GTi Mk5 or Mk6 as a race car?

[bricksnmortar]

I need some help from those who have raced between the mk5 and mk6 which will mostly revolve around engine (chain vs belt) and gearbox. This is a limited modification class, no changes to intake, head, turbo housing, compression. Exhaust free, can tune ecu, might be able to run a tiny bit more boost, small amount of weight reduction, total power would end up around 180kw @ wheels. Endurance and sprint rounds. So I have 3 questions for guys who have spent time around these race cars
1) is there any difference in power with these limited mods between the mk5 or mk6 engines?
2) will there be any difference in reliability if maintained but driven hard?
3) would the dsg or manual box produce faster lap times for a quick driver (what do guys use in the gti series and why, response to driver inputs, reliability etc)?

[bricksnmortar]

So it seems that the guys in the GTI series in the UK are mostly using full manual boxes. I heard one swapped from DSG back to manual. Partly because of engine braking which seems odd to me given manual and dsg have a direct gear connection to front wheels, no torque converter slush box arrangement.

[neilw]

Is weight and fuel consumption also a consideration? Not sure which is heavier. The mk6 Ed35 uses the same engine as the mk5 edition30. Mk6 gti has the newer chain driven engine, which has had issues with the chain tensioners (resolved with updated parts)

The mk5 ed30 engine will easily go to close to 300bhp with a remap, its the same engine used it the s3 and mk6 R but with a different tune and smaller intercooler.

http://australiancar.reviews/GolfGTi-Edition30-Pirelli_BYD_Engine.php

also some good info here

https://www.pistonheads.com/gassing/topic.asp?h=0&f=86&t=1620969

There are other people on here that race, so will probably be able to give you a better answer.

[bricksnmortar]

Hi Neil,
thanks for the reply, unfortunately the Ed30 and Ed35 both put me over the power to weight ratio for the class so I need to start with a bog standard Mk5 or Mk6 as the base. It does appear that the chain tensioner has been solved and I'm happy to check it fairly often. The pistonheads page is a good explanation of the differences.
On APRs website it shows the following

Mk6
https://www.goapr.com/products/ecu_upgrade_20tsi_trans.html
APR Stage II w/ Intake and Downpipe   93 AKI   98 RON   278 HP   341 FT-LBS

Mk5
https://www.goapr.com/products/ecu_upgrade_20tfsi_trans.html
APR Stage 2 w/ Downpipe and Intake     93 AKI   98 RON   271 HP   295 FT-LBS   
APR Stage 2+ w/ HPFP, Downpipe and Intake   93 AKI   98 RON   285 HP   321 FT-LBS   

[Shoduchi]

A friend of mine had a mk6 GTI with an APR intake and decat 3'' downpipe making near 290 HP with 98 RON petrol. It's a better engine to tune than the EA113 AXX or BWA.

[bricksnmortar]

A friend of mine had a mk6 GTI with an APR intake and decat 3'' downpipe making near 290 HP with 98 RON petrol. It's a better engine to tune than the EA113 AXX or BWA.

thanks Shoduchi, so am guessing that is flywheel hp but calculated with a percentage added back in from a wheel dyno? So for 290 and take out maybe 12% for drivetrain makes it around 190kw atw with no head work which is nice.
Do you think the intake in a Mk6 GTi is restrictive or doesn't affect hp too much?
And what do you think about DSG vs manual in a race car?

[Shoduchi]

Yes, it's flywheel. The dyno was a Bapro, so it measures wheel drag to calculate flywheel power as well.

I think the mk6 GTI intake is much better than the mk5 GTI intake. Upgrading it would be something to leave for later after testing the engine output with the factory intake. You're not aiming for very high numbers where a less restrictive intake would be needed.

DSG is better on acceleration, so on a circuit with good straights to push the limits of acceleration, it should be better. You can check teo_parvu's topic where he retrofitted a DSG to his Leon Cupra to use on Time Attack races: http://www.mk5golfgti.co.uk/forum/index.php/topic,96115.msg955433.html#new.

The DSG might need an upgraded oil cooler which isn't cheap. If you mind budget a manual car will be cheaper to setup, I think.

[bricksnmortar]

DSG is better on acceleration, so on a circuit with good straights to push the limits of acceleration, it should be better. You can check teo_parvu's topic where he retrofitted a DSG to his Leon Cupra to use on Time Attack races: http://www.mk5golfgti.co.uk/forum/index.php/topic,96115.msg955433.html#new.

The DSG might need an upgraded oil cooler which isn't cheap. If you mind budget a manual car will be cheaper to setup, I think.

I will reach out to Teo thanks for that.
Do you know if the DSG box has significantly different car corner weighting? It seems to be a 20kg heavier car weight, but are the gearboxes in exactly the same position or is the DSG weight heavily over one wheel (worst case for handling)?

[Shoduchi]

I'm guessing that the DSG improves the corner balance between the front wheels. The engine makes more weight on the right front wheel.

[bricksnmortar]

With the DSG is there a way to monitor inputs like DSG temperature in the cabin as you drive? I can see that VCDS can pull that data on a laptop but is there anything you can use while you're driving in the cabin like a gauge or readout in realtime of that measurement (am guessing its available on ODB)? And maybe engine temp as well.