.3tq/ 243.4 -235.7 tq/ 241.6 240.0tq
If someone has a Fax # Il'll fax dyno sheets so it can be posted for all to see. |
Originally posted by ajk4 your jibba jabba totally confused me. i dynoed in manumatic or e-shift mode so i shifted all the way from 1st-4th then punched it, so as nissan states that while in 4th gear the ratio would be 1.00 (which would be closest to the ideal 1:1 ratio) so i dont see how it would select a different ratio for the torque converter? of course my understanding of torque converters is very limited so i dunno.:confused: didn't mean to confuse anyone. I assumed you were doin' this manu-matic. So, even if you shift up to 4th gear, and keep it there, you will still have some discrepency with your ratios. Here's why- on all automatics there is no direct link from the crank to the input shaft on your tranny. They are seperated by your torque converter. The TC is shaped like two bowls lip to lip with each other. Inside each half there are rows of fins that are angled in opposition to each other. The TC works by running fluid from one side to the other. As the crank turns, the fluid is pushed by the fins on one side of the TC into the opposing positioned fins inside the other half of the converter. The fluid movement and the shape of the TC causes the other side to move as well. To demonstrate this, put two house fans together, turn one on, and the air being pushed through the other one will cause it to spin. This is essentially the torque converter, except it is enclosed and more efficient. However, not entirely efficient. There is some loss between the two on start-up and in constant opperation. On start-up, the crankshaft side of the TC must spin several times more than the tranny side before the tranny side is up to the same speed. This is how come an auto will not stall the engine if the brake is applied like it would with a manual. The engine can keep rotating at low rpm without turning the tranny side very much, but it does still turn. So there is some power transmiting through the tranny at idle with the brakes on, but not enough to overcome the brakes hold. Now, the ratio for most torque converters is around 2.5:1 at idle. So, while you are at a stoplight the engine is rotating 2.5 times for every one rotation of the tranny, but the brakes hold the car from moving, so the driveline can't actually rotate, so the tranny side of the TC can't spin, and the temps in your tranny start to get very hot. Release the brakes and away you go.. now picture yourself on a hill, let go of the brakes, and the car can still pull ahead with no throttle, or at least hold itself steady. This is again because at 800 rpm or so, your motor is still blessed with a lower gear of 2.5:1, or so, from the torque converter. This ratio diminishes at a fairly linear rate until the stall point, or when the two halves spin at close to the same speed. This is usually by 1500 rpm, unless a high stall converter is purchased, which will allow your motor to take advantage of the variable low ratio for a period of higher rpm. Once, above this point, the TC is still not 100% efficient. The crank side will still rotate slightly more than the tranny side, unless there is some lock-up. Lock-up is the term used to designate any device to physically lock the two halves together during rotation. This is done to save gas mileage during cruising. Allison trannies have lock-up in the top 4 of it's five gears. So, with your car, or any car with an auto, my speculation is that the dyno failed to account for some gearing discrepency. However, as I stated, I never ran a dyno, so I am not sure how the program works, but I would be curious to see what happens if you ran on the dyno in plain auto mode with the OD turned off, if that is an option for the 5AT in the Z. I really don't know, sorry, but I hope the torque converter explanation and the reduction abilities makes sense now. |
All times are GMT -8. The time now is 08:09 PM. |
© 2024 MH Sub I, LLC dba Internet Brands