poor dyno result why?

[jasn78]

DUB20V it isnt the final figure that is concerning me it is the difference like i said the car is still quick enough i am just trying to figure out the difference.

[velly_16v_cab]

it shouldnt matter what gear they are run in, the results "should" be the same.

[DubSteve]

Hey Velly there would be a difference but not much

[velly_16v_cab]

Hey Velly there would be a difference but not much

only very small, you car puts out the same power in each gear lol (well unless you have some mapping to reduce wheelspin in lower gears)

we have had this proven to us on our local RR back home, runs in 3rd and 4th...within a 3 to 4 bhp difference @ wheels.

[Jarred]

Back on topic.

one thing that hasn't been mentioned. ( i don't think, but work with me)

You have a custom intercooler yea? it' may be too "big". ie you loose too much boost pressure through the intercooler, meaning; if your turbo is "running" 14 psi, you could be loosing a few through the FMIC meaning the engine is only getting 7-8 psi of actual boost.

If that makes sense at all.
Bar that I'd whack it on VAG com, may give you a clue to if you are loosing pressure some where, and maybe tighen up your hose clamps etc etc. the small things first.


Also. someone else was expecting to get about 135kW but only ran a 130, on a stock exhaust, with some other mods. Flow mods generally go in pairs - ie, you increase the amount of intake, you (generally) need to increase of exhaust. it's all about flow rates. you flow in more air that you can get rid of, you start running into issues, ie poor breathing. My recommendation - if you want, dyno again with out the cat and muffler, or just upgrade the exhaust.

Intake and exhaust are basic and popular mods for a reason. they work, and are generally cheaper than buying bigger turbos! better flow should also help take advantage of what the ECU flash/remap has to offer. (i think you have a APR one, but I can't be sure)




Anyways, just my opinion/words of advice. Something for you pogo fellas to ponder on!

[VW GTI]

Dyno Day Results from a Polo GTI perspective

IMO the Dyno was running about 4-5kw low on the Polo's compared to the averages achieved around the country to date. This could be due to a number of factors and I'm not going to speculate as to why. Sufficient to say that a number of the (other) cars there ran higher numbers only weeks before either on the same dyno or on different ones.

Interesting also to note that the FMIC Polo's all ran 3 runs with a slight increase in power for each consecutive run whereas the std IC cars all dropped slightly in power with each consecutive run.

Tosspot 120.9kw
APR ECU
Stock turbo
Stock IC
Custom Exhaust (APR downpipe)
Custom intake (Forge TIP, std intake, std air filter)
stock diverter
Std flywheel
17" VW optional rims - tyre size would be interesting to know.
=> Was driven straight onto the Dyno from a 15min run from home. 3rd run was around 118kw, heatsoak the likely culprit.

205/40 17s
Also, my 1st run was 118, 2nd was 106 and final was 120.9. I have no idea how that happened, they opened my bonnet for the 3rd run.

[velly_16v_cab]

Back on topic.

one thing that hasn't been mentioned. ( i don't think, but work with me)

You have a custom intercooler yea? it' may be too "big". ie you loose too much boost pressure through the intercooler, meaning; if your turbo is "running" 14 psi, you could be loosing a few through the FMIC meaning the engine is only getting 7-8 psi of actual boost.

If that makes sense at all.
Bar that I'd whack it on VAG com, may give you a clue to if you are loosing pressure some where, and maybe tighen up your hose clamps etc etc. the small things first.


Also. someone else was expecting to get about 135kW but only ran a 130, on a stock exhaust, with some other mods. Flow mods generally go in pairs - ie, you increase the amount of intake, you (generally) need to increase of exhaust. it's all about flow rates. you flow in more air that you can get rid of, you start running into issues, ie poor breathing. My recommendation - if you want, dyno again with out the cat and muffler, or just upgrade the exhaust.

Intake and exhaust are basic and popular mods for a reason. they work, and are generally cheaper than buying bigger turbos! better flow should also help take advantage of what the ECU flash/remap has to offer. (i think you have a APR one, but I can't be sure)




Anyways, just my opinion/words of advice. Something for you pogo fellas to ponder on!

there is a good thread on CLUBGTI about running "oversize" intercoolers

[Jarred]

..., they opened my bonnet for the 3rd run.

This will make a difference. bonnet open = more air flow. Some dynos run fan's infront of the cars as well. help with the cool air.

Other option is to pack some dry ice in front of you FMIC!! cold air FTW!

[VW GTI]

Yeah they had the fan running, on Saturday too. We thought about dry ice but someone suggested against it to be able to compare results between cars better. Turns out that didn't work

[DubSteve]

The dyno day that I went to last November we ran the cars with bonnets up and a big fan blaring on it.

I'm guessing that the bonnet up did something good cause hot air was coming straight out from the top and keeping the cars cool

[Sharkie]

Quote from velly_16v_cab
wheel size, larger rims will give lower ATW figure.


Not necessarily the size of the rims but more the overall diameter (OD) of the new tyres will be a factor.

205-45-16 = 591mm OD
205-40-17 = 596mm OD (increase of 5mm over stock)
215-40-17 = 604mm OD (increase of 13mm over stock)

So the next question is: does larger diameter increase or decrease the power output ?

And is 5mm and/or 13mm enough for a notable difference ?

[99gti]

I have just deleted about 3 pages of useless rants that were a complete waste of mine and everyone else's time. Grow up and discuss like adults.

[VW GTI]

I know the odometer shows 0.823% too slow with 205/40/17s on rather than the stock 205/45/16s.

Don't know how that translates to power though.

[shaneth]

I asked Trent (the owner of the dyno) about the speedo difference as i was talking about how the polo reads roughly 10% under anyway, he told me they use the dyno to gauge speed.... not the cars speedo.

[DubSteve]

I know the odometer shows 0.823% too slow with 205/40/17s on rather than the stock 205/45/16s.

Don't know how that translates to power though.

Would not be much thats for sure, I ran 205/60 with my Porsche wheels and 205 with the standard BBS wheels and side by side the BBS wheels were slightly bigger by about 1 or 2mm