Johnmor
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| posted on 25/2/07 at 11:53 PM |
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Supercharger.
I have been looking into squeezing a few more horses out of my Alfa V6 and have looked at a few tuning ideas, including throttle bodies and cams
etc.
But i like the Idea of a supercharger. I can grab second hand Merc or Jag supercharger for around £250 and as I only want to run a boost of around
8lbs I think it may be feasable. I have to reduce the compression to around 81/2/ to 1. I think i may have sussed that but not sure about increasing
the fuel and measuring the airflow in relation to boost.
I think 8lb boost will give around a 40% increase in power, not too extreme as to damage the engine
Has anyone played around with superchargers and the assosiated kit.
Dont realy want to go as far as intercoolers etc.
Opinions please
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RazMan
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| posted on 26/2/07 at 12:07 AM |
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The Rotrex units look like a good starting point but if you want to use s/h oem blowers they might take a bit of figuring out.
personally I love the idea of a blower - I've done the turbocharger route and was left wanting - too much lag and too little power in too little
revs. Give me a blower anytime 
[Edited on 26-2-07 by RazMan]
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Chippy
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| posted on 26/2/07 at 12:20 AM |
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Hi Raz, surely you mean the Turbo route, if your talking about lag, non with a Supercharger.  Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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thomas4age
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| posted on 26/2/07 at 07:39 AM |
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an Eaton M90 would suit you fine!
just get a decent intercooling set up working and don't go over 7PSI boost (mostly water-air systems on eatons) and get the mapping of the ecu
right and you wouldn't even have to lower the compression probably (don't know any spec of the alfa v6)
take in mind Blimble is currently boosting a 10.5:1 compression engine which will work.
no low comp pistons leaves buget enough to get a decent ECU on that engine, which will give you 3 advantages for once the money, high comp can run
lower boost for the same output and having a decent ecu to do the thinking
grtz Thomas
If Lucas made guns, Wars wouldn't start either.
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RazMan
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| posted on 26/2/07 at 07:54 AM |
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quote:
Originally posted by Chippy
Hi Raz, surely you mean the Turbo route, if your talking about lag, non with a Supercharger. Ray
oops - I really must engage brain. Now edited 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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bimbleuk
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| posted on 26/2/07 at 10:06 AM |
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I've have to agree on that engine with low boost you want to run an Eaton M90. If you plan your install and get an efficient flow throughout
then running 6-7PSI (remember PSI is just a measure of your inlet restriction!) should not require a lower CR. Though how you control spark and
fueling will have a big influence.
On a Rotrex you need to run a higher boost as the average over the rev range is lower. So my 10.5:1 CR only becomes a factor near the RPM peak of 8K
RPM. I can restrict the inlet of the Rotrex to help solve detonation problems.
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bimbleuk
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| posted on 26/2/07 at 10:09 AM |
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Thought I'd add that one of my previous cars had a CR of 11.5:1 with a roots type blower producing 7PSI of boost with no detonation issues. So
it can be done with some decent electronics and a big intercooler!
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PeterW
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| posted on 26/2/07 at 12:15 PM |
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WARNING...!! Thicko question....
Can you supercharge via individual carbs, like a set of bike carbs, or does it need to be one large carb a la the old A series blowers...?
Or does it really need injection to work properly...?
Cheers
Pete
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Johnmor
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| posted on 26/2/07 at 12:39 PM |
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Thanks for the response. The comp ratio is 10-1. So it may be ok.
I was hoping to use the existing plenum chamber and duct the from the super charger at low boost as you metioned about 7lb.
I would then probably go via megasquirt to control fuel and ignition.
I have seen a few superchargers from mini coopers on Ebay. Quite small but as the mini is a 1600cc would they provide sufficient flow for a 3.0l.?
Having said that they run a higher boost presure.
I had a look at your archive(bimbleuk) very, very smart engine. 300bhp
OOOOOOHHH!
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vovole
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| posted on 26/2/07 at 12:52 PM |
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hey maybe this link can help, gives you also some performance maps.
http://www.eatonperformance.com/superchargers/superchargers.html
if money is no object I would go for the roots charger, better efficiency.
Have you ever considered a Nissholm charger?
if it´s been done don´t do it
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RazMan
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| posted on 26/2/07 at 02:19 PM |
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There are certainly loads of the ex-Mini blowers coming up on eBay and if they can be made to work it would be a really cheap way to get some useful
power.
I was thinking about one of these but I have my doubts that they would give enough air for a 3 litre (or even a 2.5 in my case)
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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BenB
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| posted on 26/2/07 at 03:12 PM |
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You're going to have to spin the hell out of a Mini (m45) blower to get reasonable boost with a 3 litre engine.... Roots types aren't the
most efficient- that will be a lot of heat, particularly if you're not planning on an intercooler.
Personally I'd either reckon on using a bigger blower or use a mini blower and buy an intercooler with the money saved on the 'charger.
Otherwise without dropping the CR you'll either be running with seriously retarded timing or on Avgas!!!
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bimbleuk
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| posted on 27/2/07 at 09:51 AM |
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I've sold a few superchargers on ebay from Mini units up to a huge Merc AMG Lysholm supercharger. The Merc M62 units are a good all round SC and
a bit easier to mount if you get one without the castings.
Johnmor the Alha plenum is a good design. You could leave the throttle body where it is but for maximum efficiency it should be in front of the SC.
PeterW you can use carbs but they have to be pressurized like a Renault 5 turbo carb.
[Edited on 9/3/07 by bimbleuk]
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thomas4age
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| posted on 27/2/07 at 01:53 PM |
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easiest way to set up the throttle's is to take out the original alfa throttle plate, and just use the one that's on the M90 you'll
buy, if you do offcourse.
M45 woudl work with very low revs, 've seen them used in eaton + turbo set-ups on toyota V6 engines.
grtz Thomas
If Lucas made guns, Wars wouldn't start either.
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Simon
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| posted on 27/2/07 at 08:17 PM |
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I'm going to start with 7 or 9psi, then increase to 1 bar, with standard 9.35:1.00 comp ratio.
I do have a rather large intercooler, which is fully ducted in/out.
ATB
Simon
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bimbleuk
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| posted on 1/3/07 at 10:40 AM |
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One thing to note is roots blowers make boost by compressing the air at the back of the inlet valves ad in the plenum So an intercooler isn't as
efficient as say one used with a centrifugal SC or turbo. I don't think there's an intercooler fitted to the Ariel Atom or K20A converted
Elise that I've seen.
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NS Dev
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| posted on 1/3/07 at 05:30 PM |
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I did some maths on using a mini eaton blower (M45) on a 2.0 16v vauxhall XE engine, and it just won't push enough air. I could get about 6lb
above atmospheric at 7000 revs, and that was taking the blower to over 14,000, which is a bit high.
Merc M62 is good though, spot on for a 2.0 and would work on a lightly boosted 3.0.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Johnmor
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| posted on 1/3/07 at 06:30 PM |
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M62
I agree , having looked further into the subject ,I think the M62 may be a good option. It was fitted to mercs C230 etc from around 89-93.
So i may try and aquire one of those.
It has the added advantage of a magnetic drive in the pully (similar to aircon units) so if i keep the compression ration standard i may be able to
simpily switch it on and off in the dash board.
A button labeled "Holly Shit" may be appropriate.
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sebastiaan
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| posted on 1/3/07 at 07:46 PM |
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If you are going to switch it on and of, make sure your ift a bypass too (else the intake air needs to spin the blower...)
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RazMan
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| posted on 1/3/07 at 08:35 PM |
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Magnetic drive? .... hmm interesting. But how can you bypass a blower? Wouldn't that need two air intakes?
Does anyone know how much power the M62 will absorb? *edit* just Googled and its 30bhp .I am thinking about running it from one of my cams (where I
took off the water pump) .... or would that be a no no?
[Edited on 1-3-07 by RazMan]
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Johnmor
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| posted on 9/3/07 at 06:33 PM |
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From cams!!
I think thats a deff "no"
You would put a 30hp load through the cam belt.
Result "bang"
plus cams run at half engine speed so not really practical.
Bought the book by Corky Bell
Fantastic book, a bit more study and i think it looks promising.
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RazMan
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| posted on 9/3/07 at 10:50 PM |
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I had a feeling that would be the answer Ah well, it looks like I will have to rethink.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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