Upgrades to a 3TC suck though turbo setup???

[ctrain]

Sup, my tool bonus has come through and now i can make my 3tc go faster, standard clutch slips under boost so im upgrading to HD, the turbo (VL/Sigma) stock T03 turbo has a little bit of shaft play so thats getting upgraded and it has the Sigma 32mm Garrett external wastegate, need to upgrade mainly because the wastegate hits the crossmember when reversing so i need something smaller in size. Im not good with turbos or wastegates so if anyone could suggest some that'd be great!

All the stuff is from the early 90's and hasnt been rebuilt as far as i know.

Im refitting the water and methanol injection system so that should keep intake temps a bit down, anyone know any little secrets with these setups?? Im tempted to go EFI but getting my hands on a 3TEU intake and all the other stuff seems impossible.

Cheers,
Callum

[NME308]

Hi Callum,
Should you chose to stick with the draw through setup I would actually suggest you do your upgrades one at a time. Start with a nasty clutch capable of handling 400hp as future proofing.
From there work out the tune & wind up the boost carefully & observe the results closely. Spark plug tips being damaged or gaining miniature metalic balls tell of detonation. Once you simply blaze the tires any time you go to play then it is dyno time for more development. Turbo & waste gate replacement would follow once the originals are delivering no more gains.
Efi gear for these babies is still available if you keep an eye out particularly overseas. Then any reputable tuner can give you results if you prefer someone else to tweak your ride.
Cheers,
Jason

[ctrain]

thanks man, i suppose the only way you can wind up the turbo psi is by replacing the wastegate spring yeah? i took all my turbo side off today to find out i forgot to tighten the last exhaust manifold bolt, not happy, im going to get new V bands and probably get the turbo freshened up, and check what spring is in the wastegate because my gauge reads 8-10psi yet the wastegate was rated at 5psi, unless someones changed the spring could the leak cause a different reading?

Cheers,
Callum

[NME308]

The spring in the waste gate is not necessarily a spot on measure. PSI in the manifold vs rated gate spring will vary a bit based on turbine back pressure and intake restrictions etc. A leaking exhaust manifold wont cause over boost.
You can use a boost T in the bottom gate port or a pressure regulator to the top port (my preferred ghetto solution) to increase boost pressure up to around double what you get straight off the spring.

My thoughts would be not to spend a fortune on old gear but use it to get a handle on the tuning intricacies of your draw through setup and then think about spending some coin on some more modern gear. You may figure carby turbo is not your cup of tea or absolutely love it! Either way my suggestion is to play hard with what you have (which a decent clutch will allow) and make some decisions down the track.

Cheers,
Jason

[ctrain]

update.

I made it go faster

Since the old turbo gear hadn't been touched for ages i decided to give it a freshen up, cleaned up all the faces on the manifold, wastegate, turbo and exhaust and new v bands, one thing i noticed is that there is a tab that sticks out about an inch at the wastegate side on the manifold and i think it was pressing down on the wastegate valve when the v band was done up as there was a faint mark on the valve, so i grinded it down and put everything back together and hooked up a turbosmart manual boost controller, took it for a spin around the block and yeah she pulls a lot harder, my boost gauge was reading 15psi but that was i think in 3rd so it wouldn't give me a perfect reading. but im confused because the wastegate gate has a 5psi spring, and the boost controller is preset at 6psi from the box and my boost gauge is reading 15psi, i still have to test it more after i pay rego.

Also when i decide to up the boost should i advance the dizzy a little?

[MorGo]

No,the proper advance is same in NA and boosted.It all depends the combustion chamber and intake port (the charge motion) what advance the engine wants.Sure if it knocks you can retard but then you also reduce power.Either cool the charge or increase the octane (or both)

[NME308]

No,the proper advance is same in NA and boosted.It all depends the combustion chamber and intake port (the charge motion) what advance the engine wants.Sure if it knocks you can retard but then you also reduce power.Either cool the charge or increase the octane (or both)

Codswallop! :-\

If you have no boost retardation device then you may need to retard the dizzy with more boost. With any given fuel in a given engine once you get to a certain cylinder pressure you have to retard ignition timing to avoid detonation. This is because tightly compacted air & fuel molecules propagate the flame faster. There is then a window where more boost can be added while timing is retarded proportionately & engine power continues to rise as per normal mathmatics. Eventually with our control fuel we reach a boost level where cylinder pressure dictates timing needs to be retarded heavily enough that real world power gains cease to be seen. If engine components are strong enough then higher octane fuel will allow more boost & retuning as above hence higher cylinder pressures without detonation & higher horsepower!

Cheers,

Jason