M20 super charger kit?

[djjerme]

I really just have zero use for centrifugal superchargers like the vortec and rotrex. The reason these exist is ease of install only. And you can say "yeah, it's got a supercharger." Too expensive for people who want bang for buck, imo.

I don't disagree.

My dealings with Vortech left me with some disdain for them as a company, and really the performance upgrade (for what it retailed) was just not worth it or usable.

If I ever were asked to do a forced induction install again, I would go turbo.

Perfect example I always use is the Chevy Cobalt SS. Started out as S/C for the first few years, but later went to turbo, and it was more powerful (260 hp vs 205 hp) and ultimately more upgradable.

[SkiFree]

Not jumping down the rabbit hole ..... BUT


OP, if you want another example of a supercharged M20 E30, there was a nice one featured in Performance BMW magazine last month (Oct.2015).

[Ether-D]

I really just have zero use for centrifugal superchargers like the vortec and rotrex. The reason these exist is ease of install only. And you can say "yeah, it's got a supercharger." Too expensive for people who want bang for buck, imo.

[djjerme]

This is incorrect. Look up "bypass valve supercharger". If done correctly, your streetable (or even non-streetable) supercharged e30 will have one and it (get this) bypasses the supercharger when it's not needed, aka light pedal foot.

...I agree, though the kits I have worked with (Vortech mainly) don't usually have bypass valves. Yes, they probably should, but most of their kits are low psi, and honestly I was not impressed with the quality or support from them.

[Exodus_2pt0]

^ Fair enough!

[Blake B]

This is where a properly sized Turbo comes into the equation. My S4 makes power from 3k to 7k, but I'm running 2 relatively small turbochargers. That said, after 3500rpm the power is pretty much instant. If you size the turbocharger correctly, it can offer all the benefits of a supercharger.

I dunno, I always felt my b25 had plenty of torque. As by intimidation, I was referring to all that goes into a turbo setup of piecing it together, vs a supercharger.

At the end of the day, it comes down to personal preference and ability.

I've had a centrifugal supercharger before, and IMO its a waste of time. Never had Roots, but if going supercharged its the only way to go.

You're missing the point though. A roots or twin screw is making power off idle. i.e. no wait time. This is more ideal if you're not looking for all out power and a linear power band. I don't want to have to wait until 3-3.5k. I want it down low where I can use it (1.5-4.5k).

All the videos of canyon and highway pulls are awesome, but for the 85% that don't live in places like that, but have great access to curvy roads, supercharging is where its at.

P.S. sorry OP for hijacking your thread.

[Exodus_2pt0]

Ask the turbo guys where in the rev range do they make that 300hp. I bet it's only at 6750rpm. Idk about you guys, but I like having power without every cop in a ten mile radius looking at me.

This is where a properly sized Turbo comes into the equation. My S4 makes power from 3k to 7k, but I'm running 2 relatively small turbochargers. That said, after 3500rpm the power is pretty much instant. If you size the turbocharger correctly, it can offer all the benefits of a supercharger.

I dunno, I always felt my b25 had plenty of torque. As by intimidation, I was referring to all that goes into a turbo setup of piecing it together, vs a supercharger.

At the end of the day, it comes down to personal preference and ability.

I've had a centrifugal supercharger before, and IMO its a waste of time. Never had Roots, but if going supercharged its the only way to go.

[Ether-D]

Also in our lesson today: centrifugal vs roots vs lysholm

A centrifugal sc might as well be a turbo in that the boost comes on later. Not a great around-town kind of deal.

Roots makes boost wherever you are in the rev range but when it's working hard, it makes quite a bit of heat. Also makes its boost externally (not inside the actual sc). Great around-town setup.

Lysholm is similar to a roots, but compresses the air internally and tends to be 15-20% more efficient than its roots equivalent. Even better for around-town driving.

Ask the turbo guys where in the rev range do they make that 300hp. I bet it's only at 6750rpm. Idk about you guys, but I like having power without every cop in a ten mile radius looking at me.

[Blake B]

Also, I may start selling clones of my setup, so OP, there may be an option for you.

I hope so! After speaking with you and a few others I'm ready and waiting!

[Blake B]

I've been researching this. While both have their benefits the SC definitely has its place. I dd my car 5 days a week, in town... I spend the majority of my time under 4k rpm. I think a SC would be more beneficial as I squirt in and out of traffic and highway on ramps.

The thing i like about the e30 is that I can put my foot to the floor and really ring it out in the first few gears and I'm still under/just above our backroad's speed limits. Obviously the SC would get me going much quicker but I don't need light speed HP and prefer the linear powerband. having a turbo come "online" and kicking the car out on the roads I run on would be no bueno. (yes, even with a properly sized turbo, there's still some lag). I drove a SC BRZ awhile back it was putting 275hp to the wheels and it was PERFECT.

To keep the spirit of the e30 (light, nimble, quick) I think the car would be perfect with 225-275hp. I don't want a rocket ship. This would make the car perfect in my eyes and wont allow the car to overpower itself.

I'm talking to a few guys on the forum and emailing a few companies. Here's what Rotrex said this morning:

Hi Blake,
We have a kit for the M50, but with a few modifications it's possible to use on the M20B25.
I would recommend a Rotrex C30-94, so you later on can change the pulley and get +320whp. But with a larger pulley it can run with around 225whp to a start.

The price is $3900 + shipping for a Rotrex C30-94, brackets, belt tensioner, belt, oil system, oil cooler and oil filter.
There is NO piping, intercooler or engine management systemt included.

Best regards
Brian Sørensen

So although its not a roots setup (what I'd really like) supercharging your car is still an option and a viable one. I'm still researching my options.

[Ether-D]

...and do offer a little bit more linear power profile then a similar turbo setup. Only because they are physically linked to the speed of the engine.

This is correct.

And a turbo is easier to live with on the street, a Supercharger is Always on, vs a turbo you can drive it out of the boost with a ginger right foot..

This is incorrect. Look up "bypass valve supercharger". If done correctly, your streetable (or even non-streetable) supercharged e30 will have one and it (get this) bypasses the supercharger when it's not needed, aka light pedal foot.

[Ether-D]

The m20 already has plenty down low. A turbocharger is more intimidating to take on.

Wow, this is 100% wrong. Unless you are talking about a m20b27, then it's only 50% wrong.

If you go supercharger its going to involve some level of fabrication. Turbocharger is essentially bolt on with some minor work for intercooler piping and exhaust.

Correct, which is why the other 50% of the first quoted section is wrong.

Also, I may start selling clones of my setup, so OP, there may be an option for you.

[djjerme]

MY buddy sold the Supercharger kit off his '88 vert. He says it was a Paxton 2000, but he had to fab all the mounts for it.

I have done S/C installs on non-BMW cars before, and I don't think they are any more difficult to install then turbo systems, and do offer a little bit more linear power profile then a similar turbo setup. Only because they are physically linked to the speed of the engine.

That being said, I wouldn't go supercharger on my own car. More power can be made with a turbo setup. And a turbo is easier to live with on the street, a Supercharger is Always on, vs a turbo you can drive it out of the boost with a ginger right foot..

Just my personal opinion, I would also suggest doing some of your own personal research and see if anyone in your area has a turbo'd car that they will at the very least take you for a ride in.

[Exodus_2pt0]

Just turbocharged it. The m20 already has plenty down low. A turbocharger is more intimidating to take on, but the rewards are great. If you go supercharger its going to involve some level of fabrication. Turbocharger is essentially bolt on with some minor work for intercooler piping and exhaust. Also, if you are looking for the instant boost a supercharger provides, then go for a smaller Turbo size. You will sacrifice up top and performance for low end low lag boost. Just because it's a turbo doesn't mean you have to go huge on it. Decide what your power goals are, and size the Turbo accordingly.

Start reading, once you have a solid grasp on the systems, then go for it.

[kickinindian]

none that actually ended being sold to the public.