Rb 25 Turbo Choices

[Joshbigt62r]

Hey stao what are you up to this Saturday would you be prepared to take me for a spin in your weapon? I'm from wangaratta but I'm possibly in Melbourne this weekend. Cheers josh

[hypergear]

You mean actual variable nozzle tech? If so, I love the innovation but there is no way I'd run or recommend one until they start showing any sign of realistic longevity - no doubt about performance gains, but even in OEM they just don't seem reliable.

Yes thought about that. I've altered few things.

and joshbigt message me on Saturday, i should be free to take you for a spin

[Joshbigt62r]

Can you pm me your mobile number stao if possible or just message you Saturday morning on SAU?

Cheers josh.

[hypergear]

Not sure if I can post personal phone No.s here. check my turbo thread or website for it. alternatively you can message me through the SAU message service.

[Adz2332]

Whats the go on the fp ones? ?

[Lithium]

What do you mean by that? Their performance? Where to get them? Or what they are?

The short of it is the HTA GT3076R is typically a Garrett turbo which has a modified Garrett compressor housing and FP designed compressor wheel as an upgraded equivalent. In a most cases the comp wheels are smaller (or at worst, the same size) as the equivalent Garrett GT, and flow around 15% more than the previous cast Garrett wheels. They've actually been around for quite a number of years and quite well proven, in circles where they have been used and distributed they are very well regarded - and imho make the GTX wheels Garrett released a bit redundant... especially seeing as the HTAs seem to perform at least as well given they seem to make similar power but the HTAs spool better than the GTs while the GTX were if anything a backwards step in response.

[joeyjoejoejuniorshabadoo]

Ever driven one Hamish? Put's a big smile on your face every time. lol

He sold it long ago...

have I driven what? a 3037 or a 350kw gtst?

3037, no

big power lag mosnter yes

no doubt oodles of power is awesome fun when it gets up an boogies, especially if it revs out to 11ty, but I still prefer response for most situations

[34GeeTeeTee]

have I driven what? a 3037 or a 350kw gtst?

3037, no

big power lag mosnter yes

no doubt oodles of power is awesome fun when it gets up an boogies, especially if it revs out to 11ty, but I still prefer response for most situations

Not really a lag monster.... YES you notice they are a big turbo but they spool fine and a super aggressive in the mid range I love it!

[joeyjoejoejuniorshabadoo]

really what we haven't addressed here is that lag, like art, is all in the eye of the beholder.

[scotty nm35]

I thought the general consensus was 200kw by 4k was a good result... That sized turbo should just squeeze in there.

[34GeeTeeTee]

really what we haven't addressed here is that lag, like art, is all in the eye of the beholder.

Its a lot to do with how you use the car too i guess! No good having full power at 3000rpm if its just going to be a tyre frying joke, but no good planting your foot and waiting to build boost........

Drag racing you can build boost on the line and launch, Circuit racing you have a lot of time WOT so lag isnt a major issue, i think the only real issue is street driving and the initial on/off response etc?

I'm pretty happy with the 3037, it could be slightly better for sure but its a good all round turbo for what i need...... for now anyway!

[Lithium]

really what we haven't addressed here is that lag, like art, is all in the eye of the beholder.

Absolutely, there is no right or wrong. Anyone that thinks a GT3076R (let alone something that potentially spools better) is a lag monster seriously needs to harden the f**k up though R33/R34 RB25s are one of the LEAST laggy turbocharged cars ever made due to seriously undersized turbochargers, some people upgrade them to slightly less undersized turbochargers and get a very nice performance boost. There are people who have "upgraded" to HKS GT2535 turbochargers, which is a turbo which flows similar to a stock EVO turbocharger - ie, putting a turbo similar to a turbo which goes on a stock 2litre turbocharged motor build for midrange onto a 2.5litre turbocharged motor which is inclined to deliver it's best in the higher rpm. I facepalm whenever I hear about people on a mission to fit GT28 based turbos on them - the cropped GT30s like your own I definitely find much more bareable to be fair, but then still only just tolerate the idea.

A full 56-trim cast GT3076R spools roughly the same as a late model twin scroll EVO TD05 does on a 2litre Mitsi. I know this, I've tested it with mates. While I can't say it's wrong to want silly response down low, I can I fart in the general direction of anyone who considers such a thing as a lag monster - sure, there IS lag... welcome to having a PROPER turbocharged performance car, not one destined for commuter peppiness and exponentially increasing intake/exhaust pressure ratios.

Oh yeah, in regards to what is more or less my "ideal" RB25 turbo:

http://store.forcedperformance.net/merchant2/merchant.mvc?Screen=PROD&Store_Code=FP&Product_Code=NTGT3076HTA&Category_Code=Turbo-FP

From memory the price is more or less comparable to a GTX3076R when you factor in the price of the turbine housings which come included with the HTA, but frequently additional cost with the GTX.

[joeyjoejoejuniorshabadoo]

agree re the evo...

I drive an e7 now and the lag on the stock turbo is basically the same as my 2835 was.

I'll be upgrading that to an 8mr turbo as soon as I find a second hand one as it's a street car and there is no point in massive top end as the funs are all down low for the street.

however I like that kind of response for things like mt buller rd etc where there are constant U turns and really tight twists.

the other thing I spose I should have mentioned in my choice and subsequent mindless repping of the 2835 is powerband.

If you dont want to raise the stock rev limit (i put mine to 7400 so barely raised at all) the 2835 gives the biggest powerband of the available options. It's on the sauce from 3200 and pushes through to right on 7000 and even then the drop is only slight. same with the torque figures. on e85 you can get a solid 3000 rpm of 500+ nm and the last 1000 is only a 50nm drop below this.

that's why it's my choice for an unopened RB25...

if we are cracking it open or are happy to raise the limit to 8000+ then I think the 3037 / 3076 really come into their own and are probably going to be the choice as the 2835 is goong to run out of puff

[discopotato03]

Hmm , well my R33 RB25 is still being fiddled with tune wise and I have mixed opinions of my GTRS . My feeling ATM is than tune is critical with how and when a turbocharger comes onto boost so having that out could create wrong impressions at times .

As to the RB25 well I think Nissan did a good job of making an engine that feels reasonably strong at part throttle and probably makes people think that will continue through the low to mid range . With a bit more throttle they do get going but like Lithium said not gorilla strong at that point .

Now I don't find my engine super torquey opened up in the low to mid 2000 range even with a GT28 based GTRS turbo . It will pull high gears uphill and down dale but sinking into the seat - not quite . Having said that a GTRS is a reasonable std replacement turbo for an RB25 but I wouldn't expect to go drag racing and win with one . I think somewhere in the RB25s make up they prefer to get cracking probably from 2800+ revs at wide open throttle and maybe a it more . Its possibly tune related but my engine gets serious from I think about 3500 upwards and you can forget traction in first and second when it does .

I re read this thread and I looked closer at Joeys results with his HKS GT2835 and the graphs do make it look for a great all rounder s in get you 300 at the wheels and not take all day to wind up . I think I can understand what he ment by "aggressive" - feels like it has a bit more urgency in its power deliverly and thats probably what HKS were shooting for in "power with response" .

I would like to know which sized turbine housing he has because they were made in 0.68 and 0.87 AR ratios . Its a shame they are no longer made because they sound like a good if expensive unit .

The FP HTAs do sound good and results from the 73 and 76 versions would be good to see .

So you have an Evo 7 Joey , I have a basically std 6 engine wise and while its ok it could always have more and a bit more than std boost . I bought a rebuilt second series Evo 9 RS turbo for mine but its not fitted yet , fingers crossed the later style single flap turbine housing and lightweight wheels will punch up the mid range together with a boost increase . The larger diffuser 9 type compressor housing is supposed to be worth having but it only fits the 9 sized center section/bearing housing . You could speak to Mark at GT Pumps because he knows Evo turbos inside out and has a tie up with FP as well .

Evo 10s have the advantage of a more modern engine design than a 4G63 and variable timing on both cams . With the extra weight they need it .

Tuners say that the Evo 9 MiVec head makes a big difference with the low to mid range power on a 63 and makes them feel a bit like a stroked non MiVec engine . If I could find the Mivec bits and the means to control it I'd do that on a 7 or 8 .

We are lucky that all turbo RB25s had variable inlet cam timing and its probably this that makes them feel good at light loads and part throttle .

A .

Edited May 16, 2013 by discopotato03

[34GeeTeeTee]

that's why it's my choice for an unopened RB25...

if we are cracking it open or are happy to raise the limit to 8000+ then I think the 3037 / 3076 really come into their own and are probably going to be the choice as the 2835 is goong to run out of puff

[Adz2332]

does anyone here run the fp HTA GT3076R?

[Lithium]

he other thing I spose I should have mentioned in my choice and subsequent mindless repping of the 2835 is powerband.

If you dont want to raise the stock rev limit (i put mine to 7400 so barely raised at all) the 2835 gives the biggest powerband of the available options

that's why it's my choice for an unopened RB25...

Yeah fair enough, a GT2835 for an unopened RB25 does seem like a sensible proposition - it was a serious consideration for me when I did my extensive researching and pondering. At the time I got my GT3076R I had been concerned about response, engine stretch etc etc and it was not initially my top choice. I decided in the end that I was probably going to strengthen the internals later down the line so I don't want to have to redo the whole turbo purchase thing etc, and the lag difference between the GT2835/GT3071R (probably would have been the 3071R tbf) and the GT3076R seemed existent but negligable in the grand scheme so I went with the .63 GT3076R.

When I first drove it my expectations in regards to response were exceeded quite substantially - it built boost quite effortlessly, I was well impressed. I would have been totally rapt with it, except I ended up with boost control issues and also early indications that exhaust pressure was going to start soaring as I started leaning on it. I ended up making reasonable changes and went with the .82a/r as part of it (given how much work was needed to fix boost creep) which I had previously steered clear of because I was worried it was going to be a lag monster. First time I drove it, truth be told I was a bit worried at the noticeable amount more doughiness under 3000rpm - but the way it came alive after 3000rpm started feeling much like the .63, if not identical from 3500rpm. After that point came years of happy motoring and not looking back, and strangely enough I never ended up building the motor.

So yeah, it was my choice for future proofing - the GT2835 could easily have been "it" if I didn't think I might want more in future and end up building a new motor. They sound like an awesome unit, though in all fairness I don't think that'd be an option for me now - even for that application, some awesome stuff has come out. I'd probably use a GTX3067R in it's place, or really ... imagine a GTX 67mm compressor frankensteined onto your turbo?

if we are cracking it open or are happy to raise the limit to 8000+ then I think the 3037 / 3076 really come into their own and are probably going to be the choice as the 2835 is goong to run out of puff

Funnily enough my motor was unopened and I had a 7200rpm re limit and never had any issues keeping it on boil - though you are right in the fact I was definitely wasting potential flow, while with the GT2835 I'd have probably fully utilized it's limits with a bit better response.... how much better I'd actually LOVE to have been able to find out. I was never left needing more, so was content with it and again I had the option of going cams, more boost etc etc and not choking it.

[joeyjoejoejuniorshabadoo]

I re read this thread and I looked closer at Joeys results with his HKS GT2835 and the graphs do make it look for a great all rounder s in get you 300 at the wheels and not take all day to wind up . I think I can understand what he ment by "aggressive" - feels like it has a bit more urgency in its power deliverly and thats probably what HKS were shooting for in "power with response" .

I would like to know which sized turbine housing he has because they were made in 0.68 and 0.87 AR ratios . Its a shame they are no longer made because they sound like a good if expensive unit .

The FP HTAs do sound good and results from the 73 and 76 versions would be good to see .

A .

I had the .68 (it's the standard that HKS recommend and the only option with the full bolt on kit, the .87 was available as turbo only)

It's very similar to the GTRS in power delivery, but has a lot more up top.

I was also running a greddy RB26 ex cam gear and max gain through a Blitz DSBC spec S to bring it to life as soon as possible

So you have an Evo 7 Joey , I have a basically std 6 engine wise and while its ok it could always have more and a bit more than std boost . I bought a rebuilt second series Evo 9 RS turbo for mine but its not fitted yet , fingers crossed the later style single flap turbine housing and lightweight wheels will punch up the mid range together with a boost increase . The larger diffuser 9 type compressor housing is supposed to be worth having but it only fits the 9 sized center section/bearing housing . You could speak to Mark at GT Pumps because he knows Evo turbos inside out and has a tie up with FP as well .

Evo 10s have the advantage of a more modern engine design than a 4G63 and variable timing on both cams . With the extra weight they need it .

Tuners say that the Evo 9 MiVec head makes a big difference with the low to mid range power on a 63 and makes them feel a bit like a stroked non MiVec engine . If I could find the Mivec bits and the means to control it I'd do that on a 7 or 8 .

We are lucky that all turbo RB25s had variable inlet cam timing and its probably this that makes them feel good at light loads and part throttle .

A .

I would DEFINITELY go this route with the evo if I had the cash... but then I would have a 9 anyway

this evo is not going to have $$$ spent on it. bought it stock with HKS single plate, rims, catback and a boost gauge

all i'm doing is dump/front, LICP, 8MR bov, 8MR turbo and 3 port solenoid. all second hand

should see me through to 230ish awkw for just on a grand + tuning

[joeyjoejoejuniorshabadoo]

Yeah fair enough, a GT2835 for an unopened RB25 does seem like a sensible proposition - it was a serious consideration for me when I did my extensive researching and pondering. At the time I got my GT3076R I had been concerned about response, engine stretch etc etc and it was not initially my top choice. I decided in the end that I was probably going to strengthen the internals later down the line so I don't want to have to redo the whole turbo purchase thing etc, and the lag difference between the GT2835/GT3071R (probably would have been the 3071R tbf) and the GT3076R seemed existent but negligable in the grand scheme so I went with the .63 GT3076R.

When I first drove it my expectations in regards to response were exceeded quite substantially - it built boost quite effortlessly, I was well impressed. I would have been totally rapt with it, except I ended up with boost control issues and also early indications that exhaust pressure was going to start soaring as I started leaning on it. I ended up making reasonable changes and went with the .82a/r as part of it (given how much work was needed to fix boost creep) which I had previously steered clear of because I was worried it was going to be a lag monster. First time I drove it, truth be told I was a bit worried at the noticeable amount more doughiness under 3000rpm - but the way it came alive after 3000rpm started feeling much like the .63, if not identical from 3500rpm. After that point came years of happy motoring and not looking back, and strangely enough I never ended up building the motor.

So yeah, it was my choice for future proofing - the GT2835 could easily have been "it" if I didn't think I might want more in future and end up building a new motor. They sound like an awesome unit, though in all fairness I don't think that'd be an option for me now - even for that application, some awesome stuff has come out. I'd probably use a GTX3067R in it's place, or really ... imagine a GTX 67mm compressor frankensteined onto your turbo?

Funnily enough my motor was unopened and I had a 7200rpm re limit and never had any issues keeping it on boil - though you are right in the fact I was definitely wasting potential flow, while with the GT2835 I'd have probably fully utilized it's limits with a bit better response.... how much better I'd actually LOVE to have been able to find out. I was never left needing more, so was content with it and again I had the option of going cams, more boost etc etc and not choking it.

what I really want is a 3076 with the 1.06 on a 25/30

but $$$ and no skyline anymore

[Adz2332]

so the FP HTA GT3076R seems to look reali good! flow better and more power then the 3076R and with the same response?