.86 & .64

[Black_CSR]

Hi Guys..

Just wondering what u guys think? I am gettin a 2530 Hi Flow spec Turbo soon but the one i'm gettin is

in a .86 T28 turbine housing in a .60 comp so identical to 2530 except its .64 turbine as .64 will seem too

small for RB25DET.

Will i get slightly more power @ .86? I'm thinking of running 17-18psi so get about 230rwkw and max out the

the stock injectors and AFM unless i make more n therefore get bigger AFM n Injectors.

I have all the basic supporting mods like Power FC, FMIC, 3" Turbo Back, Bosch910 pump, Splitfires, HKS EVC, Apexi Pod

with Metal Intake Pipe. Just want to know if i should get anything else like bigger AFM, injecorts or possibly step 1

cams b4 i go 4 the Tune?

Cheers

Ces

[GTScotT]

The way I look at things is that an exhaust AR indicates the turbos power band. Basically speaking the .86 will come on later and stay on longer, while obviously with a few extra RPMs you should also see a slightly higher output up top. You should also note you will lose some mid range punch.

Being built off a HKS 2530 spec results are readily available, and the .64 is not too restrictive for an RB25 no. People are using .63 housings on GT30 and GT35 based setups to great results. In saying so, if you look into the 2530 results and like what you see, you should stick to the 2530s original housing size, if you feel that it comes on uselessly early and dies off too quick (which it doesnt) and foresee a USEABLE advantage to shifting the power band up then opt for the .86.

I would consider a .86 housing in a circumstance where the turbo is maxing out the rear housing too early. For example, I am a fan of the 2871 (GTRS) but can see constraints in how much boost can be run efficiently, now the curve on a 2871 is excellent enough as it is so I can justify running a .86 on it to get a little more flow out of the back end, seeing as I believe the compressor has more flow in it too. In saying so, I still think the .64 one HKS sells it with would be better, I just thought of this theory to try and squeeze the most out of the garrett equivilent. The garrett has no surge slots and the HKS housings are possibly not garrett standard issue items SO the .86 idea was a way for it to be run a little harder in exchange for some low down torque, which was probably only a loss up till 3500 ish and it would balance back out.

Have a good think about it and compare results, also try to consider how much boost people run already... 17-18psi seems a normal number for a 2530 so maybe the .64 is the best way to go especially if you dont want to rev much beyond 7000. Remember the stock turbo is a .48 AR on a 33.

Its not the motor maxing out the housing its the front size of the turbo maxing out the rear side with the motors ability to eat air as a variable. Thats why highflows in stock housings still work and make excellent power, because the rear wheel is big enough to let gas thru that doesnt choke it.

GL and keep us updated with your results.

[discopotato03]

Firstly only HKS made a proper GT28 turbine housing in T3 flange , the Garrett ones have the smaller T25/28 mounting flange .

A real T3 flanged 0.86 A/R turbine housing would be a godsend because with much over 2 liters you need it to get the exhaust out .

I don't give a rats what anyone else thinks , I proved that the 0.86 sized T28 flanged turbine housing can and has been used with good results even on a 2L four provided the head is good - FJ20's are . Mine made positive pressure with one on a GT2860RS turbo at 15-1600 revs so an RB25 would do it easier with 25% greater capacity .

The GT2530 and GT2860RS are very nearly the same thing , only the minor differences in the compressor wheel make them different . Same turbine and can use the same housings though again that minor difference in compressor wheel profile .

One of the past Turbo Production Engineers at Garrett in the US , RC , once said that he could not understand why HKS didn't do a 0.86 housing for the 2530 because that size works really well on the GT2860RS .

A .

[Black_CSR]

Thanks 4 da Response Guys.. really helpfull Information :-)

Already have the 0.86 A/R version on the way n waiting 4 it to arrive then just gotta hunt around for a z32 AFM & 550cc injectors.

Then i'll go in 4 a Tune n c how it goes..

I'll keep u updated.

I"ll b a Happy with a Response Torque Monster which is what i'm Aiming for :-)

Ces

[W0rp3D]

Thanks 4 da Response Guys.. really helpfull Information :-)

Already have the 0.86 A/R version on the way n waiting 4 it to arrive then just gotta hunt around for a z32 AFM & 550cc injectors.

Then i'll go in 4 a Tune n c how it goes..

I'll keep u updated.

I"ll b a Happy with a Response Torque Monster which is what i'm Aiming for :-)

Ces

You will need a fuel pump too if you dont already have one, no doubt we will see each other in threads selling Z32 afm's and 044/040 fuel pumps

[paulr33]

id like to see a 0.86 rear 2530, that would be pretty funky

is the main issue with the smaller compressor style turbos (2530, gt-ss (in single form) etc) is that the rear is usually tiny and it strangles exhaust?

i know this sounds whack and goes against everything we agree on but what about a larger GTR twin in single form on an inline 6?

roy (troy) has a twin from a td06 GTR kit in single form on his rb20 and it is bulletproof (with ext manifold, gate etc).

like using a 2835 pro R from a GTR twin kit as they are external gate too ? vs the normal 2835 pro S which is single, but in internal gate

[Black_CSR]

Ok here are my results..

There are two Graphs one is Boost Level and other is the Torque..

The Boost Graph has black outline writing as this was what the Tuner was trying to Achieve.

Edited May 16, 2010 by Black_CSR

[discopotato03]

Paul I would expect a 0.86 housing to give similar results on a 2530 or a GT2860RS provided they use the same compressor housing .

I think it goes without saying that twin TD06's or GT2835's is a lot of turbo in twin form on a std capacity RB26 and I wouldn't think would boost too well down low .

I look at turbine housing A/R size a a means of tuning turbo/ine speed around engine speed - effectively where you want the thing to boost relative to engine speed .

A .

[Black_CSR]

According to Stao if i wanted to the boost to hold all the way to 15psi towards redline i would have to run an external gate or play around with the wastegate preload which i assume is the the nut and rod connected up to the actuator to the turbo.. so if i could get it to hold to 15psi towards redline it should net around 330-340RWHP??

What if i run a Front-Screamer pipe??? will that hold the boost towards redline?

What do guys reckon of the result?

Edited May 16, 2010 by Black_CSR

[GTScotT]

If you have a good dump and front pipe on it already, a screamer pipe wont do anything other than put a big hole in your wallet when the cops catch on.

If you look at results for these turbos when done by HKS, you will see they usually dont have an issue holding boost to redline. Same can be seen on HKS 2835 vs a garrett 3071 equivalent.

I feel the issue is more so the housing design rather than the need for an external gate. I personally dont think the addition of an external gate is necessary or beneficial.

AFAIK Stao is using T25 housings and modifying them for a T3 footprint. Perhaps the design needs some improvement to adopt the altered flow dynamics. Hopefully Stao and some other gurus can step in to provide further insight.

[R31Nismoid]

If you look at results for these turbos when done by HKS, you will see they usually dont have an issue holding boost to redline.

I feel the issue is more so the housing design rather than the need for an external gate.

Exactly right.

If the true HKS 2530 can hold 20psi virtually until redline - and a copy cannot, then that is the COPY failing.

[Black_CSR]

So Ok i guess it's simply the housing design is at it's limit no matter what i try to do???

So i have reached the limit of this Turbo??

[hypergear]

Exactly right.

If the true HKS 2530 can hold 20psi virtually until redline - and a copy cannot, then that is the COPY failing.

Common you are a mod sitting on front on PC reading dyno sheets every day. You know better then that.

You can not get HKS2530 to hold 20psi internally gated straight to 7000RPM. I haven't seen one that can hold 14psi to redline. I can possible engineer it to do that if I really want to, how ever you can not ever get one that can. So please give the correct correspondence.

This turbo was build and sold for evaluation purposes, which I was expecting around 220rwkws.

End result of 237rwkws, with plenty of torque. Its not a bad firgures compare to every one else who's running the 2530 units.

The other factor is this is pretty much the max of what this comp wheel is capable off. More boost can cause a negative impact on HP gain. My initial test running CA18det with GT2860RS CHRAs shown 225rwkws on 20psi and 197rwkws on 24psi, RB25det requires lower boost to reach those boundries

I'm taking neutral view for this result as I've managed better response and power with a newer prototype recently.

You can get it to hold 16psi straight with wastegate controller. I'm unsure what sort of power it can make, but I don't think it would make any thing more then 10kws.

[R31Nismoid]

Well for a turbo salesman/creator i'd expect better from you at times as well, but hey - Must be monday-itis in the air.

Either way I had RB20 in my head for some reason... I'd seen a few results holding till redline (17-18psi), so my bad... RB25 in this instance is being discussed.

Was from the Dyno sticky...

http://www.skylinesaustralia.com/forums/Rb...30#entry3498307

& another:

http://www.skylinesaustralia.com/forums/po...62-DSC00342.JPG

For references sake etc.

[hypergear]

RB25det has lot higher exhaust manifold pressure. The less pressure there is the more boost you can comfortably control.

I don't believe it is possible to hold 20psi to redline with an internal gate on a HKS2530 or equivalent in Garrett patterned housings with RB25det. Unless that is in a uncontrolled/controlled creep.

[Dose Pipe Sutututu]

2530 or 2535, the rear housing it too small, boost will drop off and will not hold anymore than 15psi or more boost till redline.

I'm with Stao... it's not a copy fail, I'm running a HKS 2535 and have exactly the same boost output, no matter how much gain is added or boost, it will simply not hold till redline due to the small ass housing. You can only force so much exhaust pressure into the rear housing to turn the turbine, after that you're just generating heat.

[scotty nm35]

So once the maximum flow of the housing is reached, boost drops, and enlarging the wastegate will just drop it more I guess. Is there a gain to be had flowing more exhaust out an external gate if the housing is maxed?

So there is no point me buying your boost controller Johnny?

Damn, I was hoping that would solve my boost drop issue.

[Dose Pipe Sutututu]

So once the maximum flow of the housing is reached, boost drops, and enlarging the wastegate will just drop it more I guess. Is there a gain to be had flowing more exhaust out an external gate if the housing is maxed?

So there is no point me buying your boost controller Johnny?

Damn, I was hoping that would solve my boost drop issue.

Using a good boost controller will give you better control of boost, will bring on boost earlier, and also elevate boost spikes, where bleed valves have no chance of controlling high levels of boost. Futhermore, with EBC you maybe able to hold the boost at your desired level for more of the RPM range.

[STATUS]

i have a few of the new bolt on gt 3076 bolt kits in the 0.82 56t making more power and better response on less boost than half of the highflows we see. If i was you i would buy an off the shelf turbo, of all the highflows and so forth ive seen through the shop (about 20-25) none have matched off the shelf items for response and power @ reasonable boost levels.

[hypergear]

i have a few of the new bolt on gt 3076 bolt kits in the 0.82 56t making more power and better response on less boost than half of the highflows we see. If i was you i would buy an off the shelf turbo, of all the highflows and so forth ive seen through the shop (about 20-25) none have matched off the shelf items for response and power @ reasonable boost levels.

How's this one Trent? PU MAX high flow Profile .63

And you need to start answering people's phone calls man. Ring you lots times for a tune never get answered.