turbocharging 390 FE
 

dear forum,

due to reasons of unavailability of 427/428 FE engines in south-africa as well as beeing too expensive to import from the US I plan to turbocharge a 390.

who wants to share experience and know-how, if I plan to turbocharge for drag racing as well as maybe short round track racing (15 minutes = 8 laps).
for symmetrical reasons I like to use two turbos
max rpm could be a reasonable 5500 rpm, intercooling I could add later, as well as water injection. my feeling tells me to use a suck-through turbo, although you could convince me usind a blow-through.


are the "small" FE con rods (3/8" bolts) suitable forturbocharging as well as the cast crank?
from which boost value on do you recommend forged pistons?
what is the recommended compression ratio (in relation to boost)?
does calculating correct carb size work like calculating for naturally aspirated engines muliplied by boost ratio, which is almost linear to an increase of displacement?
how should I curve ignition?
I like to reuse the (good) low lift cam as well. do I need harder springs?
what do I tell the turbo-shop which units to sell me (they may know, but I like to compare)

any information is appreciated.

thank you,

dominik, cape town

You might want to check out Sport Compact Car. About a year and a half ago they ran a series (about 4 issues) all about turbocharging. They offered all kinds of equations to help you figure out how much boost you can run as well as different aspects of the turbo: b-width, trim, inlet/outlet size etc. etc.

There are some other guys on the forum with twin turbo cobras, so I am sure you could talk to them about it.

thanks ike,

let's wait and see.
you are going dual quads on a 427 SO? that's what I had ...

dom

How about this?

416

Sorry, I ment to post this on the bore and stroked 390. I guess its ok because it still will be looked at by Dom.

jeff,

I can only see 416, but it doesn't "klick" although it seems like a link.

and again I battle to push the button "submit"

dom

I just ried the link, it worked for me.

The link works for me.

Dominik, try to get a copy of an olod HP book titled "How to Select and Install Turbochargers" by Hugh McInnis...it is excellent, by an authority, written before EFI, so it talks about how to sizeturbos, read compressor maps, suck-through vs. blow-through, compression ratios, valve spring requirements, water injection, ignition curves, rods, pistons, etc. He dealt a lot with RayJay Turbos, and I think they are outa bidness...but, the info is still valid.

ken,

I admit Iown the book since 199o, but was too lazy to read all over.
I do that during christmas now ... ;-)

I battle since a yearand longer with the forum's buttons. on PC as well as on Mac.
I tried another used name in addition and it worked for both for a while. now problems again.

cannot access your links, but I can go to the site "manually"
in like via toploader transmission ;-)

thanks,

dom, cape town

Dom, I got the book in 1975 when I went crazy and put a homebuilt turbo installation for a Datsun 510...ran 16 lbs of boost (good gas back then), with stock 9:1 compression, slightly modified timing curve...ran like a small-block Vette until I fried the stock clutch from too much torque...that book is like taking a class on turbos, EVERYTHING you need to make an intelligent decision. I think you're right on the twin turbo approach (if you go turbo vs. boring/stroking), for spool-up speed (turbo lag) reasons. McInnis comments that, for boost under 15 lbs (I think), stock-type bottom ends (on all except the absolutely WORST motors) are fine, since the additional boost pressures on the piston/rod/crank/bottom end are small in comparison to the reciprocating loads the bottom end sees at 5500 rpm or so. He also mentions that stiffer valve springs should be considered, as the boost pressure will provide a force that will tend to keep the intake valve off it's seat, and could promote intake valve float.
He seems to think the blow-through is not the way to go (difficult to seal entire carb, exposes carb to high temperature air, tuning problems, etc.)...suck-through is MUCH simpler to plumb and set up. He also mentions that you don't need a carb rated for total air flow at max boost, since carb ratings are for a specified pressure drop across the carb at the rated air flow, and the turbo barely notices a little pressure drop on the intake...so, a turbo motor would be happy with a carb rated at 650 CFM even though it might be flowing 750 CFM or so.
I must have read that book 3 or 4 times over about a month or two before I understood the total picture and how to do what I wanted to do...
I was VERY satisfied with my installation; you can't get power cheaper than with a turbo, and you only use it when you mash the loud pedal...most of the time you're motoring around with a relatively mild motor, and you may actually get better mileage due to the superior atomization in a suck-through application.
Good Luck!

There is a much newer book with up to date info that is by Corky Bell.....get it at Amazon.

I haven't checked out his book, but Corky is a major Guru-type...he KNOWS what he be talkin about. I had one of his kits for a Supra...incredibly fast, and well done. No doubt it's worth reading. Dom, get and read everything you can get your hands on before you finalize your installation.

thanks guys & ken!

how come I do not get any notification about new replies to the post?

keep well,

dominik

Dom, I didn't get notification either...must be disabled right now...
Cheers.

Ken,

seems towork for me again. buttons I will see just now.
no, don't work. I can't even move in the reply. I posted a note to brent.

dom

thanks jeff,

that link worked.

dom

Dominik,
I run a blueprinted, balanced 390, 427 B cam forged pistons, solid lifters and it has plenty of power without turbo(0-60 in about 4 sec). I run out of talent long before I run out of horsepower. You will find that the suspension set up is much more critical to your driving than HP. You might want to start with a built 390 and see how it suits you before you go parabolic on the bells and whistles.

Cheers, Pete C