sweetmongo

Wondering which dyno is more accurate, I've heard mustang dynos give low numbers but does that mean they are not accurate? Reason I'm asking is because there are now 2 local shops with dynos that rent them by the hour, one dyno jet and the new one is a mustang dyno. Planning on going in next month to finish wot tuning my car. Any input is appreciated thanks.

2xLS1

iTrader: (25)

Dynojet is an inertia dyno so you are just spinning up 2 weighted drums. It tries to calculate HP by measuring rate of acceleration of those drums and backwards calculates torque with a fudge factor. A Mustang dyno has a load cell attached to the rollers and loads the vehicle similar to an engine dyno with a brake. The operator is supposed to enter the weight of the vehicle and a HP @ 50 number and the dyno adjusts the load based on those values. I think it is actually measuring torque and calculating HP by the HP = Tq x RPM / 5252 formula. There is a load cell option that can be added to some 24x Dynojets but I haven't seen too many that are equipped with it. I don't really have an opinion on their accuracy as other brand dynos will measure different than either of those two. I know it is easier to do lower rpm steady state tuning on a Mustang dyno as they can be set to hold specific rpms. Dynojets without the load option are primarily WOT dynos.

Darth_V8r

iTrader: (4)

Everything the previous poster said is true. In simpler terms, the dyno jet will tell you if the car will be faster. The mustang will tell you if the motor will make more power.

Here's a simple example. Install a light clutch, carbon drive shaft, and super light wheels and tires. You've done nothing to the motor, so it won't show and additional power on a loaded dyno like the mustang. The dyno jet will show more power, because the wheels accelerate quicker, resulting in a higher power reading.

In the above example, the engine is making the same power, but the car will be faster due to the upgrades.

sweetmongo

Thanks for the info guys, so if I part throttle tuned it on the street and I'm going to the dyno for the wot pulls. Does it really matter which one I go to? The dynojet is 50 bucks cheaper an hour if it's not a big difference I'll probably go with that one.

Darth_V8r

iTrader: (4)

IMO it's more important to use the same one every time for consistency. You need to be honest with yourself on this. You want mainly WOT or you want good streetability also? If a daily driver, do the loaded dyno. Much easier to hit all the cells.

ctd

iTrader: (1)

I would do the loaded dyno & build MAF & VE tables if for no other reason than to have the reference data.

The MAF is very quick, if your using the Mustang set it to "Vehicle Sim". I use fourth gear & start were ever it is stable say 1200 rpm. Cell counts to 50 & hold each cell to near 7000hz. Maybe OL the first time & then back to CL & verify the STFT's.

A couple of WOT from 2k to your redline & you should have a good MAF transfer curve.

To build a VE table I set the Mustang to hold 4800rpm, same drill cell counts to 50. I use fourth again & hit all the cells in that 4800rpm column as I can. Change the dyno to 4400rpm & repeat. Do each rpm column moving to lower gears if you start lugging. I do OL & verify STFT's. Then back to Vehicle Sim & do some cruise verification.

Then do the WOT VE table & should have pretty decent VE table.

Slowhawk

iTrader: (12)

I have a mustang dyno. Use to use a Dynojet. I like the load for wot timing and fuel. The mustang will put enough load on the fuel system to see if any issue's, dynojet won't.

As for load tuning, I find it to be off compared to actually street tuning part throttle's.