Basic Supercharging: My M50B25 + Eaton M90

[Ether-D]

The manifold wasn't that bad to build/have welded. It was pretty fun to make, actually.

[The Dark Side of Will]

As long as you dont need AC then there should be room on the passenger side where the compressor would have been. Then you can run your supercharger outlet pipe from there to a front-mount intercooler and over to your factory plastic intake manifold on the driver's side. Pretty much like in your drawing.

I don't think he can package the blower where the A/C compressor is, fit the intake tube, throttle and charge piping along with either stock exhaust or headers. If he does manage to fit everything, keeping radiant heat out of the intake piping, blower case and charge piping will be a significant challenge.

The blower is much longer than the A/C compressor.. probably twice as long. Putting the pulleys in close to the same plane (even if the blower is out in front of BMW's accessory drive) is still going to put the back end of the blower right into the engine mount arm and the exhaust. And the back end is where the intake is, so that would put the intake tube right into the exhaust.

I think the only reasonable place to mount the blower on the exhaust side is higher up the engine, which will require some... artistic (and elaborate) bracketry.

[Q5Quint]

I understand why you're doing it that way. It's not unprecedented... just an unusual approach.

I'm curious about how well the blower and intake ducting will fit on the exhaust side of the engine, though.

Here's a thread in which a guy does a from-scratch installation of an M90 on a 4.9 liter Cadillac V8 in a Fiero: http://www.fiero.nl/forum/Forum2/HTML/127611.html

This guy is amazing, btw.

[The Dark Side of Will]

The manifold wasn't that bad to build/have welded. It was pretty fun to make, actually.

You started with an aluminum manifold... All the production 24V manifolds are plastic. There is a cast aluminum Jenvey ITB manifold... but that piece doesn't mount injectors as Jenvey puts those in the throttle bodies, which are separate.

[The Dark Side of Will]

This guy is amazing, btw.

Mechanically it's a very interesting build. He does a good job mounting the blower.

However, he needs real engine management for that setup to reach its potential.

[Q5Quint]

Bandaids can only take you so far, when a megasquirt might have been cheaper. That is a scary cliff to jump into if you have never done it before though.

Check this stuff out:

http://www.jagweb.com/aj6eng/supercharging_article.php

[The Dark Side of Will]

Bandaids can only take you so far, when a megasquirt might have been cheaper. That is a scary cliff to jump into if you have never done it before though.

Check this stuff out:

http://www.jagweb.com/aj6eng/supercharging_article.php

There is an often-overlooked advantage which supercharging can provide - preheating of the air charge in off-boost conditions to obtain significant emission and economy benefits during warm up and cruise. It is fortuitous that this takes place automatically because the losses from pumping against a vacuum appear as heat in a smaller volume of air which therefore becomes much hotter. Even a screw compressor can deliver air at around 150 C when off-boost.

However, the effect does need to be controlled by some sort of by-pass or the pumping losses within the supercharger can outweigh the gains. Another drawback is that when the throttle is suddenly opened after a short period at light throttle the boosted charge is initially heated up as it extracts the latent heat that has built up in the system. This can give rise to a brief period of detonation - usually harmless but still undesirable. The same effect explains why supercharged engines often require minimal temporary fuel enrichment as the throttle is opened.


For highly boosted engines it can be better, not only to employ a bypass system, but also to place the throttle after the supercharger so there is no heat build up off-boost. A throttled supercharger on a racing engine, in the light load, high revving, condition during the seconds before the start of a race, can heat up nearly to the point of seizure, so as the car gets off the line both the blower and the engine (as the excess heat dissipates into the system) are under extreme stresses that do not apply at other times. Reliability is much improved with a bypass and throttling after the supercharger.

This is confusing.
With regard to warming intake air, I think he's referring to diesels in winter or carb'd aircraft engines operating above the arctic circle. That just doesn't apply to cars.
With regard to heating the blower by operating at low throttle... that's just stupid. If that happens, your bypass is way too small or incorrectly operated. Period. What he says is nonsense when considering a system with a correctly operating bypass.

[Lithium]

Time to open up the can O worms...
I have an M50 Swapped E30 325i with an Eaton M90 Mounted in the AC Compressor position - Running through a front mounted Intercooler & into the stock intake Manifold.
Tuned with a Moates Emulator. (It was allot of work)
It's only running on 5.5psi right now. Will bump it up to 10psi soon.
Build thread can be found on BCBimmers.com

[The Dark Side of Will]

Do anything to keep exhaust heat out of the intake charge?

Is that a Thunderbird SuperCoupe blower? That has a MUCH shorter snout than the GM M90.

How hot does it get? It doesn't look like you have a bypass either.

[Lithium]

Do anything to keep exhaust heat out of the intake charge?

Is that a Thunderbird SuperCoupe blower? That has a MUCH shorter snout than the GM M90.

How hot does it get? It doesn't look like you have a bypass either.

Thanks for asking.
Yup Supercoupe 3RD Gen Oval Port Eaton-M90 - Snout shortened 2.75in
4Th Picture shows the Air Filter heatshield. (I also duct cool air into the chamber from a brake duct)
5th Pick shows the Dual Bosch Bypass Valves.

I measure the air temp coming out of the Intercooler & it's usually 2 to 3 deg warmer than the ambient air. She runs nice & cool.
Bypass valves take intercooled air & run it back to to blower for extra insurance @ idle & low throttle opening driving.
ChrZ!

[Victell]

I have an M50 Swapped E30 325i with an Eaton M90 Mounted in the AC Compressor position - Running through a front mounted Intercooler & into the stock intake Manifold. Tuned with a Moates Emulator. (It was allot of work)

What is the reason for putting the MAF before the supercharger instead of after the intercooler?

[Lithium]

What is the reason for putting the MAF before the supercharger instead of after the intercooler?

The MAF has to measure all of the air that enters the system before being pressurised. Bypass system is a closed loop after the Throttle.
Roots style blowers destroy throttle bodies otherwise.

[The Dark Side of Will]

Thanks for asking.
Yup Supercoupe 3RD Gen Oval Port Eaton-M90 - Snout shortened 2.75in
4Th Picture shows the Air Filter heatshield. (I also duct cool air into the chamber from a brake duct)
5th Pick shows the Dual Bosch Bypass Valves.

I measure the air temp coming out of the Intercooler & it's usually 2 to 3 deg warmer than the ambient air. She runs nice & cool.
Bypass valves take intercooled air & run it back to to blower for extra insurance @ idle & low throttle opening driving.
ChrZ!

I was referring to heat shielding between the header primaries and the blower housing, intake duct and blower discharge duct.

Ahh... I didn't see that you were running black coolant hose as the ducting for your bypass valves.

[Lithium]

I was referring to heat shielding between the header primaries and the blower housing, intake duct and blower discharge duct.

Good question - But the answer is unfortunatley no heat shield - It is all so crammed in there that there is not enough room for one. I had originally thought of heat wrapping the headers (Oh yeah I am using S52 stock headers) but it's to tight. Luckily I have had no problems with heat.
The blower runs around 80c & the intercooled intake charge is 2c above ambient temprature so no issues so far.
It will run hotter when I up the boost at some point.
Thanks.

[Victell]

I have an M50 Swapped E30 325i with an Eaton M90 Mounted in the AC Compressor position - Running through a front mounted Intercooler & into the stock intake Manifold. It's only running on 5.5psi right now. Will bump it up to 10psi soon.

How much power to you think you have with the current setup? Hows the throttle response and driving it?

Vic