Hi there good peoples, I need some clarification on these issues as the search results do not provide any straight answers plus I am not mechanically minded
Is it possible to control boost (with a good IEBC)on stock turbos as wastegates are too small??? Is it worth spending money on an IEBC?
Are there any gains to be made in an external wastegate on stock turbos?
What about dumppipes? Dont they cause spiking on stock turbos?
Wednesday, April 05, 2006 - 10:07 am, by: James Harris(Haro)
hi mate,
Im not too much of an expert on this stuff at all, but ill give it a good aussie go.
1) Yes it is possible to control boost with an ebc EVEN with stock turbos, i dont know about this wastegate too small stuff as the stockers can still run 18psi (however, i would avoid it as the ceramic wheels wont like it and it wont be effecient for the turbos) Yes spend some money on an EBC... they are fun but you dont need them to raise boost. Try GIZZMO stuff.
2) External wastegates... stock turbos... NO. doesnt work from what i could assume. Well not worth the effort anyways.
3) Dump pipes didnt give me any dramas with spiking boost, they DID raise the boost a lil as the turbo could spin easier as they wont restricted as much.
Hmmm... im sure others will help out here if my answers are incorrect.
Wednesday, April 05, 2006 - 10:45 am, by: Hanré Van Rensburg(Silent_knight)
Shyam I haven't really heard of wastegates on the stock turbos being too small...
An external on the stock turbos IMHO would be a waste of time and money. It will require a custom bit of fabrication to be done and wouldn't really provide much improvement as far as I can really see.
An EBC is a good way to controll boost efficiently and safely. It also helps prevent boost spiking.
Dump pipes like what has been said will raise your stock boost level a wee bit as it will cause better flow etc but it won't cause the boost to spike around uncontrollably.
Again with an EBC this can all be nicely controlled to levels that you deem acceptable.
I use a Greddy Profec B EBC on my Soarer and it's work brilliantly so far.
Wednesday, April 05, 2006 - 10:47 am, by: Mark Paddick(Sparks)
A boost controller like the Jaycar IEBC is very useful. It will maximise mid-range boost (wastegate is partially open at mid-range with the factory system and totally closed with IEBC so boost comes on quicker and is higher). Spikes will be less than 1psi with IEBC so you can set max boost at, say, 13psi and avoid fuel/boost cut while still having a decent amount of boost. A system like the Jaycar one will allow you to have more than one boost map so you can have one for wet weather (or other drivers) where the boost comes on slowly and gently and one map for max power/boost.
Thanks fellows, that was exactly what I wanted to hear And much appreciated for the super quick response.
Mark, I did get a Jaycar IEBC (the same time I got the hand controller and DFA) but gave up and returned it back coz it was too much fiddling around. Could you build a kit for me and send it over to sheepland?
Wednesday, April 05, 2006 - 12:52 pm, by: Leigh Kuilboer(Requiem)
Norbie (on supraforums and some times toymods) was apparently going to build an exhaust manifold for he 2jz that had an external wastegate (with stockies), I think he was going to weld up the waste gates after. I could be wrong. An external is benificial but it depends on bang for buck whether its worth doing. as u can imagine the air that would have to pass through the inlet of the ct12 and then out the wastegate would just bypass it altogether, meaning a better breathing engine. Always good.
Wednesday, April 05, 2006 - 01:04 pm, by: Hanré Van Rensburg(Silent_knight)
I know the MOD has been done on a 2JZ. There was a manual on a site somewhere in the US I think but the last time I saw it was over a year ago so wouldn't have a clue where to go look for it again.
Because I have experienced boost cut everytime I put my foot down with minimal mods, i.e opened up the exhaust with no cat. How detrimental is that boost cut, especially when the jap sign pops up and goes BLING? Is it a safety cutout for the factory settings to protect the turbos from spinning further?
Wednesday, April 05, 2006 - 02:10 pm, by: James Harris(Haro)
Id be suprised that your car is naturally hitting boost cut without some kinda boost controller.... mind you i spose it does get mighty chilly over in NZ so that may influence it a bit.
I also like the IDEA of using the Jay-car kit but im not too good at stuffing around with stuff like that. I ended up gettin a GIZZMO EBC (thanks Khalid) and it works a charm. Gizzmo are made in your country and go pretty cheap on trademe.co.nz good buy.
Hanre, it is boostcut, had it checked and a reading came up as "turbo backpressure malfunction". It also feels like a violent jerk and at the same time hitting a brick wall. The boost gauge is at about 14psi or so. It does this momentarily and goes back to normal driving condition. use to happen heaps when I was in the deep south but occasionally happens when I nail it here off the lights etc
James, I almost bought a Gizzmo EBC but returned when the mention of the wastegates being small and unable to control the spiking etc. I also love the idea of the Jaycar IEBC, just waiting for Mark's reply
Wednesday, April 05, 2006 - 09:57 pm, by: Travis Bentley(Kinny)
What is strange is that with just dumps back exhaust (manny style, so not exactly straight through, and cat is fine) and pod filter i hit boost cut when it gets around 10 degrees here in perth. Boost gauge is reading about 14psi and it comes up with that electronics error code. As Shyam describes the car just jerks and then carries on. No boost controller or any other mods.
Even stranger is that it didnt used too with these mods in the dead of winter, now its getting colder from summer i am...?
Wednesday, April 05, 2006 - 11:07 pm, by: Cihan Aday(Cihan)
Removing the CAT will give about 1 bar of boost without touching anything else.
The CT12a wastegates are indeed very small and dont flow enough to overcome additional turbine speed when exhaust restrictions are removed. Even with an electronic boost controller, the minimum boost level goes above the fuel cut trigger. If you have a few basic flow mods whilst running no CAT, it will hit fuel cut/boost cut (they're the same thing) constantly under WOT.
My advise, get a FCD/BCD (fuel cut defender/boost cut defender). Even if you dont get it tuned, there is enough fuel in the factory tune for about 15.3psi at 3500-4000rpm where most spiking happens. Natural spiking wont exceed this point so your problem will be solved. Just for clarification; the standard ECU will stop supplying 'additional' fuel after ~14.5psi. Its actually pretty rich here from the factory and ive found that ~15.3psi is fine (low 12AFR's) with a FCD set just below the boost cut trigger point. It solves spiking, and you'll be making more power with the safe yet leaner mixture.
If you have anything but basic flow mods (exhaust system, intake) even just a front mount - i would suggest the installation of a Greddy Emanage. It does fuel cut, injection and ignition. There is also a seperate injection map for when the clamp voltage set for fuel cut defense is exceeded, which allows your tuner to tune for boost pressure above the standard MAP sensor output.
Id advise using the additional injection map for anything over 16psi - it dumps in 16psi worth of fuel as soon as you touch the clamp voltage which is well before you need it. Its not really an issue becuase these turbos spool so fast, just one more reason to buy a supra MAP sensor.
Wednesday, April 05, 2006 - 11:26 pm, by: Mark Paddick(Sparks)
It should be possible to do a boost controller. now that I have a TT myself I can have it all set up, ready to go. I am rather snowed under just right now so it could be a little while before I get to it. (I haven't even done one for me yet!...the TT still has some obscure Japanese boost controller which I don't like and doesn't work very well....possibly that has something to do with the fact that the actuator solenoids were resting on the rear turbo housing when I got the car).
Boost, fuel, revs and speed cut are all functions of the ECU programming (which is why a sensor interceptor type piggyback cannot overcome them completely....revs it can't do at all as you can't 'fiddle' the sensors for that for obvious reasons)
A Mines or TOMS (or TRD and possibly others) ECU is a modified factory ECU. The actual ROM is either intercepted within the ECU or replaced with a differently programmed one so that the speed cut is removed entirely (not fiddled like an RSM) and the others are programmed up ie increased rev limit and increased boost level. For some reason they also always seem to be tuned a bit on the rich side ... probably 'cos they reckon that's safer with increased boost, ignition advance and revs. Also the 1JZ is used in cars exported from Japan so allowances are made in the fuel programming for poorer quality or dirtier fuels than is normal in Japan (I read somewhere that they allow for 15% injector blockage as normal which would at least partially account for the tendency towards running rich mixtures)
The cut you are hitting may or may not be boost cut. Speed and revs use the same circuit within the ECU as well. A few other things can trigger it too. High intake temps can lead to added fuel (helps prevent pre-ignition) so if the temps are high enough combined with highish boost heaps of fuel will be added by the ECU (if the timing limit has been reached....the ECU will pull ignition advance out first but only has a limited range to work with and once this is reached fuel will be added as well). If the injector duty cycle approaches 100% that will trigger the cut too. Cold dense air will need more fuel with possibly the same result (more quickly reached as timing is not reduced as much with cold intake air as timing does not affect pre-ignition as much at lower temps). Variations between individual MAP sensors (and temp, oxygen and any other sensor you can think of) as well as engine tolerances will mean that some cars will hit the cuts much more easily than others. This does not necessarily mean that they are making more boost or power (but in some cases it does, especially if the particular combination of tolerances within the engine results in slightly more compression or valve lift/advance). This is also why the cuts may seem to be set a bit on the low side, typical car manufacturer conservativism combined with allowances for manufacturing tolerances. This is an area where the Mines etc get increased performance; by leaving less safety margin.
Wednesday, April 05, 2006 - 11:43 pm, by: Cihan Aday(Cihan)
Mark, once there's little backpressure the exhaust naturally flows towards the turbine and keeps its RPM high..
Ofcourse the wastegate exit has even less backpressure because theres no turbine, but its too small and it presurises to the point where its higher than the turbine exit. Exhaust flow just goes where theres least pressure, and that eventually becomes the turbine.
I've tried all sorts of boost control methods and nothing controls boost below the 'natural' boost level. The natural boost level is dependant on the wastegate size in our case, because the actuators open at a set manifold pressure.
Wednesday, April 05, 2006 - 11:58 pm, by: Mark Paddick(Sparks)
Yes, that's true. You can only reduce boost so far and that limit will depend upon the wastegate size. This is one reason why it is easier to hit boost cut with a modified exhaust and no boost controller can overcome that. A boost controller can only open or close the wastegate and the main advantage of the electronic type of controller is that it can keep the wastegate closed where an ordinary manifold pressure control cannot. They can also open the wastegate earlier thereby reducing boost over the factory control but as you say not completely. The range of boost control is higher with an electronic controller but not infinite. Ultimately the lowest boost level is set by the wastegate. The boost contoller is best at maximising boost at lower revs. Personally I reckon the Mines is the way to go as the boost cut level is increased along with the right sort of fuel mapping to go with that increase albeit a bit on the rich side (any of the interceptors can fix that). This is only true for standard turbo setups though as the MAP sensor won't allow for too much more boost. The Supra MAP sensor (with a fuel adjusting type trimmer so that it matches the facctory MAP sensor in the factory ones' range) would help.
Damn, thats some heavy reading, nevertheless it is awesome
Cihan, Mark thanks again for your valuable contribution, it will take a little time ot digest the reading but what I've read so far has prompted me to get an EBC. I DO want to use it as a safety mecahnism under high revs. The Jaycar DFA will be more than enough to remove fuel/boost cut as I understand and may even have room for some minor gains??
Is there anything I will need to alert my tuner when setting the DFA and boost controller? Any ways to further eliminate the chances of spiking? I do realise that I wont be able to fully control boost
Thursday, April 06, 2006 - 11:36 am, by: Mark Paddick(Sparks)
Now that i have a TT myself I'll be able to supply the DFA and boost controllers with data already in them that should be reasonably close so tuning will be a lot easier, just a question of trimming to suit your particular car rather than starting from scratch. I'm not sure of the cost involved yet. It'll probably be in the $200 too $250 region for each but you can use the same hand controller for both which would save $100 (just can't hot-swap the controller between units, power must be off when it's connected or it won't work.
Thursday, April 06, 2006 - 11:54 am, by: Morgan Cross(Morgan)
Shyam Purushothman wrote on Wednesday, April 05, 2006 - 01:07 pm:
Has anyone had any issues controlling boost using Dumppipes?
Yes, don't listen to what others have said.
I have dump pipes on my car and when I had a bleed valve and it was set to 13.5psi and it spiked to 17psi sometimes.
When I got a name-brand EBC with the same setup the spiking still occurs at times. Originally I had it set up for max boost with a super quick spool up time and it was still spiking occasionally to 17psi every so often.
I changed all the settings, set it up for smooth gradual boost increase and it still spiked.
I've been told by some very reliable sources that that dump pipes which have a seperate small pipe for the wastegate are responsible for the spiking and a all-in-one dump pipe design is a better idea.
Although, people without dump pipes fullstop with the basic performance upgrades do get spiking sometimes too.
Morgan, could you substantiate that statement "worthless junk"? I'd like to know your experiences with it
Regarding Lew's dumps, as I was contemplating on shipping a set to sheepland, do I wait until I have a aftermarket turbo setup before fitting his dumps? What design is used? Is his an all-in-one design? Lew?
Thursday, April 06, 2006 - 12:20 pm, by: Aaron Mead(Aaron)
Ive heard the same about the Jaycar EBC too, Morgan.
Off topic: Does anyone know how well the Turbosmart Gated boost controllers work at keeping the wastegate shut right up till the preset limit? I had one years ago (just a single dial engine bay version) and I never got round to watching it on the dyno to see if it would open gradually as it neared 15p.s.i. Anybody seen one of these in action?
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plus I am not mechanically minded
. I also love the idea of the Jaycar IEBC, just waiting for Mark's reply
