1995 90 quattro V6 to 1.8t Conversion

[Dave]

So I got an old friends 90, He was actually the friend who originally turned me on to older Audis, I mostly watched and slightly helped him put a V8 into a b3 80 which became Javad's V80 (that term was coined by my friend first). After that I got my own 90 and started tinkering, he moved on as well, and came back to buy this B4 90. By that time i was much more familiar with these car than even he was. I machined a set of URS4 hubs for him at Hank's old lab in Utah, gave him my rotors that were re-drilled to 5x112 and sourced him some KW coilovers when i sourced mine. Little did I know that in the future that car would be coming my way.

So we struck up a deal, and I had the car shipped out to Utah:

his picture


Pics as delievered:






The car had a bad thermostat and undocumented timing belt history. So i knew my first order of business.

Did the belt and some clean up:



Installed a euro front bumper:


Bought a cheap ($100) set of wheels and tires since the tires were completely dry rotted and bald on the Borbets:



And i've been driving it and sorting out other small issues. I always had intentions on doing an engine swap, and I was sort of waiting to see what came along. I would have loved to do an I5 20vt swap, but there is a bit of fabrication involved and donor cars don't pop up all that often. The other idea was an I4 20vt aka 1.8t. Which do pop up pretty often. I already had sourced some 1.8t engine brakets since they poped up cheap in europe:



and so I set out to watch the local classifieds for a cheap 1.8t donor. I wasn't expecting to buy anything soon, but this popped up this past weekend and it followed me home...





Very very clean under the hood, very clean inside as well, but with a bad trans. It set me back 500 bucks, but i already have a buyer for the interior and should have one for the wheel/tire combo that will already pay off that price tag.

I have also purchased a european b4 cabrio harness from a 1.8 (non -t) which should help with the wiring of this car, i assume i'll have to add in the N75 wiring, and the MAP sensor wiring, but the ecu plugs are the same as the 1.8t, and the chassis and fuse box connections are the same as the b4, so I'm hoping it will be a mostly plug and play ordeal, I like keeping things clean and simple.

So short term plans:
Part the A4.
prep the engine
find Flywheel and clutch setup
sort wiring
and swap it all over.


Long term:
Rebuild short block (rods, clean, new piston rings, bearings, ect)
Possible valve and valve spring swap
larger turbo, most likely GTX-3071R
T3 Style exhaust manifold
Injectors and tune.
6 speed swap



We'll see how it all plays out. This is a very "loose" plan and is always subject to change.

As it sits today:

[Justin517]

Cool!

Early (AEB, through 1999 model year) 1.8T's don't have a MAP sensor.

Personally I would just use the 1.8T harness out of the A4, it might take some work, but I would rather have to make it fit than modify a harness by adding circuits that do not exist, swap pins, etc...

Love how beefy the car looks with the wheels pushed out like that, makes me want to get some spacers for the wagon.

[Dave]

Early (AEB, through 1999 model year) 1.8T's don't have a MAP sensor.

Wow, sooo the difference in wiring could be as simple as just the n75? that seems insane. I thought that all the 1.8ts had an internal map sensor that feed back info to the ecu (different from the i5s that had the map sensor IN the ecu)

[Justin517]

Could be... I have no idea how similar the N/A 1.8 is to the 1.8T...

I'm pretty sure that is why I was getting crazy boost when I had a PCV related boost leak... the ECU doesn't know how much boost is being made, it just extrapolates from MAF numbers.

[Audilard]

Out of curiosity, what is the diameter of those A4 wheel center caps?

[Dave]

Out of curiosity, what is the diameter of those A4 wheel center caps?

i'll measure when i get home, we can add them to your tab

[Dave]

Few updates:

Scored a cheap Spec Flywheel and stage 2 clutch (150 shipped, couldn't argue)






added 3 spoke wheel:



I started pulling the v6 because i got a buyer for it.









And apparently you are always supposed to take a picture with someone in the empty engine bay:


Picked up a steam cleaner to help clean up the junk:



Before:


During:


After:


Kinda before (i hit that small corner):



After:

[Justin517]

cool, I have been looking at those little steam cleaners, let us all know how it holds up for you.

[Audilard]

Did you measure those wheel caps?

[Dave]

Mr. Nsimps came over to lend a hand and yank out the 1.8t..



and trying to get it accustomed to its future surroundings.

[PRY4SNO]

Awesome... going to be following this for sure.

On a future note, I've read on vortex of some great success with a gtx28 on the 4cyl... stock-like spool with multiples more power. A 30-series turbo has huge lag. LMK if you want some links to peruse.

[Dave]

Removed the tq converter, took some measurements. Looks like i should be able to do this wothout grinding the crank. However i apparently ordered dual mass flywheel bolts and needed single mass style... so im stuck till i get new bolts. Maybe ill swing by IE, im sure they have something.




Engine mounts installed, compared to stock






So here is the flywheel, to the crank i have 12.75mm of space and the bearing is 13mm. I think it will work without grinding anything...





so some flywheel bolts and i should be able to install it.

[Audilard]

Keep at it! You better not go for a ride in my car, you'll change your mind and want an i5 again.

[Dave]

I stopped by Inegrated Engineering to see if I could find a bolt that suited me, but no dice. I searched around on the interent and found something by ARP that fit the bill, its made for a v8 Ford, but correct length and size, and pitch...
and only about 40 bucks shipped


Installed the makeshift pilot bearing, there is a thread about converting from auto to manual, and they shaved the crank down, i did not modify the crank in anyway, my flywheel has a larger center section that allowed for it to simply be cradled inside of it.







Engine resting on its mounts



Lots of front end realestate, need to find a small intercooler now...



If anyone is curious, the ADR engine mounts I got from Europe, made everything line up perfectly

[chaloux]

Nice! Looking good. A 4 cylinder seems so nice for packaging

[Dave]

Here comes the pain:




Also what is this plug for? Wot switch or something?

[lorge1989]

I wish you were closer, I just yanked out some 6AN ish sized stainless feed/return fuel lines that would fit perfect on this. Too bad you are across the country lol.

[Dave]

Are you talking about the lines from the tank forward? or just under the hood to the fuel rail?

[lorge1989]

Feed -from the pump to the fuel rail and then return - from the fuel rail to the tank. It was used for about a year or two on the stock AEB motor then on my bigger setup. My new pump requires an 8 AN return so I can't use any of it.

edit :I just double checked my info.... My pump only needs 6 AN return. Maybe I am going to use the lines after all. lol

double edit : its 5/16 OD and .028 wall. Too small for sure.

[Dave]

Did a bit of work, more cleaning and getting things prepped under the hood. I found out the donor car actually has a k04 turbo which is a nice surprise



And i found out that the ac stuff should line up very very well.



stock b5 a4 lines to the 90 ac bits

[SEStone]

That plug pictured above is the kickdown switch for the auto trans.

[lorge1989]

Lucky find on the K04. how is this coming along?

[Dave]

Still have a lot to do, but looks like i wired it right...

[youtube]https://www.youtube.com/watch?v=_3jYsDOLqWY[/youtube]

And got my bumper back from the body shop, painted and ready to rock:

[Dave]

Got the intercooler mounts mocked up, should work well:


Plenty of room


behind S2 bumper:

[PRY4SNO]

Interesting spot for the battery, is that a v1 location or final?

Car is coming together nicely!