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Model specific boards => Golf mk5 => Topic started by: joesgti on 20 November 2007, 13:47

Title: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 13:47
my gti turbo kicks in at about 2000rpm and boosts up to 6000rpm after that is just flat??!! is this supposed to be or will others boost all the way to 6800rpm.
my old scooby used to go all the way through the gears to rev limit holding the boost till gear change, i also drove my mates golf 1.8t last night with revo remap, his is no where near as quick as mine but his holds the boost to the limit.
is there anything that will help this (d.v valve....intake...miltek)??

views would be appreciated.  :smiley:
Title: Re: flat boost after 6,000 revs??
Post by: SteveS on 20 November 2007, 13:51
 duno much, but the forge dv is ment to hold boost longer.. thats what they claim
Title: Re: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 15:18
duno much, but the forge dv is ment to hold boost longer.. thats what they claim

so does you go up to the limit holing the boost??  :undecided:
Title: Re: flat boost after 6,000 revs??
Post by: SteveS on 20 November 2007, 15:19
i dont have the dv, but as standard erm... im not sure really. it pulls from about 2500 then drops off abit, but it apears to also pull higher up again after about 5-6 :-|
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 15:36
Standard GTI boost comes in earlier and should stay to the redline
ED30 boost comes in higher and only just starts to tail off before the redline.

The tail off in torque will be more noticeable on the std GTI as the torque curve also drops off earlier.

look at the links below for the graphs.

http://www.superchips.co.uk/curves/vw2lfsiturbo.pdf

http://www.superchips.co.uk/curves/VWGolfGTIEdition30.pdf
Title: Re: flat boost after 6,000 revs??
Post by: Kiddfrost on 20 November 2007, 15:53
my gti turbo kicks in at about 2000rpm and boosts up to 6000rpm after that is just flat??!! is this supposed to be or will others boost all the way to 6800rpm.
my old scooby used to go all the way through the gears to rev limit holding the boost till gear change, i also drove my mates golf 1.8t last night with revo remap, his is no where near as quick as mine but his holds the boost to the limit.
is there anything that will help this (d.v valve....intake...miltek)??

views would be appreciated.  :smiley:

Once remapped that's about right. I think what you're feeling is the lack of torque at high revs. This is greatly exaggerated after a remap (Revo used as example) as you have a massive increase in torque at 3.5k and its just a steep decline from then on  :sad:
BHP increases at a good rate until around 5k and then it starts to level off, so with the combination of this, the decline in torque and that fantastic midrange rush, it can sometimes feel a bit limp above 5.5k rpm. The ed30 is much better up top as its larger turbo will provide a higher level of boost at higher rpm.
I've got mine a little better by doing some data logging with VAGCOM and altering boost/timing with an sps switch.
A Milltek and hi flow filter will make things a little better but to get the most out of these you will need a remap designed around these 2 items installed. e.g Revo stage 2.
Title: Re: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 15:53
Standard GTI boost comes in earlier and should stay to the redline
ED30 boost comes in higher and only just starts to tail off before the redline.

The tail off in torque will be more noticeable on the std GTI as the torque curve also drops off earlier.

look at the links below for the graphs.

http://www.superchips.co.uk/curves/vw2lfsiturbo.pdf

http://www.superchips.co.uk/curves/VWGolfGTIEdition30.pdf

graphs wont open  :sad:
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 15:55
Standard GTI boost comes in earlier and should stay to the redline
ED30 boost comes in higher and only just starts to tail off before the redline.

The tail off in torque will be more noticeable on the std GTI as the torque curve also drops off earlier.

look at the links below for the graphs.

http://www.superchips.co.uk/curves/vw2lfsiturbo.pdf

http://www.superchips.co.uk/curves/VWGolfGTIEdition30.pdf

graphs wont open  :sad:

Just tried them and they do on my PC. Have you got adobe reader on your PC?

If not then just go to the superchips site and select the GTI and the ED30 and go into the graph "view power curve"

http://www.superchips.co.uk/models.php
Title: Re: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 16:03
my gti turbo kicks in at about 2000rpm and boosts up to 6000rpm after that is just flat??!! is this supposed to be or will others boost all the way to 6800rpm.
my old scooby used to go all the way through the gears to rev limit holding the boost till gear change, i also drove my mates golf 1.8t last night with revo remap, his is no where near as quick as mine but his holds the boost to the limit.
is there anything that will help this (d.v valve....intake...miltek)??

views would be appreciated.  :smiley:

Once remapped that's about right. I think what you're feeling is the lack of torque at high revs. This is greatly exaggerated after a remap (Revo used as example) as you have a massive increase in torque at 3.5k and its just a steep decline from then on  :sad:
BHP increases at a good rate until around 5k and then it starts to level off, so with the combination of this, the decline in torque and that fantastic midrange rush, it can sometimes feel a bit limp above 5.5k rpm. The ed30 is much better up top as its larger turbo will provide a higher level of boost at higher rpm.
I've got mine a little better by doing some data logging with VAGCOM and altering boost/timing with an sps switch.
A Milltek and hi flow filter will make things a little better but to get the most out of these you will need a remap designed around these 2 items installed. e.g Revo stage 2.

hummm... interesting. this is exactly what i experience after 5.5-6k. so because of the remap it feels alot more quicker midrange and because of the increase in power, mid range torque feels so much stronger.

so for example in a straight line race (drag) from still. would it be faster to 60mph and 1/4 mile to change at 6k or carry it on through to 6.8-7k??  :huh:
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 16:14
Change up at 6k to avoid torque drop off and hitting the rev limiter on gearchange :wink:
Title: Re: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 16:21
Change up at 6k to avoid torque drop off and hitting the rev limiter on gearchange :wink:

so this will achive quicker 0-60  :huh:
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 16:24
Yup. :smiley:
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 16:29
It is the torque rather than the outright bhp that determines the in-gear accelleration and as you will see from the graphs, that starts to drop off at around 5k revs. Changing gears at 6k revs will drop you straight back into the peak of the torque curve, wheras holding on to the death in each gear only benefits you if you are about to hit your target (ie 60mph or pass the 1/4 mile line). Also holding on to the death and then changing gear will drop you into the next gear just after you have passed the peak torque point :nerd:
Title: Re: flat boost after 6,000 revs??
Post by: Kiddfrost on 20 November 2007, 16:39
I tend to change between 5.5-6k. I love screaming to 7krpm but its pointless, I guess that's what a ctr feels like  :wink:
Title: Re: flat boost after 6,000 revs??
Post by: joesgti on 20 November 2007, 16:40
It is the torque rather than the outright bhp that determines the in-gear accelleration and as you will see from the graphs, that starts to drop off at around 5k revs. Changing gears at 6k revs will drop you straight back into the peak of the torque curve, wheras holding on to the death in each gear only benefits you if you are about to hit your target (ie 60mph or pass the 1/4 mile line). Also holding on to the death and then changing gear will drop you into the next gear just after you have passed the peak torque point :nerd:

good stuff hurdy. but i still dont understand which way will get you to 60mph or over the line fastest, if i where in my car and at the pod, and i changed at 6k through all gears, then did a re-run and changed at 6.8-7k which time would come out quicker do you think?  :smiley:
Title: Re: flat boost after 6,000 revs??
Post by: Hurdy on 20 November 2007, 16:50
0-60 it maybe the 6.8k rpm as I believe you can just pip the 60mph mark in second which negates the 0.2-0.3 seconds it would take you to change gear and hit 60 in third.

The standing qtr is a different matter. 6k to 6.2k changes would come out better for the torque curve you have, but we are only talking 0.2 to 0.3 seconds over a 1/4 mile. Still counts though :wink:

In a manual I always find a midrange gearchange around 5/6k tends to avoid the dreaded wheelspin and axle tramp :embarassed:
Title: Re: flat boost after 6,000 revs??
Post by: speedynz on 20 November 2007, 19:33
Joe,

A few variables here.

If you want a quick timed 0-60 you will have to hit at least 6660rpm in second gear, this equates to exactly 60mph and a standard GTI will pull a genuine 64mph at the redline (7100rpm) in second gear, the speedo will be showing higher but you'll be too busy to notice.

As Hurdy said, you will avoid the dreaded cross plane gear shift into third gear which will take longer than hanging on to 2nd gear beyond peak power.

If it's a straight out 1/4 mile run then the 0-60 increment becomes secondary and you'll be losing time overall by hanging on to the gears until the high 6000's. The standard GTI produces peak power at 5100rpm (mildly variable engine to engine) and torque remains relatively constant (at around 200lbft) until 5000 rpm. Changing up at around 6000 revs should produce the best results. Hang onto the gears any longer and you will probably be slower (it's always tempting to rev the nuts off your car as the red mist decends).

Another 1/4 mile factor to consider is that because of the low gearing in third you'll have to change into 4th just before the 1/4 mile post (third will pull 91mph at the redline and you should be doing around 92-95mph across the line).

Look to run around 15 second times and you'll be doing well.

I meant to ask, are you in a DSG equipped car or a manual?
Title: Re: flat boost after 6,000 revs??
Post by: RedRobin on 20 November 2007, 20:30
As others have said, it's the torque which matters and also what other performance mods are combined with a remap. A Forge DV plus Neuspeed Hi-flow pipes with SAMCO throughout the turbo line seems to help too.

By using the paddle gearshifts to avoid using high revs, delivers plenty of power throughout, even from 90 mph to 130 mph (autobahns :cool:).
Title: Re: flat boost after 6,000 revs??
Post by: john_o on 20 November 2007, 21:03
being sad I couldnt resist an overlay of the two graphs attempted with photoshop

(http://www.johnoldfield.dsl.pipex.com/images/weblog/bhp_torque_compare_std_vs_ed30.jpg)

wonder why the ED30 gets a 'burst' again at 6000rpm? would expect it to continue tailing off???

now wonder the ED30 feels so different to the std GTI  :evil: