I'm scheduled to dyno my truck March 4th.
Any tips for a chassis dyno newbie?
It's three pulls for $55. My wife will definately not understand, but I hope to leverage my birthday with is the day after Shameless.....

 

Well, you could always pack ice around your air intake for a few extra ponies...

 

Its good to have a tach in your truck. I dont, however I hooked up a photo tach and figured out at what speed in direct drive is 2000 RPM. for some reason they like to know where 2000 RPM is in the gear you dyno in. I think they can compute all the info into the computor if you know gear ratios and tire size, I just think its easier for them if you have a tach.
Other than that, enjoy. its fun.
Good luck

 

I've dyno'ed a couple of times on a mustang dyno. I have a tach and they prefered to put reflective tape and use their optical pickup. Its actually easier that way, their system is setup for it.

But 3 pulls for $55 is pretty resonable, the guy I goto charges $60 for 3, but we usually wind up doing 5 or 6.

With a load type dyno, like a mustang I'd say your probably want to run 4th.
On an inertia type, I can't offer any advice, never ran on one.

 

Thanks guys.

Any guesses on HP and Torque? (just for fun)

Will they give me altitude corrected numbers?

 

Your setup looks almost exactly like mine except the trans. And mine is a lockup anyway so the difference should be minor. Depending upon where the main fuel screw is set, I'm going to say 280 ±20hp.

I don't know a altitude corrected. I'm under 1000 ft above sea level where I dyno.

 

I'd dyno in 4th gear..start the run at about 30 mph and FLOOR IT..the higher the RPM the more HP you'll show.. if you had a tach I would start at about 1500 and shut down at about 2800 to 3000 or when it de-fuels. Getting 3 runs will allow you to play with this a little..I'd say your gonna be about 275 on the HP and about550 to 600 on the torque..more than enough to break stuff..I got a 41WC myself..had a 500HP 440 that WAS going in it..sold it and am waiting on a 4bt.........after my divorce is final ..28 years...**** it

 

I've read to its best to put it in overdrive (5th for the nv4600) on an inertia dyno. It is cheating to use OD on a dyno, but the dyno won't provide anough load to produce boost unless you're in OD- so it seems thats what everyone does. You said 3 pulls, so maybe one in 4th and two in 5th.

 

At the one and only dyno run I went to, I let the resident expert drive. Tim ran her up to either 50 or 55 mph, I don't remember which, and stomped it in drive using overdrive. The more load the better for spooling up the turbo. When it defueled he let off. Three runs and the best I did was 190.2/489.8 which I thought is not to bad for a stock truck with just pump and air box mods. Had fun doing it. I would like to do it again after I make my version of the "Stock Pot Air BoX".

 

5th gear, floor it at 1500 RPM and don't let off until the truck defuels. I think Mike nailed it on the results - you will be darn close to there.

OD isn't cheating. The HP is calculated using engine RPM, not wheel speed. As was said, the load is needed to make the governor fuel.

 

I start my runs a less than 1200RPM...think this is bad? BTW, I've only ran on one type of dyno...Dynojet 248C...4th vs. 5th (old tranny) lost me about 25hp and 75 or so ft lbs!!

Right or not, I'm using 6th
Chris

 

What if I don't have a tach?

 

Just do it by ear or with the speedo. Whatever speed you would normally feel comfortable laying into it in 5th will do fine.

 

I can drop the hammer at 50 or so no problem. I'm starting to get stoked!

Can't decide if I want to hook up a water injector or the intercooler chiller for one of the runs. Either one would take a bit of work, but probably worth it..

 

Good thing I have the fully splined 5th gear mainshaft or I'd be chuckin' that nut, and my lunch right after!
I drive by ear with the boost gauge anyway.