Dyno Testing

[Kenneth]

In the auto department at the college I am currently attending they have a dyno that is available to me for free testing. I am hopefully going to use it next Tuesday night.

I was wondering if anyone had any ideas on what to watch for or recommendations on technique, etc.

I just want to get the most accurate results for the rwhp on my truck. All my current engine specs are in my signature. So if anyone has any thoughts or ideas let me know.

Thanks

[More Power]

Your dyno will need engine speed to get an accurate HP number. Some of the dynos in use today use a separate engine speed sensor apparatus that clips/magnets onto the front of the engine and uses a strip of reflective tape on the damper to sense engine RPM.

To keep the torque converter locked, you'll need to run the rear wheels to something above 62-MPH in 3rd gear. So, ease up past 62, then once the TC locks in 3rd, hit the pedal... :)

GM rates max power at 3400-rpm. Max torque will be at a much lower RPM (1800-2200 or so, depending on where your turbo produces its boost peak).

It's always best to dyno the vehicle while stock to establish a baseline before dynoing with a power mod. Some dynos are overly generous with correction factors.

Jim

[Kenneth]

how will I know when the torque converter locks?

[DennisG01]

The torque converter "locking up" will feel like an upshift, with a corresponding drop in RPM's. Go out for a drive and, under light acceleration, get up to highway speeds. Take notice to how many times you feel the tranny shift. You should feel (4) shifts: 1st - 2nd gear, 2 - 3, 3 - 4, and then the tranny locking. With my '98 and 3.73 gears, the converter will lock at about 50mph under light acceleration.

Another way: If you're already at highway speeds, quickly depress the accelerator, but only about 1/2". Make note of your what your RPM's do - if they immediately jump up a few hundred (without feeling what seems like a shift), the converter is unlocked. If they do not jump, but instead rise in relation to speed, the converter is locked.

By the way, take note to what MP said above - you want to do the dyno test in 3rd gear.

[Kenneth]

thanks for the info guys.

[97GMC6.5Z71]

how will I know when the torque converter locks?

The torque converter is what unlocks and then Locks up when you running more then 45 MPH and let off the throttle it unlocks then if you press the throttle a little it will lock up same as if you tap the brake one time it unlocks then locks up again:D

it makes the torque converter work like a clutch in a standard transmission
so that it is not slipping and making the trans overheat.
with it locked up there 100% power from the engine to the tires without slipping;)

[1999GMC]

Well???? Did you dyno it????

[Kenneth]

No I wasn't able to dyno my truck :( I should be able to next month though. The auto club on campus meets once a month for a couple hours for an open car night where we can bring our cars in and do whatever we want to them. I had to fix something else on my truck and didn't have time when I finished. But I am certainly going to dyno it next month.

Thanks again for all the info guys.

[1999GMC]

Your not too far from me. I bought a Suzuki 4 wheeler from a guy in Gridley, and have a few buddies that grew up in Palermo.

[Kenneth]

where are you from?

[Jochen Woern]

Didn't even realize that Kenneth is from Gridley.

I have family in Oroville and live in Sacramento.

[Kenneth]

Wow, it's such a small town I am suprised anyone even knows where it is. I have even talked to quite a few people from Sacramento who haven't heard of Gridley.

[1999GMC]

I live in Carmichael. Just outside of Sac.

[a5150nut]

Gridly! I know where that be. I used to live in Pair O Dice.

It is a small world.........

[Kenneth]

Man, it is a small world! Great to know there are so many Northern CA people here at the TDP. I have cousins in Yuba City and Sacramento, grandparents in Sutter, and a brother in Chico attending CSU. My grandfather was born and raised in Stockton (been there a few times), and I worked 2 summers in Yuba City at Orhcard Machinery Corp.(OMC), so I am fairly acquainted with northern CA.

Great Place!!

[a5150nut]

I spent part of one summer working expanding a Prune drier up in Los Molinas until i found work in San Jose. Spent my weekends in Paradise and worked the week in San Jose for a number of years until the youngest finished high school. Then Ma figured she would move to where I worked, she was tired of being a weekend bride. We sure got along a lot better back then...........

The North Valley is nice, ya just can't make much money to enjoy it!

[1999GMC]

Holy Crap. 5150 I grew up in Cupertino. I graduated from Cupertino High. My parents still live there. I lived by Stevens Creek Blvd. and Lawrence expressway. Real small world. Hell, we all should meet somewhere sometime. There is another guy wih a 6.5 on another forum from Antelope, here by Sac. He has come by my shop a few times in last few months.

[a5150nut]

Theres a few more arround here. I think a couple down in Hollister or Gilroy and some in the East Bay. Maybe a mini Wets Coast Get Together.

[Jochen Woern]

Well, let's organize it and do it, I am all for it. But, who will have the time to get it all going???

[Kenneth]

Well, I had an open lab tonight at the college and I just found out today that the dyno is out of calibration. The professors haven't called the snap-on rep to have it re-calibrated yet. So I didn't get to dyno my truck. Anyway, I was kind of disappointed, but oh well. Thanks again for all the tips for testing the truck.

[1999GMC]

AH. That sucks. Hopefully next time.