can you supercharge a rb25de ????

What kind of supercharger you thinking of?

A Roots/Scroll type wont fit in an untouched RB25 bay - centrifugal 'may' be ok.

When I was planning this, I found the best place is where the alternator lives, as there is lots of room (beware - the p/s pressure switch lives near there and you may need to re-locate it) Water piping will also need to be made up.

The alternator will happily live above, in line with the inlet plenum.

Bracketry needs to be made to fit alty & s/c, but it's fairly sparse for anywhere to actually bolt it to.


I got as far as mock-mounting the items, before deciding to move out :screwy:

yup. seen the car in question. owned by bootilicious on gtroc. sliver r33 gts.

used a rotrexc(?spelling) supercharger and as someone else said re sited the powersteering pump (used Renault electric one)

I havent driven it, but had a peek under the bonnet.. and its running something in the region of 280 -300bhp i am told.

not huge power comparative to big turbos but thing is its linear power delivery isnt it....

its different.. and interesting..

cost was an estimated £5k ish

shawny said:

abbey motorsport done one when i was doing my turbo coversion , it cost the lady loads and didnt make the power mine did as the charger uses power as it is belt driven of the crank . they put it were the power steering pump is and used a electric PAS pump off a saxo

Click to expand...

That's because a (roots type) supercharger isn't made for high-end power - it's all low-end, boost off-idle, etc. They run out of steam where a turbo would keep giving.
If anyone wants S/C's for power, they probably don't 'really' get what they do.
Centrifugal types are a bit of a funny type - suck loads of power like a roots,
then act like a turbo, but not so well. They're a bit smaller than roots and don't stall in situation a turbo would - but that's about it.

It's why you see the hybrid types with both; counters the lag from big turbos.
People try DIY the setup, but forget what airflow & pressure is, then either end up with no boost or little boost.
I think it was VW who then went on to show how it's done on production scale with bypass & blocking valves, which is still beyond the casual DIYer.

I wanted an S/C purely because I don't go anywhere where I can go fast, but wanted something for the initial acceleration.

Costs lots as it's all fabrication and pipe, belt and aux routing. Turbos in comparison, clip in between the exhaust manifold & downpipe and air filter & throttle.