I need some help from you guys to shut a local shop up. Heres the story:

I live in Venezuela, the only dyno that exists here is a dastek brake dyno in a shop called kartec. The think they are the best and have a very big mouth, they are always putting everybody else down. They have broken a lot (and I mean a lot) of engines in they're dyno (maybe too much brake who knows) and are always exaggerating hp numbers on the cars they build.

Now I went into a discussion with one of the owners cause I said brake dynos are **** compared to dynojets as they have a bigger error margin. But I couldn't back my **** up (and I don't even know if its true). I need your guys help on which dynos are better and why. thanks

cliff notes: what is better an inertial dyno or a brake dyno and why. thanks

 

ttt
please some help

 

bump

 

come on somebody help me

 

Shouldn't talk ****, homie. Do the homework first. And not by asking on an internet forum, do some reading!

 

brake dynos are much better for tuning. inertia are better for comparison sake...especially dynojet 248c

 

I didnt talk **** I just told him that intertial dynos were more accurate for the actual TQ reading but not that they were better or worse for tuning.

If too much brake is applied to an engine too keep it at a desired RPM with the brake dyno isnt it possible to brake a rod or something

 

dyno jet is "old school"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jetpilot &raquo;</TD></TR><TR><TD CLASS="quote">If too much brake is applied to an engine too keep it at a desired RPM with the brake dyno isnt it possible to brake a rod or something</TD></TR></TABLE>

I couldn't see that being a problem. How would this be any different than going up a steep hill or maxing out a car top speed wise. The engine doesn't know/care if its accelerating or not.

Do some research and let us know what you find.

 

I've had a couple of cars on a Mustang Dyno load tuning the fuel basemaps for two to three hours, almost constant, with a few breaks in b/w columns as we got to the higher load columns.

You do have to watch that the water and oil temps don't creep too high to keep from beating up the engine while doing the higher load/high rpm cells. I had to stop a few times anyways to keep the coolant temperature correction maps from fooling with the calibrations too much.

 

I know the engine doesnt know/care but isnt the strain too much for it, going up a steep hill full throttle and maxing the engine must not be good for it, not for a brief moment but keeping it there so there is time to do the tuning.

 

It only takes two to three minutes to do a column before I stop to let it cool down, and then going up a load column to calibrate from 1500rpm to as high as 6500rpm on the LO cam.

The coolant temps usually end up around 200 to 210 deg F at the end of each column. I'll usually let it cool down to around 170 to 180 deg F before doing the next column.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jetpilot &raquo;</TD></TR><TR><TD CLASS="quote">I know the engine doesnt know/care but isnt the strain too much for it, going up a steep hill full throttle and maxing the engine must not be good for it, not for a brief moment but keeping it there so there is time to do the tuning.</TD></TR></TABLE>

Yeah, i assumed they'd only be doing it for a few seconds at a time, but i guess they dont.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jetpilot &raquo;</TD></TR><TR><TD CLASS="quote">I know the engine doesnt know/care but isnt the strain too much for it, going up a steep hill full throttle and maxing the engine must not be good for it, not for a brief moment but keeping it there so there is time to do the tuning.</TD></TR></TABLE>

When an engine is keept at full load 2 things start to happend
1-the engine oil will start to heat up a lot and fast and therefore
2-because the engine is increasing his temp slowly it will be getting pre detonation.

a car towing a boat or something sees temps of around 300+farenheit (which at those temps you start cooking things in there), that's why towing cars have large engines, so that the engine don't have to see full load all the time. For example, on off road bikes
a 600cc would see full load maybe around 2% of his life, a 400cc would see full load around 3-4% of his life, now a 250cc would probably see around 8-9% of full load during his life, now try to guess which one will last longer?

Off course, there are many things you can do to reduce wear, like do more oil changes and with better oil, or add more oil to the system or coolers. But in reality we are building high performance engines that will require a lot more maintainance and we are giving up away longevity, and we try not to, but we have too.
You can't expect a formula 1 engine to last 60K +miles, can u?
According to the helms manual for the Honda CRF450R (12:1 plus compression and around 13k rpm) you should do a top end rebuild every 15 hours.
guess you can see the point.

oh, how can u expect to tune the upper load columns without putting a strain on the system? and like invtec said, the engines doesn't have enough time to heat up too much, so there is no harm

 

ahh you dont know **** GZERO. stop posting crap you have no basis of, you have never worked at a dyno facility so stop bullshiting yourself