I heard from a guy that runs 7s in the 1/4 (not a camaro) that the dyno punishes an engine a lot worse than the track...

He told me that before he bought his engine, the builder (pro builder) dyno'ed it on a chassis dyno and that after the dyno run they changed all bearing and piston rings before sending his engine...

I would like to know what kind of beating an engine takes with it? Does it really hurt the engine???

I thought that the dyno was easier on the car since it was ~3k # that it weighs vs 3600 - 3900 # on the track, and that you only do 1 gear insted of beating the engine for 4 gears or so...

I would like to have some opinions on this matter... Thanks

 

It's no worse than doing a fourth gear roll on the street. Not that you'd normally do that...

But it doesn't stress the engine in any different ways than hard driving does. Basically like putting a track pass on the engine.

 

For what I heard, they claim that the dyno makes the engine do some unnecessary force than on the street or track

 

Alrighty then.......maybe on a 2000lb car but not on a 3000lb+ car

 

Dyno pulls generate heat very quickly because there's no way you can duplicate the amount of cooling airflow that the car would see if it were in motion just by placing a fan or two in front of the bumper. You probably run a much greater risk of detonation on a dyno because of this.

 

If you've got heat problems with a 30 second dyno pull, you have bigger problems and don't need to be on a dyno in the first place. A dynojet is LESS likely to detonate because it doesnt load a 3500lb car like its loaded on the street. Go to a dynojet with a turbo car and you will see the difference on the boost gauge....less boost on the dyno than on the street.

 

True I only saw 4.5 psi insted of 5.0 - 5.25

 

You've got a supercharger, you shouldn't have seen any negligable difference in boost. Your boost level has little to do with the load that the engine is under, whereas a turbo has everything to do with the load it is under.

Since the blower is spun by the belt, the boost level is dependent on the RPM's, and not much else. (air density, filter restrictions, misc. ignored)

 

Ehh... who would have thought the day would come when i would disagree with Mr Jimlab

The dyno i have used before doesnt use a fan or two, but a large device close to the ground that blows a huge amount of air. I mean you can barely stand in front of the car with it on... So at least in my case i dont think the cooling argument is viable.

 

I believe theyre talking hydraulic brake dynos, not chassis dynos... tho they can eat tires.

With a hydraulic brake dyno.. you can easily kill stuff... run it WFO, but load the **** out of it and hold it at 4500rpm... glowing headers.. popping.. breaking.. shrapnel...

 

I talked before about chasis dyno and I am refering now to rear wheel dyno...

Then explain to me why do I see almost 6psi in 5th and in 1st I only see 4.5?

I think that has to do with the fact that my engine is reving very fast on those gears and on the higher gears it gives the supercharger enough time to compres

 

Um a chassis dyno IS a "rear wheel dyno"

A hydraulic or water brake dyno is used to measure just the engine's output , out of the car.

 

My friend Bob Kennedy has a chassis dyno in his shop. He has made thousands of runs with all kinds of cars and has never blown one up on the dyno! He makes most test pulls in an intermediate gear and for a high-po car a third gear pull lasts only a few seconds. For final tuning and to show th customer the biggest number possible he will make fourth gear pulls (third in an automatic). But even these last just 6-7 seconds in most cars and the load is less than WOT in 4th on the road or track.


If you are going to beat on your car on the street or at the strip it's better to find out what's gonna happen on the dyno than anywhere else.

Rich Krause

 

As I have done a fair amount of tuning on a chassis dyno, I agree with most of the people above that they don't load the car as hard as on the track. The exception are the chassis dynos like the Dynapack that can actually hold the car under full throttle at a certain rpm just like an engine dyno. While you can get some good info from these conditions, they are hard on the engine and drivetrain if done for a length of time. Imagine a turbo engine under full boost at 3500 rpm that isn't allowed to accelerate; foot on the floor, engine screamin', but held at 3500 rpm. Kinda like climbing a VERY steep hill with the pedal floored. Or actually, like a tractor puller. Tough on parts!

Jody

 

highlander wrote:

"He told me that before he bought his engine, the builder (pro builder) dyno'ed it on a chassis dyno and that after the dyno run they changed all bearing and piston rings before sending his engine..."

i think we have some miscommunication here. the original post says "chassis dyno". i think what he meant was hydro dyno. unless the "pro builder" installed the engine in a car, dynoed, then removed the motor, replaced bearings, rings, then shipped. a motor coming from a motor builder was probably dynoed on an engine stand dyno, rather than an in-the-car chassis dyno.

if that is the case, brake dynos can tear **** out of a motor. refer to skaradoms post. glowing headers, all sorts of sweet stuff. anyone remember a print add from porsche with a set of cherry red headers and turbo? that's prob. why they changed stuff.