Converting a golf 2.8obd2 to obd1 to supercharge.

[Craig 0]

Hello,

 

I have used the search and spoken to one or two people but i cant find a thread for exactly what i was after so here goes.

 

Im looking at possibly replacing the engine in my VR with the plan to supercharge it in the coming months. i was thinking of using a lower mileage obd2 2.8 bottom end with an obd1 head, sp263 cams and 2.9vr manifold. Plan is to build this up with the hope to drop it straight in my coilpack engine bay and just then plug it all in and running it off my corrado 2.9 ecu.

 

As far as i can tell the VR heads are all the same, regardless of obd1/2 or 2.8 or 2.9

 

The corrado does however have a different part no. for its cams?

 

The inlet manifolds differ with the Corrado having a larger intake chamber and obd2 having a different throttle body.

 

Bottom ends are the same and only differ in the capacity between 2.8/2.9

 

Ive asked a few people and get some different responses as to yes it will work to no ill need a new ecu and the rocker covers are different? so apologise for my ignorance but im no mechanic and am just basing my build on hear say so far.

 

i would like to run a chraged vr6 on standard internals with no intercooler. i understand if i am to superchare ill need new injectors and new map. also check chains etc, water pump, crack pipe and so on.

 

if i use arp head bolts the Stealth turbo kit thread states 360bhp is a 'safe' limit for stock internals and stock compression. how far could i go on standard head bolts and stock compression

 

i appreciate any feedback as i would like to start gathering parts, i just want to be 100% sure this approach will be fine before committing to a new engine build as costs are limted and i need to be realistic in my approach and want a clear layout/plans of what work is needed.

 

If all else fails i may just sell up and look at an R32 mk4 to just keep things easy, but i love the corrado and everytime i see one on the road im proud to own one and it reminds me how much of a fantastci car they are.

 

Thanks in advance :)

[KADVR6 0]

what is wrong with the current engine? i just slapped a v1 charger onto my old corrado did the stage2 stuff with stock bolts and cams and got 298bhp and 265lb after a re map.

[Craig 0]

Current engine is on 150k, it pulls well, sounds lovely and isnt using any oil as far as i can tell as i havent had to top it up since i changed the lower crank seal last year and had the routine service etc.

 

I think there may be a slight rattle, either chains or shells and its a bit of a dog to start sometimes after its been stood a week or so.

 

if i can pick up a cheap bottom end, circa £100, i then have the option of buying a cheap ported vr6 head with sp263 cams in and thought it would make sense rather than investing in a charger then having the engine let go a few miles later :(

[Kevin Bacon 5]

As far as i can tell the VR heads are all the same, regardless of obd1/2 or 2.8 or 2.9

 

In terms of valve and port size, correct. There are however slight casting differences between OBD1 and 2, including EGR channels and a much bigger cavity in the chain area in the case of OBD2.

 

The corrado does however have a different part no. for its cams?

 

Apparently so but I've not seen any data to suggest the profiles are different for UK models. Apparently late American OBD2 VR6s got assymetric profiles to try and help with rear bank filling.

 

The inlet manifolds differ with the Corrado having a larger intake chamber and obd2 having a different throttle body.

 

OBD1 Corrado is unique and has the largest plenum of all VR6s. OBD1 and OBD2 2.8 manifolds are the same, bar the throttle body mounting.

 

Bottom ends are the same and only differ in the capacity between 2.8/2.9

 

Yep, 1mm bigger bore is the only difference between the two.

 

Ive asked a few people and get some different responses as to yes it will work to no ill need a new ecu and the rocker covers are different? so apologise for my ignorance but im no mechanic and am just basing my build on hear say so far.

 

If you want to run the OBD2 throttle and take advantage of it's better software, then you will need the corresponding ECU. Or you can run an OBD2 engine with an OBD1 ECU and vice versa, just depends on what you want at the end of it. Personally I would go fully OBD2.

 

i would like to run a chraged vr6 on standard internals with no intercooler. i understand if i am to superchare ill need new injectors and new map. also check chains etc, water pump, crack pipe and so on.

 

Yep, it's all covered in the Forced induction VR6 thread.

 

if i use arp head bolts the Stealth turbo kit thread states 360bhp is a 'safe' limit for stock internals and stock compression. how far could i go on standard head bolts and stock compression

 

I ran 321hp on standard head bolts, which was 12psi of supercharger. How long they would hold is anyones guess, so I wouldn't risk it for the sake of a £150 or what ever they are these days.

 

If all else fails i may just sell up and look at an R32 mk4 to just keep things easy, but i love the corrado and everytime i see one on the road im proud to own one and it reminds me how much of a fantastci car they are.

 

Your problems will just begin to start if you buy an R32 :D

[Craig 0]

In terms of valve and port size, correct. There are however slight casting differences between OBD1 and 2, including EGR channels and a much bigger cavity in the chain area in the case of OBD2[/b]

 

Thanks Kev, so above issue wont be a problem when boliting an obd1 head onto an obd2 block.

 

I would like to go obd2 but for the extra cost involved and hassle i might just stick with obd1 just in order to keep things a bit more simple, ie drop and away you go.

 

so no issues using an obd2 blcok, looks like ill get sourcing these parts then :) i wouldnt even consider doing an r32 conversion myself like you, just take the easy route and buy a mk4 r32 and enjoy that way, although im sure a charged vr will be just as much fun :)

Edited January 23, 2012 by Craig

[Kevin Bacon 5]

Nah none mate, you can use either management on either block!I would defo recommend OB Wan 2 if going forced fed though as it does remap better than the old Alec Guiness OB Wan 1, lol

[KADVR6 0]

is there a difference between obd1 and obd2 cam covers then??

[robo22sri 10]

I have just bought a golf 2.8 odb2 and thinking the same!

But am not sure if I will be supercharging it for a while

 

Is the odb2 that good?