VAG 1.8T Engines. All comments welcome.

[5exiAdam]

I have posted this on another thread, however it seems to deserve its own bit of space.

Everyone who is doing a VAG 1.8T install is welcome to share their experience and knowledge.

Im looking for a full blown 450bhp lump and have had long conversations with Integrated Engineering in the US.

This is what they have to say.....

Stage “1” – basics for reliability and make 400bhp

-Use any late 1.8t block w/ big port head
-82mm 8.5:1 cr JE piston / IE rod combo $824.99 -- OR – 82mm 9:1 CR Wiseco piston / IE rod - $784.99 (both in stock)
-Use stock main bolts
-Stock head bolts @ $34.99
-Stock main bearings @ $54.99
-ACL Race rod bearings / calico coated @74.99
-Stock head gasket set $139.99 (includes every seal in top end)
-Supertech Inconel exhaust valves- $259.99

I would recommend a T3 flange, .63 a/r GT3071R with that combination and expect 350-360 at the wheels on pump fuel. I would turn the engine to 7500 not much higher for good reliability.

Stage “2”
-Replace stock main bolts with ARP’s @104.99
-Replace stock head bolts with arp studs @ 194.99
-Same piston / Rod combo options
-Add a supertech spring and retainer set @ $449.99
-Add Cat Cams 1013653 grind camshafts @ 629.99
-Use an SEM or ross machine racing intake manifold – between $700-850 depending what you choose

With this I would use a T3 flange, .63a/r gt3071r… I would expect 400-410 at the wheels on pump and turn the engine 8000. Usable powerband is actually slightly longer, turbo takes about 200rpm longer to spool and you can rev it 500 higher so….

Stage “3”
-Replace piston and rod combo with 2L stroker kit @ $1699.99
-Replace oem main bearings with acl race calico coated @ $149.99
-Use a full supertech +1mm over valve set with single groove keepers $469.99
-Consider cat cams 1013658 but toss up there with the smaller 1013653’s- same price
-Have the head ported

I would proooobably stick with the gt3076r for this just because I don’t think you really need over 500whp in that car anyways… I’d expect close to 450whp on this setup on pump fuel, with more powerband yet again and much more torque out of boost as well. This is essentially the setup we use when looking for over 700whp, although we do some additional reinforcing like billet main caps etc which are not necessary for your power goals. The 3658 grind cams will take more off the bottom end and stick it up on top and of course bolster the peak numbers, but that camshaft does have a bit of a lopey idle and it does start to get quite soft on the bottom end.

I don’t know what you are doing for engine management but on the first setup I would use a 630cc injector file on stock ecu, second two I would go with a 870 or 1000cc injector file depending on who you are using for chip tuning. I recommend unitronics or eurodyne, but definitely do not recommend revo. If you are going to use a standalone ecu like pectel or similar then it is not an issue, although the injector sizes I suggested will work well regardless.

What you do for a flywheel depends totally on what transmission you use. My suggestion is of course to ditch the dual mass one as they are difficult to resurface properly and tend to break- I recommend a 12-17lb steel unit. I do not recommend the lighter aluminum ones (then that) as they cause a lot of gear chatter and in high rpm / high power I have seen them burst! Scary stuff… Shrapnel everywhere. Also beware of cheap “billet” steel flywheels which are actually cast iron cores not from true billet steel. Many of my friends have ripped the centers out of these with high power so I suggest them only for cheap oem rebuild type duty… K03’s, all that sort of stuff are fine with them. A good billet steel flywheel typically runs $3-400 depending on the transmission, with a ring gear.

We are still a bit back and forth on the clutches but have had good success with the south bend stuff. Given this car’s duty I would suggest a fairly aggressive clutch with a “6 puck” disk- this will make it shift a little quicker as it has a lot less inertia. An unsprung center is tougher, but will chatter pretty good when you let out the clutch in 1st gear / get rolling. We are just getting done putting an unsprung 6 puck in our mk4 and my mk2 has always run with unsprung centers. That’s just a question of reliability versus what you can live with…

[alackofspeed]

What gearbox are you considering? 02M or 02J? Open diff, or ATB?

[5exiAdam]

You have lost me already.

The gearbox i have is the one that is coming with the Leon Cupra.

I dont know if it will fit though.

Mark from Marlin seems to use a 5speed vag unit, but he said the 6speed was too heavy! Although he didnt say that it wouldnt fit!

adam

[limpabit]

I would have loved to use the 6 speed box from the Seat. But was too big (could not get right position for driveshafts etc.) This is due to not having much space between the top and bottom rails.

I did look briefly at the 5 speed box. But is was going to cost money at the time for a 5 speed box that I might not have been able to use.

So decide to go the Rover box route. Added advantage. Already had cables from MGF (proven mid engine car with same gearbox) and hydraulic clutch from the Rover. Easy to fit.

But I can't see you going wrong with a VAG unit.

Other option I looked at was the scobby lump. But means that the gearbox will come out the rear! But would make a great handling car with a lower centre of gravity with the engine.

[5exiAdam]

My next plan would be to use the 5 speed vag unit.

I wonder what a low mileage 6 speed box is worth?

[alackofspeed]

Sadly, not a great deal, as John (Limpabit) found out when he sold his.

One advantage of the 02M 6-speed is that it has a higher torque rating than the 02J 5-speed.

There is a rare option, and that is a 6-speed gearbox based upon the 02J casing. I think it was fitted to some MK5 2.0 FSI Golfs. A chap I know has one in his Mk2 Golf.

[limpabit]

Ebayed mine as I needed the space. Only got £20-30 from memory.

[5exiAdam]

I think it will just be a plain old boring 5 speed unit.

What do they go for?

Cant believe the 6speed has little value!

[5exiAdam]

Do any of the tdi 6sp gearboxes fit. They might have slightly higher gearing for lighter cars?

ideas anyone? Or am i barking up the wrong tree? Or just Barking!

[alackofspeed]

The TDI ratios are all wrong. The 5-speed box in the mk4 gti is fine - with stock internals, and a safe rev limit, running on 195-50-15s my mate went through the trap at Bruntingthorpe at 155 and the car was still pulling.

Just to amuse, I'm pretty sure a 02m 6-speed gearbox is around 50kg!

The 02j derived 6-speed I mentioned, is known as a 02S. Deffo worth a look, as it's more likely to fit than the 02m, and weigh less.

[5exiAdam]

I think i will just go with the plain old boring 5speed vag unit. No doubt i can change later, but i will have lots of other stuff to sort out!