Slow GTi

Chat about your MKV (6N2) Polo GTi
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andyg
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Slow GTi

Post by andyg »

I've been trying to solve the problem of my car feeling slow as crap when setting off from standstill. The car "feels" heavy and boggy when setting off, when I reach 3800rpm it starts to perk up, but I got beaten by a bog standard peugeot 307 off the lights the other day :'(

I thought that maybe the brakes are binding. They aren't red hot after normal driving. However, I jacked the front of the car up and spun the wheel by hand. The disk slightly grates on the pads and it doesn't spin very free. I uploaded a little video to show what I mean:

http://www.puppetstring.com/andy/polo/front_wheel.AVI

Is this normal? can one of you guys do the same and tell me what you get? Its been back to VW a few times and they can't find anything wrong, but the dealership in question is crap so I dont have much confidence in what they say.
Reeyad
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Post by Reeyad »

I too am having that feeling, as coming from an 8v polo the power was lower down, I put it down too it being a 16v and the power starts picking up abt 3000-4000 rpm.

Am gonna get my uncle to proper test drive it, he has been in to dubs for years has owned every Golf GTi model abt from the mk5.

It seem my car has it days sometimes its is so fast when I set off, sometimes it seems am over reving with no power......

It was at VW last saturday and they checked it over, and said nothings wrong, but there service is poor.

I took a day off work told them the HT leads replacing as VW care said it was arping, they booked me in, left car with them only for them to call me back hours later to say we dont have the lead in stock.....

I mean for f*** sake i told them what was needed before hand and it took 5hrs to call me back....

Wasted 1 days holiday, finaly got it sorted......

Well I still have 1 years used warrenty an I intend to make use of it, which why I am tended to allow the mods.....

Please update me on the findings of your investigation of the power loss...

I hope u get it sorted, I think with me am expected too much from my GTi.....

Well I hope its that once my uncle test drives it il update u here.........
JWC
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Post by JWC »

Check that you have the correct spark plugs in, mine was like that and I threw the VW plugs away and put some bosch ones in, and its much more even on the torque range now. Will not hurt to change them anyway, I would never leave them in for the recommended 40k! I know that asda crap fuel tends to wear them out by about 30k

Cannot really explain it, but its just a feeling you get, felt like the gaps were too narrow, hence its affinity for higher RPM. Also check your air filter isn't full of crap, its hard to run when you can't breath. Leaves, bugs, traffic film, very small elephants, all get sucked in when you are driving about.

Also if you have big alloys and have inadvertantly increased the rolling circumference it will destroy the torque dramatically, and you will notice this most in 1st. When they designed the car they didn't put the BBS alloys on just for a laugh, they actually designed the final drive ratio to match the wheels.

Another thing to check would be for high current consumers that are on, such as heated window, or air con, they do make it feel like driving with the handbrake on.

Finally, I found this on another polo, the hot air bypass valve from the exhaust manifold was stuck open, so it was always breathing hot air in, this is not good for performance, as the colder and more dense the air intake the more power you get. You can test this by removing it (when warmed up). Don't leave it off else it will never warm up in winter!

Every extra 50kg in weight will add almost 1 second to your 0-62 time, so big sub woofers, fat girlfriends, air conditioning, beer bottles, shopping and babies all will make a big difference, at the end of the day even 125BHP really isn't that much when its lugging all the xmas shopping about.

I only weigh 63kg, so my 0-60 times in a GTi faster than average ;) probably a bit slower after christmas... (burp)

Hope this quickies help, you can check most of them in a jiffy and every home mechanic should check these things anyway.
JWC
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Post by JWC »

[quote="Reeyad"]
It seem my car has it days sometimes its is so fast when I set off, sometimes it seems am over reving with no power......
/quote]

This is what you should expect, the engine is a breathing machine, and derives its power from burning fuel with air. The air is cold and crisp dry and high pressure your car might get 140BHP, when its hot, humid and the pressure is low, or you are at high altitude, you may only get 110BHP.

I remember driving a dodge V6 at reno - 6000ft high ground in the nevada desert, it drove far worse than normal, my dad worked out that 40% of the power would be missing due to the height and temp, he was right.

So from one day to the next, it will feel different, but also you tend to feel that it feels different depending on what you have been doing in between.

-see I been reading my Pilots License books again :)
andyg
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Post by andyg »

JWC: awesome reply, cheers. Couple of questions though:

Did you see the .AVI file i posted? Does this look like its sticking or is that free enough?
Finally, I found this on another polo, the hot air bypass valve from the exhaust manifold was stuck open, so it was always breathing hot air in,
Where abouts is this on my GTi? could you mark it on this pic for me?

Image

Cheers dude
Prash
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Post by Prash »

The GTi doesn't have a hot air bypass valve from he exaust manifold !
mikegti
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Post by mikegti »

I dont think your brakes are binding. the pads may touch the disc ever so slightly but there's also the wheel bearing that provides a bit of friction.
JWC
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Post by JWC »

the smaller pipe on the air intake is hot air?

The brakes do not have springs or anything to push them off the discs, so slight rubbing is the result. Its ok, but what you can check for is the calipers can sieze, both the sliding parts and even the piston. The well known cure is a large mallet - tap them.
andyg
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Joined: Sat Jul 17, 2004 8:58 pm
Location: UK

Post by andyg »

Cheers for the replies.

I replaced HT leads, and the spark plugs. I usually run the car on shell optimax too, and I never use cheapy supermarket fuel.

Still slow :(

Any ideas what to do next?
Reeyad
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Post by Reeyad »

My situation is ok, it was just me not really let myself adjust to a 16v coming form an 8v....

Mine seems to be more responsive the more I drive it, brougth it from VW so it may have been sitting idle for a little while. (Dam today the cold air may my car zooooom)

Maybe take it for a very long drive stick some injection cleaner and clean the throttle body.

Take it for good hard thrash, this helped once on my old Mk2 Golf, it was driving like s**t, me uncle said take it on the motorway and drive the sh*t out of it. It did the trick..............
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