Hi all, Im new to the GT4DC - Im currently speccing up a forged rebuild for my 96 JDM ST205, Id Like as close to 400bhp as I can get. But id like similar torque.

Just wondered what peoples opinions were?

Engine
86.25mm forged Mahle Pistons
Eagle forged H-beam con roads
Clevitte main, big end, thrust bearings
ARP heads, mains, flywheel bots
Cometec head gasket - 1 - 1.2mm (i read alot about people running 1.6mm head gaskets so that they can run more boost - i would like as much off boost torque as i can get - so think keeping the gasket between 1 or 1.2mm will be fine?? Am i correct this will improve throttle response due to keeping the compression ratio as close to standard as i can?)

Fueling
Sard 800cc injectors (stock rail)
Sard AFPR
Bosch 044 fuel pump

Turbocharger
Garret GT30/76 with .63 AR
OR GT30/71 with .63 AR
(was originaly planning on a 30/76 with .82AR but as im looking for good response/spool up so i think i will benefit form the smaller .63AR - you may even tell me the 30/71 will be adequate for this power level)
However i have recently been told that for an extra £200.00 i can get one of the new GTX30/76R with .63 AR (or any spec) - What do you guys think??

Clutch
Clutchmasters FX400 or similar

Management
Apexi Power FC - mapped by Ryan @ 2bartuning
OR
MoTec - mapped By adrian @ fensport

Head
Standard head
Standard valves/springs
Re-shim
possibly have the head ported as this is done where i work - so figure its probably worth doing whist the head is off??

Im working from memory now so i may have missed something off. Ideally id like your opinions on what is and what isent needed for my goals!

So what do you think so far?

with regards to the ecu i would go with a motec and i would also get Dave Rowe to map it, this would also not need a FPR with the motec, we used the motec without need for any uprated fpr etc with over 400bhp.

head is fine stock, no need for work, maybe just a tiny bit of work in the ports but nothing needed to be honest.

turbo wise, the 3071 with a 0.82 ar will easy give over 400bhp at 1.6-2bar boost.

the 3076 is more the 500bhp region at 2 bar, both with a 0.63 exhaust housing though will give more down low but strangle it up the higher end of the rev range, we went for a 71 with a 0.82 housing

a walbro 255 pump will make 400 no problems too, although we are using 870cc with a top feed rail.

hth

Hi,

and welcome

a thinner head gasket is better as his surface to the combustion camber is smaller which can occoure damage in front of the forces

greetz

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street legal?.....perhaps in tschibuti

I put my response in the wrong place!
IMHO GT3076R will be too big for your requirements and a GT3071R will easily see 400bhp. For 400 lb/ft you need plenty of boost, as a ball park I would suggest 1.7-1.8 bar.

I did some compressor map analysis a while back
http://www.gt4dc.co.uk/forum/viewtopic. ... +selection

The new GTX series do look nice but they have actually increased the BHP potential of all the turbos at the expense of low down boost threshold (they will boost later than a std GT series). When they start to come out with smaller GTX turbos such as a GTX2860RS we will have a pretty darn good road/track turbo for a 2.0 litre finally. Until then GT3071R is the best compromise IMHO for road/track. Only go bigger if you really need the power for drag purposes or are incresing the rev limit considerably.

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

you would be right jp, we saw 370lb/ft at those boost pressures but intend to make the pipework bigger and some other alterations to see more torque and nearer the 500bhp mark than the 400bhp

Hi,

some time ago i found a pretty nice turbo series from borg warner

http://www.turbodriven.com/en/performan ... s/efr.aspx

i will go for the 6758, should fit my engine well if it comes true

PS.: i hate garett, don't admonish me out of this forum in front of this

greetz

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street legal?.....perhaps in tschibuti

what do you dis like about garrett sunny?

Thanks for the advice...Diceman you are on the OC aswel are you not?

To be fair I want good response and a quick spool up. so it seems the 30/71 with .82 ar is the way to go....

Does anyone know how far over 400bhp this unit could go?
I'm just curious really....I'd hate to go for this one and then regret not going any bigger at some stage down the line!

I suppose it's torque I want more than outright power, but would like to see at least 400 on one of my higher boost settings....possibly with the option of going up to say 420/430........also having the option of running a much lower boost setting that saw me say 350??

Don't want much do I.

Cheers hues!

the 3071 with a 0.82 will make 2 bar before 4k rpm if mapped right, and on a well set up and built engine it will make over 400 with ease, have seen 570bhp on a cosworth at 2.7 bar.

the turbo is rated by garrett to over 480wheel horsepower too, so 400flywheel is not a problem

2.7 bar !!!!! must have been 6:1 compression ratio or rocket fuel

_________________
JP
GT4DC Treasurer

Grey St185 RC
Silver BMW E46 M3
Multicolour yawn Honda VFR400
Silver Honda Civic Type-R

Hi,



- they are used by everyone, mostly as people don't know any other
- they have no speciall durability
- they are simple units with nothing special (twin-entry or/and titan internals)

possible hate was not the right word, i just do not see any reason to buy a garett unti

i should also say that i set high expectations in a high power turbo which makes that i was searching 2 or 3 years to find a turbo that can hit my guidelines

- twin entry
- leightweight internals (ceramic or titan)

both for fast spool up which makes the car better driveable out of curves, especiall as i like to drive anfractuous roads also on gravel

- capable flow enought air for 400-450HP in hope to hit 500NM anyway

and this year god hear me cry and i found the EFR series, i was impressed
especiall in front of the nice bits like, boost controll selenoid on turbo, bov on turbo and the option to fit a speed sensor (just if the stand alone ECU can read the sensor), and also that you can clock any part of the turbo in any direction with any problem which makes the package easier to fit

the only one negativ point is that i don't know one that has fit the turbo to get some feedback, but i like to try new things will go that way

greetz

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KEEP COOL UNDER PRESSURE

street legal?.....perhaps in tschibuti

indeed, 2.7 bar! i shall find the link..

Dave Pritchard built Engine, 2 litre Mahle pistons WRC h/gasket, 7.2:1 comp ratio, NMS flowed head, hydraulic lifters.
Siemens 900cc injectors
Small turbo plenum with 10mm spacer
MAD modifications:
Latest type Spec-R compact Garrett cored intercooler
NO water injection (removed from car)
Latest MAD GT-3071 spec turbo kit with free-flow exhaust elbow

2.4 bar though, not 2.7

Interesting.....So it seems the 30/71 is a very capable turbo and can flow more air than i first thought...

At what horsepower/torque levels are forged rods required?

I am told the standard cams are fine for over 400bhp..as are the valves and springs?

By fitting high lift cams (264 or similar) I understand that im bringing the power higher up in the rev range....does this mean torque will actually be lost?? Would all low down grunt (off boost torque) be lost??

opinions please.

IT will be a street car that occasionaly visits Santa Pod and the odd track..i want something were the power will be useable...

Once i get this sorted i have a few suspension enquirires lol!

Thanks again

Mike

Forgot to mention i was thinking of leaving my current head, camshafts and valves standard...and seeing what i could get out of the stock head with a *bleep* hot map, fueling system, cooling system and turbocharger etc. (I assume all the above comments regarding seeing over 400bhp easily on a 30/76 are with stock head and cams etc?)

And then buying a second 205 head for future work to be carried out - for example 1mm oversized valves, 264 cams, ported head - and seeing what the gains were just with head work??

I thought this was possibly a good way of doing things!?