Blown408

iTrader: (4)

I am planning on running at least 15PSI on my 408 with an F1. Will I be able to do this on Pump gas with 9:1 compression? From what I am told, the motor should be able to handle at least 20 PSI. I am just not sure about if I will need to run a higher octane or use a meth kit when running this much boost. This is a whole new world to me, so any help would be appreciated.

Here is the info on my engine:

408 Enigine w/ET Performance heads

*Diamond Pistons -15cc dish
*Callies 6.125 rod w/ARP 2000 bolts
*Eagle 4.000 Stroke Crank
*ARP Main Studs
*FM Main Bearings
*FM Rod Bearings
*Clevite Cam Bearings
*HellFire Piston Rings
*Cometic Head Gaskets 4.060 ID .051 Compressed
*Custom Cam Of your choice
*Comp 850-16 Lifters and ew lifter trays
*LS6 Ported Oil Pump
*Rollmaster Double Roller Timing Chain
*ARP Head Bolts

ATI SuperDamper

ATI F1 Procharger

SDCE tensioner setup

LS6 intake

Kooks 1 7/8" stepped to 2" headers

3" X-pipe with Twister mufflers

Nasty Performance fuel system with 60lb (might upgrade to 75lb) injectors

The only thing is that I will be starting out with the twin high flow intercoolers. I know this will be a restriction, but I will upgrade later.

My goal is to put down at least 700HP to the ground. Is this going to be possible?

DAPSUPRSLO

iTrader: (14)

With 9 to 1 you will certainly need meth or race gas to get those numbers. I'm going with around 8 to 1 to try to stay away from race gas and will be running a similar setup to you boost wise.

Got Me SOM

iTrader: (2)

the twin intercoolers will not be able to provide sufficient cooling, you might have to go as low as 8:1

nitrorocket

iTrader: (12)

20 PSI NO! 700 RWHP YES!

Brian made 822 with a 427 and 10:1!!

Race-Prep

Depending on how the engine is built it could be able to handle 20psi, the real question is the power andif you have the system set up properly it should make over 700 with no problem at all.

-Bryan

TurboBerserker

iTrader: (1)

I'm at 8.57:1 and 15 psi is no problem with a turbo on pump gas with a little meth Meth kits are pretty cheap and are effective insurance -- cool the charge and add octane -- nice combo. You'd probably want a different intercooler set up as well.

20 psi? I built my 408 with an 18psi target. 20psi was a fallback, hold your mouth right and pray position if I didn't meet my goals on 18psi. Frankly, I'm glad I don't have to try it... I don't have much confidence that it would have lasted long that way.

700rwhp? I think you're good. I made 600awhp on a street tune, pump gas, mustang awd dyno at 14psi (FMIC and meth). You can at least get close and finish it up with a small shot.

Blown408

iTrader: (4)

I called and changed to a -35cc dish. I will probably add a meth kit later, but right now I am kind of tapped out.

Which would I benefit from more, the FMIC or a meth kit?

I am going to start with 15psi and since I get another blower pulley with the SDCE kit, I will go a little smaller to add more fuel to the fire later.

Thanks for the replies guys. Any more suggestions or opinions?

Got Me SOM

iTrader: (2)

The power level will be attained making that on pump gas is the question. I don't think so.

DAPSUPRSLO

iTrader: (14)

Intercooler with no doubt, unless you wanna run alcohol, lol.

nitrorocket

iTrader: (12)

Go with the IC. It is there forever and will help power everywhere, not just WOT.

Blown408

iTrader: (4)

So basically, if I lower the compression, I will be able to run more boost but will still have to use meth to get to my desired RWHP with the twin intercoolers?

Go easy on my guys, I am still learning..

DAPSUPRSLO

iTrader: (14)

To a point yes. I believe if you lower it too much you loose eficiency.

drozd_ws6

iTrader: (19)

I have pretty much the exact setup as you. But w/ a 9.25 comp and progressive alcohol setup. My car is currently being dyno tuned at HPE. With the f1 head unit and a 4.25 it's supposed to put out around 12-15 lbs. of boost. Chuck at HPE Thinks it should have no problem making around mid 700 to 800 rwhp. Which was my goal going into this build so lets hope so!!!

Also he said a little while back they did a heads and cam 408 stroker w/ a d1sc and 5 lbs. of boost and it made 635 rwhp!! Hope this helps.

KAOS

iTrader: (5)

what i dont get is how in the world do the GN guys claim to run 20 psi on pump gas. why cant we. i just dont get it

2000 Tran Zam

iTrader: (2)

maybe cause its a 6 cylinder?

marleyskater420

Its all about how much pressure the cylinder actually sees. Our heads are incredibly in-efficient, so when we are running 26psi(like I am) and we port our heads, we cannot run over 21psi, because there is no pressure drop, and the heads arent restrictive. Its all a matter of restriction, pressure drop, and how much air the cylinder actually sees.

You could use 8psi on one motor, and 20psi on the other, and the 20 does not make as much power. Its all in how much air actually gets to the cylinder,and the pressure that is there with it.

You guys get SO much more air into your cylinders than we do, and that is a major factor in running boost w/ pump gas. Look at how much power we make at 20psi, and how much you make at 10psi, and then compare. A V8 is so much more free-flowing than a 6cyl, so it is much easier for that air to get into each cylinder, without going through much pressure drop,or encountering much friction.

This is just what I have learned, and I could be wrong. But I own a GN, and run 26psi, and that is how I was taught we can run that much boost.

Pro Stock John

iTrader: (34)

GNs (LC2) are 8:1.

dug

iTrader: (10)

dont forget to hang on

KAOS

iTrader: (5)

i see that to a point but i would think that with greater efficiency that you could run more boost. but hey im just a beginner

Bryan Wilkinson

iTrader: (1)

Couple of suggestions.

Steel Billet Main Caps a must. I did not see those in the list, the powered stock ones will not hold and as a extra safety measure.
At 9:1 CR your dynamic CR will be about 20:1. This estimate was made using my setup. The max I have run was 18.6 psi on 93 OCT at 10:1. with zero detonation. We have taken the engine apart for inspection in our attempts to hit 1100RWHP, and everything is in pristeen order. Bearings, rods, pistsons and there no signs of detonation even on the rings. The bearings still look new. Meth nor Alky were used.

The little IC's that come with the ATI kit will not suffice. You need a big FMIC. You will also need dual filters to get 20psi in the Procharger. If you want to talk more in deatail about your setup, you can PM me. Assembly of this motor will be key to its survival. I would be careful not to trust those that have not been there.