dynoed m-tdi, incomplete

[scopefrfd]

There's a place, called Dez Racing in Seekonk, MA that does high performance Mustangs and they have a chassis dyno.  I drove up today 1st thing, in the am,  to see if he does vw
diesels and schedule an appointment, MA.   I got lucky.  He took me in this
morning.  Unfortunately, I didn't have my camera.

I wasn't prepared, but at this point....I'd take anything just to get the
engine dynoed.   The only problem was he couldn't get his optical pickup to
latch onto the car...so we couldn't do torque or hp/per rpm....only hp/per
mph because you need an optical pickup for diesels.   He was able to do
power to mph.

My car has a vw diesel tach.  I bought a vw diesel tach from Canada and it
didn't work when I received it.  I finally had a guy locally fix it, so it
works now...but it's off.   Anyway it was the only thing we had.   I told
the guy not to take the engine past 4500-5000K rpm on the tach...I know it
reads fast so I knew the engine would be safe.

We did 4 pulls....the first 2 in 4th gear... and the last 2 in 3rd gear.
The 1st three pulls the car ran clean once up to boost 21-22psi.  The last
pull the fuel screw was turned in 1 turn and it smoked a little at full
throttle.  Results

1st 93.04whp
2nd 93.83whp
3rd 94whp
4th 100.48whp

While he was testing it...it didn't really seem that the engine was going
hard rpm wise.  I thought the engine would do more by how it feels on the
butt dyno, even the guy commmented on how fast the car gets up to power.  The other thing he stated is that his dyno seems to read less than other dynos in the area.  He's had cars come in that dynoed 50hp less on his dyno versus others in the area....granted he has supercharged mustangs putting down over 500whp.  

On the way home I looked closely at the tach vs speed and I decided to take
some readings.  The speedo is in KM.

2900rpm - 100km =62mph
4000rpm- 140km= 86.8mph
5000rpm- 180km= 111.6mph

I have a tdi CTN tdi tranny, with 195/50/15's.  I punched those numbers into
a gear calculator.   At 5000rpm I should be doing 141.68mph.   The 112 mph
calculated to approx 3900 rpm...tach is off by atleast 1100rpm!!

I looked at the dyno sheet...the 100hp pull we stopped at 55mph/5000 rpm.
I checked the gear calc.  At 55mph the engine is only reving at 3500rpm!!
No wonder the hp # was a little low.   On the graph the hp is still climbing
before we stopped.


Does anyone have any dyno sheets that we can compare hp/mph.  They charge $75 for a dyno session...I'm very pleased with the engine...power wise...Christ, I went 111mph going up a bridge...so it's plenty fast for me.  Just trying to get an idea what this setup produces at say 5K rpm.   I can take some pics of the dyno sheets if anyone wants to post them.

Also, is there anyway to adjust a vw diesel tach?   At Idle the tach reads right around 900-1000 rpm...but once I rev it it climbs really fast.   It's frustrating, I paid good money for the tach...finally got it working, after it was fixed locally more $...but it's not accurate.   I'm going to borrow a volov vdo diesel tach..it was an aceesory on 240 diesels tachs the same W terminal and see if the readings are the same.

[Tintin]

I would like to see the pic of your dyno sheet.

100HP @ 3500RPM that seems to me correct, anyway, the maximum HP that this engine produced,  is located around 3800-4000RPM, you would have probably made 110-115 HP @ 3800RPM, after which, the HP start has to go down,  its the way which this engine is built.

Never a stock TDI VW engine will produce more HP at 5000RPM than have 4000RPM, if it is the case, it have there a big tuning problem in the low RPM, it's not a myth, it's a mathematical fact.

To produce HP, to some extent it is necessary to multiply the torque by the RPM, the  maximum torque in a TDI is approximately at 2000RPM, after which it starts to go down, and it remains about it enough to 5000RPM to produce much HP.

It is easy to see whether HP VS RPM are correct, in all engine, gaz, diesel, motorcicle, 2 stroke engines, etc.........at exactly 5200RPM, the number of HP (in HP) will be always equal to the number of torque (in LBFT), in a dyno sheet, the curves always will cross to 5200RPM, in all engine.

Which is your car?

For your tach, it is normal that it is erroneous in a MK1/2, the ratio of alternator TDI pulley are not the same as the 1600D/TD, to have a good reading with a AHU in a MK2, you must fitt a tach of 1.9 AAZ, or, installs the complete  system of belt, alternator, etc... of 1.6 on your engine.

[scopefrfd]

The engine is mechanically injected ALH tdi engine from an 01' Beetle.   It's not stock.  It has .205 injectors, a Fiat td Pump with a governor mod and an aftermarket aneroid boost pin.  A KKK k14 turbo and a GTD intercooler.

I'm using a serp belt setup....I'm going to right down the numbers of the alt and crank pulley and verify there for a tdi.   What I don't understand is the tach seems correct at idle but once I rev it it is off.

I would need your email address to send you pics

[Tintin]

Ok, ALH engine have smaller crank pulley than a AHU/1Z, the ratio should be much more close to a 1.6D/TD.

It is normal, the percentage of error is multiplies as you takes more RPM.

Where you took the reading ' ' W' ' on the ALH alternator?


You connected the wire ''W'' as on the pic.

[scopefrfd]

the alternator is the serp style from bosch from a late model vw...it only has a 2-terminal in a 1-plug connector, the W terminal is one of the connectors and the other connector is for the alt warning light..plus the large gauge wire that goes to the starter..I think the alt is not from a tdi...it doesn't appear to have the 1-way clutch pulley on the alt.  I'm thinking maybe the tdi alt pulley is larger than a non-tdi alt pulley.

[hillfolk'r]

yea somethins fishy with your tach,,,
my tdi-m doesnt like revving over 4200 or so,its singin by then
and who cares about revs when you have soo much down low torque?
i think on paper (if i remember )my tdi-m with my gearbox  im currently runnin,ill be turnin almost 120mph at right around 4500
ive got a small 2 inch vdo diesel tach  that ive had for going on 10years now,and it works good,even if its a little small to read
ive also got a snap on "timing pulse adapter"
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=56075&group_ID=1318&store=snapon-store&dir=catalog

that i use with  my snap on timing light/tach

http://buy1.snapon.com/products/diagnostics/time_mt2661ap.asp


yea not everyone can afford snapon stuff,,but i recommend the pulse adapter
then you can check your revs and dynamic timing if you prefer
i check or plot mine at a few different spots
first ill check the timing light to my tach at idle,then 2000 then 4000
it used to be funny to check  the max revs on the old 1.6 i had at work
id brick the gas pedal and take my time checking the revs,while all the guys in the shop would run away,thinkin itll blow up :twisted:

[scopefrfd]

Can the #3 injector be used as a tach signal

[RabbitGTDguy]

interesting thought on using the 3rd injector as a tach signal... I wonder how those of us w/ m-TDI setups could power/test the lift sensor in number 3 to see if it would work...give the correct pulse signal, etc...

I'll dig into some info I have, specifically, the SAE paper on the TDI, industrial application...but should still apply


Joe

[nkb]

anyone find out about this yet? i think im gonna pull my third apart tonight to take a look...