First Impressions of GT28RS

[BigMal]

Got my car dyno'd yesterday with the GT28RS on and have to let
anybody who is thinking on one that it is a fantastic upgrade. The off
the mark off-boost performance is great better than a n/a and
way better than a std BPT. Whoever said a big turbo will kill bottom
end should try this as it is amazing and thats just the beginning. The
on-boost just gets even better solid linear pull cant give an exact
when full boost comes on as have fried the insides on one of my tyres
to the belts so will get a balance and replace the tyre and will then
give it a full flat to the floor as just frying em at the moment.
By far the best improvement is from low revs round 2000rpm where a
downshift was a must with the VF8 you just plant it and it boosts right
up hard. I am sure that is a lot due to the .63 exhaust housing I selected.
The only downside and I am sure it is not the turbo is the overall HP
output. I ended up with 157kw at 15psi which is less than the previous
160kw at a different tuner and this is a way quicker than the previous setup.
I need to look for a restriction I got 142kw at 12psi and think I should get
more than 15kw for 3psi of boost in the prime of the flow map. Thinking
that maybe the 2" from turbo to i/c should be raised to 2.5" as fuel and
exhaust system is all good stuff. Will tinker with some things as time
goes by but overall couldn't be happier with this turbo. The final proof
comes from my son who 1) Screamed for everbody to jump in the car to go
for a second blast after he got in with the tuner and me for the first blap.
2) Any time he hears the turbo spool slightly grabs for the roof handle with
all his might :)

Regards

Mal

[sonicneo1]

hey mal,
where abouts did u score yours from? With the new ecu going in soonish i've been thinkin about maybe doing the turbo at the same time.

[Shaggy]

Good stuff Mal :D

[Ian]

turbo upgrade eh?

Id love too... after suspension, which is gona cost lots.

[project.r.racing]

sounds good mal, yeah bigger piping will help if 2" is all you got, with that turbo, even 3" if it could fit would be great :)

ryan

[Rupewrecht]

Good to hear, i was a little bit worried about what the lag would be like. Roll on payday.

Still pulling hard top end? Or running out of puff by 7000?

[BigMal]

I got it from Horsepowerinabox but first I went onto nissansilvia and looked at
the promotions which for me was the xmas deal and saved $150 off normal price.

I wouldn't say its running out of puff but it does taper off in the higher revs hence
me looking for restrictions. The dyno guy thinks head needs porting as on a CA18 with
the same bolt on goodies eg Skyline GTR injectors, 3" exhaust, GT28RS etc gets
200wkw but the CA18 head apparently flows very well. Changing the turbo side i/c
pipes is not an expensive thing to try, the turbo mouth is only 2" so technically what
I have is best for least lag but at the moment its the only thing I can think of as exhaust
is good, fuel is fine, have the GTR intake manifold and a custom exhaust one.
If not will need to wait for a year or so for me to save up the funds for a full rebuild.

[BigMal]

p.s just to clarify my I/C pipes are only 2" from turbo to I/C ie hot side and then are
3" from I/C to intake. So its only the small bit of pipe on the drivers side thinking of changing.

[Nate]

i can see why you are thinking of changing that thru the process of elimination, but is that really going to make a positive difference? i mean your turbo mouth is only 2ish and the air still has to get thru that so wouldnt you be better sticking with the 2 inch hotside pipe to keep the velocity up? i could be completely wrong here but that is jsut my 2 cents. hope you get the issue sorted out anyway.

The upgrade soundsawesome! have you got any dyno seats or pics of the new boostenator??? deffinately looks like you have your hair dryer set on hi now :p

PS - you better been around when compact acttack is on at the end of may :p i have been to sydney so many bloody times and have had the pleasure of meeting you but still havent seen your car!!!!

[Exodus323]

i can vouch for how much power the car has picked up with a proper tune.
I have never seen a astina pick up as much speed so quickly as what mals car does now.
The sound that the gt28rs makes is awesome.
Now i carnt wait to begin my conversion.

[Nate]

do it paul do it!! you car already looks sweet, now give it some serious power!!

[BigMal]

Nate
Logic says that a cat back system shouldn't make any power as the pre-cat
pipe is the same so should limit the flow but we all know it makes a diff so
hoping for a similar effect by upping the intake pipe.
Also I will start making appearences again, been embarrased of the car since the guy
reversed into it and smashed it up more but now I have basically done all my engine
mods so can hopefully start on the bodykit and bonnet and then get it straight again
and all one colour.

[89sp1.8]

sounds nice man,keep us posted on upgrades :)

[Shaggy]

Mal can you get any vids?

[BigMal]

Not of the dyno run no.... didn't think of it at the time

[Exodus323]

HAhaha i will nate in june i will complete the conversion when i come back from holidays

[BigBoyLemonade]

Good to hear that Mal's astina lives on! A polish and port with some bigger cams would make a huge difference inconjunction with the turbo. Well done, I will have to come up and visit for a ride! :p

[Nate]

Nate
Logic says that a cat back system shouldn't make any power as the pre-cat
pipe is the same so should limit the flow but we all know it makes a diff so
hoping for a similar effect by upping the intake pipe.
Also I will start making appearences again, been embarrased of the car since the guy
reversed into it and smashed it up more but now I have basically done all my engine
mods so can hopefully start on the bodykit and bonnet and then get it straight again
and all one colour.

yep thats a good point mal! and dont be worried about a few dings, you should see my beast these days lol

[BigMal]

With the way it goes now I pretty much couldn't care less what it looks like
any chance to take it for a drive puts a smile on my face :)

Tony... Anytime man, am always happy to take you for a blap remind you what a
Turbo Astina feels like.

[Exodus323]

Apperntly you shouldnt polish a turbo head only port it.
The reason being when its not polished it helps with the swirling effect that you want when you have a turbo.
This infomation is from a man that owns a tuning shop and he knows his ****

[BigMal]

Nah man, what he said was that was what he had been told....
I am still undecided on that one.

[Rupewrecht]

Mine was only ported and is still capable of flowing about 270hp apparently

[QuicKSilveR]

Mmm, the GT2860RS would lack a little power when using just a .64 Exhaust housing. It uses a much smaller Front wheel to the GT2871 and GT2876. Normally use the .86 Exhaust Housing on the Disco. But yeah, they are a great street performer.

I've just received my new turbo - a GT2876R (GT2540). I'm going to use the .64 exhuast housing on it the same. The ehxuast housing and the whole exhaust wheel is exactly the same specs as the gt2860RS but it uses a HUGE T4 style front wheel inside a .70 Front Comp Cover with 4" Intake.

I'll let you guys know how it goes. It was a hard choice choosing, with mates using GT2860s, 71s and 76s all getting good results. I'm hoping the lag is ok on mine.

[QuicKSilveR]

.....If you can take a little more lag, the .86 will give you more top end. My Turbo came with a .86, but being so large i swopped it for a .64

[ROB-80E]

Mal, the head isn't the problem. Mine flowed 200kw remember, and it was a stock head. Did you manage to get a GTR plenum in the end? I've also been intouch with Jaustech and they have seen 230wkw with stock head and cams...so yeah, i say again, not the problem. ;)

I'm with nate in saying that i wouldn't think changing the hot side pipe would make a different, but you never know, it's cheap to try, so you may as well. I run a bend using 2" off the turbo then enlarge it to 2.5 for the rest of the bends on the hot side.

Any chance on seeing the dyno sheet? I'd love to see the curve. Also, why only 15psi? :S

[BigMal]

Actually I am happier to take a loss of top end for less lag.
Been thinking about the lower than expected output and when I compare it against
GTXWGN with 180kw @ 16.5psi against my 157kw @ 15psi, at the same boost he
would probably be 170kw and you then allow say another 10kw for the diff between
the 2871 and 28RS so I am only a couple of kw off what I should be getting. On top
of that my run was using the standard astina front bumper as my Cwest is off to
be repaired and I know from previous driving the heatsoak difference between the 2
bars is noticeable especially up top. I am thinking that putting the Cwest bar back on
and also increasing the turbo to i/c pipe to 2.5" over the present 2" will give me the
10kw I was concerned about.

Having driven the car now for 4 days have come to the conclusion I dont really want
any more power and especially at the expense of the bottom end response. Driving
the car like I did with the VF8 boosting to 5-7psi the GT28RS didn't even need to go
into boost to match that performance. Boosting it up I have noticeably worn the tyres
even just over the couple of days and my biggest concern is breaking things being my
drive to work car.

[Exodus323]

Driving
the car like I did with the VF8 boosting to 5-7psi the GT28RS didn't even need to go
into boost to match that performance.

I feel bad now :( im about to use a VF10
for those of you that dont know the vf 10 is the same as a vf8 except it has a bigger exhaust wheel (is that right mal?)

[BigMal]

I feel bad now :( im about to use a VF10
for those of you that dont know the vf 10 is the same as a vf8 except it has a bigger exhaust wheel (is that right mal?)

Yeah the VF8 has a larger exhaust wheel which is why to hybrid them you
need to machine the VJ20 exhaust housing.

All I am saying is when I was just doing spirited fun driving not going flat out
I used to boost to round 5-7 pounds in the VF8 and now dont need to be in
boost to get similar results cause of the great low down response of the potato.
Considering you will be running about 15-16 pounds with your VF10 its not
like I am saying your turbo will be like mine with no boost. That would be rude !!! :)

[BigMal]

Hey Rob,
The reason only 15psi is 2 bar map sensor with the E6K. I could have bought
a 3 bar for $120 but considering I got only 12kw for the last 3psi I didn't think
in its present state another 2psi would give me much worthy of the $$$.
In the back of my mind also is a E6X which has a 2.5 inbuilt map sensor and
also the windows tuning program which I could look at running on a carpc and
displaying incar.

Yes I have fitted a GTR intake plenum so that part is covered.
Turbo exhaust manifold is not tuned length but the runner size is what I would
expect and looking inside the collector part see no restrictions.
Exhaust is 3" all the way through with a mad custom stainless muffler with
dual 3" outlets and a magic performance 4" cat(tested in zoom 734cfm flow)
and a 3" SR20 dump so I cant see the exhaust being the restriction.
Fuel is covered by a walbro pump, malpassi and the Skyline GTR 444cc
injectors(which I love to death) and know this is all fine as there were
no problems on the dyno.
That leads to the last item the I/C piping which cant be the hybrid cooler or
the 3" cold side pipes so the only thing that I can think of in my whole
setup that could be at all restrictive is the 2" from turbo to intercooler.

I will post up the dyno sheet soon. I forgot it on the day but the guy printed
it out I just gotta go get it will hopefully do it this weekend.

[BigMal]

Its an old pic but in case you hadn't seen the custom manifold here it is.

http://www.members.optusnet.com.au/big.mal/20122005(004).jpg

[Exodus323]

yes mal that would be rude :) im only kidding anyway. the vf 10 is only a starting point just to go up a step from stock so maby i will be able to boast a little about how my car goes after conversion insted of doing a stock conversion and and posting numerous post on how good my car goes. :)

[Dogo]

hey Mal just wondering if you've hooked up the water cooling or just oil still ?

my vf12 is (still) sitting in the box :(

dave

[BigMal]

my vf12 is (still) sitting in the box :(

I hear you mate and know how you feel.
1. My rear shocks are still in the box bought them last year.
2. My bonnet is still bent (3 years) the replacement bonnet been in the
garage 1 year still haven't modified it.
3. My VT SS rear wing still hasnt been finished 2-3 years.

Its never ending.

Anyway for the VF12 I did dodgey I used the copper pipe hose fittings
to reduce from the subaru size (used subaru banjo's and outlets) down
to the 5/16 mazda water ends. Looked bad but worked. For the Garrett
I did it properly with speedflow fittings. The 2 90deg fittings were $25 each,
the adapters on turbo were $10 each, 1 metre blue gates -6 hose $13
and 2 Earls hose end fittings $8 each. The look Priceless...sorry much better :)
I bought the fittings a couple each week so it didn't really seem like $100
but the look is so much better I know the copper stuff was only $15 but
it did look shocking I wouldn't do that again.

[BigMal]

I forgot to mention that the ones on Jynx's VF8 were the Subaru fittings with 5/16
fittings welded on you can see the top one in the pic above if I didn't go speedflow
that would be the way I would go just need a welder mate.

[ROB-80E]

yes mal that would be rude :) im only kidding anyway. the vf 10 is only a starting point just to go up a step from stock so maby i will be able to boast a little about how my car goes after conversion insted of doing a stock conversion and and posting numerous post on how good my car goes. :)
The whole compressor side is bigger than the VF10 as well as the exhaust wheel.

Hey mate, don't let it get to you...it would be rude of me to say that I made more power than mal with my VF10 hybrid setup than his VF8. hehehe

Mal - Welcom to my world with the tyres. :( I don't get what you mean with the map sensor either...i know that air pressure is 14.5psi but why does that effect the map sensor having to be a 45psi sensor?? The MT's come standard with a 20psi capable map sensor. :S

[Exodus323]

Im not letting it get to me.
Im just looking forward to my conversion once its turbo them ill start really looking into performance. but it will most likely be quick enough for me any way.......well for a little while

[BigMal]

Rob
The E6K uses an external map sensor being 2bar = normal atmosphere(1bar)
+ 1 bar boost so 15psi is all it will read. You can buy a 3bar = 30psi and
simply swap them out. The E6X comes with an internal 2.5 bar which will
read up to 22psi.

http://www.tweakit.net/shop/product_info.php?cPath=&products_id=821

And Rob I have always been jealous of the performance you have got. RESPECT :)
I can also live with the wearing tyres as long as the gearbox survives. Its a bit
concerning you only got 6 months from your last box if I read the fordlaser posts correct.
This weekend weapon weekday shopping trolley is a hard juggle I know I always want
more but I have to have reliability .....

[BigMal]

I dont have a scanner so heres a pic of the dyno read taken with my phone.
This is the final tune where he backed off timing a little for lower fuels not that it dropped by much.
Comes on full boost at 3700rpm

http://www.members.optusnet.com.au/big.mal/01042006(005).jpg

[Exodus323]

I was there when tat was being done all of you should here his car come on boost
good time for all :)

[ROB-80E]

Interesting that little flat spot you have there just after reaching full boost...is it noticeable when driving? I'm wondering if it has anything to do with the reason it's not making a little more power.

With my box, yeah it only lasted that long, but I think i may have ****ed up when i put it back together...so yeah, may have been induced. But i'm not taking any chances this time, hence why i'm putting in the straight cut 3rd. But my car is the same...i drive it to work and back everyday. ;)

[BigMal]

The tuner tried to tune it out but couldn't.
Getting up to 15psi there was no issues but once there its a battle. That is why the
tuner is saying there is a restriction if that curve didn't have the dip you would be
looking at the 165-170kw mark which is all I would expect from 15psi.

But I got more important issues right now I have a exhaust leak started thursday is
from between the header and turbo will need to drop the turbo and reseal it. 2 of
the studs from when it was redrilled for GT28 keep working loose will try some
threadlock otherwise may need to tack weld them in place.

p.s Rob just noticed you Conversion says convertion

[ROB-80E]

Hehehe, cheers mate. Man, i got to change that on so many sites now....it was always just copy and pasted. :$

You're at the point where I am now...basiacally fix up a few of the little things, and just drive it and enjoy it with what you have.

Can't wait till you get that map sensor and bump up the boost a little more. *thumbs up*

[BigMal]

At this point no extra boost just want to fix up the current curve, find whatever
the restriction is and then maybe later on swap the E6K for a E6X.