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V-Cam or Single turbo conversion ?

McGarryR32
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McGarryR32 Contributor

McGarryR32

Posted
Posted

Hi all,

Wondering what to go for. Currently at 580bhp on 95 octane.  2860-5s with tomei type b cams.

Im looking get just over the 600 mark and extract more response.

options are the following

 

V-Cam step 2,

Pros : Definitly more response, more power across the entire rev range  

Cons : Reliability ? still using outdated turbos. Not sure if my wossner pistons will work with it.

BG EFR 8374,

Pros : will see more power, less clutter and heat soak in engine bay. can sell current setup to reduce costs

Cons: possibly spending 3k for 300rpm or so spool difference

 

 

Vcam wise i cant seem to find any videos of an R32 with it, yes there are many dyno graphs but that doesnt translate to 2nd/3rd gear pulls and street driving etc.

Single turbo also sounds alot better, and you get the glorious SUTUTUTUTU noises which you dont get with twins.

 

 

Any advice ?

its a street car with some track use.

 

 

 

 

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PLYNX Mentor

PLYNX

Posted
Posted
25 minutes ago, McGarryR32 said:

Currently at 580bhp on 95 octane

? 95 octane ? If so this is quite good. 

Have you first considered going to a higher octane fuel, a re-tune( you didn't state your computer management system ) with more boost ?

May well get what you seek without a large out lay.

If it dose not work then up grade

joshuaho96 Veteran

joshuaho96

Posted
Posted

VCAM should be pretty reliable, it's literally just the Subaru EJ25 AVCS bits with some fittings to get it on an RB intake cam.

If your pistons have valve relief for high lift cams then they should work with 50 degree advance. Don't buy the hype from HKS, you can fit either your own cams to the VCAM system with some modification or regrind the cams to get the desired profile. If you want to save some coin in return for some labor you can buy the step 1 system, pop off the metal block that they use to keep it within 30 degrees of cam advance and regrind the cam to your desired spec. Or replace entirely.

Here are some dyno charts for VCAM:

image.png.1318c016a95a8f0a5ab202559f3799ea.png

Step 1 VCAM with -5s vs stock with catback, no VCAM:

image.png.7781f3e3cf5ea8b5feed60921888a1ef.png

Blue is Garrett 3582 with step 2 VCAM, Orange is stock with catback:

image.png.10bc142fba71cb33d48d4245abcfca1d.png

More dyno charts here: https://www.facebook.com/upgarage/photos/?tab=album&album_id=2754286177933791

As for whether you should pick VCAM or single, I would say both? But it's big money to do that. If you want to know what the benefit at the top-end will be, get an adjustable intake cam and fiddle with the timing and see what timing gets you the best top-end. That will be your peak power. Fiddle with it again for best low-end response. Do that for every RPM and load combination and you end up with what a VCAM can do for you.

Piggaz Grand Master

Piggaz

Posted
Posted

Having done this exact conversion myself, 8374/1.05 all day.

A dyno sheet only shows show much, actually, throw the bloody thing in the bin.

8374 to -5’s is much more than 300 rpm difference, more like 500-700 rpm not to mention the zing under the foot once you put the twin butt plugs in the dumpster where they belong. Transient response difference between the two setups are night and day... ALMOST 1/3rd the time, the winner going to the 8374. This was shown by logs off a mates car who also went between these two exact setups on a 3.0. Thats something that is not shown on a dyno sheet with a WOT loaded run.

Having also been in two different cars (2.6/baby vcam/-5’s and 2.6/baby vcam/8374), the 8374 would destroy it EVERYWHERE.

McGarryR32 Contributor

McGarryR32

Posted
  • Author
Posted

Sorry I meant to say 97 octane here in N.Ireland

If i was looking at a BW it would be the .92 IWG option, with the turbosmart actuator upgrade. From what ive read it tends to have better response and the turbosmart unit helps with the top end.

Ive seen those dynos before UpGarage I think ?

As i say my main goal is response and driveability.

Surely the turbo cant provide the same low/mid as a turbo ?

 

McGarryR32 Contributor

McGarryR32

Posted
  • Author
Posted

Think I’m gonna go with the single, even for the fact I can sell my current setup so itl be more cost effective. Just wondering what it would be worth ?

2860-5s with HKS actuators, 7k Miles with Braided oil and water lines 

HKS elbows 

Reimax equal length downpipes

Ported OE manifolds 

HKS intake kit ( not sure on these they’re in good condition but they’re very pricey new https://www.rhdjapan.com/hks-piping-kit-special-type-bnr32.html

 

Has anyone used the .92 8374 ? I know it’s been covered but I’m more interested in drivability than dyno numbers 

 

 

GTSBoy Grand Master

GTSBoy

Posted
Posted
1 hour ago, McGarryR32 said:

Just wondering what it would be worth ?

Just in terms of the usual drug induced thinking around twin turbos on GTRs around here, I'd suggest it would be worth about 120% of what it costs you to convert to single. Won't even have time to stand up after pushing the post button your for sale ad and it will be sold.

joshuaho96 Veteran

joshuaho96

Posted
Posted
3 hours ago, GTSBoy said:

Just in terms of the usual drug induced thinking around twin turbos on GTRs around here, I'd suggest it would be worth about 120% of what it costs you to convert to single. Won't even have time to stand up after pushing the post button your for sale ad and it will be sold.

Definitely try GTRCanada/GTRUSA on Facebook, list with a 25-33% discount off new and someone will probably bite.

Piggaz Grand Master

Piggaz

Posted
Posted
On 03/03/2020 at 12:49 PM, McGarryR32 said:

Sorry I meant to say 97 octane here in N.Ireland

If i was looking at a BW it would be the .92 IWG option, with the turbosmart actuator upgrade. From what ive read it tends to have better response and the turbosmart unit helps with the top end.

Ive seen those dynos before UpGarage I think ?

As i say my main goal is response and driveability.

Surely the turbo cant provide the same low/mid as a turbo ?

 

Forget the 0.92, go the 1.05.

Below is a back to back on a 2.7. Blue is 8374/1.05 and red is -5’s. Only change was associated pipework to make the single work.

 

7CFE9D56-12D5-4164-8342-3E1B841725D0.png

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