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R34 Gtr Garrett -5 Turbo Lag, Need Advise


baicai

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as a comparison;

prev setup 3850rpm 135kw

current setup 3850rpm 80kw

racepace comparison 3850rpm 180kw

but you can't compare std displacement vs "built motor" it could have anything in there

but there is merit in picking the right turbocharger combination as shown on the dyno plots

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Now before you guys say I should have got the -7 or -9 turbos, my goal eventually is to get above 350kw on 98 or 400kw on e85.

So my question is can someone tell me how to lower the lag down to 4500 rpm or even 4000 rpm if possible. Tuner says intake hard piping, bigger inter-cooler, exhaust shops says twin 3 inch into 4 inch exhaust, internet says cams, don't know what to do. Just want to lower the lag before I chase for more top end power, any advise or help from you guys would be much appreciated.

My set up is

Standard: motor, inter-cooler, injectors, dumps, cams, pumps etc

- Good for 300+ kW's at the rear wheels.

- 350kW's to 400kW's you will need to upgrade Injectors / Dumps / Pumps / Re-Dial Cams. Stock Intercooler should be fine until the 400kW mark.

- Also depends on the health of your engine if it can handle the 350-400kW mark.

Mods:

Apexi pods - Good, well stock Air Box can handle 300kW's at the rears (R32 GTR) and from memory the R33 and R34 GTR can handle 350kW's at the rears if not more.

dual 2.5 inch to 3 inch nismo exhaust - Go a full 3.5" for 350kW's at the rears and 4" for 400kW's at the rears.

Tomei cam gears - Good!

Splitfire coil packs - Good!

Greddy ebc - Good or does the job

Haltech platinum pro ecu - Good!

Alloy radiator - Good!

-5s are very laggy turbos for RB26. and in lot of cases, the standard "T1.5" turbine manifold gets bored out, which adds more lag. if you are using adjustable cam gears, dial +5 on the inlet and leave 0 on exhaust. That will advance response by roughly 300RPM. Or get HKS V cams with active VCT cam set, that knocks out about 700RPM of lag.

Alternatively get -9s or check out our latest single development on our thread.

^^ This.

You can Re-dial Cams / Crank Angle Sensor / e85 and a Re-Tune but the is not much more unless you go HKS V-Cam on a 2.6lt or go 2.8lt. or 2.8 V-Cam / Rebuild.

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^^ This.

You can Re-dial Cams / Crank Angle Sensor / e85 and a Re-Tune but the is not much more unless you go HKS V-Cam on a 2.6lt or go 2.8lt. or 2.8 V-Cam / Rebuild.

Cheers for the comments, yeah looking for a 4 inch exhaust now to future proof.

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Interesting views about -5s being lag monsters.... I never really notice because I am always in the right gear and never go WOT when I am at 2500 rpm. Depends on the style of driving. I keep mine at 3500+ when I drive daily. Suppose it's my style of driving that makes my -5 setup very responsive. As mentioned previous if I am on part throttle at about 3500rpm and give it a boot, I feel minimal lag as it's at least 50% boost and ramps up so quickly I don't even notice it. If you expect -5s to come on hard at less than 3000rpm, well they won't, so to match your driving style you need smaller turbos. If you drive similar to me then -5s definitely are not laggy.

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Interesting views about -5s being lag monsters.... I never really notice because I am always in the right gear and never go WOT when I am at 2500 rpm. Depends on the style of driving. I keep mine at 3500+ when I drive daily. Suppose it's my style of driving that makes my -5 setup very responsive. As mentioned previous if I am on part throttle at about 3500rpm and give it a boot, I feel minimal lag as it's at least 50% boost and ramps up so quickly I don't even notice it. If you expect -5s to come on hard at less than 3000rpm, well they won't, so to match your driving style you need smaller turbos. If you drive similar to me then -5s definitely are not laggy.

Lol. It only "feels" more responsive because you are always high in the rpm.

Op should've taken the time and read the 30 40 pages on comparing -7 -9 -5 turbos.

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So what's ur point?

My point is that I have no lag problems because it suits my driving style OR I have adapted my driving style to suit the car. Either/or it doesn't matter. Perfect set up in my eyes.

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Interesting views about -5s being lag monsters.... I never really notice because I am always in the right gear and never go WOT when I am at 2500 rpm. Depends on the style of driving. I keep mine at 3500+ when I drive daily. Suppose it's my style of driving that makes my -5 setup very responsive. As mentioned previous if I am on part throttle at about 3500rpm and give it a boot, I feel minimal lag as it's at least 50% boost and ramps up so quickly I don't even notice it. If you expect -5s to come on hard at less than 3000rpm, well they won't, so to match your driving style you need smaller turbos. If you drive similar to me then -5s definitely are not laggy.

Ive been quitely haveing a chuckle at this thread, and this is the first real post thats nailed it.

If you want linear power with no lag, some people should realize they need to fit smaller turbos and get rid of the high power dreams or just go and buy a NA.

How would most here survive driving a S2000, the cars dont produce anything under 6500, yet they are blindingly quick when driven as they are designed to be.

If you think -5 are too big and you want more power, shift down a gear to get them into their RPM range or fit small turbos, it shouldnt take pages to relize its in the driving style or turbo choice.

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Hmmm. And I can change my driving style to suit a car that has a t88 on it as well

Yes but you may find its a little too much power on tap.

-5 wont present this, unless your in the wet on Kmart china special tyres and have absolutely no driving ability and throttle control in your right foot.

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