R34 Gtr Garrett -5 Turbo Lag, Need Advise

[Missileman]

dyno is just a tuning tool. your lap time or ET/mph is where its at

[mr skidz]

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.

can you show me your logged afr numbers on your dyno sheet please then id like to see how your ign values look at the point of on boost.

all camshaft specs?

gears?

exhaust dia?

which injectors?

fuel?

plug type gap?

coilpacks?

is engine warn out most people wouldn't know!

easy to blame a turbo.

there are many factors.

[mr skidz]

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.

can you show me your logged afr numbers on your dyno sheet please then id like to see how your ign values look at the point of on boost.

all camshaft specs?

gears?

exhaust dia?

which injectors?

fuel?

plug type gap?

coilpacks?

is engine warn out most people wouldn't know!

easy to blame a turbo.

there are many factors.

[Hadouken]

Wow. I think this thread is taking a turn for the worst.

[mr skidz]

in what way

[Mick_o]

In the fact that you cant take a blokes word who owns and tracks the setup in question for them being a bit big for a 2.6L. Then wanting to try pulling apart his setup to try justifying his response that's how I'm sorry but the choon ain't gunna make the improvements in boost response like the breathing mods will!

[Hadouken]

Just drop a 3l in it

[Piggaz]

Just drop a 3l in it

Uh oh. Now you've done it. .

[mr skidz]

y not just trying to help him..and im sure others with more responsive -5 set ups will chime in with advice also what's wrong with that we're just here to share ideas and help each other out there are some very knowledgeable people on this forum in different areas for different reasons can't hurt

Edited February 22, 2015 by mr skidz

[Mick_o]

I don't think he asked for help though? He was sharing his -5 RB26 experience with you

[mr skidz]

i don't care if he asked for it im offering it..

[Borci88]

I don't understand what there is to argue about though? -7s and -9s spool up a lot earlier than -5s, that's a fact. Therefore -5s ARE LAGGIER. You're interpretation of "How much lag is too much lag", might vary greatly to someone elses in this thread. At the end of the day some people say -5s are amazing, but I'd say an equal amount say "-5s are too laggy for me". Most of the time because these people only drive theirs on weekends down to the shops.

While you are right that a tune can make a massive difference in response (in comparison to a SHIT tune). The size of the turbos still stop it from ever coming near the smaller turbos response time. I have driven, and continue to drive multiple different GTRs on a weekly basis, I will never recommend -5s to a customer with a STOCK motor. While they are more exciting on boost than the smaller turbos, you're not driving above 4500rpm for 99% of your driving.
I also don't want to have to blast the ears of people I overtake because I needed a louder exhaust to make close to 400kw for the street.

[XKLABA]

Oh the lols

People keep mentioning only driving to the shops on weekends and the -5s being to lagy only for them, that is where matters least, it's on the track that laggier turbos show the weakness

While you can drive it above a set rpm to keep it "on boost" that is only half the story, ever wonder why there are GTRs out there that run 13 second quarters at 140mph, it's because there is also lag between gears and/or if you have to pedal it then there is lag waiting for it to boost up again, this is also true for circuit for ever gear change and when come out of a corner and the back end tries to overtake the front and you have to get off the gas

Most people won't know enough or have enough experience to feel this

[XKLABA]

Also it has been mentioned about advancing or retarding the cams, this is where twin cams come into their own

What happens if you advance one and retard the other and vise versa

Please note there is no question mark as I'm not asking, I already know the answer

It was also mentioned tuning with EGTs, this is only truely beneficial for tuning if done with individual EGTs, one for each port

This I have never seen done on a true street GTR with factory mount turbos

I also think what Mick-O was saying is if you are taking the car to a half decant tuner and not trying to tune it yourself ( this applies to the average Joe and not people actually capable of tuning ) then taking it to a different tuner isn't going to make a world of difference to turbo lag where mechanical changes can, this also doesn't apply to power at given RPM range but where in the RPM range the turbos hit full boost

[XGTRX]

With all that lag, high revving, obnoxious driving with -5s..... mmmmm, we love going to the shops

[Mick_o]

^^^ Hahaha this guy!

[XKLABA]

Atleast your 2.6 sounds good while being a shopping trolly

[Mick_o]

Read my mind Micky haha!

[XGTRX]

A boosted shopping trolley... Get it right will u

[XKLABA]

Gotta beat dem tree hugging hippies in their hybrids