Austarion

Hey guys
I did a TC conversion many years ago.
Car has been sitting idle for 5 years and have decided to get it up and running with a bit more poke.

Orignal conversion involved runing the VR4 ECU.
Wide block
Machined decompressed pistons
Hi flow TD05
Vr4 Intercooler
Vr4 T/B, intake manifold, blue top 450cc injectors
Balance shafts removed.

Now I have a new GT2860 garrett turbo
BC 272 cams with ajustable casm timimg fitted and running again with VR$ ECU & MAF.

I have more to do on this thing like a HaLtech p1000 sport and additional tuning, but has anyone experienced a nice lump to thier idle in any TC conversion?

It was present when it was first built it but after a years of being driven hard I suspect a vacume leak developed and it use to go scavanging.

This lump is more like a tame buzless rotary type of lump, not a WRX bleep.

272's will definitely give u a lumpy idle ;)

rad's car has 272/264 and it's pretty rough..

my gemini has 290 degrees duration and sounds like a PP 13B lol

yer the 272 are pretty lumpy i have them in my car and it sounds pretty cool.

I may be wrong but isn't the lump of an engine usually created by the cam lob overlap.

I am just surprised because it is similar to the lump I use to get out my mini years ago where you have to overlap cam lobs to get max intake .

I suppose thats where the adjustable cam timing will eliminate the over lap of the cams

The overlap causes the lumpiness. Adjusting the cam wheels can induce/reduce it too to some degree.

Seems like a very unusual combo, those cams are way too big for the turbo you are running. It is a 300hp turbo with 600hp cams

Adriano wrote:Seems like a very unusual combo, those cams are way too big for the turbo you are running. It is a 300hp turbo with 600hp cams

Adriano thanks for your input and concern about the combination that I am running, but where do you get your HP numbers.

The Garrett web site indicates that @ 17psi the GT2860 will produce 370hp

The Brian Crower web site has a 4g63 with a T3 @ 22psi produced max 425hp a far cry from the 600hp your quoting.

I think this set up will be a pretty good balance but isuppose only time will tell.

I should have more info on dyno results shortly.

Im basing my comments on a 2860 being a stock size sr20 turbo, which max out around 210rwkw. Ive got a 2876 which is much larger and it is rated at 440hp

Im running 272's in my gtr which is really too big for it at 850hp, but it is a different motor. 264's would have been a better choice for me.

Stock evo3 cams are good for over 240rwkw when dialled in correctly.

Adriano wrote: Stock evo3 cams are good for over 240rwkw when dialled in correctly.

can i derail this thread ever so slightly? are stock evo3 cams the same as vr4 cams?

No, bigger, cant remember the specs exactly, but ive had plenty of vr4's making over 200rwkw on the dyno with stock cams and camwheels

Adriano wrote:Im basing my comments on a 2860 being a stock size sr20 turbo, which max out around 210rwkw. Ive got a 2876 which is much larger and it is rated at 440hp

Im running 272's in my gtr which is really too big for it at 850hp, but it is a different motor. 264's would have been a better choice for me.

Stock evo3 cams are good for over 240rwkw when dialled in correctly.

GT2860RS is a disco potato, T25G is an S13 SR20 turbo, S14/15 used a T28 in ball or plain bearing depending where they came from..

Disco Potato's are a little weapon of a turbo, looking at about 250kw ATW from one cranked right up.. they're only one step below a 2871R..

BUt he doesnt have an rs, or does he?

Evo 3 cams are the same as VR-4 cams as far as Mitsubishi CAPS is concerned, as the VR-4 part number has been superseded by the Evo 3 part number. The lift and duration is also the same between the two. It is the Evo 1 which has smaller lift and duration compared to the VR-4 and Evo 2/3 cams. This is comparing JDM to JDM models though, for all I know the AUDM VR-4 cams could be different again, but the JDM VR-4 cams certainly are the same specs as Evo 3.

Here are the cam specs for various 4G63s:

Inhalation lift quantity (mm)
Inspiration angle (degrees)
Exhaust lift quantity (mm)
Exhaust action angle (degrees)

RVR SSG - 8.5 252 8.5 252
Evo 1 - 8.5 252 8.5 252
RVR HSG - 9.5 252 9.5 252
Evo 2/3 - 9.5 252 9.5 252
VR4 - 9.5 252 9.5 252
AMG - 10 260 9.5 264

ive got a pair of tomei cams in mine there 260 degree with 11.5 mil lift . its lumpy at idle and a bitch to drive a low speeds , it also comes down to the tune i think , they call it a fat idle or something when they put more fuel in at idle .

thanks adriano and dg :beer

back to the thread, if you have 272 cams but are running a stock vr4 ecu, that might be your problem.