Category Archives: Discussion

Volkswagen Golf MK7.5R Sunday Morning Drive

The only reason that I have not put a down-payment on the new 7.5R is because I couldn’t afford another one which looks quite similar; I posted a picture of me washing the car and I guess no one realized, its a different car, other than it having an additional door.

Follow me on instagram @k3v_7r

I don’t blame them, its like asking me what’s the difference between a pair of NMD and Yeezy, which until today, I have no idea.

Having said that, I must say, the new styling on the MK7R is growing on me – especially with a new set of wheels – well, its not new but I swapped it from the Golf 5 R32 for the heck of it and look at that!! 

If you spot someone in the car, don’t worry – that’s my “human” lowering spring

I am sure you have read about the spec of the car from the world’s automotive blogs so there’s no need for me to share on that. I have driven the 7.5R in Nurburgring, Sepang and now for a short back route driving – the result is the same, I love it.

The only reason that I did not take the Ulu Yam route is to save it from stone chips – the car is for sale still, but its a test drive unit – perhaps the only test drive unit available.

Whenever my friends and I have a conversation about the Golf R, I always get the same question  “DSG7 safe anot?” The 7 speed gearbox fitted on the Golf R is not similar to that on a dry clutch DQ200 DSG7 found on the 1.4tsi (except the tiguan mk2) / 1.8tsi Volkswagen models in Malaysia.

The 7.5R with a wet clutch DQ381 7 speed gearbox, feels is a lot more smoother overall vs the DQ250 6 speed gearbox. In fact, I always tell my friends that it felt like driving a CVT gearbox sometimes. On hindsight, I do miss the RAW DQ250 on the 7R but the saying goes, you can’t have your cake and eat it too.

The 7R in my opinion is already a very versatile car, drag/track/daily; been there, done that. I don’t know how else I want to elaborate on its versatility but once you drive it, you will understand what I mean.

Its a keeper, really,  and that’s why I am not selling (unless you offer me crazy price… please?) and the 7.5R provides the needed interior improvement for Volkswagen Golf fans.

Well, there’s only one way you can find out more about the car, head over Wing Hin Autohaus and get a test drive. Call +603-9076 6628

The Volkswagen MK7.5 R Dyno-ed

Forget what the brochure says, we put the new Volkswagen MK7.5R on the dyno.

The question that we are going to address is, how much improvement of power vs prior generation of MQB platform MK7R. Its busy day for me and more things to do before end of the day so I will keep it short

Lets take a look at the graph of two different dyno – Blue belongs to the new MK7.5R and the red one belongs to MK7R (my car). Both cars have clocked under 1,000km for dyno, using Ron 97 fuel with equally stock hardware. My 0.02 cents;

  1. 7.5R is rated 310ps but detuned to 290ps in Malaysia and runs 277hp on the dyno – which gives us around 5.5% power loss. Don’t ask me why some use 15% powertrain loss to calculate BHP or how a GTI from 230bhp to 340bhp;
  2. I noticed that the 7.5R is choking at the end of the RPM, i reckon it needs more air;
  3. My datalog (no time to study thoroughly but i recall very briefly) the intake air temp is on the high side and we should get a better HP with better temp;
  4. Note also the AFR is a little bit lean and from my logs, the Golf R is pushing 1.3bar boost stock – will look a the data again later;
  5. Overall, i find the transmission on the 7.5R much smoother than the 7R DQ250 but I did not do a full out test mode – why? because contrary to believes, the car is NOT MINE.

However, I would like to get one to do FULL ON test mode but I guess that’s going to be tough unless someone kind enough to lend me for a few days – free stickers for you ok?

The question that everyone is asking – how does the Golf R benchmark against the Honda FK8R?

A few months back, I had a FK8R for a few days – I did say that I am going to compare the car, but this is not a review – at least not now. Based on this chart that i extracted from the same dyno; my 0.02 cents again;

  1. FK8R peak power (green) seems to be higher than Golf R (blue) but from early to mid range, the Golf R seems to be better than the FK8R;
  2. It does felt the the FK8R has more power at higher RPM when I drove it;
  3. For drag, I reckon both cars will be quite similar depending on the distance – 200m, launch control, I think the Golf R will emerge as the winner but anything more than 400m, I believe the FK8R may have advantage.

Anyway, that’s just my very tip of the iceberg view – without looking at data / performance boxes, its hard to make a conclusion – heck, I did not even push the Golf R through corners but I do note that the 7.5R feels more agile vs the 7R – something I noticed at Nurburgring too.

Till the next update.

 

Pre-Detonation, Knocking and RON Rating

First of all, I am not thermodynamics engineer and I am not in the oil and gas industry but I read a lot online and I have seen many people posting on our Facebook Group about the usage of RON95 and RON97 and its effect on Volkswagen cars – some even compared it to Naturally Aspirated (N.A) cars they previously own.

Trying to put everything as layman as possible  so that we don’t need a degree to understand the relationship between Pre-Detonation and Ron Rating.

If you are up for it, the internet is really an awesome place to find answer, you can literally find everything online and that makes illustration and explanation so much easier.

Let’s have a look this particular illustration of how engine works;

Source : https://animagraffs.com/how-a-car-engine-works/

Take note of the process of 2/3 – This is where octane rating matters and the debate of “knocking”comes into play.

Octane rating is a measure of fuel performance; the higher number, the more compression (and heat) the fuel can take before it auto-ignite / pre-detonation, a detonation other than ignition spark. When fuel auto-ignites, it creates ping/knocking to pistons and on a long term basis will damage piston rings and in some severe cases melt pistons.

Power is produced during power stroke, the further a piston can travel in its compression stroke, the more power it produces. All these processes are controlled within ECU’s parameter; fuel-air mixture (air fuel ratio), boost and ignition timing. The higher timing means the pistons will travel further in its compression stroke but this is irrelevant because we are talking about a stock car and not a tuned car. Any turbo car with chiptuning on it will benefit from higher RON (community service reminder that chiptuning will void your warranty blah blah blah…. ).

Ok before I get carried away, so what does all these means?

  1. Higher Ron rating lowers chances of pre-detonation means less chances of knocking but if you car engine is designed for lower RON, then you should not have issue;
  2. Does using higher RON means more power? Theoretically no, unless you have advanced ignition timing but we have seen dyno results of GTI running on higher RON 97 better off than a RON95;
  3. Does using higher RON means better fuel consumption? Theoretically, higher octane fuel running on engine designed for lower octane can result in incomplete combustion and worse off fuel consumption.

The million dollar question, is your Volkswagen car safe with RON 95? A stock car tuned for RON 95 usage obviously means acceptable ignition timing, proper AFR which allows spark ignition before any pre-detonation. If so, why do we hear stock cars having blown pistons?

  • Could it be a pistons design flaw or;
  • Wrong Fuel Air mixture (too lean) for our fuel and climate or;
  • Climate too hot causing too much pre-detonation for a turbo car or;
  • Maybe owners are not educated about misfiring (causing knocking) and they continue to drive causing damage to pistons.

I leave you to connect the dot but I can tell you from experience, a number of 1.4tsi on RON 95 with extensive timing retard (knocking) but runs perfectly fine after changing spark plugs and coilpacks.

I can tell you there are owners continue to push their car despite misfiring and blew their piston (stock cars).

I can tell you too that a stock 1.4tsi AFR is quite lean – possibly to get the desired fuel consumption from the numerous dyno session we used to have.

I can tell you that CAVE/CAVD engines have piston revisions but what I can’t tell you is how to spend your money. The difference in savings between 95 and 97 is quite substantial over time but more importantly, if you have misfiring symptom, please do not take it lightly.

Throttle off, pull over and take out your phone and dial 1-800-88-2389. Stay safe and happy motoring.