Hks 2835 Intake 3" Or 4"?

[nakuma]

I recently purchased Dan/Halle's old HKS 2835 Pro S and am getting it fitted by Sam at Dr Drift at the end of the month.

My concern is though; Sam told me, because the bellmouth of the turbo is 4", that a 4" intake will need to be fabricated to stop compressor surge occurring. Unfortunately this means, having to fit a 4" pod filter because I don't want to butcher the standard airbox and relocating the Z32 AFM to the cold pipe because it's only 3". Which then means having to relocate the bov so it doesn't count the recirculated air again (I think). All which means a lot more money to get the thing installed.

My question is: The HKS kit, brand new, comes with a solid 3" intake with a 4" to 3" reducer which can be directly bolted to airbox. I can't imagine HKS would release a kit that is prone to surging. Should I pay Sam to do all the extra work, or is it not necessary and can I save myself a lot of money just asking him to fabricate and fit a 3" intake.

Anyone running the same kit, what did you do?

Cheers

[R31Nismoid]

I ran a GT30 4" intake that fed back to a Z32 AFM size... 24psi/370rwk was no issue on fuel, 270rwkw on 17psi on PULP.

As long as there is a reasonable amount of 4" piping to a reducer to the AFM size, it'll be fine.

There was a thread about this recently actually, ended up 2-3 pages long with examples of a 3" to 4" pipe, lots of setups 300rwkw without a problem.

[nakuma]

Thanks! Were you running that set up with the airbox?

Could you post the link to the thread you are talking about? I'm not having any luck finding it.

[nakuma]

Found it.

It keeps to be the exact same question as mine

[JonnoHR31]

yer just run a reducer. aslong as you have a bend and decent bit of pipe between the turbo and afm it'll be fine

[Thelen]

Sam told me, because the bellmouth of the turbo is 4", that a 4" intake will need to be fabricated to stop compressor surge occurring

WTF? That is nonsense

[89CAL]

alot of the 4" inlet of the Pro S is the port shrouding. That is why it is 4" not 3". The turbo inlet itself as far as I'm aware is still 3"

[nakuma]

WTF? That is nonsense

Sorry, you're right. It was something else that he tried to explain to me, but I didn't understand. Something about returning to idle after load could cause stalling.

Anyways, I called him back to question whether is was totally necessary. He convinced me I should do it anyway. Dr Drift comes highly praised from friend and here, I decided to trust his judgment.

[89CAL]

Just FYI.... HKS provide the 4" to 3" reducer along with the 3" intake pipe with the kit.

[R31Nismoid]

Something about returning to idle after load could cause stalling.

If you do not use a stock BOV, then this might be an issue.

Using stock BOV (or GTR), no issue.

[nakuma]

Just FYI.... HKS provide the 4" to 3" reducer along with the 3" intake pipe with the kit.

I mentioned that, and asked why would they supply a suction pipe that could cause issues.

He replied with, HKS also sell shitty mushroom filters and the hectic ssqv

[Thelen]

LOL. True that

If you don't run a BOV, you'll have idling issues regardless of 3-4" change, although he *is* right in saying it would probably be even worse.

[JonnoHR31]

how does he explain all the people successfully running reducers with 4" turbos? magic?