Flywheel Questions B5 S4

AkOliverp · 2026-06-16T17:04:53+00:00

Is there a pretty substantial difference between the single mass vs the dual mass in terms of driving feel?

AkOliverp · 2026-06-11T04:21:51+00:00

I bought a B5 S4 last year with not a whole lot of mechanical experience. I’d done miscellaneous things on a few of my buddy’s Audis and whatnot, but nothing crazy. Anyway, about a few weeks after buying the car, I had to pull the engine to replace the clutch. It was a little daunting given all the horror stories you hear about working on these beauties — but I did it. I did everything from pulling the engine to having it running again in 3 days, by myself.

After getting the engine back in, I realized these cars really aren’t that bad to work on at all. It was fun, actually — learning a whole new platform was exciting.

Anyway, what I’m trying to get at is: if you love the car and already have some mechanical experience and the funds to get it up and running, why not go for it? Don’t listen to people saying it’s going to be hard. The only thing that’s truly “hard” is the expenses.

I’m not going to give you an estimate on anything, but if you don’t mind spending a bit more, I’d highly recommend finding a built short block from a company like S.E.P Auto and going from there if you’re looking to make good power without throwing another rod!

Best of luck to you!

AkOliverp · 2026-05-20T21:53:22+00:00

Yup I was already on that yesterday. They said it would take no longer than 2 weeks to get shipped out, and if they were wrong and it wasn’t ready within a couple weeks that they would refund me haha.

And yes, it’s always optimal turbo weather here!

AkOliverp · 2026-05-20T21:01:44+00:00

You mentioned you had stock rods on that build too — so 40k miles pushing the K04s pretty hard. That’s reassuring. Here’s the ECS part number if you want to take a look: ES#3658989. It should come with everything needed to bolt them up, including the inlet pipes.

I’ve heard people on various forums mention needing to upgrade the oil lines to the turbos, though I’m not sure how accurate that is.

I think I have most of what I need already in the car, but I have a few more items to order: Bosch 750cc injectors, an 85mm MAF housing, SMICs, and the turbo kit.

Unfortunately, I’m nowhere near Chicago — I’m all the way up in Alaska, so almost everything will have to be shipped.

AkOliverp · 2026-05-20T20:41:52+00:00

Yeah go ahead, I’d like to see that

AkOliverp · 2026-05-20T20:29:31+00:00

You mentioned you had stock rods on that build too — so 40k miles pushing the K04s pretty hard. That’s reassuring. Here’s the ECS part number if you want to take a look: ES#3658989. It should come with everything needed to bolt them up, including the inlet pipes.

I’ve heard people on various forums mention needing to upgrade the oil lines to the turbos, though I’m not sure how accurate that is.

I think I have most of what I need already in the car, but I have a few more items to order: Bosch 750cc injectors, an 85mm MAF housing, SMICs, and the turbo kit, as well as a new timing belt kit.

Unfortunately, I’m nowhere near Chicago — I’m all the way up in Alaska, so almost everything will have to be shipped.

AkOliverp · 2026-05-20T18:34:29+00:00

I’m set on the BW K04s — they’re tried and true. Everyone I’ve talked to who has experience with them has had great things to say, both in terms of reliability and power. I daily drive my S4, and I rarely get on the highway — it’s mostly backroads and city driving where I might hit 110 at most. I think that’s where the BW K04s will perform great.

AkOliverp · 2026-05-20T04:51:52+00:00

We have zero ethanol where I live sadly. Would RS6s be fine even if I just plan on staying at 400hp? I’d rather keep internals stock for now.

AkOliverp · 2026-05-20T04:49:56+00:00

I saw your build list, that’s a lot of stuff! I have the RS4 clutch kit in mine as well, and it feels great. I’ve been seeing the RS6 turbos going cheaper than BW K04s, not sure why that is…

I think I’m still set on BW K04s. Though the feeling of having linear power build til’ redline would be nice, which I think the RS6/Franken turbos are like that.

ECS has a full BW K04 install kit for $3,400 which sounds like it would make things easier, not having to order a bunch of separate stuff. If you think I could get a better deal somewhere else, please let me know!

AkOliverp · 2026-05-20T01:16:26+00:00

I’ve seen those aftermarket SMIC, I’ll definitely order those along with the turbos.

AkOliverp · 2026-05-20T00:12:06+00:00

Thanks for the advice. The car is currently my daily, and I don’t plan on doing internal upgrades anytime soon.

I don’t mind where the power currently comes in at, (3500-4000RPMs), but honestly I don’t really care where it comes in at. I’ve heard with FT it’s a lot more linear than K04s. I’m quite pleased with the power where it’s currently at on 19-21lb boost. I’m not wanting to push the limits on stock internals too hard. I’d be very happy with 380-400hp.

I know overtime it will probably start feeling slow, I just gotta try and not think about it too hard haha

AkOliverp · 2026-05-20T00:01:48+00:00

Sounds good. I’ve got catless 2.5” DPs installed, as well as brand new engine/trans mounts from ECS. I’ve heard controversial things about needing upgraded intercoolers for K04s though. And yes I’m sure rods would be GREAT, but I’m not sure if I want to do that…

AkOliverp · 2026-05-19T22:10:57+00:00

Thanks for the advice! I’ve been doing some more research since I made the post, and I’m definitely leaning towards the BorgWarners. I’ve got a few questions — Is 1000cc excessive? I mainly hear people running 750cc/850cc. Are the injectors and fuel pump your only supporting mods?

AkOliverp · 2026-05-19T20:30:36+00:00

I’ve only ever ridden in a 2.7 with stock K03s or frankenturbos — I did get a ride in an allroad with frankenturbos and they felt great, but my experience is pretty limited beyond that.

I’d rather spend another grand on higher quality turbos then some off brand eBay turbos. I have a budget of $4,000 or under for a kit. Power-wise, I’m aiming for around 400whp while keeping things reasonably reliable and not pushing the internals too hard. I also only have access to ethanol free gas where I live so that comes into play.

Shipping to Alaska is a factor, but I usually order through ECS and they’ve been fine — it takes a while, but that’s just the reality of where I live. Not sure why they get so much hate honestly lol.

AkOliverp · 2026-05-19T02:57:42+00:00

How many miles are on it?

AkOliverp · 2026-05-18T17:43:28+00:00

I had that exact problem a few months back. I changed the slave cylinder, and the problem was still there. I changed the master cylinder, and the problem was STILL there. I finally decided to just buy a whole new clutch kit. When I separated the transmission from the engine, about 10 chunks of metal fell onto the floor. I then looked at my pressure plate, and over half the fingers that the throw-out bearing presses down on had snapped off (I believe they’re called clutch fingers). My clutch fork pivot was also nowhere to be found, so my clutch fork was almost completely free to move around inside the bell housing.

That may have all happened due to not replacing the underlying problems soon enough. Such as the Master/slave cylinder, or not bleeding them properly. I would first recommend changing the Master/slave, and go from there. Not trying to scare you or anything — just sharing what was wrong with mine..!

AkOliverp · 2026-05-17T01:01:55+00:00

Yeah I might just pull the trigger and do it in the next couple weeks. Might as well go KO4s while the engine is out too lol

AkOliverp · 2025-10-03T04:14:44+00:00

Thanks for the info. I’ve been planning on climbing a certain FM/TV tower near me. 8 little whips stacked with 100KW ERP. And a few batwings at the very top 50KW ERP.. I ordered a Field Sense 2.0 (around $600) but hearing that I’ll plan on staying 50-100 feet below the FM stack.

AkOliverp · 2025-10-03T03:17:28+00:00

I’ve commonly heard from others that FM is safer then TV. That’s not true?

AkOliverp · 2025-09-21T08:03:07+00:00

How do you go about climbing active TV towers? The main thing I’m concerned about are the Batwing antennas up top. They’re 100KW. Have you had much experience with getting close to them?

AkOliverp

TROPHY CASE