GTI tuning modifications - what would you do?

[geoff_gti]

Yeah, I heard dyno's don't work on them.

Indeed. If you can't compare a Mk V GT and GTI, I'd hate to bring a Mk IV into the equation

I'll live - just taking it day by day at the moment.
(and just to introduce ANOTHER tangent...) How is the gearbox?

Hoping it may not need to be replaced now, but I'll update you on that in the appropriate thread

[BarneyBoy]

My brain hurts - it's like rolling down an infinite hill, inside a rainwater tank with a bunch of marbles...

[geoff_gti]

Feel sorry for decksla this has gone so far off track. Lucky not every thread degenerates like this. It was a relatively harmless quiestion to begin with too!

[Maverick]

Feel sorry for decksla this has gone so far off track. Lucky not every thread degenerates like this. It was a relatively harmless quiestion to begin with too!

It's still on a related topic so it hasn't wandered off course (much)

[TDIESEL]

Mav, besides speculating, what do you actually do for a job?? It can't be too technical...

Maybe he's a wanna be jet fighter pilot but seeing Goose died, it would be bad luck using his name

[Greg Roles]

Fugg me, if some of you spent more time under the bonnet, rather than at the keyboard, the dyno arguement would be made redundant by your car's performance. If I was after a dyno beastie, well, it wouldn't be a VW Golf. They're all just slightly tough chicks cars really.

I'll use my contacts at VW to see if I can spend some time in a stock TSI and a stock GTI with my Vag com, just for sh#ts and giggles..

or if anyone out there in Brisneyland is up for it...... giddy up!

[G-rig]

Got a question for you lot:

How do i go about comparing dynos with different intake temps and other variables? Is there a formula or conversion?

[Greg Roles]

Basically depends if your are Polarphillic or Mavphillic.

[Maverick]

Basically depends if your are Polarphillic or Mavphillic.

I have dyno manufacturers and the dynolicous software company to back up my claims.

Polar has a hacked up GT TSI, dodgy dynos and dodgy dynolicous data.

[Maverick]

Got a question for you lot:

How do i go about comparing dynos with different intake temps and other variables? Is there a formula or conversion?

Look at the info/link I posted early about the shootout mode, still far from perfect but let's you compare cars around the country (tyre pressures, strap down tension and so forth will affect the results).

If the results you have indicate flywheel HP and Torque this is purely a calculation based on estimated drive train losses and can vary a lot between dyno operators/manufacturers and also of course different cars and to a certain extent those from the same manufacturer.

To get around all the variables with strap down tension, tyre pressures, wear on the rollers, tyres and so forth hub mounted dynos are a better choice.

Review of one setup http://autospeed.com/cms/A_2654/article.html

www.rototest.com = Eddy Current/Strain Gauge (this is apparently a better method)
www.dynapack.com = Hydraulic Fliud displacement

"The Dynapack™ direct couples to the wheel hubs and applies a precisely controlled hydraulic load. This method of direct coupling plus its built-in strength means the Dynapack™ is always in control of the vehicle.

Controlling a powerful car on a roller dyno can sometimes be a daunting task. With Dynapack™ you have TOTAL CONTROL of the vehicle, with no wheel slip due to its direct coupled design. With that there is no inertia to mask the results, giving you greatly improved sensitivity, repeatability and significantly reduced time spent tuning and mapping!

With the power of the Dynapack™ literally at your fingertips, you have complete control over the test and the demands placed on the vehicle. Flexible data presentation and analysis is available direct from the Dynapack™ in seconds.

Dynapack™ chassis dynamometers are such a radical departure from the stereotypical roller dyno that it really is in a class of its own. Most of the previous assumptions made about chassis dynos (the roller type) simply do not apply to the Dynapack™ series."

[Greg Roles]

Polar has the balls to actually do some unproven, first time, experimental mods, in the face of endless criticism and keyboard bound warriors. He may be rough around the edges, but he's not all talk, and he's my kinda guy.

[G-rig]

Polar has the balls
<snip>

He may be rough around the edges, but he's not all talk, and he's my kinda guy.

Just in time for Valentines Day

Has Polar got any real dynos to see if any of his mods work, or tinkering?

[Greg Roles]

You need to gang up with the TSI crew, that was a good one.

[POLARBEAR666]

I could spend $250 to get a full run up on my tuning shops hub dyno. That would give me all the readouts, a/F ratio, hp, torque, air temp.

But at the end of the day. Whats the point? If the reading is 300hp or 2hp my car is just as fast as it was when it went in. I only get dyno time when my car is getting tuned or after a tune to check the A/F ratio's at all the different rev ranges.

I know what works on 4cyl turbo's. I have built a subaru from stock power to 300kw@wheels and completed a full gearbox and drivetrain conversion from 5 speed 99 manual to 6 speed 2003 variable ratio STI gearbox.

I know about custom fuel systems, intercooler sizing and how different pipework changed my boost threshold and reduced or increased lag. I know that a huge front mount is not always better than a smaller well made one due to pressure drop etc.

At the end of the day. I know that the things I have done so far will have taken the car from 135kw stock to about 140kw.

I have also reduced my cars weight by about 35kg with the seats in and 55kg with the rear seat out.

So in the real world ... regardless of my cars power figure it is at least 70kg lighter than a GT TDI which makes up for the difference in torque. I would be almost 90kg lighter probably than a GT TDI with my seats stripped.

So yeah... 6.89 is real when i strip the car.

[G-rig]

You need to gang up with the TSI crew, that was a good one.

Yeah was just kidding- need a few funnies to break up the bickering.

I'd go broke if i went to the dyno's before and after every mod too, as well as the wasted time. Some people have said you should do that to go about it methodically, but it doesn't really affect the outcome and by that stage already bought the mod anyway (unless you get a free trial).

It's also a bit pointless if you can't compare dynos to other cars with the same mods, unless they were done on the same day and other conditions the same etc. It's good that some tuning shops provide dynos but people can get upset if they do a dyno and it doesn't measure up. i would have thought you could still get it within a 1 or 2 kW. (mine was 11kw atw under what i expected from the Harding Performance graph of the mods i got).

BTW Polar I wouldn't mind trimming some weight off my car, and meant to ask if the tyre shops like changing a tyre after that foam is put in.. doesn't wreck the tyre i assume??