Eaton ABF - calculating pulley size

Hi Guys i have just finished my ABF + eaton M62 conversion to my MK2 and need a bit of info on pulley sizes, does any one know what size n7ndo/eaton 16v was running? on mapping on emerald K6 we found only 2psi on standard pulleys still made 160@wheels so is looking good for planned bar of boost i saw in one of eaton16v build treads he up sized his crank pulley not sure to what size though and what was done regarding the harmonic damper within the standard one? apart from that car is already rapid and very responsive! cant wait for more boost! Cheers in advance. btw will be taking car to retro weekend @ santa pod this weekend if anyone is going?

 

btw pulley ratio is at present 1.8

 

The forum user called eatonMK2 used originally, a Merc W203 M45 supercharger with pulley sizes calculated to spin the charger around it's maximum rated speed. This resulted in boost pressures of up to 15psi of manifold boost. A new crankshaft pulley was made that had increased size to achieve this.
From what I have been made to understand this charger was then replaced with an earlier and bigger M62 unit from the W210 CLK Merc although I do not know what pulleys are used now.

You can calculated what you require by reading the Eaton site and looking at compressor efficiancy for pressure ratio and compressor revs.
The compressor needs to run ~ twice times the engine if any usable boost is to realised.
You should avoid over-speeding the compressor in areas of low efficiency as this will mean you are pumping in boosted heat!
There was a previous ABF car that was built some time ago that had an M62 charger integrated by eatonMK2 and myself with MS controls that achieved 230bhp @6000rpm and 210lbft at Garage Streamline. This charger was developing 8 psi of manifold boost.

If you get stuck with calculatiing a pulley size ratio let me know.

Regards.

 

Thanks !! eatons site was a bit sparce but have found kennebell and he thinks i need a ratio of 3.0 this would result in charger speed of around 21000 rpm @ 7000 not quite in eaton efficiency island

 

Look again on the Eaton's site, all the general compressor maps are there in the product section. Use these as your starting point.

 

i am now a bit stuck calculating the ratio required i would ideally like 12psi but am unsure what size charger pulley would be required against a standard ABF crank pulley?

 

Thread renamed from "calling n7ndo/eaton16v" to "Eaton ABF - calculating pulley size".

I prefer threads not to be posted as a FAO for specific people. It's an open forum where anyone can potentially help, and decent thread titles allow people to find this topic in future via the search function.

 

ok thanks

 

Thing is, not alot of people know how to read compressor maps. Don't think you need to calculate for 7200rpm. As mentioned earlier peak power is around 6k so calculate for a little higher than that. It'll get there in the lower gears but will probably be spinning the wheels so wont be there for long.

 

that is pretty much the pulley ratio you get with a standard crank pulley and standard merc pulley on the M62 crank pulley=130mm eaton m62 pulley=70mm = ratio 1.85 found this sum online supercharger size in litersxpulley ratio divided by engine size divided by 2 x14.7-14.7= boost have worked this out for my abf and got a figure of 11.76 psi but ive only got 2 psi very confused[:^(]

 

That boost figure doesn't always work out. As i found out when trying to work out required output for a given turbo boost pressure. Using compressor maps

 

So what will be the ratio with the ABF pulley vs the default pulley on the chragfer currently. Work this out and then see what you need to do from there.
Hint you will see the ratio is less than what is on Merc W210 engine.

From there work out how big you will like the pulley ratio to target max compressor efficiency in the range of driving rpm you are likely to encounter and setr a rev limit if you will end up on the far right of the plot. You dont wont to be there as that = Heat = Hot combustion chamber = Knock!

As already said the ratio needs to be ~2:1. With slip on the belt = around 12psi with some slip nearer to 8. On Stock ABF with stacked gaskets, tested at 230PS@6000 and 220-230lbft, 200lbft from 2000rom to 6000rpm.
Regards

 

On a side tangent abit. A good book for a guide for all the calculations that I bought first was this

http://www.amazon.co.uk/Supercharge...=sr_1_1?s=books&ie=UTF8&qid=1309955393&sr=1-1

It has helped me out to get my head round the maths.

 

looks like the merc has a crank pully size of 151mm so a ratio of 2.15 i achieved on the merc

found this link http://www.boost.xu1.net/

 

Forget the Merc. Apply to the Golf engine.

 

at the moment with current abf pulley size and standard pulley on charger ratio is 1.85

 

The key is make the ratio bigger. It may mean thinking out of the box .
Solve that first hurdle and you on your way to forcing more air into the engine.

 

Hi Tommy, sounds like you have an m45 (750cc) eaton, as the M62(1000cc) eaton uses a clutch type pulley in the Merc with a 100mm pulley.

People get hooked on maps and eaton rpm, but the truth is the eaton's aren't that great, at its best is only 64% and 54% at worst so only a 10% -/+ diff.
Speed wise, the M45 and M62(low mass small roots) max holding rpm is 14000 and can peak @ 16000, no one sits at 7k+ so look at gearing it to 15500ish @ 7k.

Also look at boost leaks and belt slip, try to get 180+ degrees of belt rap around the eaton pulley.

 

The M45 supercharger map is pictured below taken from eatons website.



If the charger is one of these, then apply the same principle to determine what pulley ratio is required.

Usable range of revs on a stock ABF engine is 2000-6500rpm. Attempt to run the charger via pulley size between 65 and 55% efficiency @ 1.6-1.8 pressure ratio.

 

the pulley on the charger is black with a bit of a snout i will try and put some pictures up when i learn how i was sold it as a M62 by a merc breakers i hope its not a M45 would be gutted! on the dyno plot the boost holds strong 2psi all the way to redline with no peaks or drops so did not think i had a leak or slip the belt has prob 160deg contact. the engine is running 8.9.1compression using a farriday ali spacer and multi layer gasket the head also has been ported and flowed matching manifolds and all bolt changed to ARP.