jcburris

Hello, I have a PFM twin turbo setup for a BBC, it has Rotomaster 3AJ1EE1881 turbos P/N 600586-1 I am guessing it was sized for a 454, and i am trying to fugure out if it will supply enough for a 489 BBC, does anyone out there have or has had / used on of these systems, it is a waster intercooled setuo with the turbos mounted on top a standard center rise manifold, any help is appreciated

THANKS
CHRIS

Longrange4u

I dont know about boats... but I race turbo charged LS1's. The sizing of the turbo vs the cubes does matter.... but not allot. The difference between a 489 and a 454 is not too huge, you need to look at the AR of the turbos, what size the turbo's are (you gave the serial number, and I think thats the p/n to the housing). Turbos are all about what CFM you are trying to get... exhaust will push through them regardless, the cubes of your motor have more effect on how fast the turbos will spool.
http://www.rotomaster.us/index.php?p=products&cid=1

Kanookstr

I use to and still have a PFM setup. does it look kinda like this. except for the custom intercooler

Kanookstr

Or like this one,

Kanookstr

Yes the standard PFM kit was designed to mount on top of stock center rise manifolds.

jcburris

Thanks, I will take a look and see if I can find any additional numbers, I am thining about a 4.310 bore by 4.25 stroke mark IV wih a 4340 crank and h beam rods (eagle?) with an 8.5 or so static comp ratio, heads I dont know, I have seen some Austrailan cast alum sq port heads, but I dont know of what quality they are, they look fine, and seem to have a thick deck, add a hyd roller and I hope to get around 650hp, I understand the turbo setup i have will produce some pretty good boost (10-12lbs) it is a draw-trough system, but it thnk that wll be fine, I have had some experiance with a draw-thru before and it worked fine, what about carbs? how big you think they need to be? Vac or mech secondary? boost referance power valves, or just plug em'? How are the intercoolers plumbed, do you bleed cold water from the engine sea water pump, or run a seperate electric centfical?

Thanks for your help!

Kanookstr

That Small Block in the picture make 689 HP. I ran an 800 Holley with mech seconds. The power valve was a low 2.5 (don't need to waist fuel when cruising which in my case cruising was done at 3.o in vac.). It now has the PFM programmable muti port EFI. The intercooler gets raw cold lake water from a "T" in line from the out drive feed hose, no separate pump needed. Then it dumps overboard. I had a project boat I wanted to put the engine in, but bought a new bigger boat instead. So now she sits on an engine stand for sale.

SB

Pro-Comp ?
I'd pass.
E-bay 'knock-offs' . More Chinese than anything else.

If RHS/Comp Cam's Pro-Topline's they should be fine.

Remember, you must get 'killer' valves and such. Remember, Boost also requires more valvespring than NA.