Gt-rs Vs Gcg High-flow Vs Hks Gt2835 Pro S Vs Gt3071r

[paulr33]

i think disco posted it somewhere else, not sure what thread

the gt-rs is aimed at the 2 litre and the 28xx series is for the 2.5

so this would yield the 2835pros as the most suitable

[Birnie]

i think disco posted it somewhere else, not sure what thread

the gt-rs is aimed at the 2 litre and the 28xx series is for the 2.5

so this would yield the 2835pros as the most suitable

I remember the 2530 being aimed at the 2litre and the 2535 for the 2.5litre...

But the GT-RS is better than both so i'd think it'd be great on the 2.5 ???

[paulr33]

i think everyone saw thizzle's figure and went yeah ill make 300rwkw no problems

then there was the onslaught of the gt-rs for rb25 uptake

and everyone has fallen short

i think the typical max from the gt-rs is spot on 250rwkw, i haven't seen many go over?

i thnk the 28 series is more likely to go into 270-280rwkw

[Birnie]

had a real quick flick thru the past dyno figures.

I saw 2 at 255rwkws on about 1 -> 1.1bar but they can take heaps more than that.

Don't know why they don't push em harder ??

[paulr33]

depends on the wheel and trim - might not be efficient past 1 bar

[zafeniak]

had a real quick flick thru the past dyno figures.

I saw 2 at 255rwkws on about 1 -> 1.1bar but they can take heaps more than that.

Don't know why they don't push em harder ??

GT-RS:

There were 3 figures greater than or equal to 250 rwkw (excluding that insane figure of 301 rwkw)

250 rwkw @ 16.5 PSI

255 rwkw @ 14.3 (1 bar) I think he had after market cams, not sure?

255 rwkw @ 16 PSI

I think a couple of more pounds of boost ie. 17 - 18 PSI and the GT-RS will max out on its efficiency range (ie. marginal cost will exceed the marginal benefit)

IMO, I think anything above 17 PSI wont be to good for the rods etc.

People always look at the best figures the GT-RS pulls out in the dyno threads (natural bias), what about those 2 people running the GT-RS running 15 PSI and only managed to get 229 RWKW, makes one seriously consider the high-flow option from GCG......

[Bumblebee]

tune kills rods... not boost. i ran 20psi on stock sr20det everyday for 2 years and it made 211rwkw with a highflowed T3 item.

car was smashed and engine sold.. it was later stripped down by my mate who bought it and it was still in perfect condition.

Its the tune that kills the rods. Abnormally high combustion pressures and temperatures that kills motors. Detonation. Not boost.

My own stock gtr ran 17psi, till the one of the turbos exploded... nothing worng with the rods.

Id go 2835. HKS turbos love boost since always. they get into theyre stride @ around 18-20psi and when ur sittin @ around 22-25/26 theyre gonna be singing.. just make sure u have a headgasket that'll support the extra boost

[zafeniak]

tune kills rods... not boost. i ran 20psi on stock sr20det everyday for 2 years and it made 211rwkw with a highflowed T3 item.

car was smashed and engine sold.. it was later stripped down by my mate who bought it and it was still in perfect condition.

Its the tune that kills the rods. Abnormally high combustion pressures and temperatures that kills motors. Detonation. Not boost.

My own stock gtr ran 17psi, till the one of the turbos exploded... nothing worng with the rods.

Id go 2835. HKS turbos love boost since always. they get into theyre stride @ around 18-20psi and when ur sittin @ around 22-25/26 theyre gonna be singing.. just make sure u have a headgasket that'll support the extra boost

So basically, your telling me, with correct setup ie. making sure AFRs are correct, bigger injectors, fuel pump, exhaust, cooler etc etc etc. AND a very good tune, that boost wont effect the engine?

This is how I interperet what you are saying:

Car A with the correct setup and a good tune running 20 PSI, compared to car B that also has the correct supporting mods however running only 15 PSI, will last as long and be just as reliable as car B. That doesn't seem right to me.

Moreover, you stated that "Abnormally high combustion pressures and temperatures that kills motors". Now, what do you think happens when you increase your boost?

I'll tell you what happens:

1) Turbo spins faster since it needs to create more pressure (eg, winding up boost from 15 to 20 PSI), and due to the faster spinning motion, it creates heat, which is transfered to the intake mainfold. Hence, engine temps will increase.

2) Since the turbo is creating more pressure and is directing that pressure to the engine, there will be higher combustion pressure.

Thus, your statement is contradictory. "Abnormally high combustion pressures and temperatures that kills motors... Not boost. "

Increasing boost CAUSES these things to happen, no matter HOW good your tune is.

Furthermore, when I wind up the boost, I noticed an increase in water temps on the Power FC.

So, in conclusion, yes, boost DOES and CAN kill your engine.

[zafeniak]

Not only that, but there in only so much pressure the engine and cooler piping can take before there is a large amount of back pressure created to the turbo.

Simple phyics, have you ever noticed the fan in your bathroom spins faster with the door or window open?

Same principle with the turbo, maybe 20PSI will place unnecessary back pressure on your turbo and will force it to work harder ie. you'd be damaging your turbo.

Anyway, IMO, the standard internals were not build to handle that much pressure, I think 16-17 PSI is the absolute maximum people should be running with their after market turbines with standard internals.

Cheers

[Birnie]

I can see where you're coming from....but.....more boost means more power.

It's the pwoer that is produced that kills the rods.

If you theoretically could produce 30psi and make 150rwkws, your engine would be fine (excluding gaskets)

But if you had 10psi making 350rwkws, then your engine would be screwed...understand ?

[PM-R33]

My GTRS gets tuned next saturday with the microtech finally in and running. I have faith with my tuner and told him to keep winding boost into her until she gets out of the GTRS's efficiency rating. So if he says its fine on 20psi, im cool with keeping it on 20psi as long as the tune is good and doesnt knock. As i said earlier, its not a SR20 where you have to worry about valve float or rocker arms smashing off. The rb25 head (as far as im aware) in standard form is fine to take the pressure. Obviously the head gasket will suffer the most but i still believe it should be fine. Aslong as engine temps, no knock, and not driving the car like a maniac bouncing off limiter, i think it should be fine on those boost pressures.

Ill let you know how the tune went next week.

Edited February 10, 2008 by PM-R33

[zafeniak]

I can see where you're coming from....but.....more boost means more power.

It's the pwoer that is produced that kills the rods.

If you theoretically could produce 30psi and make 150rwkws, your engine would be fine (excluding gaskets)

But if you had 10psi making 350rwkws, then your engine would be screwed...understand ?

Yes, but remember, increase in engine temperature, increase in combustion pressure, increase in power etc etc are symptoms.... Symptoms of what you ask? The casue, BOOST

[GeeTR]

Dood,

Bumblebee stated things pretty much correctly. His mention of "abnormally high combustion pressure" wasn't in reference to the gradual, linear like rise from a simple boost increase. I read it to mean, the combustion chamber/cylinder pressure spikes from detonation, or knock. Your doing well at 50 posts telling ppl, that 1bar is about the limit for a stock RB25. A simple search of the thread compiled just for ppl like you, would show you that MANY have have run more then this for many a year - reliably.

Boost doesn't kill an engine (comparatively) you think 5psi makes a difference, when the area it takes up is then reduced 9 fold when the piston rises and then lit?

In your example A and B - if both cars never det, i would say both cars would show almost exact levels of wear. In fact, whos to the the car with more boost, has less wear, as it gets up to cruising speed and low revs @ 5th gear quicker?

Forced induction combustion motors dont have a linear rate of combustion pressure to rod load, because the charge isnt burnt in a linear, even fashion. More boost and fuel ends up increasing the burn time if you will, right where the rod goes 90degress and leverage is at its best.

Anyway det changes everything, the car with more boost could very well suffer more damage.

Set it up smart, tune it right, manage chamber conditions and you can push a stock combustion motor very far (sound like a broken record i know)

Edit:

Yes, but remember, increase in engine temperature, increase in combustion pressure, increase in power etc etc are symptoms.... Symptoms of what you ask? The casue, BOOST

Dood, stop rambling and listen

Edited February 10, 2008 by GeeTR

[paulr33]

more boost only means more power whilst the compressor is in its effiency zone or island on the compressor map

once you go past that island zone you get mininmal gains per PSI increase

the lower the boost the better

if you can make 250rwkw on 8psi or 250rwkw on 16psi i know which i would prefer

but that doent mean to fit a GT40 so you can run 8psi and make that power

so its a balance of power and resposne - but lower boost is better

less heat, less stress, less expensive components etc

[paulr33]

we can see here where hks place the turbochargers on the map of power vs repsonse

its obvious the 28xx series makes more power, but has a little less response

this is from the 2006 HKS catalogue

[discopotato03]

Getting warm in here again isn't it ?

When some of you people talk about 25 series as in eg 2530 it really means 28 series in current terminology , so to keep things consistent 2530's or 2535's are really GT28 series and technically a 2530 is a GT2860 - its just HKS's dated numbering system .

I call a GT-RS a GT2871R 52T because that's what it is .

Ditto for HKS GT2835 because technically they are a GT3071R 56T in cropped turbine form .

Using the current Garrett terminology means its easier to compare turbos because their formula tells you the turbine family ie GT30 followed by the compressors major or outside diameter in mm . If you apply this then you can see that a "GT2871R 56T" and a "GT3071R 56T" use the same identical compressor wheel .

The turbine side is quite different the GT28 series turbo having a 53.8mm 9 blade 76 trim wheel and the GT3071R in cropped form has a GT30 10 bladed wheel at ~ 56.6mm and 84 trim . The HKS GT2871R 56T uses a custom GT28 turbine housing with the T3 flange cast into it and in 0.64 A/R . The HKS GT3071R Pro S uses a custom GT30 turbine housing in 0.68 or 0.87 A/R ratio , it also needs their unique dump pipe to suit their custom housing .

If you were to look at both kits side by side you can plainly see that the 30 series kit is more involved with its turbine housing and dump pipe . The 28 series one can use the std dump pipe so more OEM like .

Better ? There are degrees of better .

Ask yourself if you're buying the lower price or the better result , I think its impossible to argue that the slightly larger turbine version is the lesser of the two on anything except price . The Pro S housing is going to offer greater flow capacity than any GT28 0.64 housing and particularly in 0.87 A/R . The limiting factor of both turbo types is the exhaust side so if you opt for the smallest going its more rats jammed in the pipe sooner .

People are again starting to claim more power from higher boost where more power from more air is the guts of it I think .

I also think that GT25/GT28 series turbos are a little dinky on an RB25 unless a mild upgrade is all you want . To go to 250-260 Kw and beyond means the engine needs a less restrictive hot side to do it without unhealthy temperatures and pressures trying to fry your exhaust valves and pistons . That's not to say it can't be done with a 25/28 series dryer but its pushing too hard for my liking .

I don't like to quote numbers but if pushed this is what I think the turbos potential reliable outputs would be

2530 - ~ 220+

2871 - ~ 240+

3071 - ~ 250+ 0.68 A/R

3071 - ~ 260+ 0.87 A/R

3037 - ~ 270+ 0.68 A/R

3037 - ~ 290+ 0.87 A/R

These are all HKS spec turbos and while they could probably be pushed further your engine won't thank you for it .

BTW you can substitute Garrett's GT3071R and GT3076R now that IW T3 flanged GT30 turbine housings are available .

Your calls , cheers A .

Edited February 11, 2008 by discopotato03

[paulr33]

i agree %100

[zafeniak]

Dood,

Bumblebee stated things pretty much correctly. His mention of "abnormally high combustion pressure" wasn't in reference to the gradual, linear like rise from a simple boost increase. I read it to mean, the combustion chamber/cylinder pressure spikes from detonation, or knock. Your doing well at 50 posts telling ppl, that 1bar is about the limit for a stock RB25. A simple search of the thread compiled just for ppl like you, would show you that MANY have have run more then this for many a year - reliably.

Boost doesn't kill an engine (comparatively) you think 5psi makes a difference, when the area it takes up is then reduced 9 fold when the piston rises and then lit?

In your example A and B - if both cars never det, i would say both cars would show almost exact levels of wear. In fact, whos to the the car with more boost, has less wear, as it gets up to cruising speed and low revs @ 5th gear quicker?

Forced induction combustion motors dont have a linear rate of combustion pressure to rod load, because the charge isnt burnt in a linear, even fashion. More boost and fuel ends up increasing the burn time if you will, right where the rod goes 90degress and leverage is at its best.

Anyway det changes everything, the car with more boost could very well suffer more damage.

Set it up smart, tune it right, manage chamber conditions and you can push a stock combustion motor very far (sound like a broken record i know)

Edit:

Dood, stop rambling and listen

DOOOD, stop rambling and learnt o read

stop writing things that I never wrote about. quote '' Your doing well at 50 posts telling ppl, that 1bar is about the limit for a stock RB25'' When did I ever write that?

Learn to read...

By the way, it's common sense, more boost = more damage all things remaining the same. Now, knowing you, you'll say "yeh, but not with the right supporting mods and a good tune" Everytime you turn the boost up, the life expectancy of you car decreases. Yes you can get mods to slow this rate down, along with a good tune, nonetheless, it will be a quicker rate than had you run 15 psi in comparison to 20 PSI.

I haven't seen a car been able to run 250,000 km on stock internals running 20PSI, have you?

Anyway, the thread is not about that, if you got concerns, please PM me and stop high jacking this thread.

Cheers

[GeeTR]

Whoops, yah toasty indeed, 3 years here and i finally upset someone with my keyboard diarrhea

DOOOD, stop rambling and learnt o read

stop writing things that I never wrote about. quote '' Your doing well at 50 posts telling ppl, that 1bar is about the limit for a stock RB25'' When did I ever write that?

Learn to read...

You said...

IMO, I think anything above 17 PSI wont be to good for the rods etc.

Never the less, sorry if I seemed agressive. Was (too passionatley) disagreeing with ur opinion that a stock RB25 needs to be baby'd, and that boost soley is so wear inducing. Watching other ppl blow up good motors due to bad tuning / lack of understanding is racking my nerves

Anyhoo, back on topic

Edited February 10, 2008 by GeeTR

[zafeniak]

Whoops, yah toasty indeed, 3 years here and i finally upset someone with my keyboard diarrhea

You said...

Never the less, sorry if I seemed agressive. Was (too passionatley) disagreeing with ur opinion that a stock RB25 needs to be baby'd, and that boost soley is so wear inducing. Watching other ppl blow up good motors due to bad tuning / lack of understanding is racking my nerves

Anyhoo, back on topic

dude, your doing it again lol, when did I say that boost is SOLEY is wear inducing?? I believe it is a contributing factor, but I never said solely.... As I said before, please read what I've written.

Secondly, I wrote IMO anything ABOVE 17 PSI ain't too good for stock internals, so how does this equate to 1 bar(14.3PSI)????

Cheers