R34 Gtr Garrett -5 Turbo Lag, Need Advise

[baicai]

Get your tuner to look at it, -5's should be on song at 4500, get him to check your accuators are shutting properly so your not losing anything and advance the cam timing a few degrees to add bottom end while adjusting the tune.

In our books, nothing can be as laggy as a S2000 compared to a GTR on -5's, yet you see it the other way around.

In both cars, step down a gear or 2, get it in the zone, feed the power on, no issues.

How would you overtake in a 1.3L manual?

Its just a matter of picking your revs to the situation and driving as the vehicle responds.

We know of a GTR thats been to 2 tuners, owner of the vehicle commented on how much bottom end power he picked up with the second tuner, what use to be laggy is a totally different vehicle now after getting a second tuner to look at it.

Fuel graphs timing etc were all over the place, the vehicle owner was shocked when he saw the before and after results.

Once you have that part sorted readjust your driving to suit the vehicles setup.

The way we drive a GTR compared to a S2000 is quite different, however the theory on where the power is, is the same, if your not in the zone and you want to be brisk, its a slug.

However your tune, can totally change the power dynamics, if its setup to come on up top, you will have nothing down low, if the tune is crap overall expect lower power everywhere.

And remember, being a GTR (heavy) it will not feel as racey as a S2000, but it will be a shit load quicker if sorted.

Thanks for the tip, have thought about getting another tune, spoke to CRD in silverwater before and thought they were a bit expensive, how much would a tune cost normally cost?

[mr skidz]

just goes to show how many people get ripped when asking for a tune and drops the car off then tuner does a cut n paste "its close enough tune" especially when uneducated people ask for a safe tune i reckon that person got a dirty rich and retarded block tune and if any of these people are in here i bet there the ones complaining there 5's aren't spooling quick enough.

but thats just my 2 cents

Edited February 22, 2015 by mr skidz

[Mick_o]

Or maybe they made the wrong choice in turbos?

A tune isn't gunna do "miraculous things" to make turbos come on! Everything around it is responsible.

As said before its having a good intake, a good flowing exhaust & cam choice/adjustment thats gunna bring things to life not a tune.

People get caught up in chasing a number up top instead of chasing the numbers everywhere else.

This talk of 5's are better for the track etc is absolute bullshit!

Better for which track? The 1 with the longest straight?

This idea of "I can just keep the revs up and their will be no lag" is also bullshit because the more times you have to change gears around a track chasing off "that lag" the more time its gunna cost you because its less time your spending on the accelerator its as simple as that!

A car with a better spread of power is gunna be faster all day everyday on the street and the track!

[paulr33]

average power is what makes the car quick

don't forget your effectively running 1.3L inline 3 per turbocharger

looking at the specs, assuming im reading it right

the -5's are rated around 305hp each (average)

front is 0.60 and rear is 0.64

i think std BNR34 is 0.48 and 0.53 a/r

[Mick_o]

I believe they are 360hp each Paul

[GTRPSI]

Or maybe they made the wrong choice in turbos?

A tune isn't gunna do "miraculous things" to make turbos come on! Everything around it is responsible.

As said before its having a good intake, a good flowing exhaust & cam choice/adjustment thats gunna bring things to life not a tune.

People get caught up in chasing a number up top instead of chasing the numbers everywhere else.

This talk of 5's are better for the track etc is absolute bullshit!

Better for which track? The 1 with the longest straight?

This idea of "I can just keep the revs up and their will be no lag" is also bullshit because the more times you have to change gears around a track chasing off "that lag" the more time its gunna cost you because its less time your spending on the accelerator its as simple as that!

A car with a better spread of power is gunna be faster all day everyday on the street and the track!

A tune will do miraculous things, if you dont understand what a tune is and whats involved, so be it, bury your head in the sand.

Advance the cam timing brings in the bottom end, retard it and induce top end, same turbos, its been like this since the 70's on push rod engines and probably decades before i was playing with engines back then.

Add timing, take out timing and fuel at certain points of the power curve, guess what?

Night and day.

Hell S2000 owners dont have a issue withg lag because they dont select a gear that allows revs to drop....just feel like banging my head into a wall how people cannot fathom some basics or knowing where the torque and power band is and making good use of it.

Hey with your thoughts on tuning doing nothing, can i ask you if you know what cam gears are used for?

Why timing is adjustable?

Why different injectors behave differently?

Why compression can effect lag?

Why air temperature effects tune?

With your method of reasoning one tune should do all.....-5, X injectors, Y base timing...hey presto a one fits all tune, just hand it out to everyone and charge $1000 regardless of the setup.

Till someone adds a more effiecient intercooler, temperature changes, fuel pump changes, fuel changes, compression changes, cams get changed, heads are ported, boost is changed and the list goes on.

If you had spent any time with a tuner willing to do a proper tune, the usual question is driving style and expectaion, power down low, up top, conservative, on edge, economical, powerful etc etc.....

Not tune it and call be when its ready.....

[Mick_o]

Peter WTF are you on about?

Where did i ever mention injector sizing or turbo size etc?

Where did i ever talk about MY methods of tuning?

Is the subject not about -5's on an RB26?

Why do you keep talking about S2000's?

The way i see it is without wondering off into compression ratios,timing and Hondas etc is that IN THIS CASE a 2.6L motor will only produce so much exhaust gas to spin up 720hp worth of turbos yeah?

In order to give it the best chance of spooling up as fast as it can you need to get the air into the turbos with the least amount of restriction possible, Get the exhaust gasses out the back of the turbos as fast as possible to create efficient turbos! Cam timing & cams will control how air and exhaust get in and out of the engine.

All these things are the basic fundamentals to making a turbocharger work efficiently. How the engine is tuned will change how and when torque is produced yes WHICH will change how the car drives (night and day as you put it) BUT it will not make a turbo spool up any faster!

[XGTRX]

It's funny how everyone refuses to change gears when over taking then all of a sudden says the set up is laggy. Driving my hsv 6.0l auto daily for 6 years, with all that bottom end torque it still geared down when overtaking or pulling out quickly from traffic.... go figure, maybe the computer and converter got it wrong for all that time. Based on everyone's theories it must of been laggier than an rb26 with -9s because apparently you guys never change gears to overtake. My experience driving mine daily is that it remains off boost for 90 percent of the time and when - need to cut in or overtake, I hold my revs up wait for the right time and rape the road, no lag, not waiting for anything to happen just instant torque and power as soon as I need it, and we are talking 3500rpm up not holding it at 4500 rpm as some of you suggest you need to do with -5s, that opinion is garbage and false. If the op want quicker spool up rates and lower rpm max boost, he needs the suggested breathing mods and tell his tuner to tune it for response/ cam gear settings etc, as already suggested. And yes it will be a totally different car. If he wants a demonstration I am more than happy to show him with my exhaust valve closed where the turbos take an eternity to spool and with it open where it ramps up aggressively from 3500rpm. A pure and honest comparison of the 2 extremes of a choked up exhaust system compared to a high flowing exhaust system that change the car characteristics immensely.

[mr skidz]

A tune will do miraculous things, if you dont understand what a tune is and whats involved, so be it, bury your head in the sand.

Advance the cam timing brings in the bottom end, retard it and induce top end, same turbos, its been like this since the 70's on push rod engines and probably decades before i was playing with engines back then.

Add timing, take out timing and fuel at certain points of the power curve, guess what?

Night and day.

Hell S2000 owners dont have a issue withg lag because they dont select a gear that allows revs to drop....just feel like banging my head into a wall how people cannot fathom some basics or knowing where the torque and power band is and making good use of it.

Hey with your thoughts on tuning doing nothing, can i ask you if you know what cam gears are used for?

Why timing is adjustable?

Why different injectors behave differently?

Why compression can effect lag?

Why air temperature effects tune?

With your method of reasoning one tune should do all.....-5, X injectors, Y base timing...hey presto a one fits all tune, just hand it out to everyone and charge $1000 regardless of the setup.

Till someone adds a more effiecient intercooler, temperature changes, fuel pump changes, fuel changes, compression changes, cams get changed, heads are ported, boost is changed and the list goes on.

If you had spent any time with a tuner willing to do a proper tune, the usual question is driving style and expectaion, power down low, up top, conservative, on edge, economical, powerful etc etc.....

Not tune it and call be when its ready.....

GTRPSI is smart please listen to him as i think this is a gee up it has to be...

i give up

[GTR_JOEY]

I'll end this..

Get a single conversion!!

I win I win

[mr skidz]

GTRPSI is smart please listen to him as i think this is a gee up it has to be...

i give up

had one but cops didn't appreciate it or the gate all that much . Edited February 22, 2015 by mr skidz

[r32-25t]

My god this has gone way off topic, if you need 3500 to spool a set of -5s compared to 2500 for the -9 than the -5s are obviously more laggy end of story

Now to answer the original question

To reduce lag the following things will do it and the amount of money it costs verys

Cam gears, exhaust sizing, compression ratio, increase capacity, removing inlet restrictions (if present) and fit smaller turbos.

That is how you reduce lag, which ones you chose to do is up to you

[Mick_o]

GTRPSI is smart please listen to him as i think this is a gee up it has to be...

i give up

I agree Haydin clearly a smart guy no doubt. Everyone has a difference in opinion thats all. If you have 5's on your car and love it then who cares what anyone else thinks yeah?

We all have our tastes on how we like our cars setup and we all have our driving styles. XGTRX loves his lag and believe it or not i can see why he likes it as going from nothing to getting a big kick in the ass is a big rush! But thats just not how i like my power. At the end of the Day we are just debating our opinions on things as we all like getting out points across & of course being blokes we don't like being wrong lol

[GTRPSI]

Peter WTF are you on about?

Where did i ever mention injector sizing or turbo size etc?

Where did i ever talk about MY methods of tuning?

Is the subject not about -5's on an RB26?

Why do you keep talking about S2000's?

The way i see it is without wondering off into compression ratios,timing and Hondas etc is that IN THIS CASE a 2.6L motor will only produce so much exhaust gas to spin up 720hp worth of turbos yeah?

In order to give it the best chance of spooling up as fast as it can you need to get the air into the turbos with the least amount of restriction possible, Get the exhaust gasses out the back of the turbos as fast as possible to create efficient turbos! Cam timing & cams will control how air and exhaust get in and out of the engine.

All these things are the basic fundamentals to making a turbocharger work efficiently. How the engine is tuned will change how and when torque is produced yes WHICH will change how the car drives (night and day as you put it) BUT it will not make a turbo spool up any faster!

Because the OP has owned and driven a S2000 and GTR, just like we also own one of each, a direct comparison so HE understands, S2000's are gutless till 6K then they come alive, you need to drive them differently to most other cars.

Tune not increasing turbo spool?

EGT's ring a bell?

You do tune to EGT's right?

Do you want me to go on? Its a long list which incudes maximizing power off boost to bring the turbos on earlier, yep more flow sooner is better, including off boost.

I also give up, seems like another thread of -7, -9 can produce the results rather than why -5's are not perfoming right.

I think the OP has more than enough to think about now.

Pretty much everything been covered from mechnical checking, blocked flow to tune, he has all the know how now to tackle the problem systematically......just find a good tuner who is prepared to spend the time.

If your in Sydney (you mentioned CRD), try CRD, try GEM, Sydney is full of good tuners, im sure many here would offer more good names.

Dont base your choise on price through.....

Yes we are debating what one man likes over another, a timeless argument, one thing we can all agree on is the OP should be getting on boost earlier.

[XGTRX]

Yeah but it shouldn't be a timeless argument because these unqualified opinions of -5s being lag monsters on the street and so unacceptable to drive daily is just garbage. Maybe I should post up a video on my daily driving for people to actually see the truth rather than listen to incorrect opinion.

[Hadouken]

-10's are lag monsters.

[Missileman]

Lag is only a state of mind ...if you have the right gear

[Mick_o]

My opinion is most certainly qualified ive driven the Garrett range of twins from 7's - 5's on different capacity engines too and for daily duties for me they are just too big.

[Country Cruzin]

R32-25t is right. Cam gears, compression ratio, changing the engine capacity or putting smaller turbos on is what will increase response. Of course a good tune is always necessary but won't make the turbos smaller, I have -5's on a 2.6. 4500-5 k is where they hit full boost. An on tight corners an tracks I wish I had smaller turbos sometimes, as some corners 2nd gear is too Laggy you can drop it back to first but ur got 6000rpm n close to 400kw on tap which isn't really what u want either. Fast corners or straight lines -5's are great.

[omnigear]

... look at the dyno post and you can see all the -5's with their setups and dyno chart. if yours look like a drunk crayola then you your tune might need some correcting.