Supercharger pulleys

SuperV8 · Post by **SuperV8** » Thu Aug 25, 2011 11:38 am

Hi Guys,
Running a supercharged rover V8, using a 7 groove serp pulley as can be seen in the photo's:

I'm already getting black dust near the supercharger pulley and I haven't really 'driven in anger' as i'm still tuning it, so i'm getting belt slip. My pulleys are all in line, I have maximum belt wrap arround the supercharger pulley and the belt is tight (maybe too tight) but still getting slip! The suppercharger pulley is from memory 65-67mm and I want to go to 60mm eventually which would be even more belt slip!

Thinking of re-designing it with a seperate toothed drive for the supercharger.

Does anyone know where I can get toothed pulleys? need a 2.5:1 upto potentially 3:1 ratio Idearly off the shelf! or failing that someone who can machine toothed pulleys?

Thanks,
Tom.

kiwicar · Post by **kiwicar** » Thu Aug 25, 2011 1:19 pm

Hi Tom
I get toothed belt pulleys from the US, I buy CV pullies, they are the ones that take the rounded tip tooth belts, (pretty sure they are referred to generically as Gilmer pullys) I have 2 sets, one for dry sump pump one for injection pump they are high quality items, I think 3/4 inch (I'll check when I get home) but they do other sizes. Kevin the mole has got belts for me in the past, he may be able to do the pullys aswell, I do not know.
Bought the first ones off e-bay, then directly from the company selling them, mainly as it was easier to order what I wanted directly.
Best regards
Mike

mgbv8 · Post by **mgbv8** » Thu Aug 25, 2011 8:09 pm

Does anyone know where I can get toothed pulleys? need a 2.5:1 upto potentially 3:1 ratio Idearly off the shelf! or failing that someone who can machine toothed pulleys?

Tom
Try Nigel Jenkins at UK Blowers.. He gets toothed pulleys made for my 4/71 blower.

01564-703976

Perry

kev_the_mole · Post by **kev_the_mole** » Thu Aug 25, 2011 8:56 pm

I make toothed pulleys

cammmy · Post by **cammmy** » Thu Aug 25, 2011 9:50 pm

Would it pay to confirm the cause of the issue first before getting a toothed belt? If the issue lies elsewhere do you not run the risk of stripping teeth off your expensive new belt or worse?

I thought the advantage of ribbed belts is that they allow slip so if something goes wring, it just slips instead of stripping or damaging other components.

kev_the_mole · Post by **kev_the_mole** » Fri Aug 26, 2011 9:25 am

As the biggest load on the belt driveline the supercharger is the likeliest culprit. This being confirmed by the dust you're seeing at that pulley. Any chance that the supercharger is not running freely as I've seen worse setups that have performed better (slipwise)?

Cheers,

Ian

Eliot · Post by **Eliot** » Fri Aug 26, 2011 12:37 pm

I was thinking how impressive the amount of wrap you achieved. I'm suprised that you are getting slip.
Where is the tensioner? - Stevie may have some advice.

JP. · Post by **JP.** » Fri Aug 26, 2011 1:47 pm

UKblowers made mine.
He does custom gilmer drive setups and makes custom gears for it.
He made several gears ( for differend drive ratio's) for my sc engine.

SuperV8 · Post by **SuperV8** » Sun Aug 28, 2011 10:35 pm

Thanks for the comments, i think im getting slip as the pully is so small. im trying to drive it up towards its max rpm of 80,000 rpm! it has a 4.7:1 gearbox so i need to run something like a 3:1 pulley ratio to max the supercharger at 6000 rpm. most installs I've seen have a much larger supercharger pulley.
the sc does run free checked recently when i re tensioned the belt a little tighter. the tensioner is on the slack side of the belt after the alternator.
i don't even know if the sc will be big enough for my engine? the marketing bs quotes much more cfm than i need so just sucking it to see!
I've just read about htd pulleys are these the same as glimmer? was thinking of how to do the crank pulley and have read about mandrels which will then accept an off the shelf pulley which will also mean i can change the ratios easy enough.

SuperV8 · Post by **SuperV8** » Mon Aug 29, 2011 11:22 am

Thanks for the comments, i think im getting slip as the pully is so small. im trying to drive it up towards its max rpm of 80,000 rpm! it has a 4.7:1 gearbox so i need to run something like a 3:1 pulley ratio to max the supercharger at 6000 rpm. most installs I've seen have a much larger supercharger pulley.
the sc does run free checked recently when i re tensioned the belt a little tighter. the tensioner is on the slack side of the belt after the alternator.
i don't even know if the sc will be big enough for my engine? the marketing bs quotes much more cfm than i need so just sucking it to see!
I've just read about htd pulleys are these the same as glimmer? was thinking of how to do the crank pulley and have read about mandrels which will then accept an off the shelf pulley which will also mean i can change the ratios easy enough.

kev_the_mole · Post by **kev_the_mole** » Mon Aug 29, 2011 8:22 pm

Gilmer drives are just a brand. They were one of the first to come up with the idea of using toothed belts and pulleys on supercharger drives a long time ago but they don't make belts. It's like Hoover for vacuum cleaner.

HTD, RPP or STD drives are all similar types of belt but can't necessarily use the same pulleys. They are generation one polychloroprene rubber, glass fibre tension member belts. Generation two belts are still rubber but with fibre reinforcing matrices and can have glass or Kevlar tension members. Gen three belts are polyurethane with Kevlar or carbon fibre tension members. Later generation belts mean that you can use narrower drives giving less overhung bearing loads and lower losses.

stevieturbo · Post by **stevieturbo** » Tue Aug 30, 2011 11:36 pm

What belt are you actually using ? Looks like Gates, but is it a heavy duty version ? Some ordinary belts just stretch and stretch.
Some dust doesnt mean you are getting slip worth worrying about..although obviously it isnt a great sign.

And how tight is tight ?

There are places that can make you custom pulleys. Some expensive, some not so expensive.
The place that made mine I thought was very good value. However......lets just say it wasnt a smooth process and I'm still trying to resolve problems.

He can make them for sure, but you'd need to ensure you do very detailed drawings with dimensions, and then make sure he actually pays attention to your instructions and doesnt just make them whatever way he wants instead. Oh the joys

A custom cogged setup would be doable, although not sure what width you'd end up. And the large diameter crank pulley would be expensive unless you can adapt an off the shelf item somehow.
Some blowers wont be happy with cogs though, as it can be very hard on their internals. And belt alignment is far more critical with cogs than it is with ribbed.

SuperV8 · Post by **SuperV8** » Mon Sep 12, 2011 12:57 pm

Thanks for the replies, sorry for my slow response but just got back from my hols

Yes i'm using a standard gates belt from my local motor factor, 7 rib. I don't have a tension gauge but it is tight, I think you'd struggle to twist it 90 degs!

I agree that although black dust isn't a good sign it doesn't neccessary mean supercharger slip! Actually when checking the pulley bolt I had to put the engine in gear it it was turning the engine over!

Im not sure on what boost i'm getting as i'm having comms/reseting issues with my laptop and ecu. I think before I change the pulleys i'll try and tune it properrly and see what boost I am actually getting?

I've been looking at electric waterpumps to help with the belt setup but that will be a new thread

Thanks,
Tom.