exist3nce's Turbo Optra - New Direction and setup (CT12B)

[exist3nce]

Not an Aveo, yes I know, but those who have been following my project for a while would be interested


I've been looking at getting another car for some time as something fresh to start. The Optra has served me well, however I think its time for a new project.

A few reasons, as the Optra would require at least these things to go further:

- Good condition F28's are quite rare these days, and rebuild parts have been discontinued - mine is working ok, but mileage is high and its getting old
- The motor is a little tired, compression is slightly low, it could use a rebuild
- I would need a standalone EMS to push any more power safely (along with custom cam/crank sensor setup) - Would go with AEM EMS
- Stronger axles (already broke one)
- New set of 750cc+ injectors




The answer:

2002 Lexus IS300

For those who don't know it has the 3.0L Inline 6 cyl 2JZ-GE motor (basically a NA Supra motor). 232,000 km on the clock. Color is Intensa Blue Pearl. All factory options, heated leather + LSD. Previous owner already installed Tien S tech springs and Clutchmasters Stage 4 Ceramic clutch. Also has a nice sub custom built into the floor of the trunk.






And now for the goodies that I've started to collect.... More to come here

Divided T4 Stainless manifold
Racetronix SMP 850 cc/min injectors

[exist3nce]

As for the future of the Optra, my original intention was to remove the turbo related parts and use every bit I could on the IS300, thus converting the Optra back to NA. However when I was at the shop I was convinced to keep it turbo, but with a setup oriented towards driveability, useful torque and quick spool. Essentially converting it to a factory turbo car.... how it should have come from the factory :P

We used a CT12B turbo which is one of the stock twins from a 1994 USDM Supra. Max power it can push is about 220whp. Here you can also see the modified section of the downpipe and the custom internal gate setup with a 6psi actuator. Also the manifold has been modified to fit the smaller turbo with a set of T3 flanges. The whole turbo/manifold package is very compact.



CT12B taken apart:



Stock IS300 muffler adapted to fit the Optra:



The setup with new intercooler and a random oldsschool HKS BOV:




The following parts will be donated to the IS300 project (yet still allow the optra to run low-mid boost)

- Precision FMIC
- T4/T04B Turbo
- Walbro 255 Fuel pump
- Return fuel system
- Apexi AVCR
- Supra TT OEM muffler (in trade for the IS300 OEM muffler)
- Turbosmart 38mm external wastegate
- TurboXS BOV
- Water/meth injection kit

The Optra will be tuned for 91oct gas.

[petrified.rabbit]

Can i ask, with the m32 readily available now (on ebay) why not swap out the f28?

Sounds like your keeping the optra

[exist3nce]

Can i ask, with the m32 readily available now (on ebay) why not swap out the f28?

Sounds like your keeping the optra

Reasonable question. There are newer transmissions available yes, but that would require new custom mounts, custom shifter linkage, new clutch and some kind of solution for the vehicle speed sensor (I haven't even looked into whats required). I feel that the IS300 will be a much better platform to make more power and put it to the ground.

Having said that I was originally thinking about turning the Optra back to stock and parting out the non transferable parts such as the KW coilovers, 6 spd setup, projector headlights, turbo piping & manifold, etc and then selling it. Then I realized it would be good to have a backup/winter car and voila the Optra had a new purpose!

[exist3nce]

So I thought I would update this thread for those interested since I've all but forgotten about it and there have been significant changes.. Heres the timeline since my first post...


January 2012: The CT12B initial setup was finished, and running as shown in the pictures on the internal wastegate. It ran decent enough but the power was fairly low due to the exhaust back pressure from the extremely small turbine forcing the wastegate open. With a 7psi wastegate spring, boost would come in around ~6psi and drop to ~3psi by redline giving me about ~150whp. Nothing to really get excited about..


March 2012: Added a manual ball and spring boost controller to try to stabilize the boost better. This worked somewhat better and let me have the boost come in around ~7.5psi but still dropped to ~5psi by redline due to the same issue. Power was a little better at around ~165whp.... still not great.

April - December 2012: Optra in storage, driving my IS300 around



Continued in next post...

[exist3nce]

March 2013: I've gotten tired of the mediocre power and need more, so my goal is 200whp on the small CT12B turbo. To achieve this, I've collected the following parts again..


External wastegate (for more precise and stable boost control)
Apexi AVCR (the one I had went to the IS300 project. But this boost controller is absolutely amazing for RPM based boost - so I've acquired a second one)
Return fuel system (I already have the modified pump basket and Walbro pump, so I just needed to find another regulator)


Right now the car sits at about ~165whp .... so another ~35whp to achieve my goal


Oh and I'm still keeping the stock Lexus IS300 muffler on here for the near-OEM quietness...



Here's some pics of the new (and used) parts:


Another Used AVCR for progressive boost control




A friend hooked me up with this, after his project outgrew it lol. I must have return system to run any more than 8-10psi. Yes I could have just kept the car return in the long run, but I didn't have the cash to do that during the IS300 build.




Going back to external wastegate.... the internal one just sucks for precise and accurate boost control.

[exist3nce]

March 2013 continued:

Here we have the new external gate welded on along with a slip fit recirculated dump tube...


Also if you look closely, you will see that we ported the compressor cover for anti surge and increased turbo spooling sound




Here's some pics of the fuel system setup... I have switched my 2 additional injectors over to Siemens Deka 63 lb/hr as they are supposed to have one of the widest spray patterns which is well suited for the throttle body type injection they are being used for. We also tried to run as much hardline for the return as possible under the car (the line actually goes up into the engine bay).




Couple views of top and bottom of the turbo area / piping.

[exist3nce]

March 2013 continued:


Finally got this little badass setup tuned, and I'm quite happy with the results.




Despite the turbo being undersized for 2.0L we managed to squeeze out:


214 whp / 207 lb ft.



Through progressive boost tuning I was able to keep the torque nice and stable until about 5500 rpm where the tiny turbine starts to choke its life away haha. We were able to verify this by testing exhaust back-pressure pre-turbo during the dyno runs with a boost gauge. This is about as far as we dare to go on this turbo, and the numbers make perfect sense. Two of these turbos on a Supra 3.0L can crank out about 450whp max, so we are pretty much at the limit.




All in all not a huge amount of power, but this is quite fun to drive on the streets because the power is always there from almost any RPM.



Dyno Video:

[exist3nce]

February 2014 (current): Got the itch to change something again with the Optra, and decided it was time to get a proper management system which would also allow me to run a very nice coil on plug Honda S2000 ignition system





Will be working on creating some wiring diagrams in preparation to install this over the next little while. There is a chance it may be able to read off my stock crank/cam pickups so I will be testing that first prior to building custom pickups.

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Spent the past 3 days wiring up the Haltech.... After a few glitches and mistakes we got the car running with the new setup!!


S2000 coil on pug FTW



That's a shot of it running - but we are not ready to tune just yet. Still have to clean / tidy up all that wiring and then sync up the timing and install larger injectors (stock injectors are still being used at the moment).


Some facts / discoveries:


- The Haltech Sprint500 was able to share the factory cam and crank sensors with the stock ECU. Both ECUs are able to read RPM, etc at the same time.
- The stock crank trigger wheel is a 60-2 pattern with magnetic reluctor sensor... I was previously told by someone else that is was a 36-2 pattern and was trying to use that with little success. Luckily the Sprint500 comes with a Motronic 60-2 pattern that I could use.
- The stock cam sensor is a hall effect and has just 1 window. Again luckily the Sprint500 has the 60-2 + 1 pattern
- The coolant and air temp sensors are able to be shared as well.... but it seems the Sprint500 does not have any suitable scale/calibration for them. I will either scale them myself, or just install dedicated Haltech sensors.


For convenience I made a quick swap harness for the injectors so that I can swap back and forth between which ECU is actually controlling the injectors in about 30 sec

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- We were able to sync up the timing and able to free-rev it up to 7000RPM without any issues. However.... When we put it on the dyno, under load at RPM's above ~4000 or so we start missing counts of trigger teeth - the higher we try to rev it the worse it gets and no amount of filters or adjusting settings seemed to help. When it gets bad enough the Sprint500 looses track of the engine RPM and basically shuts off the injectors. So it looks like I'm not as lucky as I thought with being able to share the stock sensors.... Will have to make the custom triggers now.


- Neither of the stock air or coolant temp sensors are usable with the Sprint500. I tried scaling them, but around ~50 deg C the stock ECU changes its pullup to adjust its resolution and there's nothing I can do to change this. Since I already had the AEM water temperature sensor+gauge with 0-5VDC output, I just used that signal and it works well. For air temp, I just installed a dedicated AEM air temp sensor in the charge pipe and wired it to the Sprint500. Both sensors required manual calibration/scaling.


Soo the car is actually driveable to about 4000RPM right now and its drives quite well considering the tune is still pretty raw - more to come when I get the cam/crank sensors figured out.

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More good news..


We were able to sync up the timing correctly last night with the new pickups, which confirms they are running properly and reading clean signals. Was able to free rev again to ~7000rpm without any hesitations or drift in the timing which is certainly a good preliminary test. Next will be back on the dyno hopefully in the next couple days to confirm all is good under load and tuning.


Here's some pictures of the custom pickups reading off the stock exhaust cam gear and also modification of the timing belt cover to accommodate the new sensors and allow for quick adjustments if necessary while maintaining a "stock" look. Left sensor is for cam and right is for crank.










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So after a few more slight headaches playing with the sensor gaps and filtering settings I believe I've got it running right. Dyno tune happened a few nights ago and here's the final results:


225whp / 212 lb ft





Something interesting now that we have full control of timing is that we were actually able to squeeze about 10whp more out of this undersized turbo by lowering the boost a touch and running a little more timing. 11.5psi on stock ECU and now about 10.5psi with the Haltech. Overall I'm pleased with the numbers - they are where they should be for this turbo that is beyond maxed out LOL.


Dyno Video

[Pooh Man]

That's awesome, props for a lot of custom/DIY fabricating