Thought i would post up some info on my HKS S/C MAF relocation (attempt)

Car info-
'06 revup track roadster. HKS GT S/C, Cosworth Plenum, DW600's, Tomei Headers, Berk HFC'c, 243rwkw ( 325hp )

I must add i ditched the supplied HKS Fcon and had my ecu tuned locally (MAF). The Fcon is MAP tuned.

So i thought 2 things could be improved not just for hp gain but to get some better tunability. I never liked the way the HKS inlet pipe stepped from 60mm up to 80mm at the TB. I am also MAF tuned. The location of the MAF( it also functions as AIT sensor) is pre blower. I thought it would better located post intercooler to get best possible reading of incoming charge.

So i purchased a MAF flange and had welded onto a new 80mm diameter inlet pipe custom made.


Well a mixed bag of results for my MAF re-location and new inlet pipe.


The oem MAF hated the new location for 2 reasons - it peaked at 4.9V's at 4500rpm, so given i didnt have an uprev GT MAF that i could overnight we put it back in the original HKS position which is a night mare to get to as it's under the blower. Also the position in the new inlet pipe was too close to the step up from 60mm to 80mm. It was proving too difficult to tune as the step up was creating terrible air flow, even under the 4500rpm that he could work on. I tried!!! MAF re-location failed. The new inlet needed to be a gradual smooth transition from 60mm - 80mm given the position of the MAF. May be down the track i'l get another one made up.

BUT the new inlet on it's own was a revalation as it matched the diameter of the TB, the HKS pipe was thinner due to fitment issues. The inlet must have help flow as Dave was able to re-tune to 260kw, an increase of 17kw over the previous tune. Looks like the VQ really likes more flow, this would an interesting NA road to look into as FI does this with exhaust gases or belts. Also i know this sounds alot for a oem MAF tune but the increase flow has given this result . Everything used is fixed the only variable was the new pipe. Dave also did some more tuning on the L/R bank imbalances ( i'm not exactly sure ) and now the idle is a lot more stable and the throttle response down low is crisper.
You can see in the pic the original HKS diameter on the inlet pipe and the step up that caused the MAF to have kittens in the new location.
Anyway just posting this up for info for the VQ.

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GTM makes a 3" intake for the GT kit.

 

If only i'd known!!!! The power upgrade looks interesting as well, they have some nice goodies.