New Turbo Setup
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Hi all,

well i have finsihed the new turbo setup and am a little disapointed to be honest.
I have not had it on a dyno yet so i cant say i am 100% sure but it certainly does not go any where near as well as it used to for the same boost.

so the old setup was a T25 with .48A/R comp and .49A/R turbine on std metro manifold and 2.5inch zorst.
new setup is GT2554R with .80A/R compressor and .64A/R on a new manifold and a 3inch zorst.

I knew boost would be a little higher in RPM but i thought with ball bearing turbo it would spool up quicker which it does, i start making boost in top from 2800 but it does not reach 15 pound till around 6000 where the old setup was reaching 15pound by 4500 and then would rip your arms out and screem (best time of 13.8 @ 104) now it feels like a NA 1380 almost.

so i will chat to turbo man today and see if he can change housings to a smaller one but keeping the dual bearing centre.

has anyone else tried this turbo at all?

cheers guys

Grant

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

The turbine is definatly too big,

It will be interesting what your turbo man says, as far as I know the 2554R is the smallest turbo available with roller bearings, I dont know if it will e possible to transplant in a smaller turbine :/

Also I'm not sold on the compressor in the 2554, you'll need to spin to 7500rpm to get it near to is sweet spot, you my find the T25 was making less heat...

IMO a TD04 form a WRX is about the best bet with the 13T compressor, at 6k-7.5 you should be right in the sweet spot, and stay in it up to about 22psi, the stated max eficiency on the 13t being 76% vs 71% for the 2554R. The turbine should be a more suitable size too.

Also, with the RE13T, whats your peak power RPM? I'm jsut about to bung one in mine :)

Ok well I have spoken to the turbo company where I bought the unit from and discussed the issue, he said he has a .48A/R turbine housing off a GTR skyline brand new that will bolt straight up, only difference is the dump pipe flange is slightly different so I will have to mod my dump pipe a little to suit the new flange.

As for Cam's I am trialling another cam from Graham Russell, he has not used this one in a turbo motor yet only in NA motors, he has opened the LCA's so we will see how it performes.

The RE13T was great, with the old turbo it would start coming on boost at about 3500 or there abouts and hold the same boost level to 7500, on 14psi on Grahams engine dyno it made 184hp without intercooler or megajolt. so when I sort this turbo out I will be interested to see if the new setup prooves to be a benefit or not.
I hope to crak the 200 mark
bloody hope so.

Edited by RED850 on 17th Jan, 2011.

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

OK Guys,

I have a questions.

as you will read above i have boost issues.

now i need to go down in turbine A/R size to get the turbo to spin faster to get more air volume.

what are the differences in changing the compressor A/R down and leaving the turbine Versus changing turbine A/R down and leaving the compressor A/R

surely there is a difference

thanks

Grant

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

A very interesting question that I have actually been looking at over the last couple of weeks,

I have been looking at it from the point of view of how my variable vein turbo (variable exhaust A/R) affects things, and what will happen if I put a different compressor on it,

I'll collect my thougts after work and reply.

If you put too small a turbine on a large compressor you will run the risk of surge.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

what do you mean by surge?

as in slowing compressor down to much when throttle closes? if so the dump valve should assits to minimise this.

Edited by RED850 on 18th Jan, 2011.

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

Right,

first off, forget the Compressor A/R, just look at the compressor map,

the most comprehensive thread on turbines on TM is here...

http://www.turbominis.co.uk/forums/index.p...tid=182558&fr=0

essentially if you look at a turbine map it is giving info on when the turbo might spool, but you need to know a lot of info about what the engine is doing, or measure it... in the thread above Paul S has generated a nice little chart for the GT2056 exhaust, but unless i'm missing somthing it appears to be assuming that boost pressure will equal turbine inlet pressure which is unlikly to be the case,



I belive the turbine in the 2554 is similar to the t25 one, so swapping to the .48 housing on the 2554 is going to bring the point it hits 15psi back down to a similar level as your old turbo,


regarding surge, have a play with this sheet, on the compressor map the left hand vertical line is the surge line, if you push a turbo into this region of operation (too much pressure for too little flow) the air in the compressor will start "pushing" back through the compressor can can cause damage to the turbo.

http://www.motorgeek.com/?fullpage=true&page=flowcalc

Surge is where the compressor wheel cannot maintain the air flow volume and the air reverses back through the compressor wheel causing a reverse thrust on the bearing. It can be catastrophic.

Thanks Guys,

all this has been very helpfull.

Can you feel turbo surge, what are the symptoms to look out for?

will he boost die off top end rappidly? will i not know at all?

thanks again

Grant

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

you'll hear surge, its a fluttering sneezing kind of sound, you should see it on the boost gauge too as rapid oscillations in the boost pressure.

go watch 'the fast and the furious' most of the shite cars on that do it

well the FKN saga never stops does it, i am not sure if i have killed someone in a previous life and its now catching up with me or if it is my turn for some serious anti good times....

SO i have now had the car running again for a few days and just cant seem to get the POS to run well, it drives off boost and just into boost (5psi) really well, very smooth and clean etc, althought turbo surge noise is very evident so this could be my direction indicator, but as soon as the boost starts to rise and you feel the car is going to catapolt into the next stratosphere (like it used to) pop farrt bang, popping and farting in the intake (which i belive is usually lean mixture i believe) and crack bvackfires out the zorst.
my wideband 02 says the mixtures are ok and if anything a tad rich and my laptop for EDIS says all is fine and tacho and EDIS do not seem to drop out as if it is an ign problem.

I just do not know where to go, i might piss of this turbo (GT2554R now with .48 AR turbine) and rebuild the old T25 and see if this is the concern.
as soon as this has been fitted it has been a nightmare.

for so many years the car was great and i had to go and change it didnt I.

my rant is over.

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

Is your trigger wheel/sensor correctly orientated? Have you verified your megajolt with a timing light? If they are wrong you will get more or less advance than you where expecting and things can go very wrong. Ask Mike Race

Edited by apbellamy on 8th Feb, 2011.

grant ,
sounds a little like the old fuel pressure not going up with boost thing ..

you could try winding the fuel screw in to max rich so it will just tickover ,then drive it .

if it makes a diff id look to two questions ,

1)are all the pipes on right and the fpr working ok .

and

2) is the new system just much bettter and you need to drastically richen the needle ?

regards
robert .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Really I think you need to loose that 0.8 a/r compressor. The turbine you have now should be ok but the comp is way to big for such a small engine.

Be interesting to see some photos of it though..

should be ok kean ?




not perfect sim with the bsfc data having the effect it does on this package but usable for indications :).

Edited by robert on 8th Feb, 2011.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

That's better than I thought it would be Robert, but still quite close to surge.

When it starts to splutter, can you feel the surge through the throttle pedal? Also, what boost setting and control are you using?

Edited by Kean on 8th Feb, 2011.

Ok, a little update, I have found a decent air leak at inlet gasket, bit of water spray prooved this, I have just changed the gasket with the turbo in sitchu (what a fun job with a solid oil drain and not having to undo the drain (remove studs and slide gasket out and then the new on in)
it cerainly idles better but as soon as it even free revs it pops and farts through into intake.

Robert, i have fitted fuel pressure gauge and it seems fine, 4psi on idle and even with a little rev it jumps to 10 and when i apply a smal amount of comprerssed air the gauge rises rught up so im sure that is ok.
APB, I think you might be right, the sendor brkt is a new one i have made but it is in the correct pos 90 btdc, missing tooth is at top of balancer when at tdc and sensor is in the front of the pulley, however for testing i added 20 degress to the already set timing mark now being 40 degrees (dont worry not driving it just free rev and its so much cleaner not popping at all and no hesitation, so i just have to pop out in the garage again and check to see if it is lined up on the 9th tooth after the missing one to ensure its spot on, if it is for some reason the system is playing up, when engine is on TDC and megajolt set to 0 the timing light is showing only 1 to 2 degrees off, so not sure what is going on yet but getting there.

thanks again guys.

P.S Kean, yes there is a lot of wastegate surge noise which does worry me a little.

Thanks again

Grant

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

Ok, so i might have found the issue,
checked the Megajolt site and it says the sensor should be at the 9th tooth on the wheel, so i check mine and its on the 7th, surprised it ran as well as it did, made a new sensor brkt and lined it up and it was certainly smoother, and free revved much better, hoever on road test when i would bring revs up to around the 3k mark ignition would drop out tacho drop to 0 as f loosing power to Megajolt, looked at VR sensor and it was sitting about 5 to 7mm away from wheel adjusted it in and whamo all ok on the next drive, now just needs some final sorting and the boost adjusted as it was down to abput 12 or so.
so i will leave it for tonight and see how it is by the end of tomorrow and get some miles on it and then see when i can book it in on the engine dyno.
thanks again guys

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

Thinking of going to the GT2560

Hi Guys, as you will see from the above i have a GT2554 with a .48 turbine housing on my car and it is now ok but it has never gone as well as it used to with the old T25 with .48 and .49 housing and i think this is due to the .80 comp housing.
Speaking to a turbo place and they said the .80 will mov the same amount of air for the 15psi that the GT2560 with a .48 turbine will, he feels i would need to run around 20 to 25 psi to achieve the same air volume.

what do you guys think?

thanks

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

the comp housing is rarely a part that you would change .id say go for a smaller a/r turbine housing to try 1st .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

as i mentioned on aus mini i think the GT2554 looks a bit wank for somthing like a mini,


my compressors of choice would be 2056or 2559, (same as 2259)

then as robert says ths needs to be coupled to a suitable turbine, this is what will have the big effecot on how it boosts. (and is the hard part)

thanks for the feedback Joe, already got ths 2554 installed etc so i will work with this for a while and see how it performed on the dyno and with a bit more boost.

Cheers

179hp on 12psi 1293cc of pure A series
14.0et @101 mph

Im not sure if it is possible but the rebuild kits from garrett online seem to be gt20-25 so could you not use so.e gt22 parts or a compleate setup just with the gt25 bb core?
Jimster uses a bb turbo on his could it be a modified gt turbo?

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