jeffp1167

what if it blows on the dyno? is that going to be a choice?

I say 240hp at wheels.

73jst4fun

As is before tune up:
305 rwhp
335 tq

RunningMan373

That's why i won't dyno mine,, not gonna stall the engine at 5500 rpms,, eff-in crazy

baxsom

how is running on a different any different that a full throttle run on the street?

timgman

I don't know but my pal ran his ford 460 like hell on the street but when he did his pull at the dyno (450 na whp prior to tuning) a wrist pin froze and chewed a big hole between two pistons... Now he uses srp pistons with floating wrist pins.. he has yet to dyno it.. Can't blame him hehehe
He want to race me.. He'll kill me hehehehe

toddalin

So it would have been better if this happened to him on the street in traffic?

If it happened on the dyno, it was going to happen sooner or later and was just a matter of time.

v2racing

After years of running dynos I can say unless the dyno operator is incompetant, the dyno is not going to be detremental to the health of a healthy motor.

gkull

Somewhat!

An engine dyno can create the max stress that can only be duplicated on the road by doing things like running the car with gas petal on the floor in over drive at high speed. Where the air wall resistance is forcing the motor to strain. Like when I floor my car at 150 mph and it just slowly increases in speed compared to how fast it can get up to 150. But a typical dyno only does a run for a mater of seconds

You see lots of motors blown up at places like Bonneville Salt flats because the motor is under max stress for 30 - 60 seconds.

QuicheLorraine

You are mistaking a dyno HORSEPOWER RUN with Dyno tuning. They are completely different.

A horsepower run is just a single run-up to the redline, measuring the RWHP. Dyno Tuning on the other hand is many runs, over and over again at different throttle settings to simulate vehicle speed at different loads. Tuning modifications/adjustment is done between each run. The dyno is loading the wheels to simulate vehicle weight and/or uphill motion. The dyno does a very good job of simulating driving conditions.

That being said I agree with the poster that suggested that failure on the dyno isn't from what's happening that particular day. It was bound to happen on the road somewhere under similar driving conditions.

pauldana

3 blown engines in the past year, all 3 dyno tuned, all 3 dyno run for horse power...... all 3 blown on the street.... I am very hard on my engines, never had a problem on the dyno.... I agree, if it blows on the dyno, it will blow on the street, there is something wrong with the engine... I think I would listen to gkull,,, I believe he really knows what he is talking about.

cv67

if its going to go it will do it idling in traffic or going down the track, it doesnt matter. Doing a dyno run or anything else isnt to blame.


To the OP, get your run done yet?

RunningMan373

there's an 'outlet' for the power- ie, car goes faster. stalling the motor- no outlet, no pressure release, dynoing is going to produce more strain in the chain- so i would not do it, on any motor, that's why you see so many motors that blow on the dyno, that would of driven just fine on the street for many years.

"If it happened on the dyno, it was going to happen sooner or later and was just a matter of time. "

toddalin

There's an 'outlet' on the dyno. It spins faster requiring more power to spin stalling the motor.

However, I can see where the dyno could blow up an engine if it wasn't up to snuff and the owner never takes it up to redline.

I'm sure that there are a lot of people in this boat who are either afraid of blowing up their matching # engine, or are, well...

billla

*sigh* The dyno discussion is "interesting"...for another thread Today's likely our last shot for getting in a guess...ummmm estimate!

OzzyTom

I can see your point, Runningman... if one was to build up the top end for power only on a well used motor, and not check the pistons, conrods, crank or bearings... then sure.... you've got a potential time bomb waiting to go "BANG!" when you do put some real stress on the motor.

But like said by so many above.... it will go "BANG!" just as easily on the street under full load as it would on a dyno if there are weaknesses.

Better to find the weakness whilst it's in the workshop, rather than 150 miles away from home on a power cruise!

Main benefit of the dyno is for tuning purposes to verify correct A/F ratio under all load conditions. This improves driveability, performance, fuel economy and reliability if done correctly.

Having said all that, I would steer clear of putting my car in any dyno comps at car shows for entertainment purposes.....
That's when you may have an inept untrained cowboy operating the controls.

But a dyno run at a reputable tuneshop... Go for it!
Should NOT pose any problems at all.

OzzyTom

Thanks Billa.... getting us back on topic!

I reckon 285 rwhp....

RunningMan373

The bottom end of my motor was rebuilt ~4 years ago. Crank and bearings checked ~1 year ago.


That said , a well built motor should have No Problems on a dyno, however, stalling the motor will produce more stress on it then acceleration. matter of mechanics. FYI. Back to on topic. I say 290 at the rears.

Glass Act

320 hp

MotorHead

275RWHP if just one or 2 pulls with no tuning. If tuning session you might see 300RWHP but it is much harder than you might think to get that kind of HP out of a street driven 355ci. I know I tried and fell short by 4 hp

63Nova

293hp