Dyno numbers 240Z

[E-ticket]

Hi all,

Just thought I'd post my recent Dyno numbers.. Below are the basics - used the basic set-up from The Datsun Garage . http://datsunzgarage.com/

2.8 - P90 Head shaved .080 - Triple Webers - 5-sp - 3:90 gears.

These are the numbers:

HP - 180.84 at the wheels

Torque - 187.02

Using the basic 20% drivetrain loss this gives about 220 at the flywheel, not bad..!!

[Zed Head]

Shaving .080" and using Webers adds 50 HP? There must be more to the story.

[E-ticket]

Not hiding anything, I'll try to post the dyno sheets for everyone to see. Check out the website above, I used the same WebCams grind "# 94a" grind with .430 lift, 230/230@.050" duration, no stroker crank or power adders.

[madkaw]

That sounds about right for a well tuned machine.

Congrats!

[madkaw]

Would like to hear more specifics as far as timing, type fuel, afr readings

[LeonV]

First off, nice job. Looks like a clean and well-done setup.

Second of all (and don't let this burst your bubble), by themselves, dyno numbers are truly useless. What those numbers are good for, is comparison between cars and setups on the same dyno and preferably on the same day (for obvious reasons, this isn't always possible). It would be of more use to have dynoed the car before and after modifications, on the same dyno. For example, JustAFantaZ on HybridZ recently had his V8 Z dynoed on 2 different dynos. The difference in the results between the two dynos was 74hp (428hp vs. 502hp)! That's over 15% variation!

We have to realize what dyno numbers are. This will lead to less fuss and confusion. Power or torque is calculated based on the type of dyno. There are variances between dynos, no two are the same. It is not a hard, true number although some dynos are closer than others. Was this done on a inertial (Dynojet, Superflow, etc.) or brake dyno (Mustang, Dynomite, etc.)? Inertial dynos, like a Dynojet, produce more inflated numbers. In JustAFantaZ's experience, the Dynojet showed over 15% more horsepower than the Mustang dyno!

I'll copy/paste my post in the longtubes thread on HybridZ:

Dynojets are plain, inertial-drum dynos, which measure how quickly your wheels can spin up a drum of known weight. Power is calculated as Torque * Speed. Torque is calculated using T = I * a, I being rotational inertia of the drum and a being angular acceleration of the drum. This is a less accurate way of measuring actual power, since you're inferring power from how quickly you accelerate the drum. This also means that changing things like flywheels, brake rotors, tires, driveshafts, etc. will show a change in hp on a Dynojet, even though your engine isn't making any more power.

Conversely, something like a Mustang dyno is a "brake" dynamometer, which uses a fluid or electromagnetism to put a force on the roller and against the wheels. These types of dynos measure (not calculate) actual torque delivered to the drum by way of a lever arm connected to the brake and a load cell that measures force at the end of the lever arm. This force is used to calculate torque, which is then used to calculate power, using Power = Torque * RPM.

Therefore, a brake dyno (e.g. Mustang) provides a much more accurate depiction of actual power than a purely inertial dyno (e.g. Dynojet).

Please, take dyno numbers with a grain of salt.

[Unkle]

Next thing you tell us there ain't no Santa Clause . : )

[madkaw]

Hey Leon,

At the dyno today, we will see!

Hope you don't burst my bubble if the numbers are good

[LeonV]

Hey Leon,

At the dyno today, we will see!

Hope you don't burst my bubble if the numbers are good

Steve,

No need to burst any bubbles since you already had a baseline test done on that same dyno and can make a valid before/after comparison, right?

Rest assured, however, that Dynojets inflate numbers by 15%, give or take a few percent, compared to the more accurate brake dyno.

Edited March 20, 2012 by LeonV

[LeonV]

Next thing you tell us there ain't no Santa Clause . : )

What, then tell me who gave me those socks for Christmas!

[five&dime]

Very impressive. Post the sheet so we can see your torque curve!

[madkaw]

Well I could only muster 150/150 with my 2.4 and SU's.

In relative terms to the OP, I'm in the ballpark with the smaller engine and carbs