I didnt touch any of the bearings last time i stripped it then put it back together so i don't think i altered anything clearance wise. I think the marks on the ends of the rotor shafts are just where the grease has stuck to them rather than actually wearing the steel away.

I tried rotating the rotors before they were pushed fully home in the housing earlier and they seemed to rotate fine in the needle bearings in the big housing so i dont think it's them that are seized.

Do you reckon this 'charger is a write off now then Phill or salvageable?

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Goldie the track car.

If you look at the fueling map i've only really adjusted the cells at 10% throttle from 750-1000rpm then it jumped up to the 15% column where i sorted the fueling from 1000-2000rpm.
They seemed to be the only cells that i used going up and down the short bit of road down the industrial estate.
What sort of figures would you try for the timing in them cells? Change the two 20's to 15's at 10% for 750 & 900rpm?

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Goldie the track car.

you charger damage is classic rotor pack bearings which are not replaceable due to they are fitted at factory then crimped over, If it was rotor timing id expect to see rotor slap between the blades. The rotor pack is tappered to the case so it doesnt need any seal etc and only fits one way as im sure youve noticed. Ive experienced this first hand with my first m90 its not nice. Have you checked your ic for filings as it gets everywhere?
Have you considered ditching the twin body setup and keeping it simple with bov? If Storer gives you jip send em my way

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1990 205 gti6 supercharged

Yup i ran 3 bosch recirc valves as bovs for ages and the difference is night and day my maps are lot more settled and smoother too.
I just washed my out with a hose and airline. I just ran it without boost pipe to inlet incase anything was missed.

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1990 205 gti6 supercharged

Well it passed it's MOT.

I've got a few knocks and rattles, i think some of it is the driveshafts. Theres a few mm of plunge on them and no play in the cv joints, but i'm guessing the cv joints arent happy with the internals using new resting points with the changed track, they should be an extra few mm further out now as i'm using split washers between the locknuts at each end as the locknuts were coming loose previously.

I've also retarded the ignition lower in the rev range to around 14 degrees, it now idles much nicer, and tweaked some of the fueling to keep it around 12-14:1. Should be alright to get it to the mapper next thursday as that will be the next time it gets taken out i suspect.

I've removed the intercooler and pipework and washed it all out to get rid of the filings. That's all hung up drying ready to be refitted when the new 'charger arrives.

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Goldie the track car.

Thanks for that Allan.

The new charger arrived yesterday, it looks to be in better condition than the old one and span round much nicer which is a bonus.
I've got that fitted now and refitted the intercooler and pipework leaving the dump valve out for now to keep it n/a.
I started it up and was playing with the chargers throttle body feeling the air at the dump valve T, with the throttle body closed theres obviously vacuum as the engine sucks air in, then when i open up the throttle body theres quite a decent amount of airflow blasting out which is a good sign.
Have you set your second throttle body so that the airflow is pretty neutral at idle Allan?

I've just been for a short drive to check it all runs ok and everything seems alright, the only concern is the temperature the charger seems to be getting to, according to my infra red thermometer the housing was around 105c, which im thinking may be a little too hot?

I'm scared i'm going to shred this charger too, mapping is booked for this thursday but i've got a ~15 mile drive to undertake to get the car there, plenty of time for things to go wrong with it.
Hopefully i'm just worrying about nothing but could some of you who are running eaton chargers or have more knowledge of them let me know if that sort of temperature is to be expected?

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Goldie the track car.

Cheers Allan, i'll do that to mine tomorrow, i can hear it struggling for air at idle with the throttle body as it is now.

I havent touched anything on this charger, just fitted my pulley and the spline adapter.
I've left the bolt and shim washers off of this one, theres around 0.5mm of room for expansion along the splines (My spline adapter could theoretically move 0.5mm closer to the pulley before the rotor shaft would touch the inside face of the splined adapter plate) I've left it like this so its just the splines that are connecting the rotor shaft to the pulley and it should allow for any thermal expansion and not put any forces onto the rotor if the pulley does move a little back and forth, though theres almost no potential pulley movement so i dont think that would be an issue anyway.
I hope that explanation makes sense

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Goldie the track car.

I'll try and explain it with pictures then

IMG_5176 by Steve Count, on Flickr

Thats how i've got the pulley located on the 'charger. Just the bearing and circlip hold that in place and allow it to spin without turning the rotors.

IMG_5143 by Steve Count, on Flickr

IMG_5142 by Steve Count, on Flickr

Thats something i turned which houses the female splined part that was once part of the original clutched pulley setup.

On the first charger i had a 2mm thick nylon spacer that sat between the actual pulley and the turned ally adapter plate, but it melted.

IMG_5175 by Steve Count, on Flickr

The new charger has the same spacer size wise but this time made out of ally so it can't melt. (Or hopefully wont get hot enough to anyway )


If i don't have the 2mm thick spacer in place and push my turned adapter up against the pulley there is a 1.5mm gap, so with the spacer in place i've essentially given myself 0.5mm of room for expansion/movement.

Hopefully that makes a bit more sense for you

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Goldie the track car.

I've made it to the mappers place. Not on the rollers until 2 so just waiting round now

IMG_5180 by Steve Count, on Flickr

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Goldie the track car.

Well, mapping went ok. It was making 6psi to around 3000rpm then dropped off to 4 psi to redline. Not sure on the cause of that.
It made 170bhp at the wheels consistently which I suppose isn't too bad.
After mapping we took it out for a test drive and the second charger crapped itself again, same symptoms as the first one

John the mapper said he's done hundreds of supercharged cars and never heard of them failing like this, especially two in a row now and said the only thing I'm doing differently is the second throttle body.

I think I'm going to ditch the second throttle body and opt for a massive dump valve, even with the second throttle body the dump valve couldn't cope with the boost when shutting off at higher revs causing belt slip and all sorts of noises.
On the search for a third charger now though

IMG_5181 by Steve Count, on Flickr

IMG_5182 by Steve Count, on Flickr

IMG_5185 by Steve Count, on Flickr

Charger damage

IMG_5186 by Steve Count, on Flickr

All stripped and washed out again!

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Goldie the track car.

Bad times man. Keep going. it will yield to more money and effort being thrown at it!

You're getting a pressure wave from the downstream throttle body when you shut the throttle by the sound of that, it can cause what's basically a high pressure air bubble between the lobes which:

1) Pushes them toward the nose of the charger.

And 2) Builds up a lot of heat.

If your dump valve doesn't react very fast and dump all the air (which you say it isn't), then that's going to happen every time.
You need more control authority from the upstream throttle, I dislike dual throttle setups because of this, to get any benefit out of the downstream throttle to generate pressure you need to be balanced pretty well between them and hope you never have any slop or stretch in the cables to throw you out of alignment.

Most of the MX5 lot run them but when you actually look they've got the front throttle doing all the control and the second one may as well be in the bin half the time.

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Not much to update with, picked up the third supercharger on Saturday but still haven't unboxed it yet, I've been rebuilding some 6 pots for a mate in the hope he'll be able to make it to the next trackday with me.
I've ordered a tial q blow off valve with 2psi spring, hopefully that will be able to deal with the boost issue, I'm just waiting for that to arrive before I put it all back together.
I might make a start on rebuilding it tomorrow evening if I'm in the mood, been a bit fed up with the car since the second supercharger

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Goldie the track car.