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S15 boost cut

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Hey guys,


I've just bought an S15 with a few engine mods, although it has a couple of running problems. Firstly (my main concern), it has a harsh boost cut, worse when cold but still evident when hot. Blows a tonne of black smoke when it cuts too. Secondly, cold start it runs a little rough and seems to choke when you tap the throttle. It's fine after driving up the street and getting a little heat into it. I've lowered the gain a little on the greddy profec II ebc but it hasn't made much difference.


So my question is - does this sound like a tune issue? List of engine mods are as follows:


HKS stage one cams

740cc Nismo injectors

Splitfire coilpacks

Tomei Arms turbo

Tomei Expreme low mount manifold

Tomei dump

HKS 3" exhaust

Oil catch can

HKS fuel pump

Greddy Profec II dual stage boost controller

Sard fuel pressure regulator


Apexi Power FC with hand controller


Any advice would be awesome, also recommendations of where to take for a tune if necessary. It's been to hyperdrive before I owned it and it was tuned there but I don't think it should be hitting boost cut like it does.


Thanks in advance, Evan :)

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Thanks mate, so you were the guy meant to check the car out after me, sorry, haha. I can't fault the fuel pump as of yet but it's going in for a tune in a couple of weeks. He said himself that he took it into hyperdrive and got them to check it out when it was running like sheet and they found an air leak but I'm not sure what else they did. Hopefully I get an answer when it goes in!

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