Jump to content
Notice to Hotmail/Gmail & BT Internet users - Please check your SPAM/JUNK folders for our emails. Please add our email as a contact to your email account.
Light/Dark Mode Enabled: You can now select the option by clicking the moon/lightbulb in the top right corner!

Turbocharging my ARC engine

Recommended Posts

Long time since I've posted on here!


Have had an ARC engine for a number of years now, and with a fairly recent purchase of another breadvan it's time to do something with it.

was planning on ITBs although driveability concerns are putting me off. Then with the recent finding that a 1.4tsi k03 turbo/manifold bolts straight to the 16v head (bar 1 bolt) I have decided to go down this route. Current planned purchases are:


K03 turbo from a tsi

AGU throttle body (yet to confirm it bolts to manifold)

will port the head myself after my successes on both AAU and AAV engines.

Speeduino management (pnp on AGU, same sensors on ARC)

Either AGU loom or custom.

Turbo plumbing (oil and air)




Fuel pump


Parts I already have include:

1ltr flywheel

Aftermarket clutch

Various 084/5 boxes

Slim starter

Shortened oil pickup

Short sump

Complete front subframe from a 6n2 (engine, box, brakes, suspension etc)


This leaves me with lowering the compression of the engine, seems that the stock ones melt on 7lbs of boost @180bhp.

Ive been looking at various internals until I found a German company that build specialist head gaskets at various thicknesses to drop the comp down to between 10.5 to 8.1 depending on specs.

My only concern is valve timing issues from the decomp gasket, and haven't found a vernier cam pulley yet.

Also looked at various oem piston combinations but they all seem to raise the CR instead!


Any advice welcome.!


Link to post
Share on other sites
  • Replies 4
  • Created
  • Last Reply

Top Posters In This Topic

  • samuelj




  • dvderlm



Won't the cam timing be the same? The head will be just further away from the block on a overhead cam engine. A push rod engine may need longer push rods. Most of the power gains will come from the turbo charging. A vernier pulley will give minimal gains. A thicker head gasket will increase the chance of leakage so the block and head can do with being flat as possible with a very good finish. I have used studs from ARP on the head to improve clamping force. That was good that you have found a company that will make a thicker gasket. My engine has a decomp steel gasket combined with a stock one so I am hoping that it will all seal OK. I looked for for years for pistons and had to settle for Wossner which yields a CR of 8.5:1.  Yes my CR is high but I want driveability off boost and concentration on charge cooling with the biggest interccooler possible, water methanol injection and a fan pushing air through the intercooler when the engine comes up on boost If you are using a wideband sensor does that mean you are running a programmable ECU or are you just measuring AFR?

Link to post
Share on other sites

I'll be running a speeduino ECU, runs the same software as megasquirt, so yes full standalone, as for cam timing, by increasing the distance between block and head using the decomp gasket the timing won't be able to be set if it were to be half a tooth of distance apart if that makes sense? Although looking into it I could match the thickness to the tooth size so I wouldn't get any descrepancy.

I was looking at the ferriday decomp plates, but the boys on the continent seem to have good results using the reinz modified gaskets.

heads getting full rebuild as above.

I'm aiming for a similar CR with a target hp of 180 (based on boosted AAV).


I do have an AAV I was going to boost, would hold the power a lot better, but it has a cracked head and hence why I'm now looking at the ARC lump before the crack becomes a major issue...

Link to post
Share on other sites

surely it is the ratio of cog sizes that determines how cam moves at half speed of crank and a vernier pulley can fine adjust up to a tooth plus a gap offset

to have valves both valves closed (lobes upwards) when cylinder 1 at TDC.


I reckon there's enough slack in the belt to ease the tension that you should not need  to change to a longer belt with one more tooth.


Link to post
Share on other sites

My concern is the cam being half a tooth out, would that affect running at all? In theory the distance between two cogs, and the distance between the teeth should be an exact number not a fraction. By spacing the head there's the possibility of changing the length/teeh ratio to a fraction.

Although with a spaced head theres less possibility of valve to piston if its out by a small amount.

All spacer manufacturers recommend a vernier pulley to adjust for any unequal length/tooth ratios.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.


  • Notice to Hotmail/Gmail & BT Internet users - Please check your SPAM/JUNK folders for our emails. Please add our email as a contact to your email account.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. Terms of Use Privacy Policy Guidelines