Guest SECTION25 Posted February 10, 2008 Share Posted February 10, 2008 Hi everyone, Im looking to buy a Supra, and am unsure as to what model to buy. I want the latest I can get, but Ive heard that the single turbo VVTi is not as good for power production. What modifications can we perform to these? Are they the same as the TT? How much boost can the single run? What flanges are the turbos on the TT, and the single? And popular turbo upgrades? Im looking to go BPU almost immediately, and do not want to be limited by the turbo system straight away. Thoughts? Cheers Quote Link to comment Share on other sites More sharing options...
Nic Posted February 10, 2008 Share Posted February 10, 2008 The JZA80 Supra was never made with a single turbo, the non-VVTi and VVTi models were both twin turbos. If a Supra has a single turbo, then it has had an aftermarket kit fitted. The VVTi TT has more torque compared to the non-VVTi TT, both are easily tunable. The stock TT turbos use a Toyota specific flange, the only turbo upgrade would be to get the stock turbos fitted with bigger internals. Doing away with the stock manifold and turbos and fitting an aftermarket single turbo kit is a common upgrade. The fueling, cooling, ECU, etc. would all need to be upgraded to support the bigger turbo. The amount of boost a turbo can run is down to the turbo, fuel used and engine spec, 1.4bar on a small to medium sized single is a safe limit on a stock motor and normal pump fuel. Quote Link to comment Share on other sites More sharing options...
Guest SECTION25 Posted February 11, 2008 Share Posted February 11, 2008 Thanks so much for your input on this. Now that I know that VVTi are twin, I have a few more questions. The VVTi turbos are larger than the TT turbos, is this correct? Being from Australia, I would be looking to get the JDM as I doubt there would be any USA or UK spec machines over here Taken from http://mkiv.supras.org.nz/specs.htm JDM CT20A (Ceramic) 60mm/48mm (inducer/exducer) 62mm/39mm (inducer/exducer) Ceramic 600 0.42 Export (I assume this covers both UK and US spec) CT12B (Steel) 52mm/44mm (inducer/exducer) 58mm/39mm (inducer/exducer) Steel 740 0.53 So does this mean that the VVTi still runs ceramic wheels? As for upgrading the factory turbos, what is done to them? I would figure on an upgrade to steel wheels for the JDM, but what else? And what for the export models? If you have any advice on this it would be greatly appreciated. Cheers Quote Link to comment Share on other sites More sharing options...
Jake Posted February 11, 2008 Share Posted February 11, 2008 The VVTi turbos are larger than the TT turbos, is this correct? No, they're exactly the same. VVTi still runs ceramic wheels? Yes, see previous reply. Quote Link to comment Share on other sites More sharing options...
Nic Posted February 11, 2008 Share Posted February 11, 2008 As Jakes says, the J-spec non-VVTi TT and J-spec VVTi TT use the same size ceramic turbos. Basically all Japanese Supras use the same size turbos. The Japanese turbos are all ceramic (lighter), which are more responsive (less laggy), compared to the smaller export turbos. The export TT (Euro, UK, US) use steel turbos which are slightly smaller and laggier. As for upgrading the factory turbos, what is done to them? I would figure on an upgrade to steel wheels for the JDM, but what else? The stock turbo housings can be machined out and bigger steel internals fitted, these are referred to as Hybrid turbos. They will produce slightly more hp, but will be more laggy. They retain the original housings, so there are limited to how big they can be made. Usually the only reason to do this would be if the stock turbos blow. With the extra lag and only slight increase in HP, it is not a very economical upgrade. There are limits to how much boost can be run on all the stock and hybrid turbos, push them too high and the exhaust gas temperatures start to get dangerously hot. There are no bolt on aftermarket turbos available to fit the stock system (space is the main problem). The only other option is to remove the stock turbos and manifold completely and replace with either a bigger single turbo or bigger parallel twin turbos. Quote Link to comment Share on other sites More sharing options...
Guest SECTION25 Posted February 12, 2008 Share Posted February 12, 2008 Thanks for this information. So running a safe boost level at BPU mods, what is the expected HP or KW from the stock turbos (both VVTi and non VVTi)? I would like to know how much power I can hope to have before going the super expensive route of changing turbos and exhaust manifolds. Cheers Quote Link to comment Share on other sites More sharing options...
Nic Posted February 12, 2008 Share Posted February 12, 2008 Thanks for this information. So running a safe boost level at BPU mods, what is the expected HP or KW from the stock turbos (both VVTi and non VVTi)? I would like to know how much power I can hope to have before going the super expensive route of changing turbos and exhaust manifolds. Cheers In the UK 1.2bar is considered max boost to run on stock turbos, I know in Australia though you have to keep both cats fitted, so 1-1.1bar might be a safer level. At that boost you should make around 375(ish) flywheel hp, on both the VVTi and non-VVTi. The VVTi will have a bit of extra torque due to the variable cam. Max possible on stock J-spec turbos with all supporting mods would be around 430hp at 1.2bar Quote Link to comment Share on other sites More sharing options...
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