what is the best turbo for a 300-6

I need your guys help on choosing a turbo for my truck. I have a stock 300-6 and i plan on using it for pulling and haling. I only plan on running 5-10 lbs of boost MAX, so i know i will have to change the head gasket to a copper gasket. But i like if you guys can tell me what kind of turbo that will start spooling at 1800-2000 rpm and that has a internal wast gate. I would prefer diesel turbos like cummins or GM turbo because they be easier for me to get. Also if my truck can handle the boost and if i can keep the stock injectors. Also how more power i can expect. If you want you can E-mail me a smeddly21@hotmail.com. Thanks for the help.

play with this to find the right turbo.

http://www.squirrelpf.com/turbocalc/

hint, the turbo off of a Cummins 6bt is going to be too big for what you want to do. not sure what turbo came on a 6.5 GM diesel but it's probably closer, may still be too big to spool on the low end.

you probably won't be able to run 10psi without detonation in a 300 with your intended use, 4-7psi is more realistic I think. you can probably skip the copper gasket. the stock injectors are not going to work for you here, they only good to 200hp or less.

have you considered how you are going control your injectors or tune the ECM for boost?

I have gotten another 300-6 to build to my spec, because i start my internship are (CAT) so i need a truck.

I can build the motor the hard thing for me is figuring out the EFI and getting the air fuel mixer right. it seems most people running 42lbs injectors presser. how do they do this with a different computer.

what is magasquert i have a idea but not sure.

what options do i have for getting the air fuel mixer right.

The turbo from a Dodge 5.9 will be fine. Thats what I use, spools around 1700rpm. The internal wastegate is too small, so be prepared to replace the flapper valve and increase the diameter of the port.

megasquirt is an ECM that you can either buy or build from scratch to suit your build. it seems to be pretty popular in apps like this.

i'd just like to qualify my response by saying, that I have not actualy done this myself, (yet?) and I only responded because it had been over a week since you posted and none of the knowledgeable members had responded yet.

You don't mention what tranny you have.
If it's an automatic, it needs the Ford EEC processor to operate and Megasquirt won't be of much help :nono:

The transmission is a cast iron 4 speed.

where would i buy the different fuel mod

thank you guys for your posts.

I'm am 17 and i want to learn about the efi stuff because i already now diesels and how a carburetor gas engine works.

For starters you might want to read up on turbos a little bit.

Turbochargers by Hugh MacInnes is extremely dated and skewed heavily to carbureted applications but the theoretical stuff about reading turbo maps, selecting a turbo and which features to look for is 100% right

Maximum Boost by Corky Bell is much more contemporary and all about EFI applications.

Can any one tell me what flashing the computer does and how to do it.

"Flashing" means overwriting the programming in the E-PROM in the EEC-IV module. Easily done on a 5.0 Mustang since everybody and his brother has cracked the codes, not so easily done on a 300

Ok i am trying to learn about how megasquert works because flashing the computer in my truck is not going to work so can I

get a megasquert and plug it in to original wires and upgrade the injectors to 42 lbs (running 5-10 lbs of boost).

or am i going to have to tune it and how hard is that to do.

will i have to change a lot of sensors or will the new ECU do all that.

Thanks guys for your help I'm trying to learn i am used to every thing being mechanical (but i guess i best get use to it)

At those boost levels you're not going to need anything like 42 lb units. 42# injectors would be good for something in excess of 540 HP.

So what size injectors are need and how and is it to put in megasquert in the truck?

Injector size is determined by peak HP
HP is mostly determined by volumetric efficiency and RPM.
You cannot arbitrarily pick an injector size and a boost level and expect things to work. You need to plan your entire build around a specific performance goal and select parts that complement that goal.

For starters you need to decide how high you're going to spin the engine and if it's much over 4000 RPM you need to be thinking about the internal engine mods you'll need for durability. Then you need to decide what maximum boost you want and at what RPM range you want the turbo to be in its sweet spot. Then and only then can you even begin to think about the extent of the head work you need to do, about sizing the turbo and working out the fuel system and engine controls

I wasn't joking when I said you needed to do some reading and suggested those two books

As for Megasquirt, start here: http://www.diyautotune.com/
Then go here: http://www.megamanual.com/index.html

I got the one book and started reading it.

I'm looking for 400 lbs of torque and 200-250 hp No higher than 3000 RPM 10 lbs of boost

I'm not worried about building the engine me and dad built a lot of puling motors and head work with porting and polishing. I do not care about hp I like to pull/work and spin big tires.

me and my dad are new to EFI its not like changing jets.

You may not care about HP but your EFI does. Injectors are rated in lbs./hr. Anytime you have time as a unit you're going to be dealing with HP rather than torque. The two are related

HP = Torque x RPM/5252

Torque = HP x 5252/RPM

For example a stock 300 makes 260 ft-lbs @ 2000 RPM which works out to:
HP = 260 x 2000/5252 = 99 HP

It also makes 150 HP @ 3400 RPM which works out to:
T = 150 x 5252/3400 = 232 ft-lbs

The injectors have to be big enough to support the peak HP requirement of the engine, and are usually sized for an 80-90% duty cycle

A couple of things to keep in mind with injectors:
They are usually rated at a pressure drop (the difference between fuel rail pressure and manifold pressure) of 39 PSI. The stock regulator on a 300 raises the pressure drop to 55-58 PSI. That increases the actual flow of any injector you put in by about 18-19%. The stock 14# injectors flow something on the order of 17 lbs/hr.

When you turbocharge the system, the pressure drop decreases as boost increases which can lean the engine out very quickly with predictable and expensive results. You need a fuel system which is boost compensated or has injectors sized for the reduced pressure drop you will see under boost. This can be problematical because it can lead to injectors that are way too big when not under boost. That's why they make rising rate regulators, they compensate for the loss of pressure drop..

300-6 Little Blue":2wmxraj9 said:

The transmission is a cast iron 4 speed.

where would i buy the different fuel mod

thank you guys for your posts.

I'm am 17 and i want to learn about the efi stuff because i already now diesels and how a carburetor gas engine works.

Click to expand...

Glad to see you are posting asking question BEFORE buying parts and later asking why it doesn't work.


And StrangeRanger is giving you GREAT instructions/ information. He KNOWS what is talking about. If he say s read a paticular book it will have good info in it.

OK i think i did the math right

if i can get 250 hp at 3400 RPM then i should get 386 tq at 3400 RPM.

so by rights the 386 tq should go up at max tq 2000 RPM and put me around ware i want to be (400 tq)

so this will be my goal set.

You did the math right.
Now to size the injectors:

For a boosted engine, use a BSFC of 0.55 lbs of fuel/HP-hr
So for 250 HP you need 137.5 lbs of fuel per hour
Spread over 6 injectors that would be 22.9 lbs/hr each.
since you want to work an injector at 90% duty cycle of less that would be a rating of 25.5 at your actual pressure drop

Injectors are typically rated at 39 PSI but if you use the stock fuel pressure regulator for a 300 that goes up to 55 PSI or more. However when you increase the manifold pressure with a turbo, you have to lower the injector pressure drop by a like amount. Since you're looking at 10 PSIG boost, that would mean the actual pressure drop becomes 45 PSI. The rating of an injector increases or decreases as the square root of the increase or decreases in pressure drop. So at 45 PSI your injectors would flow (45/39)^1/2 of their rating or about 107.4%

If you need an actual flow of 25.5, you would have to have a rated flow at 39 PSI of 23.7 lbs/hr.
It looks like 24 lb. injectors will just barely do the job with that 10% margin of safety that restricting the duty cycle gives you. If you back the boost off to 8 PSI, 24s will work like a champ.

You do not want to go bigger than you have to on injectors because they can run overly rich when you're off boost.

You need a fuel pump which can supply at least 10% more fuel than the injectors demand or about 151 lbs per hour at 6 lbs per gallon, that's 25.2 gallons/hr or 95 litres/hr. The stock pump for a 96 is rated at 95 LPH at 55 PSI so you might just barely squeak by if you were building a a 96. Problem is that Ford has used several completely different fuel pump systems over the years so to work out the pumps, I'd need to know which system you have

As for sizing the turbo, you need to learn how to read a turbo map to pick the one for your application. I'll leave that part of the project to you

Ok thank you for the help I'm still reading the max boost book.

I'm sending the block out to get punch out if i did the math right with a 4 inch stroke with a 0.30 rebuild kit it give it 6 extra cubes to make it a 306 ruffly (bigger than a 305 Chevy ).

thanks for all the help if any one wants to give advise go right ahead.