Sigma-galant.com

Hi all,
Siggy is currently running a 128rwhp NA 4G54, which this engine is now 3 years old and has been run hard in nearly 50 local competition events. Siggy isnt for the street, its used for Motorkana, Kanacross, Autocross, Rallysprint, Hillclimb and might try Drifting. Time for another upgrade to Turbo and EFI. Needs power from low through to high about 6500. Dont need a 500hp engine, just another reliable safe engine. This is what I am planning and questions I have:

4G54 2.6 wideblock (needs rebore)
Stock 2.6 crank and rods
Flattop pistons (Forged or Hypers)
M6 Head (9-1)
Turbo cam
Roller Rockers with Hydraulic lifters
Remove Balance shafts
TS Magna oil pump
TS Magna Intake & Plenun
TS Magna Throttlebody
Haltech ECU
TS Magna Dizzy
Starion Fuelpump
Frontmount Intercooler
Custom Exhaust manifold
Garrett T25 Turbo (16psi)
2.5 inch Mandrel exhaust with Supercat muffler
Starion Flywheel with Extreme clutch
Stock MMC gearbox
Custom Borgwarner 78 series Diff (28 spline 4.1-1 Spooled)

Questions I have:

Is compression ratio 9-1 about the right mark? (Dont want too much lag)

Is Boost at 16psi about the right mark?

Where do I find Forged or Hyper pistons? (Nobody stocks them)

Where do I find a Turbo cam to suit roller rockers? (Nobody lists them)

Will stock head gasket be ok or use Steel?

Will the TS magna blue injectors flow enough?

Is the TS magna throttlebody OK or use XF Falcon?

What have people used with success and any advise would be much appreciated.

Cheers

No need for flash pistons acl cast will see out your rods which will support 400whp through an auto.
T28 will run out of puff early in the rev range but would be great down low gt30 would be nicer IMO.
Better off with a xf throttle body but not necessary.
Camshaft talk to camtech.
Everything else sounds about right.

Cheers Mic

All sounds good. I got my forgies from top end performance in the US they are JE pistons running 8.5-1 comp at 15 psi on 98 octane and still holding up fine. Found cast pistons were cracking ring lands more due to me pushing to much timing into the poor thing. You don't need custom 28 spline BorgWarner, a skyline diff will fit length wise and you just need to change brackets ect. Blue magna injectors are to small you will need bigger unless you run big fuel pressure and this can cause problems with injectors not opening. Can find calculators to figure out injector size on net. I am running a haltech ps1000 can send you map for mine if you like.

jigganought, you maybe the guy to help me with a proposed Haltech 500 installation.

I am going to convert my carby-turbo to NA magna injection. RPW can supply the haltech and sensors as a package..and a base tune to get it running. I have a 40 minute drive to get to a haltech tuner. If I took it easy, would a base tune cause me any serious issues during the drive?

My last motor had acl cast and 318whp through an auto on 18psi with 98ron then I changed it to E85 and made a max of 363whp at 27psi and maxed out the injectors. Rx22nv is also running acl and he has around 380whp. Forged pistons are not needed until you are pushing bigger numbers but rods will give out before the pistons if your tuning is correct. Only other thing I would add is ARP studs and bolts through out.

Cheers Mic

Sorry Mic just told Dion where he could find forged pistons like he asked and give my experience with cast pistons. But if you read the post properly I did state that tuning was an issue with my cast pistons, but I belive that had I had forged pistons in the tunning stage they may have survived the detonation. Would love to run E85 like yourself but can't get it local, future plans on running flex fuel sensor so where I can get it I can have more fun. I would not drive to the tuner sigmaproject on an unknown tune unless you know what you are doing.

Thanks all for the advise

mic_77 wrote:T28 will run out of puff early in the rev range but would be great down low gt30 would be nicer IMO.
Better off with a xf throttle body but not necessary.
Camshaft talk to camtech.

I was given 2 turbos T28 from a mate in a shed cleanout. If too small I could upgrade later. My NA engine runs a Camtech regrind. I will call them to see if they can do a custom regrind on the stock roller cam.

jigganought wrote:All sounds good. I got my forgies from top end performance in the US they are JE pistons running 8.5-1 comp at 15 psi on 98 octane and still holding up fine. Found cast pistons were cracking ring lands more due to me pushing to much timing into the poor thing. You don't need custom 28 spline BorgWarner, a skyline diff will fit length wise and you just need to change brackets ect. Blue magna injectors are to small you will need bigger unless you run big fuel pressure and this can cause problems with injectors not opening. Can find calculators to figure out injector size on net. I am running a haltech ps1000 can send you map for mine if you like.

I was hoping to avoid importing pricy pistons from the US. Cast ACL might be the go. I already built the custom 28 spline diff 3 years ago and is tough, the car is abused on and off the clutch and hydro handbrake constantly. Yes it is a R31 skyline housing with custom machining to retain the factory Sigma brakes and rotors with Sigma studs. I took a heap of photos if anyone wants a detailed thread. What Injectors are you using? I will be running a Haltech E6A, if you have a suitable map that would be a great start before the Dyno.

mic_77 wrote:My last motor had acl cast and 318whp through an auto on 18psi with 98ron then I changed it to E85 and made a max of 363whp at 27psi and maxed out the injectors. Rx22nv is also running acl and he has around 380whp. Forged pistons are not needed until you are pushing bigger numbers but rods will give out before the pistons if your tuning is correct. Only other thing I would add is ARP studs and bolts through out.

Which Injectors did you use before they maxed out?

jigganought wrote:Sorry Mic just told Dion where he could find forged pistons like he asked and give my experience with cast pistons. But if you read the post properly I did state that tuning was an issue with my cast pistons, but I belive that had I had forged pistons in the tunning stage they may have survived the detonation. Would love to run E85 like yourself but can't get it local, future plans on running flex fuel sensor so where I can get it I can have more fun. I would not drive to the tuner sigmaproject on an unknown tune unless you know what you are doing.

I will be doing all the building and custom work, only the machining will be done outside our workshop. then once running it will be trailered to Dyno

Cheers

Injectors were 880cc and microtech computer. If you are keen on forged pistons have a look at vw 92mm B comp height (35.03) they are around .5mm shorter in comp height compared to stock easiest way to get forged flat tops. AA brand can be had for sub $400 dollars right here in aus but are not recommended for more than about 400hp.
What power level do you want to reach with your set up.

Cheers Mic

i had a dirty cheap ghetto turbo build that was actually quite good.

dead stock astron1 bottom end with astron2 head. (a crappy M2 casting)
ebay t3/t4 turbo
TR manifold with falcon throttlebody
silvia CA18DET 370cc injectors.
cheap megasquirt ECU

with a poor tune it made 209rwkw at 18psi (maxed out injectors) and i did almost 15000km of thrashing with it in this state.
i then put 800cc injectors in and ran 22psi for about 5000km.
it eventually died (broken piston ringlands) when i upped the revlimit to 7000 on the stock 240,000 odd km wrecker engine.

the response and torque was amazing. it would fry the tyres in 3rd gear as soon as it reached max boost at around 2800rpm.
for my next build ive only changed pistons to ACL duratecs and gone for a better head with some porting and a cam. and will be using a turbo with a larger exhaust housing as it was choking it in high rpm.
it was great for motorkhana as it was so responsive.

Now looking at turbo's and have a choice of 2. The GT30 and the Hybrid T3. The GT30 has compressor .70 and turbine .63, and Hybrid T3 has compressor .50 and turbine .63. Whats the effect on compressor size and which one will spool quicker

Cheers

what size and trim wheels are in them? that will make a big difference.
generally speaking theyll probably be similar. if theyre cheap chineese turbos theyre probably the same turbo with different housings

is it a base spec GT3071 or GT3037/GT3076
and what housing on the back of each? again, makes big difference.

i had a .63 T3 and it was on boost early, had epic midrange torque then choked hard around 5000 and up. i would want atleast a .8 rear housing on either option.

i would go GTX3076 with a .8 housing. should come on boost around the 3000ish's rpm and pull over right through to 7000+RPM with the right setup engine.

Not sure how to read the specs. It says turbine Trim 73 inducer 65.5 exducer 55.9. Need something with internal gate and budget bit over $500.

which one was that? the t3 or the GT30?

put up links to the turbos if theyre online.

Its a Hybrid T3 ebay item 251320003752. I cant find the GT30 internal gate I was looking at. Or its not too late to modify the custom manifold and use an external gate like ebay item 121209924344. I don't want a turbo too big its laggy nor a turbo too small it will choke under 6500rpm.

The work done already:
Block machined
Crank machined
ARP bolts, Mains, Big ends, Head studs
Endurotec Duratec pistons
TR magna rods
TR magna intake and Throttlebody
Haltech ECU
Custom turbo manifold

Head not back from machinist:
M6 magna
Mild porting
Roller rockers
Custom Crane cam
Double valve springs
Compression around 8.8 - 9.0

The car has existing 2.5 inch mandel bend exhaust with supercat muffler. Is this big enough?