Call me crazy for even considering this! But I'm really sick of the lame performance of my 1985 4kq
I've thought of doing 5k turbo engine, but why waste the time and money on an engine that nothing performance wise exsist,for lack luster performance. A 20 valve turbo would be the shiz-nit so I could stay with the bullit proof I-5.
But again... Not much in the way of affordable performance parts. And super expensive! So what about the little engine that could? The 1.8L turbo. Plenty of great performance parts available. Or maybe even a Vr6.
So here is the problem... Will the 1.8 bolt up to the stock 4000 quattro tranny?
Any thoughts on this?
Thanks!

As far as i am concerned, i run a 1.8 with a k04 and all the goodies listed below, it runs somewhere around 300hp at altitude and is a great little motor, however the rally car is a k24 powered 1-5, much better motor as far as total performance, needs some tlc and mechanical know-how to tune the thing, but it has dyno'd at 400whp and 420tq at wheels. The I-5 is as you said near grenade proof. The I-5 is also much cheaper to get the parts, just don't always count on new if you're a budget racer.
In conclusion for your use, performance would be close but i think you'd save a few headaches with the I-5 motor

Yeah, I really want to stick with the I-5. But I'm only going to do a 20VT. I just don't know much about them... Which year is a good one? I'm thinking maybe 93-94 S4 engine, but big $$'s. I really don't know. Do you have any leads on 20vT for sale?

it might be easier to get the motor out of a 95-96 s6 that's where i'd first look junkyards ect, just as long as they didn't throw a rod, which is extremly rare it's gonna be a good motor, sometimes you can even get the junkyard to remove the motor for you for a small fee, just make sure you get everything you need when you pick it up, shoot me an e-mail and i might be able to see if i can do something

out of a K04ed car? isnt that WAY over the K04s efficency range? we are talkin about a K04-15 here right, not some hybrid? I thought the K04 was good for 260 hp MAXX, what would the point of stg III be (270+hp)?
correct me if im wrong

Ignition timing, methanol injection, a good head and intake, take out some rotating mass and it's all gravy. those stage 3+ kits are extremely horrible, my friends doesn't spool until 4800 and his range is 4800-7000 that's a nuts range to try to get a good time around a track. My little K04-15 is only pushing 18psi and keep in mind this is a fully customed tuned engine, Jaeger Engineering style

A well tuned 1.8 will reliably produce 300 after that the block is huge and you have to wait for some monster of a turbo to boost

the guy is right tho with the fact that if you have things running at their best and properly tuned nice things can happen

to get more power, you need airflow. Airflow is a function of boost and motor efficiency. Sure, you can have a highly efficient motor, and run less boost and still make power, but only to a certain extent.

Here's a K04 compressor map:
<img src="http://home.comcast.net/~s4what/images/k04-0025.jpg">

The farthest line is 0.18 m^3/s, which is ~795kg/hr (220 g/s) And this is at 15psi (ignoring pressure losses), at a whopping 55% efficiency, so basically a lot of hot air. 220g/s is probably good for ~260hp or so, a far cry from 300hp.

I don't care what you say, but a K04 will not flow the amount of air necessary for 300hp, short of slapping NOS on it (but then the turbo still isn't supplying all the air).

As for your comments on Stage 3+ kits, it all depends on the turbo and tuning. Even my poorly tuned 3+ kit hits full spool by ~3300rpm, so your friend must have a pretty big turbo.