i have one of these on my new car, its the first one ive ever had.
ive been having a read about how they work.
driving hard through the gears am i right in thinking the ported shroud housing will impact boost build after shifting and when coming on boost aswell ?
it feels alot softer coming on boost to me, feels like a lul after shifting before pulling hard again, it definately doesnt have the instant response the supra had after a shift and i want it back lol.

 

I was after a ported shroud on my new turbo, I ended up gettin a brand new garret turbo from someone who never used it but it had no anti surge ported shroud and when I spoke the CRTurbo's they said its better without as it will be slightly more responsive than if it was ported

 

thats what i was thinking, if theres a small open port leading back into the filter side it must impact response after a gear change, i need to find out how much now i could gain and if it will work ok and possibly get a non ported shroud if there available for a gt4094r.

 

Doubtful that's your problem. What boost control setup are you using ?

Of course the other thing is, there is no point running a ported shroud unless you were actually experiencing ( or expecting ) compressor surge in the first place.

 

its got greddy profec boost controller.

ive spoken to owen developments today and the gt4094r only comes with ported compreesor housing they say the wheel is so efficient it will surge without. im also on the smallest available turbine housing 0.85 a/r, it just seems lacking abit of response after a gear change. i guess it could be external wastegate not seating properly il stick my borescope up the screamer pipe tommorrow and check it.

 

My GTX3076R has a ported compressor housing and after some research found out that the GTX range only come with a ported housing there was no option for it without.
Rich

 

i did enquire about about that turbo today and owen developments said only ported shroud on gtx turbos, the bigest they do with no ported shroud is a gt35.

 

What way is the w/g plumbed up ? And what are the gain settings, set duty etc set up like ?

All of those can impact spool.

If you have a screamer pipe and the w/g wasnt sealing properly, you'd hear it during normal driving or at idle as it would be leaking then too.

Dump valves are another aspect. I did hear somewhere that you want to retain some boost in the plumbing during lift off, so a fast responding and high flowing dump valve isnt what you want.
I'd find that hard to believe though. I'd think a fast acting and high flow valve would be what you want, to vent the air as fast as possible so the un-driven compressor doesnt have to work against it.

So no idea what's best there.

 

I think the GTX3076R is awesome makes 5psi at 2600rpm on my engine very responsive.
Rich

 

my gt40 is the same makes a little boost below 3000 rpm, its when i come on proper boost it comes in soft, i want it to come in harder and faster like the supra did. i have the instructions for the boost controller il have a read of that aswell and see what i can try.

 

Mine goes from 0.4 Bar to 2.4 Bar in a 1250rpm bracket
Rich

 

Dont forget too...the Supra is 3.0 and the Nissan 2.6

Those extra 400cc will make a big difference to spool with any turbo.

 

its potentially worse than mate really i supose, the gtr is said to have 2700cc and uprated cams unknown and ports unknown, the supra had 3400cc, 272 cams and a big port head.

im not unhappy with it i just miss the instant boost reponse the 2jz had.

 

I guess without some definitive info, or something similar to compare to it's hard to say if there is a problem, or if that's just the way it is.

Can you datalog the setup to actually show how long it is taking between gears to reach full boost again ?

 

i cant all i have is the performance box speed, time curve showing the dip of shifting. i may just be the way it is and ive gotta get used to it i dont know the car is new to me.

 

2.4 bar thats what i need instead of my pathetic 1.3 - 1.5 ish bar i seem to be holding lol

 

Check out the boost control setup.

Or maybe a smaller more responsive turbo might be a better option. yes you'll maybe run more boost to make the same power, but it will be over a wider range and probably feel much better.
Surely a 4094 is just a big turbo for what you currently have ? A smaller unit would be better

 

thats my exact thoughts its a big turbo for the power its running but then again its been super reliable the previous owner has done 18000 miles in it engine and gearbox/diffs are completely untouched in that time ! all its had is new clutch clutch plates, lots of services, converted from t88 to gt4094r approx 4k miles ago as turbo failed and was stupid laggy, huge rad and low temp stat as track days was getting quite warm, thats it and hes done quite a few track days, been to nurburg etc !
i dont wanna give it any reason to get upset so to speak touch wood its super reliable i just want abit quicker response, i guess i gotta see how much better it will be with a lightning shift first, and make sure my wastegate and boost controller are working perfectly.

 

T88 to GT4094....

From super laggy, to just very laggy lol

Something like this would spool well and make very good power, and wont cost the earth. A friend has a 6266 on a smaller engine and it's superb.

http://www.precisionturbo.net/Street...-CEA%C2%AE/494

 

it made it respond 1000 rpm sooner on abbeys dynapack, i have an overlay from abbey.
its not massively laggy tbf its got a big useable range :




its just after shifting it seems abit delayed to what im used to.
i am going to have to monitor exactly where its makeing full boost in the real world on a 3rd gear pull and check my boost controller is seeing correct pressure aswell by my gauge.

 

As Stevie suggested,

realtime data from sensors is essential,
MAF, Inlet temp sensor, could cause lack of bollocks on/off boost gearchange scenarios

surely a man of your calibre, Mr.Slayer, could retreive some data

 

Its funny i was just reading on another forum of a guy with a Supra saying the Nissan GTRs bog down on the line and his Supra does not,

A different boost controller cam make quite a difference, some of the best ones have anti- lag programs built in, and are fast with a quick response (run at a high frequency) the Profec is an old design

Even the pick-up ponts for the controller sensor can make a difference

Im just thinking out loud but a shorter, fatter single pipe exhaust - perhaps a side exit, and a heat-wrapped exhaust manifold may help (if its not already)

I run an anti lag system that shuts the wastegate virtually the moment i lift off so the wastegate is (always) shut automatically when i go back on the throttle, it only makes a slight difference but it all adds up- and if you are drag racing even a tiny advantage may mean the difference of winning

A smaller (internal volume) intercooler (with waterspray to compensate), shorter boost hoses or an water/ air chargecooler (with ice tank for your races) - im sure you have though of these already!

Ithinkthere are a lot of people that wish they had your problems!

 

A Nissan with a bad driver is more likely to bog down as it's 4wd, plain and simple.

With correct driver or setup, it will not bog down. It will just launch hard.

 

stevie, ive just been looking at the gt4088r its outline interchangeable with the gt4094r and rated to 675 hp instead of the 800hp of the gt4094r.
so would bolt straight on im gonna have a look into how much more responsive they are, or get the 4094r up to 2 bar if possible and see how it goes ....

 

A friend has a GT4094 sitting and un-used. In Comparison to the Precision unit, the Garret's turbine looks huge and bulky and carrying a lot of weight.
I think the modern Garrett billet units also have improved turbine wheels compared to the old stuff, although the only ones Ive seen so far are smaller direct replacement type units, so cant compare to the generic stuff.

So not honestly sure switching to another old design Garrett would be the best option.

The Precision unit could be bought for less than £1500 new. Not sure how that would compare to a new billet Garrett of similar performance. They also do Garrett replacements that should be almost a drop in unit

If the rest of your car will support 2 bar, then go for it. It still wont address boost lag between gears though.
Cheapest and easiest thing is to ensure boost control is optimised as much as possible first.

 

well i got the car back on the ramp today.
the wastegate is sealing perfect.
the turbo was leaking slightly where it bolts to the manifold, and the manifold is still blowing on number 6, so i ve got it off again tonight.
im gonna try get someone to square it off on a bench sander tommorrow.

 

none sealing manifold issue, why not thrash it a little, get it hot and see if it'll tighten down with the heat allowing it to flex more.