Syan48306

I've looked a lot into the Aristo VVTI Twin Turbo Swap into our IS300's and have just a couple questions that the docs and guides don't explicitly cover. Perhaps someone can help me knock them out.

Assumptions: I'd like to use the existing twin turbo for a ~300 whp goal. Using a W55 or W58 transmission & clutch. Keep IS300 ECU but run a standalone Engine Management System in parallel for the engine - Perhaps an AEM.

1. Can I use the Aristo wire harness with the standalone unit in parallel with IS300 ECU running other things? Or do I use the IS300 harness (The IS300 harness can't run the twins right)? Is there a Aristo VVTI plug & play + Engine Management Unit Recommendation?

2. The JDM GTE is rated for 280 HP flywheel. Is it possible to get 300 whp using the existing twin turbos in sequential mode or is a TTC mod absolutely necessary to hit the 300 to 325 whp mark?

3. I think stock twin turbo output is around 11psi. I see people talking about up to 15 PSI. IS that due to the standalone tuning or a physical mod to the waste gates?

4. If modded for TTC at what RPM do you get full boost? Is it possible to be fully spooled up on both at 3000-3500 rpm?

blkaltezza

iTrader: (1)

I'm no expert but I could answer a few of your questions.

This is what is commonly done, wire in the standalone with the is300 ecu in parallel. This allows the standalone to completely control the engine but still retains your gauge cluster, a/c controls, etc.

Most people swap over the GE harness to the GTE and do the ttc mod. The ttc mod is physical so it eliminates the need for the ecu to control the turbos. Every sensor on the GE harness will be used on the GTE engine, but as you said the GE won't control the turbos so those plugs are not used. You will need a standalone ecu, or a piggyback like the Greddy EMU at the very least.

Another option is to run the JDM Aristo ECU, this route will use the existing aristo harness and also require repinning your body wiring harness. You can send it in to dr. tweak to get it done if you don't want to repin your connectors yourself. It'll basically run like a stock aristo and you keep the sequential turbo setup. Downside is that some of your gauges won't work without alot of work, and your car will no longer be oboii compliant if you care about that. Also you will have to run the 4 speed transmission that comes with the aristo motor.

Full boost should be the same regardless if you do the TTC mod or not. It just makes the turbos operate in parallel instead of sequential. At full boost they should produce the same amount of power.

I'm not too sure since I have a NA-T setup on my car, but you'll need to install a boost controller so you can turn up the boost. It'll hook up to the stock wastegate and control how much boost the turbos produce. I never worked on a 2jz-gte with a TTC mod personally so I'm not even sure you can use a boost controller on the stock wastegate, but i don't see why not. I'll let someone else chime in on that.

As stated above, that's probably because they installed a boost controller to raise the boost.

Not sure about this since I never been inside a car with the TTC mod, but the supra guys seem to hit full boost around 4k rpm.

codeXsupra

This shouldn't be seen as a negative since it's stronger than the W55/a650e in the IS300. 1 less gear can be a positive with the right differential to sit on a gear in power longer for pulls. GS400 differential (3.266) is perfect for this with A340E above stock twin power levels. The A340E's 4th is also taller than the W55 and A650E's 5th, so better highway MPG while cruising. A340E+3.266 = ~2000rpm at 65mph, while A340E+3.909= ~2000rpm at 55mph. Stock IS300 AT/MT is 51mph/47mph at 2000rpm. All of this is with 25.5" diameter tire, so that'll influence all rpm at MPH a little.

For my IS300, I fully plan on eventually going with a full 2JZ-GTE VVTi Aristo swap, including A340E transmission and GS400 3.266 with TRD differential.


TTC = same power as sequential with the lag of a single. All it does is make the torque build-up more smooth, but reduces power under the curve. It *can* help keep the #2 turbo alive in higher boost levels, so that's the only real benefit.

Installing a downpipe & cat-back will free up the exhaust, usually resulting in higher boost without the use of a boost controller on a 2JZ-GTE with twins. 300whp on JDM twins is easily possible without going TTC, which doesn't increase power. 3+" downpipe and full 3-4" cat-back exhaust will do it. Boost controller will help push it higher, and Boost Cut Controller (Greddy BCC/Speed4Sale BCC) will eliminate boost cut over ~14psi. Don't push JDM twins higher than 16-17psi - they're ceramic and aren't as strong as the USDM turbos. Plenty of Supra guys have gone high 300/low 400whp on JDM twins. JDM 2JZ-GTE has 440cc injectors (USDM has 550cc), so you're going to be limited to around 400whp anyway due to injector size.

All you need is the 3" downpipe, 3+" cat-back exhaust, BCC, boost gauge, and boost controller to get well over 300whp on JDM stock twins. Just don't boost over ~16psi to keep the twins alive for the long term.

Yep, full boost around 4k, with none of the benefit of maxing the first turbo's boost around 3k rpm.