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The mkiv Supra Owners Club

Changing boost 'on the fly'


RobSheffield

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just a quick query

 

do all of the current ECU systems available provide to be able to change boost levels on the fly, as in without going for a remap all the time

 

so you would go for a mapping session to create a map for say 1.2 bar, 1.4 bar and maybe 1.6 bar (on a big single)

 

im primarily interested in the AEM, but also the others - F-Con pro etc

 

how easy is it to change? would you need for example a lap top in the car with you if you want to change boost or is a dashboard unit provided?

 

cheers

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You'd map the car at all those boost levels and then change your max boost via the boost controller. One map should deal with all as one load axis will be airflow/manifold pressure. Any ECU has to be able to do this otherwise it simply can't do it's job :thumbs:

 

-Ian

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Rob, you don't work at that little furniture place by any chance do you? Used to own a Skyline GTS? :hijack:

 

I wish i used to own a skyline GTS!

 

not worked at a furniture place! which one did you mean?

 

anyway - back to the thread! someone must know if you can have an AEM system with a boost control type function, so you can bimble around on a low bar setting, and turn it up as the occasion suits!

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It was answered in the second post!

You only need to map the car for the maximum boost you'd ever run.

For example - You'd map it for 1.4bar and then you would set channel 1 at 1bar, chnl 2 and 1.2 and chnl 3 at 1.4.

 

You would never ever set the boost controller to more than the maximum your mapped for as obviously it can't take any more.

 

If you're looking for a big twiddly knob linked to the ECU directly then I doubt if it would be as cheap a solution as useing a BC as I'd expect it to come with something like a MoTeC.

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it wasnt really answered in the second post, ian c pointed out that boost is mapped to all pressures, but i want to know if it is possible to adjust/change via a boost controller type button. but since only me and ian seem to see what im getting at i shall pm Terry S, as apparently he will know what i mean

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On the same note....or maybe its different :confused:

 

A standard ECU that has been tuned using an Apexi AFC, one is then running a boost controller with different profiles per the 4 settings - how would the boost effect the Air/Fuel mixture as I have noticed that the Apexi's correction seems to be the same regardless of the boost settings..

 

Hope that makes sense...

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I thought Alex was agreeing with what Ian had said in second post, set/map the car up to maximum boost, then you can play with your boost "on the fly" as you put it, till your hearts content, if thats what you wanna do. The ECU should be able to provide the correct fuelling etc for boost levels below the max boost it was set up for or as you put 1.2bar, 1.4bar and 1.6 bar (1.6 bar being max boost mapped for)

If you get summing like the Apexi Power FC i think you can tweak the mapping with the controller, or if you get Greddy Emanage (i know it's only piggy-back) you can hook that up to a Greddy E-01 Boost controller and tweak the map with that or a Laptop with the Emanage support tool software you can mess around with your map on the run. Otherwise i'm not so sure how you get your hands on HKS F-Con, Motec or AEM mapping software youd have to keep visiting an appointed/authoised tuner who has.

You'd need decent Wide Band 02, Knock Monitor, EGT sensor to safely mess around with map parameters yourself though.

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So I think you're talking about an ECU controlling boost and being switchable.

Possible - probably big bucks full standalone. That's why no one can answer the question you ask cause how many of us have big bucks standalones??

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Just to straighten this out, Rob was asking this:

 

"Can I change my maximum boost level on the fly via the aftermarket ECU or would I need a boost controller as well?"

 

Due to perhaps the wording I misread the question, as have others :)

 

My answer in a PM was:

"Some aftermarket full ECUs may well offer this function but I have no experience of them - Terry S is your best bet as he's got experience of most of them"

 

Although of course the Profec can hook up to the E-Manage and also control boost, it costs more than a boost controller anyway so I didn't really count it as "an aftermarket ECU".

 

Imi - the AFC can only map throttle position against rpm (and not with very many load sites at that), so yes, the correction factor at X rpm and Y throttle position will always be the same regardless of boost. Of course, as boost increases the stock map load site will change and fuelling will increase, so you'll get the fuelling go up as the boost does, but of course your correction factor is a bit once-size-fits-all. The E-Manage deals with this by allowing you to increase injector duty cycle on a boost-versus-rpm map, so you can change the airflow for the best AFRs under cruise and add on fuel if you need it under load.

 

-Ian

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Wow Cheers Ian, it all makes sense now, and i've learnt a couple of things too!

:kneel:

I remember when i used to have my Integrale, place called Avanti Motorsport International did an ECU upgragade which had facility for x2 different "ECU chip" map set-ups and its own 2stage boost solonoid so when you flicked the switch it changed the complete map and changed to boost setting, sort of STD/Fast Road setting and High boost race setting. I remember it was no where near cheap many years ago, but that was for Webber Marelli System.

Anyway i'll just shut-up now at let people know what their taking dish out the advise i guess.

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Guest Terry S

Rob, yes you can. I had my autronic controlling boost, and I beleive the AEM Can. The thing is generally the ECU's do not control boost as well as aftermarket EBC's. I changed the purple car back to a Blitz SBC-ID. The nice thing about doing in via the ECU is it will alter boost dependant on charge temps & water temps. I also had it set up to run different boost in each gear.

 

The boost controller I now use can have 3 dash switches for the 3 different boost levels.

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Guest Terry S

Stevie, it is a reduction in pressure once the water/charge temp etc gets above a certain level. You can also put in boost cuts for these, and they work with any EBC not just those linked to the ECU.

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Thank you everyone who posted, especially Terry!

 

to be fair i was not at all clear in my original post what i meant. i know what i mean, and can think it through in my head, but im no engineer (not even close in fact!) so find it hard to explain what i meant.

 

as it happens, i was thinking in terms of a big single. my plan is to go from standard twin turbo to single next year, without needing boost controllers, fuel controllers and FCD in the mean time. as i see it, most people buy the boost and fuel controllers and FCD and restrictor rings and by the time they do all that have spent a fair amount. if you went standalone AEM, with upgraded fuel, alright it would be a massive outlay, but better than replacing 'good' items with better!

 

just my thoughts, and by no means likely to be correct!

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Guest Terry S

OK I think I get your drift, trying not to waste money, makes sense, but IMHO you should drive a BPU+ Supe for a while before you jump into a single. If that is your intention, then a good electronic boost controller is still a worthwhile investment, I have yet to see an ecu control the boost as well as a decent unit like the Blitz etc.

Thank you everyone who posted, especially Terry!

 

to be fair i was not at all clear in my original post what i meant. i know what i mean, and can think it through in my head, but im no engineer (not even close in fact!) so find it hard to explain what i meant.

 

as it happens, i was thinking in terms of a big single. my plan is to go from standard twin turbo to single next year, without needing boost controllers, fuel controllers and FCD in the mean time. as i see it, most people buy the boost and fuel controllers and FCD and restrictor rings and by the time they do all that have spent a fair amount. if you went standalone AEM, with upgraded fuel, alright it would be a massive outlay, but better than replacing 'good' items with better!

 

just my thoughts, and by no means likely to be correct!

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but IMHO you should drive a BPU+ Supe for a while before you jump into a single

 

tbh, i have been thinking that. i can be very restrained in a car, but im sure everyone said that just before having an accident in an overpowered car! im fairly sure that after a while i will 'get used' to the power of a standard twin and want BPU. i suppose i can always sell any redundant bits!

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