MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: Ant b on November 26, 2017, 09:01:41 pm

Title: Boost rpm
Post by: Ant b on November 26, 2017, 09:01:41 pm
Hello just wondering on your mk5 gtis were does your boost cut in?
Just had a map put on my car (flash) I know but only temp.
And it dosent really boost downlow like I thought a small ko3 turbo would it all up top.
My mates a3 1.8 boosts low which is how I want mine
Title: Re: Boost rpm
Post by: Dan_FR on November 27, 2017, 08:18:15 am
Too many variables..... It depends on what RPm you plant your foot, what gear you are in, and what sort of incline you are on for starters......

But it should feel very spritely down low as its a tiny turbo.

You either have a hardware issue, or a very bad map, or a combination of both

For example, Mine is Stage 2+ so I have more low down fuelling available for more performance, but my car can make well over a bar of boost by 2,000 RPM in a high gear if I load the car up... Day to day in the lower gears its spinning the wheels by 3,000 RPM
Title: Re: Boost rpm
Post by: Ant b on November 27, 2017, 09:33:22 am
I assume it’s just that map tbh,it’s only temp till I go to rtech
Title: Re: Boost rpm
Post by: pudding on November 27, 2017, 12:07:10 pm
As above.  Throttle pedals as we once knew them were replaced with 'driver demand' modelling years ago.

Anyway, mine is similar to Dan's, albeit a KO4 engine.   If I nail the 'driver demand' switch to the floor at 2000rpm in 4th gear on a flat road, I see 20psi by 2600ish rpm and 30psi at 3000rpm.....holds it for a bit, then starts falling on it's arse past 5000rpm.  An intake would help that a little bit in my situation, but I don't want the noise.

Sounds like your map could be a little better.
Title: Re: Boost rpm
Post by: Ant b on November 30, 2017, 12:38:11 am
Yeah it defo could,I’m not sure if I have a boost leak or not as this ra air is so loud
Title: Re: Boost rpm
Post by: pudding on November 30, 2017, 10:34:02 am
Yeah, all of the filter on the end of a pipe type intakes are very noisy.   It could just be the noise and lack of throttle response below 2500rpm that's making you think you've lost boost?   
Title: Re: Boost rpm
Post by: Ant b on December 01, 2017, 05:59:30 pm
Potentially as the ram air is silly loud,to loud.
But it dosent seam to open up and go really well till about 4k
Title: Re: Boost rpm
Post by: Ant b on December 16, 2017, 11:17:52 pm
Sorted it,the clip on my bottom intercooler hose came out and the pipe was half out,plus I put a new pre cat 02 senser on.
The issue I have now is wheel spin
Title: Re: Boost rpm
Post by: Dan_FR on December 17, 2017, 08:38:07 am
There are plenty worse problems to have! I think we all have that issue when its this cold and damp out!

Nice one for updating us, glad its sorted
Title: Re: Boost rpm
Post by: Ant b on December 20, 2017, 09:05:56 pm
Still feel flat after 3rd or 4th but I’m guessing that’s a tiny turbo for you and a sh*t map
Title: Re: Boost rpm
Post by: pudding on December 22, 2017, 10:13:14 am
What map is it?  It might not be that.  As you say, little turbos run out of puff quickly.  Not even the KO4 is a VTEC (yo!) mega master past 5000rpm either.
There is a ton of exhaust gas squeezing into a ridiculously small scroll.  Great for spool, shat for top end.  It's the age old compromise of Turboing.

Unless there are some significant hardware problems, I would say you're just underwhelmed by the GTIs performance.  Nothing wrong with that.  I know people who've grown up with Super bikes and even Ferraris are slow to them.
Title: Re: Boost rpm
Post by: m1keh on February 25, 2018, 03:14:55 pm
Have you checked the basics? PCV and the recirc valve? Those failiing will make it slower to build boost.
Title: Re: Boost rpm
Post by: Ant b on April 30, 2018, 06:16:20 pm
Have you checked the basics? PCV and the recirc valve? Those failiing will make it slower to build boost.
Yeah there all new