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I supported Toymods
Location:
Berowra-Sydney
Registered:
July 2002
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Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 12:15
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ok, getting my hands on a free turbo wont let it go to wast and will chuck it on my car just for fun. only thinking of running 5 pound of boost as i don't really want to do any mods to the engine and i reckon i would get away with 5p easly.
Now problem is EFI engine, can the map for most NA EFI engines able to handle a small boost pressure or is there no option but if you plan to force air into the engine you have to re map the computer, and with 5pound would a unichip be able to compensate for this or is an aftermarket computer the only option?
any comments from guys that have done this before very welcome.
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Location:
Brisbane
Registered:
February 2003
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Re: Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 12:28
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Something like a Unichip will be needed.
The standard ECU won't cope with any postive manifold pressure well. You can dodgy things with fuel pressure mods and an extra injector that is opened by a pressure switch etc... but thats a pretty ghetto way to control fuel.
The Unichip seems quite good for mild installs. Seen it work nicely on a Honda Civic turbo.
Why not go for one of the cheap Microtech MTX8s that seem to go for around $550 on here and other forums. Would give greater tuning potential than the Unichip.
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Location:
Brisbane
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 12:37
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Actually it depends on the engine. Most AFM-type EFI systems will handle a small amount of boost without a problem, but if you have a MAP-type EFI system you're pretty much screwed... you'll need a Unichip-type device as mentioned above or a whole new ECU.
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Location:
Montrose, VIC
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 12:59
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some people DO get away with a rising rate pressure reg... but I still don't condone it always myself 
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Location:
Syndey
Registered:
December 2002
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Re: Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 22:26
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we did this on my misses car, bolted a turbo on, the first time it came on boost my head just about went through the windscreen, 1/2 hour later it had a microtech on it!!
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Location:
Brisbane
Registered:
February 2003
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Re: Turbo charinging EFI NA engine, what to do
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Tue, 24 February 2004 22:40
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| Norbie wrote on Tue, 24 February 2004 22:37 |
Actually it depends on the engine. Most AFM-type EFI systems will handle a small amount of boost without a problem, but if you have a MAP-type EFI system you're pretty much screwed... you'll need a Unichip-type device as mentioned above or a whole new ECU.
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How do they handle it? Just with a bit of headroom in the fuel maps, or do people just let it lean out naturally when the vacuum is => 0 and the TPS is 100%?
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Location:
Brisbane
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Wed, 25 February 2004 05:33
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AFM type EFI doesn't care about manifold pressure, it only measures total airflow going into the system. This happens pre-turbo so the addition of a turbo makes no difference except that the airflow is increased! Of course the AFM has limits to the amount of airflow it can accurately measure, but there are ways around this if you reach those limits.
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Location:
Brisbane
Registered:
February 2003
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Re: Turbo charinging EFI NA engine, what to do
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Wed, 25 February 2004 05:42
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yes, but will the ECU have fuel maps for this level of airflow?
Most vane AFMs go to full reading a fair way before the max power level... and when they do, the ECU just goes to WOT fuel maps varying on RPM..
I just feel that advising someone to fit a turbo without modifying the fuelling maps and providing a way of measuring boost is unwise. Its going to lead to detonation.
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Location:
Brisbane
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Wed, 25 February 2004 05:52
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As I said, there are ways around this problem... it usually involves adjusting the AFM spring pressure or installing a larger AFM from another car, and increasing the injector size to compensate. This is the idea behind the Lexus AFM mod for 7M-GTE's which is so popular in the US.
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I supported Toymods
Location:
Berowra-Sydney
Registered:
July 2002
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Re: Turbo charinging EFI NA engine, what to do
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Wed, 25 February 2004 22:20
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thanks guys, computer it is then, as my car only has a MAP sensor on it and thats it.
and its standard maping is already lean.
now we just wait for my Mercedes Benz diesel turbo to finish its time in the warranty room.
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Location:
Brisbane
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Fri, 27 February 2004 01:33
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I plan to turbo my car its AFM (7mge) and use a Safc to help control the fuelling.
I was hoping the the safc would give me enough tuning scope for a turbo conversion.
Is this a good idea?
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Turbo charinging EFI NA engine, what to do
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Fri, 27 February 2004 02:02
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Turbo-ing your NA-7M? This sounds like a terrible idea. You'll need the turbo AFM to start with because the NA one is a crappy "flap/vane" type.
I guess you could try and find all of the gear from a 7M-GTE (AFM, manifolds, injectors, igniters, ECU etc)and bolt it on (if it bolts on) and see what happens with low boost... but at the end of the day why not just do a proper 7M-GTE or 1jz-gte or 2jz-gte conversion?
An SAFC has only a few "points" to control mixtures. A greddy emanage would be a much better way to go (with injector and ignition harness) but it won't be easy.
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