Tell me about the Eaton M112 Supercharger and using on carbs

[Dave Dorson]

Jan 18, 2016 13:46:44 GMT mk2cossie said:

Jan 18, 2016 11:56:00 GMT Dave Dorson said:

are you sure that outlet on the charger was for an EGR?

I'm pretty sure that because they ran blow through, to stop pressure when the throttle was partially closed, they ran a bypass valve on them similar to the mini with the M45's

If that's the case, you really want something like that installing too, that will prevent you backing air up when the throttles are closed.

I drove an E36 BMW with an M42 that was supercharged, and it drove like the NA car until you booted it, and didn't generate a load of heat, because of that little valve. It's like a secondary TB that bleeds off air when the throttle isn't open.

Yup, that second hole by the throttle plate is the air bypass valve take off.
As above, when on partial throttle or cruising essentially the supercharger isn't as parasitic and improves economy

Also, as the OP has a 4.6 v8 surely he has all the associated efi bits from that engine?

I think they bought it as a bare block and heads, and used the P6 ancillaries.

I could be wrong though.

[alex]

Jan 18, 2016 11:56:00 GMT Dave Dorson said:

are you sure that outlet on the charger was for an EGR?

I'm pretty sure that because they ran blow through, to stop pressure when the throttle was partially closed, they ran a bypass valve on them similar to the mini with the M45's

If that's the case, you really want something like that installing too, that will prevent you backing air up when the throttles are closed.

I drove an E36 BMW with an M42 that was supercharged, and it drove like the NA car until you booted it, and didn't generate a load of heat, because of that little valve. It's like a secondary TB that bleeds off air when the throttle isn't open.

I was making a guess of what it was. If that's a bleed valve then yes I suppose I should do the same. My guess it was electronically operated on the Jag so I'll have to figure something else out.

[alex]

Also, as the OP has a 4.6 v8 surely he has all the associated efi bits from that engine?

Nope, I ditched the EFI bits as Dave says.

[alex]

I will be keeping it on carbs Plan at the moment is to use blow, not suck so that the charger works the "normal" way as suggested by sowen it makes much more sense, and space out the carbs so they don't get in the way. I've got a Holley fuel pump and a basic regulator, but no biggie to change the regulator to something more suitable.

Not thought about timing or anything else at the moment but I am in no rush.

[Dave Dorson]

Jan 18, 2016 14:28:12 GMT alex said:

I was making a guess of what it was. If that's a bleed valve then yes I suppose I should do the same. My guess it was electronically operated on the Jag so I'll have to figure something else out.

They're vac actuated I think, certain are on a Mini. If the stock one used some odd electronic control, I dare say it was also vac actuated but got the signal from the ECU, rather than physically and was actuated using 12v signal.

I know you're trying to simplify it by keeping it carb, but you're really not, you're making it a lot harder for yourself.

[alex]

From the offset we did it with carbs not really through simplicity alone (it'd arguably been easier to use everything from the donor engine - it came with everything) - but partly just because we wanted carbs and not EFI. No particular logic, just wanted it that way.. Now it's my sole project I want to continue that theme.

In the same way years ago when I was fiddling about with the Astra MK2 and was told the 8V was a waste of time and I'd not have had enjoyment through tinkingering and SantaPod days trying to get it into the mid 15s. It would have been more logical to just buy a 16V GTE rather than messing about with an 8 valve SRi 5 door. Logic would say a SWB 1963 Land Rover, petrol, is not the best choice of car to do a solo drive to China. And a P6 is a daft car to modify when I could have spent a lot less money on something more economical, quicker and better handling.

If I get it totally wrong and this never works, so be it : - ). But I'd like to think it through as a bare minimum.

[sowen]

I'm sure the Jaguar bypass is vacuum operated, my Jaguar M90 throttle body stuff has a vacuum bypass built in.

Best thing by far is to ditch the dizzy and go coilpack, Megajolt would work well, not sure about Nodiz if that can handle positive manifold pressures happily? Or go all out and buy something like a Megasquirt ecu, even if you only use the ignition side of things and keep the carbs? Seriously leaving the distributer on will make it a right dog of a runner, the advantage of fully mappable coilpack ignition is that you can run healthy advance off boost for economy/driveability and then it retards however much you want as the boost builds. Really really really get rid of the distributer....

Also ditch the 2" SU's, you'll struggle to get the needles right, then you'll run the risk of blowing the fuel line from the float chamber to the venturi off, very high risk of catastrophic fire there. Find a pair of stock RV8 HIF44's and fit the turbo seals and needles, job done.

With the fuel and ignition sorted all you've got to do is mount the blower any way it would fit, turn the key and drive. Doing it any other way I see you being stuck struggling with something that doesn't work, and if/when it did work, would have it's wiped clean by a bog standard 3.9efi.

[alex]

I am open to ditching the dizzy and going for a coilpack but not to ditch having carbs

[sowen]

You'll want the Malpassi fuel regulator that Dave Dorson mentioned and a high pressure fuel pump, Bosch 044 etc with fuel return line. To make the carbs work under pressure the fuel pressure must remain about 3-4psi above atmospheric or boost pressure, so if the supercharger was to pump 10psi into your V8, you'll need the fuel pressure to be 13-14psi. I don't know how well an external float SU carb would handle that, I was getting some of the dashpot oil pushed out at 10psi boost and a slight weep from the HIF44 base seal at the bottom of the float chamber.

Seriously HIF44's are proven to work, and I've been told a single SU can handle 200bhp, standard Maestro turbo was about 150bhp. Have a pair of them and in theory you've got the fueling capability to support 350-400bhp on the Rover V8 using a standard intake manifold

[Dave Dorson]

Jan 19, 2016 0:44:56 GMT alex said:

I am open to ditching the dizzy and going for a coilpack but not to ditch having carbs

You're limited then, to either going with turbo prepared SU's, re-engineering your SUs for boost or equalizing using a pressure chamber.

[Dave Dorson]

I'd not suggest using a chamber though, it's old hat and only any good for really low boost.

I think because you were going to go for draw through the SU's were a good choice, but as mentioned, they do leak if you try and put boost through them, through the spindles and probably blow all the oil out the dash pots.

An RR FRP will help, you do want an EFI pump and I'd suggest a swirl pot too, you'll want to modify your carbs to allow return if they don't already do so (I know not all do) Something like a Bosch pump suggested will do fine, or modify for an in tank one if you want to do away with the swirl. Those pumps don't like to run dry, so I'd suggest you use the other one as a lift pump.

Metro Turbo carbs were configured for blow through, but if you get the right manifold, you can open up to other options too, I'd not discredit using something else carb wise.

If you decide to sell your existing SU's, you'll get a decent amount back I expect.

And if you're junking the dizzy to go with coilpacks and some sort of trigger for that, you're half way to EFI anyway, which even if you do boost on carbs, you'll end up doing when you don't get the results you wanted .

[sowen]

There's a reason I've converted my P6 turbo from twin blow-thru SU to full efi, I'd simply hit the limit of what the carbs were reliably handling. Performance was stunning, no flat spots and minimal lag, really worked well for a pair of carbs thrown on the side of an engine and fed with pressurised air! Ultimately, the fueling could've been a lot better, I ran them rich to be on the safe side, even so it was still relatively economical.

Carbs are fun when you can get them working right, and also very satisfying to make them work well. Downside to carbs is a smaller capacity well tuned efi lump will make more power, use less fuel and be a nicer runner in comparison.

Fitting something like full Megasquirt or one of the other aftermarket ecu's will allow you to monitor the fueling and log it if you have an AFR fitted too, which I'd also say in an absolute must have with any home-brew forced induction. As I've seen some people do they've made a very basic fuel map based on the readings from a carb using the MS TunerStudio making the transition from carbs to efi slightly easier.

[alex]

I will bear all these points in mind. Thanks guys.

[bmwv8capri]

you've probably heard this already, but just in case is hasn't been bandied here - the teflon coating on the eaton rotors cracks & peels with petrol going through it in a draw-through setup. My brother tried it & found out the hard way, the whine became an awful shriek!

The aftermarket draw-through eaton kits for old mini & mgb (Moss) have the teflon stripped off the rotors, as the fuel itself closes up the tolerance (& cools the blower down too). If you can face stripping down the blower & removing the rotor coating then a draw-through setup with enough throttle/jet area could work nicely!

[dodgerover]

There seem plenty of people running them in Aus as draw through on dedicated LPG, not one I could find has mentioned problems with the coatings.

[ChasR]

That is surprising, given that LPG is meant to be abrasive.

[ChasR]

That is surprising, given that LPG is meant to be slightly more abrasive and have almost no lubricating properties (which is meant to be the reason for the former point).

[joostvdw]

The rotors were meant to compress only air which has no lubricating properties whatsoever

[sonus]

Interesting thread!

I was considering supercharging my Daimler 2.5 V8 with draw through a Weber DCOE. However I worry about backfiring and the possible damages. I am removing the dizzy by using a programmable ignition only ECU. My plan was to use a Eaton M62. I did the calculations according to Corky Bells book and found that I would be able to run 9 psi before the intake charge became too hot. At that pressure I should be seeing close to 220BHP. To keep charge temps low I could considering methanol/water injection to cool the supercharger, but haven't looked into it enough to answer any questions yet.

I have spoken to a gentleman in the UK running a M62 with Weber DCOE draw through on a 2 liter Bristol engine and he has run 10.000km without any problems.

Here is my thread asking for advice regarding Eaton draw through - retrorides.proboards.com/thread/172311/petrol-eaton-supercharger

[hario]

Those m112's are 1.82 litre per rev displacement I think?

Have you considered using the complete jaguar manifolds, water/air charge coolers and pipework? Obviously would need to cut the flanges off and weld on rover ones to the inlet runners? And you'd need fuel injection of course..
Dirt cheap mind

Check out this item I found on eBay:

End time: 27 Feb 2016 19:35:22

Item: Jaguar V8 supercharged charge coolers/inlet manifolds fit 97 to 2002 XJR andXK

URL: pages.ebay.com/link/?nav=item.view&id=371542826091&alt=web

(Sent from eBay Mobile for Android)