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Discussion Starter · #1 · (Edited)
Basically my gtr runs a hks downpipe, sard sports cat and an amuse cat back which I want to change for a mines downpipe, tomei decat and tomei exhaust and I am worried that the car will need a remap to run correctly?
I am guessing the downpipe and cat back will not really change anything as they will be just the same restriction wise however the sports cat to decat is what concerns me although a few people have told me that a sports cat and a decat are very similar restriction wise?
 

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Discussion Starter · #3 ·
i should probably mentinon my cars on an r34 n1 engine with 500bhp+ so you would think the current set up wouldnt be restrictive at all.
 

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^^i dont think it will change the fuelling on your engine, otherwise you would need to. if you are really worried about it, get some opinions from our traders as well for peace of mind.
 

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Hey dude,

I do some mapping on my car with the apexi Power FC and a wideband AFR sensor/gauge -it's an old ECU but still works fine for me but takes a while to do anything.

I find that changes in the weather and adding/removing components requires a slight tweak to the map. If there's a tiny bit more flow, you may go that little bit lean and get some overboosting but if you've got a boost gauge and a controller, you can monitor this yourself.

When making exhaust changes that involve flowing more freely, the turbo can spool up faster which can change the fuelling requirements quite a bit. Your sports cat will probably be a 100cell and your decat, obviously nothing, so you are freeing up quite a lot. You'll find that your turbo does spool up faster and because of this, you need to tweak the fuelling and maybe your boost controller.

I'd recommend a tweak to your current map; it would also give you the benefits of your new components!
 

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I rarely hear anything good about the fc. I was told that if you've got the money, maybe a syvecs ecu and map would be better. I don't really have problems with the fc but it's a bit trickier than some of the other software I've used. Tweaking the fuel map is ok but getting a good base map to start with is a bit of a pain. Apexi ECUs are really quite old now and don't have as many safety features but they can get the job done.
 
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