Got my hands on a set of KR cams (casting # 027) and was really excited, till I found that they'd only make a difference on the 9A motor, and that the ABF cams were actually superior thanks to higher lift... So, I suppose there's no point in changing out the ABF cams for KR's.

So here's the setup at the moment..
ABF on stock internals and cams
Exhaust & Branch
Modded Mk1 MP9 Airbox
VR6 OBD-II Throttle Body
MP9 ECU running a 16V map from Ray in PTA

Got the itch to mod - in a bad way - the GTI-R is very nearly done, and then it's the Mk2's turn for some headwork, lightened flywheel and most likely cams - I know it's been debated at length, and the general concensus has been to go for something in the region of 276/268° split... I'm not looking to go any higher than 7800 RPM, as I'd still like to keep the head hydraulic (I think) and I definitely won't be fitting throttle bodies..

I'll be keeping the VR6 throttle body - so the choice of cams needs to be somewhat based on its flow capability... I know the stock injectors are 225cc items, which are good for in the region of 180 bhp... so the car may run lean at the coast when it's modded, but I rate there's still some reserve for the injectors at altitude?? Would there be any merit in fitting larger 275 cc's from a Primera or similar?

Oh, and how well does MP9 handle cams on the 16V? Bearing in mind that I'll be taking the car for a Uni-Chip and tuning when the work's done.

Thanks in advance!

Philip

Im gonna be running mine with 276inlet and outlet cams on MP9, ross said it will fine, maybe just idle a bit higher than normal.

There was a red playa at the show and shine runnin 268/272 cams on mp9 and he made 110kw atw.

SHAUN wrote:Im gonna be running mine with 276inlet and outlet cams on MP9, ross said it will fine, maybe just idle a bit higher than normal.

There was a red playa at the show and shine runnin 268/272 cams on mp9 and he made 110kw atw.

yes afaik the 276 setup is best on the ABF

billybob how sure are you the cams are better in the ABF , Shane at KAR says they fitted abf cams to a 9a and remapped it with NO power gain at all?

sixteen10 wrote:billybob how sure are you the cams are better in the ABF , Shane at KAR says they fitted abf cams to a 9a and remapped it with NO power gain at all?

Lets not get into shane's tuning skills.

The ABF cams are better, its been proven in many cases and on many forums, piper street cams even sells cams that have been profiled to exact ABF spec as upgrade for the 9a motors.

Cam specs

Grant - ABF cams have higher lift but shorter effective duration than KR cams (dependent on how they're set up) - so it pretty much evens out in terms of the performance stakes... The KR cams have a steeper ramp angle, so it comes in "harder" than the ABF cams when the engine comes on cam.

Either cam is way better than the strangled 9A cams though, and helps the 9A rev a lot better - if it's set up correctly, that is.

Shaun - I'm not so sure about that chart of yours TBH - 9A cams were cast on 051 if I'm not mistaken, so the part number starting with 027 makes no sense...

I guess I'd win a little bit on duration if I cut this KR exhaust cam to fit on my intake - but 6 degrees of duration traded off for .5 mm lift isn't going to make a world of difference - so I think I'll hold out for a new set of cams altogether..

Now, what tickles me pink would be how to convert the 220/228° reported durations @ 0.040" on that graph into the kind that compares with manufacturer claims of the likes of Schrick, Techtonics, Piper, etc - where is their duration measured on a set of 276° cams for instance? From 0.004"? From 0.040"?

Very befuddling.

Good to know MP9 could handle aftermarket cams with a bit of tuning though.

AAaahhh, that makes sense.. it's amazing what one can come up with if you do a bit of searching on the net.

I take it Schrick and most aftermarket cams are then measured at 0.1 mm or 0.004"... does anyone have the effective 0.004" duration figures of KR/9A/ABF cams, for the purpose of comparison?

Shaunie - I don't know where that graph of yours gets its info from, but ABF cams are 219/220° at .040" (1mm) according to every other resource I can find on the net..