2.7 supercharger build pix - test run vid uploaded

[racecar]

finally making progress:


this is where its going to be located - similar to lennie's i think


we are still working on bracketry and getting heads round suitable belt tensioner mechanism



alternator has been switched to other side - with a bracket with drilled holes in!!!! - must save half a ton! - gotta re-route cables - which i'll do this week one evening when its not dreary outside - probably going to need to extend cable

waiting on news re availibility re one of lennie's old 6.5" pulleys - nose of m90 = 10 rib think lennies pulley is 6 or 7 - if no longer available have a mate coming into office tomorrow and i'll bring a spare crank pulley in if i can find one to use as a base template

sourcing a fan belt just slightly smaller than stock for alternator - which we can then suss out belt tension adjustment etc. probably will get some bling hose with lovely push on connectors to replace oil cooler pipes

other stuff to do when physical brackets/tensioners made = pipework - have some nice agricultural plastic drainage pipe for template - + intercooler stuff - belts for blower + visit to A-tech for mapping and watch it go bang after 5 mins

WILL be ready mid april - ha ha

[Ant]

Looking good Ross/David

can you not spin the oil filter take off 180' to assist ? will move the O/cooler take off backwards and away from the Alt maybe ?

[racecar]

ant
thats a good plan! - will try that! it was getting late afternoon on sunday and pubs were beckoning - i'll look at it tonight - phone you later dude
ross

[dark_sounds]

isnt a 2.7 high comp? F.I needs low comp?

what have you done to low comp the engine??

looking good so far

[Ant]

Ali, the engine was built 9:1 CR with the Charger in mind from the outset

you can boost a high CR engine, not an issue but the max boost threshold will be lower

[dark_sounds]

interesting

so out of interst, what was involved in creating a low comp 2.7? what kind of work?

whats the comp ratios on a standard 2.5 and standard 2.7? just to compare.

[racecar]

it was v frustrating building a low comp 2.7 with boost in mind and then running it n/a for a year - well ok it's only probably done 3 trackdays!

low comp bottom end in this case = m20 block not decked as much as you would for optimum n/a c:r

however not sure anyone has used eaton m90 on a m20 yet? - lennie the pioneer on all this kind of stuff used an eaton m60 i believe from an slk - whereas this little bad boy comes off a db7 and should run a decent amount of boost - well hopefully more than those ebay electric superchargers anyway....

[jkarran]

...this little bad boy comes off a db7 and should run a decent amount of boost - well hopefully more than those ebay electric superchargers anyway....

I suspect you'll manage that. 1500cc/rev into 2700cc engine is more than 1bar with 1:1 pully ratio, are you going for big boost with an IC?

<edit>Of course what I meant was 2:1 pully ratio </edit>

jk

[racecar]

yeah to make it worthwhile and justify the low cr build - reasonable boost is expected and the M90 specs mean that with a "little" engine to feed - the blower will not be operating past it's efficiency range - m90 is aimed at 3.0-5.0 lumps and has double the capacity of the m45 which seems to be ok on smaller 4 pots

IC has just been ordered from ant which will be fitted on mapping day

just found out that i can get a 2nd hand OE "vane edis pulley?" from an aston parts dealer with the correct 10 ribs
to match the nose pulley on the blower - for about £50 - which WILL be made to fit onto the existing pulley - should save some time!

[Apal]

To clarify boost and pulley sizes. The 2.7 needs to draw (without any super/turbo charging) 1.35Lts of air per crank revolution, assuming 100% volumetric efficiency. So the M90 will only be delivering an additional 0.15Lts of air to the engine with a 1:1 pulley. Which is an additional 11% and therefore 0.11 bar of boost above atmospheric (ie relative).

We are talking fixed displacements therefore increasing the amount of air being forced into a fixed volume will increase the pressure by that ratio (adiabatic being assumed). As 1 bar is approximately 14psi this equates to 1.6psi.

On this basis a 2:1 pulley ratio will deliver 3Lts of air per crank revolution giving a theoretical pressure of 3/1.35 = 2.2 bar absolute therefore 1.2bar relative 16.8psi.

[jkarran]

What boost do Aston run? You'll need to scale it M20B27_boost = Aston_boost(Aston_capacity/2700) if you plan to run the standard AM crank pully.

I'm fitting M45 to my 998cc Yamaha engine.

jk

[jkarran]

To clarify boost and pulley sizes. The 2.7 needs to draw (without any super/turbo charging) 1.35Lts of air per crank revolution, assuming 100% volumetric efficiency. So the M90 will only be delivering an additional 0.15Lts of air to the engine with a 1:1 pulley. Which is an additional 11% and therefore 0.11 bar of boost above atmospheric (ie relative).

We are talking fixed displacements therefore increasing the amount of air being forced into a fixed volume will increase the pressure by that ratio (adiabatic being assumed). As 1 bar is approximately 14psi this equates to 1.6psi.

On this basis a 2:1 pulley ratio will deliver 3Lts of air per crank revolution giving a theoretical pressure of 3/1.35 = 2.2 bar absolute therefore 1.2bar relative 16.8psi.

You are of course right. Put that down to end of day brain failure! I rounded the engine size up to 3L, divided by two to give 1.5L. M90 gives 1.5L/rev you're quite right M90 on 100% efficient 3L engine gives no boost, not 1bar. MUST THINK HARDER

I'll edit my post.

[Apal]

Good point jk re Aston boost pressure and relative cc of both engines. Simple but effective way of getting things close without too much head-work. I'll get Ross to find out from his HWM friends.

[jkarran]

I wrote a spreadsheet that takes most of the relevent factors and calculates boost and temp rise/drop at various parts of the system for M45. It also calculates crank pwr, available crank pwr and a whole load of other bewildering numbers If anyone wants a copy then I'm happy to share it. Could also be addapted for M62/M90 or any other positive displacement blower if you have:

pwr input vs rpm curves
temp rise vs rpm curves
probably something else that escapes me at the moment

If there's a way to host it here then it's free to a good home

jk

[jkarran]

What boost do Aston run? You'll need to scale it M20B27_boost = Aston_boost(Aston_capacity/2700) if you plan to run the standard AM crank pully.

jk

My maths is shit today! that'll get you a ball park figure but this will give you a better answer, my brain's really letting my mouth down at the moment I'ts done in two steps.

Step 1: AstonPullyRatio = ((AstonBoost+1) x AstonCC) / (2 x M90CC)

so say Aston boost is 0.6bar on 5L engine:
AstonPullyRatio APR = ((0.6+1) x 5000) / (2 x 1500) = 2.67

Step 2: M20B27 boost = ((APR x 1500) / (2700 / 2)) - 1

IF the example figures are close for the Aston (a total guess) engine that's 1.96 bar boost on the M20b27

jk

[jkarran]

What boost do Aston run? You'll need to scale it M20B27_boost = Aston_boost(Aston_capacity/2700) if you plan to run the standard AM crank pully.

Or simpler yet correct... M20b27_PR = AM_PR x (AM_CC / 2700)

Where PR is pressure ratio. Just use (boost + 1), units of boost must be bar.

Wasn't having a very clear thinking day yesterday
jk

[Apal]

Thanks for the maths lession jk. Also would appreciate a copy of your blower calcs spreadsheet as a sstarting point re the m90. Possible to pm...?

[jkarran]

I think it's me that needs the lesons PM me your email address and I'll send it on to you. You'll need to addapt it but if you have the data on the M90 I can maybe do it quite quickly.

jk

[Apal]

Bit more progress today with the fabrication of blower mounting brackets on the spare block. Should have the alternator working in its new position this weekend so another step closer.

[Apal]

Any ideas why the image does not display?

[sam325is]

http://shutter14.pictures.aol.com/data/ ... SP0280.jpg

you cant use [img] on a whole gallery you need to use links to single picture like the one above, you can get the link by getting the picture in large and then you right click on it and go to properties and then you copy the address from there

[Apal]

Thanks for that - next 'obvious' question - how do you make a picture appear in the body of a post?

[BigPerformance]

If there's a way to host it here then it's free to a good home

If you send it to me I can host it for you.

[Apal]

Not worried about the hosting, its the command/syntax to embedding a pic in the post as opposed to a link.

[jkarran]

Apal, try photobucket. There's an img button you click once you have uploaded your pic, it puts the string you need on the clipboard, all you need to do is hit ctrl-v to put the pic in your thread.

I think the hosting comment related to the blower spreadsheet I offered
jk

[racecar]

jk

can you email the blower spreadsheet to ross AT racecar DOT co.uk?
thanks!

we are working on it this afternoon - and trying brackets that have been made on dummy block on car. understand that the blower takes 40hp to run at 12k - so we are keen to make it "stout" - also alternator will be set up/cables moved etc

on another note gonna order a grp bonnet from taffy next week - which will save some weight but crucially make it sooo much easier working on it

- vane edis pulley thing did n't work out from parts place - we will be aiming for a 2:1 drive ratio i think
- getting a mate to "shadow graph" the pulley on the nose of the m90 - and then he will make to diameter we want

from another post on here - can't remember who - just got "Supercharged!" by Corky Bell - looks as if it's a good read!

ross

[Ant]

just got "Supercharged!" by Corky Bell - looks as if it's a good read!

Andy335 was kind enough to lend me both Corky Bell "bibles", they were an excellent resource, to my shame I had them almost 2 years I think, sorry again Andy

[bottlecapE30]

I'm working on a supercharger build with an m90 on my 2.7l as well http://www.e30tech.com/forum/viewtopic.php?t=30929
i can tell you the Corky Bell book is worth the read a lot of info.
Looking good

[racecar]

bottlecape30 - thats a good read on your project - i can see you have the finishing tape in sight - keep it up!

first pix of pulleys from MDTS :







MDTS made 2 pulleys for me 5" and 6" - made out of billet aluminium and hard anodised - look v factory - tough as steel and half the weight

any of you boys on m20's want similar - speak to mike:
01329 829388 - looking around £100 - although mike can do all sorts of one off stuff - he's a car head - building a 350 CI small block powered cobra replica

reckon we'll have blower on + piping ready for 1 st week in april!

[Demlotcrew]

OT but can these guys make me a overdrive pulley for the water pump and power steering?

Andrew

[racecar]

andrew

yes i am sure of it they mainly do trick marine engineering proto stuff - but think mike is keen to do more car stuff

if you can send dimensions will help - i'd give mike a call and ask the question - i can say that the workmanship is shit hot!

ross

[bottlecapE30]

wow those pulleys look great. that is some top notch work

[racecar]

tensioner pulley just been made - good work david!(Apal) - then gonna be anodised + shaft being made tomorrow - by the end of the week all bracketry will be ready for trial fit to engine in car.

once trial fit done on saturday - they will be taken off to be painted/finished off

hopefully intercooler will arrive this week ready for install/move oil cooler etc - then subsequent pipe creation. was due to drop car off to btb for the weekend for the pipes to be made up - but running out of time now - so probably will make pipes as tem fix out of suitable flexible hose and then make metal pipes after if there is time. when pipes are made - they are going to be tapped for temp sensors before and after i/c + provision will be made for water injection. thinking of creating an alloy tank in spare wheel well with this in mind...

also hks ssqv blow off valve + boost gauge etc has arrived and on a non-mechanical note - at the weekend bought some pimp rims off the 'zone - 15x8 deep dish - just fitted some new toyo r888's - so ignore tyres in pix

[bottlecapE30]

Comeing along nicly. Those wheels are the tits

[racecar]

Ok - we got it running - without pipes - so really just a test of mechanical pulleys/brackets - but it sounds cool!

Click below for first run vid (top one on page):
http://www.etribes.com/video/gallery/73127

http://www.etribes.com/sites/etribes.co ... review.jpg

pic of install

20 mins later blower and bracket removed - all bracketry to be painted/idler pulley to be anodised - i/c arrives next week - oil cooler to be relocated higher up - then i/c fitted - then we play with pipes to connect it all up/add SSQV etc - then off to ants for map etc - we'll run 5" pulley for start - then think about switch to 6" - takes minutes to switch!


random pic of finishing up


new pimp rims fitted!

off to pub now to bore everyone about it - big up to david c for cool fabrication work - brackets etc fitted first time![/img]