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Post by howardb66 on Feb 10, 2023 10:44:27 GMT
After running my TD04 set up, it seems that I’ve finally discovered a ‘thing’. Recently had the ECU remapped by a self proclaimed experienced mapper & respected engine builder- I was looking to have the ELectronic Boost Controller configured & get the idle adjusted. I went to pick the car up after he declared it was finished (after he said he had to refit my Manual Boot Controller as my wiring loom is knackered apparently) & took it for a test drive….. At approx 3500 rpm the boost gauge was off the scale & then bled back to about 12psi at the red line. This is because the TD04 isn’t really up to the job I was told. I should really be running an EFR. Sorry mate, can’t afford it… The idle is sh*t too- I have the wrong throttle body on the car to enable the ECU to work correctly so he said. That’s strange as the idle was much better when it was supercharged, which I would’ve thought been more tricky to sort with the drag of the SC… I got back to the garage, the bloke said that was the best he could do. PISSED OFF, I drove home very carefully as it was raining really hard. Put the car in the garage & decided to have a quick poke about. It turns out the guy had reconnected the MBC back to front!!! To say that I was extra pissed off was an understatement. No wonder the boost was all over the place….. I emailed the bloke & told him what he had done- oh, it’s a schoolboy error I was told. I also mentioned that the idle didn’t get any better as he’d said it would. Would I like to take the car back for him to check out the map? Not a flipping chance. Just write it off as another place to be avoided. Anyway, I’ll get to the point. I took the boost controller off, gave it a thorough clean (in my wife’s ultra sonic jewelry cleaner😁) & reassembled it the correct way round. Having driven the car for a few weeks, I’ve noticed the boost gauge is showing about 3psi of ‘sag’. It always used to do this but I ignored it, but now it’s on my radar & is more noticeable.. It turns out that this is a known issue. www.miataturbo.net/diy-turbo-discussion-14/boost-sag-no-you-dont-need-ebc-47532/ |
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Post by scottydugg on Feb 10, 2023 11:12:19 GMT
That's how I've got mine setup, post intercooler, I think I read that article. You might need to retune as you'll see higher boost at the turbo to see the same 14psi after the intercooler.
Sounds like the "tuner" won't be in business long.
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Post by howardb66 on Feb 10, 2023 11:58:51 GMT
That's how I've got mine setup, post intercooler, I think I read that article. You might need to retune as you'll see higher boost at the turbo to see the same 14psi after the intercooler. Sounds like the "tuner" won't be in business long. You’re right, there’s a very convenient port on the TD04 that looked so obvious, I just used that. Suppose I was lucky I didn’t cause any damage or the bloke who had the car for 3 hours on the rolling road ‘tuning’ the ECU with the MBC fitted back to front. To be honest, he’s built a cracking engine for a good mate of mine (1.6 Mk1 that gives 195hp on ITBs), the problem is that the guy who used to do his mapping has left & is doing it himself. Oh & the guy also told me my Intercooler needed replacing as it was too small, he recommended one that I should get as this is what he uses all the time….. As there was some doubt in my mind, I did a few measurements & it turns out that as well as all the extra 90degree bends to get it to work, mine has 1200cm3 greater capacity & a bigger frontal area. |
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Post by atlex on Feb 10, 2023 22:33:56 GMT
After running my TD04 set up, it seems that I’ve finally discovered a ‘thing’. Recently had the ECU remapped by a self proclaimed experienced mapper & respected engine builder- I was looking to have the ELectronic Boost Controller configured & get the idle adjusted. I went to pick the car up after he declared it was finished (after he said he had to refit my Manual Boot Controller as my wiring loom is knackered apparently) & took it for a test drive….. At approx 3500 rpm the boost gauge was off the scale & then bled back to about 12psi at the red line. This is because the TD04 isn’t really up to the job I was told. I should really be running an EFR. Sorry mate, can’t afford it… The idle is sh*t too- I have the wrong throttle body on the car to enable the ECU to work correctly so he said. That’s strange as the idle was much better when it was supercharged, which I would’ve thought been more tricky to sort with the drag of the SC… I got back to the garage, the bloke said that was the best he could do. PISSED OFF, I drove home very carefully as it was raining really hard. Put the car in the garage & decided to have a quick poke about. It turns out the guy had reconnected the MBC back to front!!! To say that I was extra pissed off was an understatement. No wonder the boost was all over the place….. I emailed the bloke & told him what he had done- oh, it’s a schoolboy error I was told. I also mentioned that the idle didn’t get any better as he’d said it would. Would I like to take the car back for him to check out the map? Not a flipping chance. Just write it off as another place to be avoided. Anyway, I’ll get to the point. I took the boost controller off, gave it a thorough clean (in my wife’s ultra sonic jewelry cleaner😁) & reassembled it the correct way round. Having driven the car for a few weeks, I’ve noticed the boost gauge is showing about 3psi of ‘sag’. It always used to do this but I ignored it, but now it’s on my radar & is more noticeable.. It turns out that this is a known issue. www.miataturbo.net/diy-turbo-discussion-14/boost-sag-no-you-dont-need-ebc-47532/TDO4 / EFR comments - oh god the cunit tried to upsell you, and he was full of prarrie canoe too re: throttle body - 2 star review time (aka, ship). re: position, I run my EBC using the just after turbo feed aka, because this will respond best to boost spikes (it's the peak pressure location so this gives the best chance to control it) but I have a notable taper configured with the wastegate duty cycle going from 30 to 45 % between 3K and 7K at full chat to compensate for the pre-cooler pressure increase. If you're prepared to pull a copy of your MAP off your ecu I'd be happy to look at it. Idle included. I've spent significant time getting my cars streetmapped on G4X, but a lot of that was referencing my existing ME maps. P.s. your wiring loom is almost certainly not knackered. |
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Post by howardb66 on Feb 11, 2023 17:27:17 GMT
After running my TD04 set up, it seems that I’ve finally discovered a ‘thing’. Recently had the ECU remapped by a self proclaimed experienced mapper & respected engine builder- I was looking to have the ELectronic Boost Controller configured & get the idle adjusted. I went to pick the car up after he declared it was finished (after he said he had to refit my Manual Boot Controller as my wiring loom is knackered apparently) & took it for a test drive….. At approx 3500 rpm the boost gauge was off the scale & then bled back to about 12psi at the red line. This is because the TD04 isn’t really up to the job I was told. I should really be running an EFR. Sorry mate, can’t afford it… The idle is sh*t too- I have the wrong throttle body on the car to enable the ECU to work correctly so he said. That’s strange as the idle was much better when it was supercharged, which I would’ve thought been more tricky to sort with the drag of the SC… I got back to the garage, the bloke said that was the best he could do. PISSED OFF, I drove home very carefully as it was raining really hard. Put the car in the garage & decided to have a quick poke about. It turns out the guy had reconnected the MBC back to front!!! To say that I was extra pissed off was an understatement. No wonder the boost was all over the place….. I emailed the bloke & told him what he had done- oh, it’s a schoolboy error I was told. I also mentioned that the idle didn’t get any better as he’d said it would. Would I like to take the car back for him to check out the map? Not a flipping chance. Just write it off as another place to be avoided. Anyway, I’ll get to the point. I took the boost controller off, gave it a thorough clean (in my wife’s ultra sonic jewelry cleaner😁) & reassembled it the correct way round. Having driven the car for a few weeks, I’ve noticed the boost gauge is showing about 3psi of ‘sag’. It always used to do this but I ignored it, but now it’s on my radar & is more noticeable.. It turns out that this is a known issue. www.miataturbo.net/diy-turbo-discussion-14/boost-sag-no-you-dont-need-ebc-47532/TDO4 / EFR comments - oh god the cunit tried to upsell you, and he was full of prarrie canoe too re: throttle body - 2 star review time (aka, ship). re: position, I run my EBC using the just after turbo feed aka, because this will respond best to boost spikes (it's the peak pressure location so this gives the best chance to control it) but I have a notable taper configured with the wastegate duty cycle going from 30 to 45 % between 3K and 7K at full chat to compensate for the pre-cooler pressure increase. If you're prepared to pull a copy of your MAP off your ecu I'd be happy to look at it. Idle included. I've spent significant time getting my cars streetmapped on G4X, but a lot of that was referencing my existing ME maps. P.s. your wiring loom is almost certainly not knackered. Yeah, you’re right, the take off just after the compressor will show exactly what’s going on there. It would be really good of you to take a peep at my map. Interestingly, the idle is 100% reliable when is going through the cold start/ warm up phase, it only becomes problematic when warmed up. It’s not an issue on track but normal driving I have to heel&toe coming up to junctions to make sure it doesn’t stall. I need to whip the ECU out to see if the bloke soldered up the 2 posts to get the EBC to work. |
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Post by atlex on Feb 11, 2023 21:37:36 GMT
^^ Also try to make a log. A map is one thing but doing a log in meite, if you load that up into MLV, will make it easier to analyse.
It's ctrl L or logging drop-down menu, start logging..
Then take it for a drive with the laptop laying there on the passenger seat. Make sure the laptop is configured not to shut off until say, 1 hr without battery or interaction.
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Post by scottydugg on Feb 12, 2023 16:37:59 GMT
We had to balance the TB stop and idle screw to get it to not die at junctions. Or bump up your iacv, it's a black art, the tuner did all the work.
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Post by warpspeed on Feb 13, 2023 4:15:47 GMT
Agree, logging is the only way to know for sure what is going on. Two things can cause boost to fall off at higher rpm. As previously mentioned where, and how, you measure and control boost can make quite a big difference if there are significant pressure drops around the system. The other is high turbine inlet pressure simply blowing the wastegate open off its seat. Now the spring in the wastegate is what holds it shut, we all understand that. If you fit say a 12 psi rated wastegate spring, the wastegate starts to open at 12 psi (or whatever) with simple direct boost control. Now if you fit an electronic boost controller, you can only adjust it to set boost pressures higher than the control spring that is fitted to the wastegate. If you want a wider control range, some guys might fit say an 8 psi spring, or the wastegate may have already come with a lower rated factory spring fitted to it. So you tweak your expensive new electronic boost controller to deliver maybe 20 psi of boost, and lets assume the wastegate only has the original 8 psi rated boost spring. So while boost is building up to 20 psi, the wastegate is kept closed below 20 psi by limiting the control pressure to the wastegate diaphragm to be below the spring opening pressure. No problem there. However for the turbo to generate the much higher 20 psi, might require the turbine to have say 18 psi inlet pressure or more to drive the compressor hard enough.
Now its entirely possible that may be enough pressure to force the wastegate open if it only has an 8 psi rated control spring holding it closed. As rpm rises, total exhaust system back pressure increases (after the turbo) as well as turbine inlet pressure (before the turbo) both can rise very steeply. A wastegate can chatter from powerful exhaust pulses, and can bleed off a lot of exhaust around the turbine, causing boost to actually fall off as rpm rises. This all has to do with the ratio of areas between the control diaphragm in the wastegate actuator can, as well as spring pressure, and the area of the wastgate poppet, or flapper valve. All must work together. Making changes can easily upset the balance of forces and crate issues. The original factory set up was probably fine, but you can easily get yourself into trouble in several ways. Increasing boost well above the original factory setting with some kind of boost control and leaving the original weak spring in the wastegate. Boring out the wastegate hole and fitting a much larger flapper, without also upgrading the actuator can to a suitably larger diameter. Its commonly believed that fitting an electronic boost controller will solve ALL boost control issues. Boost creep, boost sag all go away if you fit expensive enough electronics to your vehicle. Nothing could be further from the truth. If the wastegate does not have complete and total control over the turbine, because its either too big and fitted with too weak a spring, or far too small to bypass enough exhaust, its never going to be able to work properly. The internet Forums are clogged with bad advice about boost control problems. Its pitiful reading some of the advice, even from well known and respected engine tuners that should know better. First, log everything, boost obviously, but also exhaust pressures before and after the turbine, then think the whole thing right through. If its not behaving properly there will be a definite cause. Once you know what is actually happening, fixing it should be both logical and fairly straightforward. |
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Post by atlex on Feb 13, 2023 8:42:57 GMT
There's probably a guide to appropriate wastegate opening pressure vs boost target since imo an 8psi spring and chasing 20psi seems insensible
For reference...
On my stock refurbed TD04-13T with boost control disabled hits 150kpa and then trails off to maybe 147kpa - so in the kings money it starts at say 7.3psi boost and ends up at 6.8psi boost. I'd call that an 8psi spring, but I'd need to test it with a tyre pump to be sure XD my boost control target is more like 11psi so 175/180psi..
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Post by warpspeed on Feb 13, 2023 10:04:23 GMT
How much exhaust turbine inlet pressure you need to force open the wastegate depends upon the ratio of the areas of the control diaphragm and the flow area of the wastegate. A typical smaller factory turbo might have a control diaphragm diameter of perhaps 45mm and the wastegate hole in the housing might be about half that diameter, maybe 22mm covered by a 26mm flapper. If the control diaphragm is set to open at 7psi against the factory spring, 28psi of exhaust pressure will blow it open because the area of the wastegate hole has one quarter of the area of the diaphragm. So four times the pressure will be enough to create a problem. If you are running at only 7psi of boost, the peak pressure of the heavily pulsing exhaust is hardly likely to ever reach 28 psi. However if you do some kind of demon tweak to increase boost pressure to reach a much higher boost level, using a bleed orifice or maybe a pwm controlled solenoid valve, using that same 7psi spring, the flapper might start to dance around a bit at high boost. Now if you use a larger diameter boost actuator, such as one that has a 65mm diaphragm, still with a 7psi spring fitted, the spring will be a lot heavier.
If the diaphragm diameter is increased from 45mm to 65mm that is a x1.44 increase in diameter and a x2.09 increase in area. The actuator might still be designed to open the wastegate at the same 7psi, but the seat pressure on the flapper will be more than doubled. It now might take something like 8.7 times opening pressure or 61 psi to force the flapper off its seat with a 7psi spring. So its not just the spring, but the spring in combination with the actuator diameter that determines the seating pressure of the wastegate. Some of the sellers of these electronic boost controllers recommend upgrading the actuator, which might be a very good idea.
But it does look to some people as if the boost controller seller is just trying to sell you something at extra cost without explaining why it may be necessary.
The appeal is that someone that has a 7psi factory car just buys and fits an electronic boost controller that enables him to make boost fully adjustable from 7psi up to as high as he dares. That will work up to some boost level above which its not going to control very well. That may be insensible to us, but because he can set 20 psi, that is what he expects to see, and wonders why boost pressure is unstable and all over the place.
But a larger actuator fitted with a suitable spring, may allow a much wider range of adjustment, and far better control.
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Post by schercheeroo on Mar 4, 2023 10:31:35 GMT
Oh dear,
That doesn't sound like a good experience at all.
If you want to have a go at tuning your idle, check out this video.
I wouldn't be scared about having play, just make sure you save a copy of your cal in a safe place so you can put it back if you make it worse.
I'm sure the EBC will work fine, from your description it sounds like the tuner is inept. If you're feeling confident get it fitted and try tuning it to hold your boost steady.
Have a look at the closed loop boost control post I made some years ago, the info there might be useful. I would recommend staying with open loop boost control though.
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Post by warpspeed on Mar 4, 2023 23:26:23 GMT
Regardless of what you have, the wastegate MUST have full and complete control over the turbine.
When its supposed to be fully closed it must not leak.
When its supposed to be fully open, it must have sufficient flow area.
There will be a control pressure where it just starts to crack open, and a higher applied control pressure where it is fully open.
All of that needs to work properly, if it does not, because of some problem with the wastegate itself, fitting an electronic boost controller to it is a complete waste of time.
Think about it.
If the wastegate itself cannot function properly, no amount of controller sophistication can fix that.
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Post by atlex on Mar 6, 2023 11:24:39 GMT
Regardless of what you have, the wastegate MUST have full and complete control over the turbine. When its supposed to be fully closed it must not leak. When its supposed to be fully open, it must have sufficient flow area. There will be a control pressure where it just starts to crack open, and a higher applied control pressure where it is fully open. All of that needs to work properly, if it does not, because of some problem with the wastegate itself, fitting an electronic boost controller to it is a complete waste of time. Think about it. If the wastegate itself cannot function properly, no amount of controller sophistication can fix that. worth testing your wastegate diaphram with a car tyre pump  td04-13t should have wastegate fully open by around 7 psi. |
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Post by howardb66 on Mar 14, 2023 13:53:30 GMT
So I changed the source for the boost reference point to just after the intercooler. The boost is definitively delivered in a less spiky manner in the midrange rpm & seems to hold better to higher revs. Is it as good as EBC? Dunno, hopefully got one arriving tomorrow to try out.  |
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Post by scottydugg on Mar 14, 2023 15:23:23 GMT
Would be interested to see how you get on with the EBC, if you manage to get it wired in and it works let me know how you did it, mine doesn't work yet (I think it's my dodgy wiring!).
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le sigh