Was a Paxton supercharger conversion, now a Rotrex C38-91

[kiwicar]

Hi Tony
I had worked out the pullys and ratio (max speed of the supercharger) for 8 psi with a ribbed belt at 8 psi @ 5800 revs, if you want 6 then fit a sslightly lower ratio, 1.25:1 should do it. if you use a toothed belt then it won't slip and you can reduce the ratio by 5% to 1.2 :1
I would have a nice bid intercooler either way and
best regards
Mike

[JP.]

Dont talk gibberish.

All compressed air gets hotter, have you no notion about how they work ? It it will not increase lag one bit.

No I drive a Roots type so I don't know how they work.
Thats why Ford GT's & Lightnings run their blown air through an aftercooler which is heated by engine cooland..........at about 85-90'Celcius.
I am pretty shure with about 6psi there's no real benefit for an intercooler unless your running it in boost all the time.
At least 95% of the time I only see vacuum while I drive the car meaning my supercharger aint compressing air so no real air heat up until I WOT it.
With the ¼mile I shift 4 times meaning I only see four times boost for a few seconds so how much heated up air could there be. We are not talking about a rally car here or a track day car which is boosting all the time.
IMO Water Methanol injection is a better route than an Intercooler for Tony

Thereby a centrifugal supercharger does not heat the air nearly as much as a roots blower. They are almost 100% diabatic efficcient
It only peaks boost at aprox 6000rpm so the most heat built-up will be there. If a centrifugal blower is set at lets say 6psi@6000rpm it will only deliver aprox 1,75psi @3000rpm.

Interesting book to read, A DO-IT-YOURSELF GUIDE TO: Street supercharging, how to instal and tune blowers By Pat Ganahl ISBN 1-884089-29-1. It does have a complete section of centrifugal blowers including the Paxton.

[Coops]

over on the supercharger forum i joined they have this speed calc,

http://www.superchargerhelp.com/attachm ... 1082764586

not sure if you need to be a member to view it,
if so let me know as i have on the pc now.

[Coops]

just thought,
im run single springs on the heads, will i have to change these to dual now?

[topcatcustom]

Are you changing to a blower cam tony? Singles may be fine for you, as mine is carbed I wanted to go dual as didn't want to risk backfires if they don't close quite fast enough with pressure behind them- unlikely perhaps but thats what was recommended by the supplier.

[Coops]

no still running that new crower cam for now mate,
the charger wont be on until end of the year,
as im short of a few parts that im trying to track down,
overhaul kit,
dipstick,
BOV/recirc valve
Intercooler,
charger manual,
and anything else im missing

[stevieturbo]

Cam will be fine


Springs...depends how strong your current ones are, and how much boost you might use. More than likely they'll be ok though.

[Coops]

DW060 TLR50 spring
These springs have less coils, eliminating spring binding with higher lift
cams. For use with cams DW262/DW270/DW268 with SD1 cylinder
heads, not for Racing. They must be shimmed to 1.54”, or breakage will
occur.
O.D. 1.212” Press. 75lbs @ Check Ht. 1.54” Press 200lbs @ 1.04”

thats the ones im using mate from RS.
6-8psi max mate for me as dont want to break anything,

whats the best bypass valve to use mate?

[stevieturbo]

at such low boost, an air bypass probably isnt essential.

Any typical BOV will do just fine

[Coops]

why is it so hard to find a manual for the SN92 charger

[daxtojeiro]

why is it so hard to find a manual for the SN92 charger

When I fitted mine it was deamed as old, that was a few years ago, so now I guess it is very old.
There was only one company that dealt with them, as Paxton were taken over by Vortech or something along those lines. The company was called Coastline or similar and was US based, I rang them and they were helpful.
Phil

[Coops]

Cheers Phil,
have taken the charger apart to check it over and it seems ok inside,
there does seem to be a bit damp in the snail housing, as if the seals have leaked or started weaping,
same on the front,

[Coops]

[topcatcustom]

Still struggle to believe how those tiny little blades move so much air!

[Coops]

i know same as mate,
when i took it apart i though something had fell off,