Digital Posted August 4, 2009 Share Posted August 4, 2009 (edited) Having the stock twins on the work-bench I want to try something that I can't find here on the forum, can somebody tell me if this will work or what will happen? Observing: -the front turbo has a actuator with 2 vacuum-tubes, and 1 vacuum-tube on the compressor-side. -the back turbo has a actuator with 2 vacuum-tubes, and NO vacuum-tube on it's compressor-side I would like to take off all original vacuum-hoses and disconnect all solenoid-valves. After this I would like to make the turbos true-twin by connecting a good boostcontroller(like a Apexi AVCR of Greddy E-01) between both actuators and compressor-sides. Will this work? (could I make an extra tube on the compressor-side of the back turbo, or is it on the stock piping? haven't got it by the car) Could I remove the big actuator which is right in front of the downpipe and permanently open the gate? Edited August 4, 2009 by Digital (see edit history) Quote Link to comment Share on other sites More sharing options...
legendswraith Posted August 4, 2009 Share Posted August 4, 2009 Just put them back in as you found them, then search true twin conversion at least then you'll have the option of returning to sequential easily when you find out you don't like TTC Quote Link to comment Share on other sites More sharing options...
Digital Posted August 4, 2009 Author Share Posted August 4, 2009 I would like to try this first, just to see if this works, anyone else have answers to my questions? Currently I'm driving with a single Greddy T88 so there is no problem, making true-twins is just an experiment. I just talked to someone who said the internal wastegates on the turbos are to small for my idea, so it will overboost, is this true and would it be over if I port the wastegates or narrow the downpipe? Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted August 4, 2009 Share Posted August 4, 2009 Just put them back in as you found them, then search true twin conversion at least then you'll have the option of returning to sequential easily when you find out you don't like TTC Or, do TTC properly and enjoy it like I did. A lot of people who did the full conversion, including tweaking the fuelling to suit, love TTC. Quote Link to comment Share on other sites More sharing options...
legendswraith Posted August 5, 2009 Share Posted August 5, 2009 I'm on the fence with that one i can see the benefits and the downfalls. However you are correct in saying i didn't adjust the fuelling/timing. I'm open to any offers of TTC EMU maps for a bpu auto vvti though . Doesn't the soarer use pretty much the same turbo set up in True Twin? In which case toyodiy might give some exploded diagrams on how its configured on that. Quote Link to comment Share on other sites More sharing options...
AlexJames Posted August 5, 2009 Share Posted August 5, 2009 Im on Electronic TTC, love it... however, i hardly ever use sequential any more as it makes the engine rough when the ECU has to re-learn. Much better driving experience, IMHO Quote Link to comment Share on other sites More sharing options...
Digital Posted August 6, 2009 Author Share Posted August 6, 2009 Can somebody help me getting the original intake piping on stock JJDM-twins, the turbo intake-piping and compressorsides-piping? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 6, 2009 Share Posted August 6, 2009 There is only one waste gate on the twin turbos, on the front turbo, the one on the rear is not a waste gate as such, have a look inside the exhaust housing;) and you will see the difference, in order to convert to true twin mode you need the front actuator and then wire open/closed the other relative actuators, there are several guides around. Quote Link to comment Share on other sites More sharing options...
Digital Posted August 6, 2009 Author Share Posted August 6, 2009 What is the wastegate of the back turbo for then? Because it's actuator does close/opens a gate.. Will the front turbo wastegate be enough for both turbos then? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 6, 2009 Share Posted August 6, 2009 What is the wastegate of the back turbo for then? Because it's actuator does close/opens a gate.. Will the front turbo wastegate be enough for both turbos then? Have a look here http://www.mkivsupra.net/vbb/showthread.php?t=35926 it will help you understand how the std system works, and yes the front WG is the only one, and small at that, thats why they overboost when decatted and need a restrictor ring. Quote Link to comment Share on other sites More sharing options...
Digital Posted August 6, 2009 Author Share Posted August 6, 2009 Ok thanks, will check it out after work! Have to make an external wastegate then.. Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 7, 2009 Share Posted August 7, 2009 Or, do TTC properly and enjoy it like I did. A lot of people who did the full conversion, including tweaking the fuelling to suit, love TTC. What fuelling tweak can you do then? Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted August 7, 2009 Share Posted August 7, 2009 What fuelling tweak can you do then? You will obviously need to fit something to control the fuelling, but then you can tweak the map to get the optimum fuelling for TTC rather than twin turbo. The curves are obviously going to be different as in TTC there is no first turbo boost so will overfuel until both come in. Also, the Supra overfuels on the switchover point between the first and second turbos, so this can be addressed too. Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 7, 2009 Share Posted August 7, 2009 Ahh, so you'll need an aftermarket ECU. There's no tweak you can do with the stock ECU. Cheers Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted August 7, 2009 Share Posted August 7, 2009 Ahh, so you'll need an aftermarket ECU. There's no tweak you can do with the stock ECU. Or a piggyback fuel control device such as an E-Manage. The stock ECU is widely regarded as impossible to remap as it's never been done effectively IIRC. I believe someone in Australia was trying to do it but with little to no success. Quote Link to comment Share on other sites More sharing options...
little num Posted August 7, 2009 Share Posted August 7, 2009 I run a uk tt6 with electronic TTC but dont have any fueling mods as yet, i also prefer to drive in TTC when on track or road, mostly as i run 1.35 bar all the time and hit 1.4 in 5th - 6th gears. By running TTC your taking alot of stress from Turbo 2 as it always gets kick started by Turbo 1, Its the kick start that kills turbo 2. And as i run high pressure its alot more stable at the wheels and dont just wheel spin all over the place. Problem with TTC is noise i hate the sound it makes, so i swapped my HKS silent for some unknown jap exhaust and its lovely now, no noise but still plenty of boooost lol. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 7, 2009 Share Posted August 7, 2009 You will obviously need to fit something to control the fuelling, but then you can tweak the map to get the optimum fuelling for TTC rather than twin turbo. The curves are obviously going to be different as in TTC there is no first turbo boost so will overfuel until both come in. Also, the Supra overfuels on the switchover point between the first and second turbos, so this can be addressed too. The std ECU does not overfuel in TTC mode below 4,000RPM or until positive boost is reached, as it will still be in closed loop and controlled by lambda feedback. However it does have a lot of timing pulled because of the first turbo early spool up so fitting a piggyback can help a lot in this area. Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 7, 2009 Share Posted August 7, 2009 Is it at all dangerous to run in TTC with a stock ECU? If it's at all overfueling, am I risking bore wash? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 7, 2009 Share Posted August 7, 2009 Is it at all dangerous to run in TTC with a stock ECU? If it's at all overfueling, am I risking bore wash? No! as i said in TTC you are in closed loop until positive boost or 4,000 RPM just the same as in sequential, and that runs things pretty rich anyway. By adding a piggyback you can just get things a bit better dialled in. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 8, 2009 Share Posted August 8, 2009 You actually run lean in TTC mode under 4000rpm when on boost. Offboost it's all the same. No idea where the idea it runs rich came from, why would it do that? You also get a fat boost spike around 3500 to 4000 as well, because the stock wastegate doesn't "need" to come in until 4000rpm. -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 8, 2009 Share Posted August 8, 2009 By running TTC your taking alot of stress from Turbo 2 as it always gets kick started by Turbo 1, Its the kick start that kills turbo 2. And as i run high pressure its alot more stable at the wheels and dont just wheel spin all over the place. Ugh. OK first, turbo 2 isn't "kick started", it's prespooled by exhaust gas bled off from the first turbo as soon as the first turbo has reached max boost. Second, even if it was subjected to a lot of exhaust gas suddenly, that's what every turbo ever is built to do - spinning up as fast as possible is a primary goal of the design. Third, what kills the turbo is people running them way faster than they were designed for (ahem 1.4bar ahem), not them spinning up -Ian Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted August 8, 2009 Share Posted August 8, 2009 You actually run lean in TTC mode under 4000rpm when on boost. Offboost it's all the same. No idea where the idea it runs rich came from, why would it do that? You also get a fat boost spike around 3500 to 4000 as well, because the stock wastegate doesn't "need" to come in until 4000rpm. -Ian On one of the sites that shows how to do the TTC mod, it states that it'll run rich during the early revs, where the first turbo should cut in, and until the computer sorts itself out. http://mkiv.supras.org.nz/articles/andy.htm Last paragraph on this article Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted August 8, 2009 Share Posted August 8, 2009 You actually run lean in TTC mode under 4000rpm when on boost. Offboost it's all the same. No idea where the idea it runs rich came from, why would it do that? You also get a fat boost spike around 3500 to 4000 as well, because the stock wastegate doesn't "need" to come in until 4000rpm. -Ian Oh! OK i guess my AFR gauge and data logs must be wrong then:taped: Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 8, 2009 Share Posted August 8, 2009 Oh! OK i guess my AFR gauge and data logs must be wrong then:taped: Well the stock ECU runs 13:1 AFRs when on boost on the first turbo according to all the datalogs I've got of various Supras. I can post them up here if you want me to - can you post up your stock 1st turbo recordings please -Ian Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 8, 2009 Share Posted August 8, 2009 (edited) As luck would have it I have a couple of representative datalogs at work, from some EMU units I did a while back. I've highlighted the interesting bit in blue, the boost pressure and revs columns in some nasty green, and the AFRs in red. You can see the fuelling fall off it's cliff between 3500 and 4000rpm, just as the blue highlighting ends. That's when the stock ECU decides turbo #2 is about to come into play so it's time for proper fuelling. Before that it's around 13:1 AFRs. Caveat - these aren't 100% stock, they are both on larger injectors. There *is* some trimming already going on because of my basemap, but when you compare the AFRs before and after the transition point (taking ad 1.xls, 13:1 to 10:1) you can see the stock injector duty cycle changes radically (11ms to 14ms duty in no time at all), whereas the correction in the EMU map do not (-12% airflow constant, 0 to 1.3% change in duty cycle) - so it isn't the map artificially producing this condition. I've seen this behaviour in every TT supra I've datalogged, and I know Ryan had to overcome it with the piggybacks he's used as well. The stock ECU runs 13:1 AFRs on the first turbo below 3500 to 4000rpm. -Ianad 1.xlsbt 1.xls Edited August 8, 2009 by Ian C (see edit history) Quote Link to comment Share on other sites More sharing options...
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