'90 Coupe Quattro - '15 S8 4.0t Swap

[90quattrocoupe]

Am I assuming you are going to cut and splice the axles? Doesn't the outer CV of the later axle have the same internal splines as the stock coupe?

On the radiator, you should make it a triple pass now and not wait. Your V8 motor puts out more heat than my 99 S8 motor and I ended up with a triple pass radiator. When you put a V8 in a coupe, you are basically putting a wall behind the radiator. So the air goes through the radiator and hits a wall. Not good for air flow. It took me almost a year to get my cooling down where I wanted it. It all changed the day I installed a triple pass radiator. Same fans, same shrouding and same thermo-switches. Only difference was installing a triple pass.

Like air, water takes the path of least resistance. When you use a front mount single pass radiator, you do not have even flow across the radiator. The pressure across the core is not the same. Some areas will move faster than others giving you uneven flow and uneven cooling.

My radiator is the exact size as the B4 radiator, as far as height and length goes. It is a little thicker as the dual cores used were a little thicker. Mine bolts in the car using B4 stock mounts. My radiator is lot smaller than your and thinner. My fans are set on a 93 degree switch and the thermostat is 85 degrees. If I am driving in any weather that is less than 80 degrees outside the fans never even come on.

Greg W.

[varia]

you can use B3 and B4 FWD manual axle as well, they are the thickest from that era

[Haenszel]

No the stock coupe bearing cage and housing is significantly smaller and presumably weaker than the b7. Hence the knuckle clearancing. The internal splines are also significantly larger than the coupe parts. I’m not going to mess around with trying to keep factory parts, I’ll make the larger parts work. Will be getting custom shafts done by a company I’ve used before. They can make any shaft needed to make it all butter together like factory.

Radiator needs a bleed port welded in so maybe we’ll put some plates in the tanks then for triple pass!

[Haenszel]

So got the transmission mounts and modified shifter rods sorted and a B7 shifter box in the car (with sound deadening for stealth).






And I think I'm going to make custom hub knuckles all the way around to accept the a8/s8 wheel bearing and hub so I can run these trusty outer CV's... so that will essentially give me unbreakable axles (100% s8) all the way around.




Next up is making the knuckles and making rear diff mounts for the b7 rear diff.... then measuring axle lengths and getting bars cut.

[audifreakjim]

You had me at knuckle. Are you planning on dropping the ball joint mount at all?

[Haenszel]

You had me at knuckle. Are you planning on dropping the ball joint mount at all?

That could be very easily done, what's the benefit on these cars? To keep arm angle at the correct angle when lowering?

What's the usual drop?


Also, the mail just came today and..... somebody sent me free RocEuro intake tubes!! They need some minor modification to fit, but they’re definitely gonna work so that’s awesome. Thanks Ahmad!!

[audifreakjim]

A few of us have played with dropping them around 1.5". I got major torque steer and went back to stock, but the idea is to get the arms pointing down again so you don't loose camber in the corners.. You should address the tie rods at the same time so you don't end up with crazy different angles.

[Haenszel]

Got S8 hub machined down to fit inside the new rotors for the Boxster calipers. Will be pressing in the hub into the bearing tomorrow then on to designing the new knuckles for all 4 corners.







Got the stock clutch/flywheel in for now, and transmission, mounts and shifter modified/installed. I have to bend the stabilizer bar a slight bit more for the shifter box to line up perfectly, but it works as-is so that's nice.




I also got the ECU back again, and now I can get the idle down to where its supposed to be. Was having throttle body alignment issues before and it would only idle at 1350rpm.

Bit lopey, I like it.

[lorge1989]

[Haenszel]

Intakes chopped.

Driveshaft at the shop. Spare center diff welded. Next thing you’ll see is this thing moving under its own power. Rwd till proof of concept happens.

[varia]

amazing!!!!!!!!!!!!!!!!!!!!!

[Grillage]

This is some next level shit right here -- unreal!

[dana]

This is some next level shit right here -- unreal!

That statement pretty much sums it up. I have nothing to add, but I'm glad you're posting here for the bench racers like me to drool over!

[the german]

ungh. so good.

[Haenszel]

Thanks guys. It’s gettin there now!

Car has been sitting for over 10 years outside, so the paint turned into a black chalkboard. Spent the afternoon shining up the drivers side and roof, and boy did it make me feel a whole lot better about this car! Lookin great now!

.... still 1 more side to do...

[PRY4SNO]

Nice thing about these cars having such hard paint is it buffs up nicely. It's going to look filthy by the time you get out of the driveway though, haha

[Haenszel]

It’s the little things. B7 s4 factory fan control modules integrated into the s8 Ecu. All factory, all good. Fans themselves will have to be slim, probably 4x10” SPAL curved blades.




Also modeling for the new hub knuckles has begun. Have a friend Erik helping me with this stuff, so hopefully we can get this finished up in a week or two and start cutting metal!

[Haenszel]

It’s time for business socks.

[PRY4SNO]

Saw this on Instagram, congrats! Sounds like a beast!

[jbrentd]

Gonna be a beast! Nice job.

[Haenszel]

FIrst drive, Success!

Clearly needs some calibration, but proof of concept seems good in my book!

[Lucky]

Link to video

https://www.youtube.com/watch?v=_ux7hcjGdv0

[speeding-g60]

such restraint you show.

i wouldnt be able to contain myself and i would stab that biotch like no other.

[lorge1989]

Do you even lift? Keep the power steering pump at home.

[Haenszel]

such restraint you show.

i wouldnt be able to contain myself and i would stab that biotch like no other.

Well, there's only 2 flywheel bolts cuz I just plopped an s4 flywheel in so..... safety first Plus the tune definitely needs love.

Do you even lift? Keep the power steering pump at home.

I have a Mini PS pump on the way, I ain't no man!

Next up is clean up of bay, clutch, wrap up fuel lines, brake lines, and whatever else, then off to my friend Jay for exhaust.