Author Topic: dhyno  (Read 3993 times)

March 25, 2006, 07:15:46 pm

Malacaco

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dhyno
« on: March 25, 2006, 07:15:46 pm »
Hi there ppl. I have a new problem. Took my car the other day to a dhyno to see how the engine was behaving and the result is no very good.



At about 4000 rpm (cant tell exactly) the engine starts to cut a bit as you can see in the graph and the result is almost 10 hp less than it should have. What i want to know if anyone does indeed know is what is one (or more) cause of this. The car is a Golf MK1 1.6 TD (non intercooler) with a bout 100.000 miles. Thnx in advance


1983 VW Golf MKI with swapped engine (1.6D to 1.6TD)
http://batracer.com/-1FrontPage.htm?1E.
--->check it out

Reply #1March 27, 2006, 11:48:31 am

fspGTD

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dhyno
« Reply #1 on: March 27, 2006, 11:48:31 am »
Did you leave the stock naturally aspirated exhaust on there, or any other parts?  IIRC, the naturally aspirated exhaust is 1.5" diameter which would pretty severely restrict the TD.  The OEM 1.6lTD exhaust diameter at 1.75" diameter is still very restrictive, but would be much less so.  Are there any other differences you are aware of your setup different from a factory TD setup?

Are you seeing full boost pressure, which should be 9-10psi?  Is there any smoking under wide open throttle?  Lack of boost and/or lack of fuel could cause low power output.  As could mechanical problems, like poorly spraying fuel injectors, a badly timed fuel injection pump, or perhaps partially melted piston tops or other internal damage.  A poorly timed fuel injection pump can also drastically effect power, but is relatively easy to fix.

When was the last time you changed your air filter?

PS - Is the red dyno plot a plot of another 1.6lTD engine that is running better?  Dyno results aren't always 100% accurate by the way.  It is recommended to do 2 or more tests if there are any questions, and make sure the results repeat.

Also, make sure the dyno operator depresses the accelerator pedal 100% during the test and that the input lever on the fuel injection pump hits the stop.  Good luck!
Jake Russell
'81 VW Rabbit GTD Autocrosser 1.6lTD, SCCA FSP Class
Dieselicious Turbocharger Upgrade/Rebuild Kits

Reply #2March 27, 2006, 07:24:31 pm

Malacaco

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dhyno
« Reply #2 on: March 27, 2006, 07:24:31 pm »
thnx for the reply. You spoke about the exhaust and indeed i left the NA exhaust in there wich makes a lot of smoke. Never remebered that detail. So should i change only the final mufller or the entire exhaust. All the data is about my car only, It measures the normal ouptut, engine output, whell, and transmission losses. Thnx once again m8. Ill attend to the exhaust imediately.
1983 VW Golf MKI with swapped engine (1.6D to 1.6TD)
http://batracer.com/-1FrontPage.htm?1E.
--->check it out

Reply #3March 27, 2006, 07:35:25 pm

mainer

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dhyno
« Reply #3 on: March 27, 2006, 07:35:25 pm »
Do the full exhaust go to at least 2 inches, maybe even 2.5. If it were me I'd try it with no muffler, and see if it is too loud. The turbo should get rid of some of the noise. If it is to loud put on a diesel muffler, its just stright though with bumps on the sides to brake up the noise.

Coop
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Reply #4March 27, 2006, 08:23:41 pm

Malacaco

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dhyno
« Reply #4 on: March 27, 2006, 08:23:41 pm »
Here in portugal i must only fit the car with original parts because here we have anual inspections and they are very rigid with the car specs; all must be original, or only manufacturer aproved tuning parts.


fspGTD- My car runs on a K&N box filter and the injector tips are Bosch brand new, when i got the engine it had a blown gasket so i checked the pistons and they were just fine. I opened the fuel in the pump just a bit and it goes much better now, but still i can notice the power loss at higher revs. I beleive the exhaust is the cause of all of this, or maybe the LDA?

The schematics are
Red- Normal power
Black-Engine power
Blue-Wheel power
Green- Power loss with transmission

Max. power at- 116km/h(72.5mph)

The test was made in 4th gear
1983 VW Golf MKI with swapped engine (1.6D to 1.6TD)
http://batracer.com/-1FrontPage.htm?1E.
--->check it out