CyaPussy

iTrader: (1)

Lookin to get everything out of my f1a. What size motor an what could it run in say a 3400 lb car kind of would like to go back to an aluminium block. Let's here some thoughts.

DEFYANT

I would do an LS2 block either 364CID or 402CID (4" Crank). In either of those I would do a forged crankshaft to take the added stress of the blower.

So.

LS2 Block
Forged 3.622" or 4" Crankshaft
Callies CompStar 6.125" Rods
Forged 4.005" Pistons and Rings
ARP Main and Head Studs
ACL, Clevite, or King Bearings

Blown06

iTrader: (32)

Don't forget to double key the crank.

CyaPussy

iTrader: (1)

I figured 402 408 maybe 416 going to be the most common thoughts. Right now I have a 376 but don't think I'm willing to push anymore with the parts it has.

The Alchemist

iTrader: (19)

If you don't already have a block, I'd chose the ls3 over the ls2 since it is stronger and has improvements vs. the ls2, oh and it has slightly larger bore as well, 4.065 vs 4.000.

CyaPussy

iTrader: (1)

So 416?

LJMSJohn

Not with an F1A.... I would stay 370

LivernoisMotorsports

iTrader: (1)

It depends on total HP you wish to achieve. The O.E. blocks can hold up to a 1000 flywheel with good prep and parts. If you are looking for more than that you will need to sleeve or go aftermarket.

Rise of the Phoenix

iTrader: (27)

Could you elaborate on why you don't think a 416ci LS3 would be good?

LJMSJohn

Personally i believe its gets the pressure ratio too low on the wheel... Centri blowers are just like turbos...

Sean Moore just dyno'd his 370/ F1a combo this weekend... and made 790 to the tire on pump gas... through a converter thats prolly a tick loose with it slipping almost 10% on the track... We redid the top end of his motor and a new cam... and made more power on pump gas this time than the car made on race gas with the old combination...

Blown06

iTrader: (32)

I'm certainly not trying to call out a guru here, but do you have any evidence to substantiate that claim?

CyaPussy

iTrader: (1)

I guess I'm confused. Always thought bigger was better. I'm confused about some of the things about how the 370 is better.

Bob@BruteSpeed

iTrader: (16)

We've made exceptionally good power with LS2's with a 4.0" stroke with F-1A's, it is a very good combination. Bob

The Alchemist

iTrader: (19)

Yeah, I'm not sure what he means by the 'pressure too low on the wheel' statement as well.

I have just a street car, and building a new setup and decided to go with a 4.000" crank because of the added torque down low for being a street car and part throttle fun. I know it will run out of steam and not be a dyno killer with the D1SC on it, but having more out of boost torque was appealing to me.

CyaPussy

iTrader: (1)

Bob how do you feel about the f1a on a 416 aluminum block ? I know the iron block is better for boost but I'm trying to save weight just don't see the f1a being to much for that size motor.

LivernoisMotorsports

iTrader: (1)

The 4" arm will help that F1 turn, don't go big on the bore std. or 4.070" and it will be a good combo. Top it off with some CNC'd LSA's, double key the crank and you will only be limited by the octane your going to run.

rotary1307cc

iTrader: (5)

Don't expect blower guys to get it lol

It is a centrifugal compressor just like a turbo. It follows the same principles.

A centi doesn't just carry a blanket efficieny accross various mass flow rates and pressure ratios

Just because there isn't a compressor map published doesn't mean their isn't one lol

CyaPussy

iTrader: (1)

You guys are to smart for me. I just want to get my car in the 8s with the right motor and f1a. On pump gas is the goal.

The Alchemist

iTrader: (19)

Ok, so instead of talking in secret, non-descript terms, why don't you guys actually help some people out and explain what you're talking about.

I get it that the blower needs to match the cubic inches, but isn't that more critical with a turbo where the exhaust gasses are needed to spin it? Too big of a turbo, and it's a turd down low, too small of a turbo, and you create too much backpressure. So how does that translate with a blower that spins at the set rpm determined by gearing and engine rpm, so it produces xxx cfm at a specific rpm?

I get it that by having a 416, it's going to eat up the D1SC and it won't make a lot of boost, but I'd rather make 800rwhp with 10psi of boost than 18psi of boost.

Here's a D1SC on a 572.... seems to make decent power to me. Bet it's fun as hell on the street.


Here is a LS3 based, 414 (probably a 416) with an F1-R that he isn't spinning high, and it made good power.

I understand that with a bigger blower, if you don't spin it fast enough to get into the efficiency range, it won't make power, ie, won't move air efficiently. But does the efficiency of the blower depend on the pressure it sees at the intake? I would think that it would be the opposite, that with a lower pressure, it would be more efficient, and make more overall hp.

So please, share some of the super secret turbo knowledge you have, and make this site live up to it's name and bring some technical discussion in here.
Thank you.

JoeNova

Andy Fangman made 1200 hp on a stock bottom end 5.3 with an f1x. He made over 1400 on the same 5.3 with forged internals, stock displacement.

Just throwing that out there.