Reducing lag

[nogutsnoglory]

As some of you might know I sold my red k03s ibiza and have got matts old yellow ibiza gt2871r, loving when it comes on boost but it is rather laggy, apart from going 1.9 what other ways are there of reducing the lag?

Spec is:
One piece supertech inconel exhaust valves and black nitride inlet valves.
Mahle motorsport forged alloy pistons 8.5:1 CR
THS H beam conrods and new Big end bearings
JBS Equal length manifold (Ceramic Coated)
GT2871R Turbo
3" DP and exhaust system with Jetex rear box.
3" Inlet with Green filter and S3 MAF.
Pro Alloy front mounted intercooler.
Genesis 550cc injectors. @ 3 BAR
Audi S3 Fuel pump and External 4 Bar race pump.
Evo Heat shield gasket for inlet manifold.
Custom Engine Tie bar to limit engine rock
Innovate wide band Lambda and Gauge
Apexi AVC-R Boost Controller
Oil Temp Gauge
10 row oil cooler
Custom Code Phase 3 mapping

Cheers

 

[caney]

what do you call laggy?

 

[minimivic]

T3 or T25 turbo?

 

[pj1985]

Its just the nature of a gt2871 on a 1.8t. Going from a k03s which spools instantly to a gt2871 which starts to pull hard from 3.5k rpm is going to feel laggy. Rev it higher as thats where the power is and if you are off boost drop a gear. Its never going to be anything like a k03 based turbo spool wise though.

 

[stewbie55]

Don't know if a large bore inlet mani (e.g. SEM) would help at all?

 

[pj1985]

Larger bore I would imagine would make it worse as its more space to fill/air to flow.

 

[h17och]

boost pipe capacity makes near on no difference to lag

 

[stewbie55]

In terms of going 1.9L or 2.0L, how much difference does that make?

Whilst I can see it would be an improvement, is it very significant?

 

[h17och]

you need to ask someone who has been runnning a set up then increased capacity.

i done it all in one go

 

[Feel]

Post up some logs, you neveer know there might be a problem...

 

[Poverty]

cant you just fit an anti lag system

 

[nogutsnoglory]

I will try and get some logs done at some point, it had an eml when i first picked it up but was missing a post cat lambda probe in the engine bay as its decat, plugged one in and cleared the codes and all seems ok, just get the odd cylinder misfire so will look at changing the plugs in the new year.
I realise that going from a k03s to this is going to seem laggy, and that its a well known fact with turbos this size, it starts spooling prob around 3.5 but full boost around 4k
dropping a gear usually means 2nd and its just an animal and eats tread, still got to set up the apexi properly though so can look at limiting boost once i get my head around it
It also got me thinking that many moons ago my polo 1.4 16v was quite rev happy and up to 3k it could beat anything off the line, so just wondered what things could be done to make it faster - off boost, if that makes sense?

 

[caveo]

My IHI fels laggy compaired to the K03s , but thats the trade off for pulling to red line. Shot of NOS will help.

 

[nogutsnoglory]

T3 or T25 turbo?

its t25, i've been re-reading matts thread lol

Turbo is GT2871R 743347-2 76 Trim 0.64 A/R

Here is spec http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2871R_743347_2.htm

 

[beattie17]

Id go for SEM inlet and 80mm throttle body. Nice and simple bolt on. and get map adjusted.

 

[ibizacupra]

to get less lag from what you have without rebuilding the engine with larger capacity, you have what you have i think. unless you want to add some nos to fill in the low end and get spool going sooner.
higher compression would reduce lag, but again not possible unless you strip your motor and change components. worth checking the fueling on it, as i have seen overfueling on inital foot down bog the turbo/engine down, before its actually producing boost, in which case some fuel trim adjustments may help a tad, as could some timing, but this is all conjecture sight and log unseen.
you know where i am if you want me to have a look see at the mapping in case i can tweak some more out of whats there.
regards
bill

 

[traumapat]

you don`t realise how good a remapped k03s is until you take it off

 

[ibizacupra]

depends on what you want from your power delivery... if all you want is low to mid range then k03s, and a similar powerband to a diesel.. buy a diesel then.

If you want a more linear power delivery, as k03s are all at once uber spooling things, then the bigger units will roll in later and more progressively and rip the more you rev the motor.. using the whole rpm range.

not everyone wants this tho.

twin turbos', K03s to get things going and BT from 4k up.. but compex plumbing

 

[Damoegan]

twin turbos', K03s to get things going and BT from 4k up.. but compex plumbing

That would be awsome. Have you seen it done, Bill?

 

[Spud_G40]

I have recently changed over from KO3S to GT2860 and the difference is huge, my KO3S + all the extras used to spool from 0 and be annoyingly like a diesel as Bill said. I was always on boost before. The GT28 definately has the top end the K03S never. You're never going to have low end grunt on a relatively small engine and big turbo like this. But like people have said, if you need that then a well modified K03x based car is the answer if capacity increase or rotrex charger is out the question.

My car now has far more potential, and is already a much faster car as boost never tails off to 7K, and I am only running it at actuator pressure till I get an apexi.