Peer Review! -ST185 GT4 Modification

[ViPeR_NiPPleX]

Alright. I'd suggest doing sections in one go. For power, aim to have the ECU, injectors, turbo, front mount, new piping, exhaust, uprated clutch, etc ready to go. Basically all the bolt on power upgrades without opening the motor.

Suspension, tyres, rims. Can be done in smaller stages, but i'd do them before power upgrades personally. Will make having the extra power more rewarding than getting annoyed at how badly the body rolls.

Gauges consider a diagnostic tool only if you are to use them. Otherwise they are there to look 'pretty'. They can be done first as they are simple. Blow off valves, well that's another whole debate i'm not going to put my finger into.

*cough* ST184 SX gear for the sleeper look

[areayeforty]

Sleeper is the exact thing I'm looking for, but I didn't want to say it because I thought I might get mocked <.<

So you're suggesting:

1. Diagnostics & Suspension/Handling
2. Bolt-on Power
3. Internals

Which seems obvious now that you say it like that... (Feels like an ass right about now).

Do you think the BOV is superfluous? What would you suggest in its place?

[ViPeR_NiPPleX]

That's a better list

BOV, well some people believe that preventing compressor surge aids in keeping the turbo spinning freely between gear changes and avoids damaging the turbo in ways of bent fins and such. However other people say to look at Formula 1 and other motorsport where turbo's are used, apparently not many blow off valves to be found, and they are running high boost pressures. Personally, i'm not sure what to believe anymore

[Billzilla]

Do you think the BOV is superfluous? What would you suggest in its place?

You don't need a BOV of any sort anyway. It'll be better without one.

[areayeforty]

So if not a blow off valve, what then? Just stick with the standard internal wastegate? Or add an external wastegate and bleed valve?

[ViPeR_NiPPleX]

Blow off valves and wastegates are not directly related to eachother in operation. One is designed to control turbo boost pressure and the other is designed to vent inlet pressure when the throttle is shut... or something along those lines.

A bleed valve is a simple way of manipulating an internal wastegate actuator, it doesn't have much purpose on an external wastegate as they can be adjusted by changing the preload on a spring. An external gate is a better way of dividing exhaust flow, where as an internal gate is a more compact way to package it. I'm sure most people would prefer an external gate because of the extra control and you aren't limited to the turbine casing for flow.

[areayeforty]

External gate it is. Thankyou for all this. let me post up the new list so you can have a further poke.

[-=DV=-]

That's a better list

BOV, well some people believe that preventing compressor surge aids in keeping the turbo spinning freely between gear changes and avoids damaging the turbo in ways of bent fins and such. However other people say to look at Formula 1 and other motorsport where turbo's are used, apparently not many blow off valves to be found, and they are running high boost pressures. Personally, i'm not sure what to believe anymore

while this is true, these motorsport teams and such do not need to keep a turbo/engine package alive for xxx thousand ks...they replace everything after just about every race anyway...F1 in particular...and even then their equipment doesnt even last one race.....a bov is more about preserving ur turbo than anything else...run one, or dont whinge when ur turbo destroys itself alot quicker than it should have........my 2c

[tooch]

There is a BOV discussion in another thread guys, lets not start another one

Wank factor aside, if I was installing a nice shiny expensive turbo like the HKS, I would run some kind of BOV, even if it was just a standard bosch plumback one. It's nice to know that it COULD be protecting your investment.

[areayeforty]

So I've taken everything into account and the new list has been edited from the old one. Have another look and see if there's anything else to add/subtract.

[Hen]

I'm not 100% up on the ins and outs of 3Ss, but it seems to me they are pretty indestructible in factory form. So if you have a fairly healthy example, I'd be cutting the stage 3 list down to:

Stage 3: Internals
- High-rise Camshafts
- Vernier Cam-gears
- Metal Laminated Head Gasket
- Underdrive Pulley

And at a maybe depending on whether they are really needed:
- Port & Shave Head
- Lightened Flywheel - Would be nice, but with oodles of turbo grunt, may not be required
- Performance Valve Springs
- Stainless Valves

And the dropped items. Factory parts could well be up to the task. Though I'm sure others can support/refute this.
- Upgraded Crank Shaft
- Forged Pistons & Rods
- Performance Piston Rings

With stage 4: If you have money to burn.
- 2200cc Stroker Kit

Good luck
Hen

[Roundy]

upgraded crankshaft isn't needed (tho stroker means using either the 5S crankshaft, or buy a HKS or JUN stroker kit)

stock rods are very strong, but heavy, forged rods (apparently) make it rev easier, and probably a touch more power

Porting, Gen2 has HUGE ports from the factory just a bit of a tidy up of casting marks and you would be fine!

under drive pulley, is it really neccesary, 300hp isn't pushing huge hp so the 0.5% diff this might make isn't a lot!

is the 300hp at the wheels or engine? engine you won't need much of anything at all, 300hp can be had with stock cams, stock internals, stock everything really, a larger turbo will make it easier, and more fun due to more top end stomp.

also if it is 300hp at the engine a 2.2l stroker is wasted, the turbo needed for 300hp at the engine will spool VERY easily on the 2l, and you probably wouldn't notice a huge difference with a 2.2l

for 300hp at the wheels, 550cc injectors are probably a little bit too small, but other then that you are pretty close

Cheers
Nathan

[scorpion2096]

just on the BOV discussion... if it is a sleeper the effect will kinda be ruined if you get some big whoosh type one.

obviously people who are into cars should be able to hear the difference between an NA and FI car so they probably won't be fooled, but i'm guessing you wanna hide the actual power from the bogandore drivers who would only be able to tell by a BOV.

(please note i am not intending to insult all commodore drivers, just the ignorant bogan ones)

[-==L=a=N=c=E==-]

Since i got a PM about it, i thought i'd reply here as well into my thoughts.

Since your only aiming for 300hp, then you don't need to go all out to get there. In my experience, 300hp can be done in 'bolt ons' alone. And you don't have to spend a lot to get there either.

Engine:
highflowed CT26 or CT20b
FMIC using 2.5" piping + BOV if you need it.
3" exhaust with hiflow cat
ECU (microtech or similar)
Metal Headgasket, and ARP head studs
Walbro 255lph or similar intank pump
bored or new fuel rail using 540cc injectors
possibly rebuild engine with forged pistons, shot peened rods, and balanced

Driveline:
Heavyduty or button clutch
rebuild stock gearbox if crunchy, or replace with st205 unit

Handling:
Whiteline The Works kit and get coilovers if you need them.
ST205 brakes, or R33 front brakes, using STI rotors and custom mounting bracket
rear brakes, whatever you can fit (ST205 or similar)

Cooling:
oil cooler
possibly larger radiator.


That should see a ncie all rounded streeter/track car. Although i love GT4's it isn't the most ideal track car out there.

[SilverGhost]

Im just worried about the SX bonnet contributing to engine bay temps....

Anyone who owns a gt4 know how hot they like to get under there....If your goin FMIC i recommend the Grp A bonnet, that way you can see the heatwaves emanating from the vent rather than stayin in there cookin all your hard work