Engine on dyno: your experiences?

[grouseman]

We see it all the time in the magazines, how the freshly rebuilt engine is put on the dyno, tuned for max HP, parts swapped, optimized, etc. 

What have been people's experiences in putting either a new or used engine on the dyno?  How do the tuning cycles go?  Do they allow you much time to fiddle with timing, jets, etc, between runs?  Can you easily swap parts like carbs between runs? 

I'd be curious to do this myself sometime.  Like I've got nothing better to do. 

[Mefirst]

Well I just droped of my 440 and the shop took care of the rest..

/Tom

[firefighter3931]

Mine was dynoed after being built. A total of 85+ pulls were made with multiple carb, header, manifold, spacer and timing adjustments to optimize the tune. It was a 2 day dyno session 

INMO, the dyno is a great tool and helps you optimize the combo for peak performance. Parts were being swapped out left, right and center during this dyno thrash...we know what works and what doesn't. There was a lot of good info on the old board....i posted direct manifold to manifold comparisons, direct header to header comparisons and cam to cam comparisons.

It's not so important what the power numbers come out as....different dynos can produce differnt results with the same engine. Basicly, optimizing the tune should be priority #1. The cars track results will tell you how well the engine is (or isn't) working. 

It helps if the dyno operater has a known history with his particular machine. If a motor making "X" amount of power goes "X" mph in the 1/4 mile then you know whether it's working like it should, or not. The fellow that dynoed mine has been using the same SF 901 for years so he knows it well and is able to project how fast a car will be making "X" amount of power on that particular unit. His own engine made 15hp more than mine did on the same dyno....and his runs mid 10's in a 3700 b-body. My engine in his car would be a 10.80 combo, or thereabouts.

My car is heavier than his, has less stall and less gear so it won't be as fast. It should go mid 11's with ease and hopefully faster with some tuning.

From now on, any serious street/strip engine i build will be seeing a day of dyno time....money very well spent, inmo. 


Ron

[Chryco Psycho]

most engine I tweak can be done in 2 hrs , generally find 20-30 RWHP or more

[Beer]

Three or four hours (including setting it up on the dyno, and getting lunch midway through it), I did not have any parts to swap, think we did 6-8 runs, First run was a cam break in, then we tried various Timing, then reset to to best timing. I should have had some jets to play with the carb a bit, but I did not. Next time I will. The dyno was free (shop charges I think $200 for the break in and tune), I made the machine shop a website in exchange for the Dyno Time (but I did spent a small fortune at their shop with the 402). There is video of a dyno run on my 402 thread.

Chasis dyno getting about 4-6 runs an hour, depending on what we are changing (Nitrous jets/ or PCM tuning) usually they charge by the hour and log the AFR ($100 per hour no logging, $125 hour logging AFR).