M3 Cams/software vs Diff Swap

[Casmells]

Hi All,

1997 2.8 Roadster with M50, CAI, and magnaflow eith 55k on the clock. Cooling system has been taken care of, IE subframe bushings done, many other suspension parts refreshed. Looking for the next go-fast (ish) mod. No FI for now (wife and $$ and all...).

Weighing my options between a diff swap or M3 cams plus software. I'll be doing the work myself so labor isnt an issue.

What will make me happier? Dont care about going 100 plus mph, just want more pull.

Thanks.

[BimmerBreaker]

Diff is noticeable everywhere
Cams youll feel more in the top of the powerband and also need a tune...

My vote, diff

[daven]

I vote diff, too.

[bluptgm3]

Differential, and subframe reinforcement, with two (2) ear cover.

…and six speed swap.

Sent from my iPhone using Tapatalk

[Remotion]

Cams and dynotune, absolutely. diff swap is not faster, it renders situation with rosetinted glasses but in reality you will spend more time shifting gears and being just as slow.

[zellamay]

I'm no fan of lower gearing, unless your only goal is 0-60. For most driving 1st is almost too low, causing a lot of immediate shifting. And, highway speeds feel strained. As most on this site say, cams/software is not the efficient way to spend your money, compared to FI. I vote to stash the money for future FI, or buy an M.

[daven]

OP said "Dont care about going 100 plus mph, just want more pull." A lower geared diff will give him that for the least investment.

[Casmells]

Yea, i know FI is the way to go. It will happen in the future, but not right now ( too much hobby spending, wife yada yada).

I need to figure out which diff i currently have...any ideas? VIN says a limited slip.

I thought the M50/CAI made a pretty noticeable impact
Will cams plus software be a bigger gain than the M50 was?

I would prefer more power over gearing, but gearing may accomplish what im after...

[Tim95M3]

S52 cams and a good tune with your existing mods will put you somewhere around stock S52 power. Your current diff is a 3.15 Torsen. I have a 3.46 Torsen in both of my 2.8's and it's lovely. I hate the stock lazy gearing on these.

[328 Power 04]

The 2.8 responds well to cams, m50 manifold, and a targeted tune for those mods. That means a tune specifically for those mods, not an off the shelf shark injector (especially for the VANOS switch timing). You will get good hp at high rpm when done right, because of similar airflow to the 3.2.


On the other hand, the 3.2 with M50 manifold is tricky.

[s8ilver]

Another option: M54 manifold swap. Did that on my 2.8 (along with headers and a 3.46) and it's no slouch. It feels very close to a stock S52 off the line; in fact at Jon Martin's BBQ last summer, guy behind me in his supercharged S52 Coupe was somewhat confused by the "wimpy" 2.8 in front of him.

Total cost for the manifold and DISA rebuild kit was <$200, but I was lucking enough to find a 3.0 manifold on eBay with DISA intact. 2.8 DISA on left, 3.0 on right.

20161102_154136.jpg20161109_190128.jpg

Edit: Oh wait, you've got a '97...this might only work on the TU motor, but I don't know for sure.

[KBH22102]

OP, reading your mod list is likely reading the spec sheet on my own car. I swapped my stock 3.15 for a 3.46 (from a 3.0 auto). The off the line and 30-50 passing response is much crisper. I do pretty well at auto-x events and I kept up well with much more powerful vehicles at Z car driving events.

Does your budget allow for lighter wheels and top shelf tires? That would be another area for noticeable dynamic improvement.

[Casmells]

Hi KBH,

i like my wheels. Not sure how light they are, PO installed them. Tires are brand new Indy 500 Firehawk summer tires which seem awesome so far.

With the 3.46 diff, what rpms are you at in 4th and 5th at 70mph?

[Tim95M3]

Edit: Oh wait, you've got a '97...this might only work on the TU motor, but I don't know for sure.

That's correct. What you did only applies to 99-00 cars. I did the same on my 99, manifold/DISA, B30 intake cam and catless headers. Made a very nice difference!

[Cel2318]

Hey s8ilver I have a ‘00 328i I drift but don’t have a crazy budget looking for more torque and alittle more power, I’ve heard a lot of people talk about the m50 manifold swap, would you the m54 manifold swap onto the 328 m52 is better and what headers did you get

[s8ilver]

Hey s8ilver I have a ‘00 328i I drift but don’t have a crazy budget looking for more torque and alittle more power, I’ve heard a lot of people talk about the m50 manifold swap, would you the m54 manifold swap onto the 328 m52 is better and what headers did you get

Sounds like the M50 on the the M52TU isn't easy...
http://forum.e46fanatics.com/showthread.php?t=550219

All you need for the M54B30 swap is a throttle body adapter plate, the intake and the M54 DISA valve (I'd do a DISA rebuild as the 3.0 had issues). It took me most of a day to do it, but if I were to do it again I could probably do it in under 2 hours. It was that whole learning where everything is and wondering how hard to yank on things to remove them that took most of the time. I would also recommend replacing water pipes when the intake is off.

https://www.turnermotorsport.com/p-4...take-manifold/
https://www.germanautosolutions.com/...repair_kit.php


As far as my headers...I have no idea as they came on the car but I'm guessing some version from eBay.

[KBH22102]

With the 3.46 diff, what rpms are you at in 4th and 5th at 70mph?

4th at 70 - 4000 rpm, 5th at 70 - 3250 rpm.

[deni2s]

I don't see much point in M50 manifold without the cams. There are a lot of dyno graphs around proving that m50 manifold synergises well together with cams. Do the cams with tune first.

[Casmells]

Im leaning towards cams/tune. I already feel first gear is too short, diff will make this worse.

Do u think the cams will be a larger gain than the m50 was? My butt dyno was smiling with the m50... i can wind it up and get more than just noise!

[Luftwaffe1O1]

Why not both? Granted we have different motors so yours will respond quite well to cams.

I did zhp cams and a 3.46 diff around the same time. As well as a tune, but i will say off the bench tunes for the m52tu are crap, really needs a dyno.

But even with that in mind it completely changed the feel of the car. Then when i added headers, it completed the package.

[328 Power 04]

He already has an M50 manifold.

Yes, the cams will make a nice difference. I believe a better jump than M50 by itself.

[Luftwaffe1O1]

He already has an M50 manifold.

Yes, the cams will make a nice difference. I believe a better jump than M50 by itself.

I feel like cams +manifold benefit each other, both add more ooomph to your top end, and the more aggressive diff will help with the percieved weaker lower end. Even though i doubt there is really any loss down low, just a perception, but for me the 3.46 diff felt like it evened out the way the car delivers power.

[Casmells]

Cool, thanks guys. Good info.