4.0 OHV eaton m90 supercharger help

[shaggy101]

Hey so I am soon to be acquiring a eaton m90 supercharger with a custom intake plenum for the OHV 4.0 and am thinking of running it at about 6-7 psi I know their is things that are needed for proper tuning such as bigger fuel injectors but what else would I need any help would be great

 

[4pointslow]

M90

I will start off with a little and maybe more people can help out as well.
Injectors
Maf
Custom tune

 

[vroomzoomboom]

fuel pump
wideband

 

[Dono]

Minor welding- depending on the M90 mount.
-coolant neck needs to be clocked slightly counterclockwise as the end will but up against the M90.
-Where the gas line mounts to the fuel rail needs to be turned slightly so the fuel line can be re-attached. The M90 is in the way otherwise.

Just things to watch for.

 

[shaggy101]

ok thats good things too look out for and as far as maf, fuel pump,wide band and injectors for a 6-7 psi set up running around 250-300hp what size should i be shopping for

 

[4pointslow]

Injector size

To get injector size use this formula

Injector Size
(CFM x .44298) / (# of injectors x.8)

Note .8 is 80% duty cycle of the injectors
/ is the divide by symbol



To get CFM use this formula
CFM: Cubic Feet per Minute (of airflow)
(Eng CID x RPM x VE x PR) / 3456


CID: Cubic Inch Displacement or Engine Size
Liters to CID = Liters x 61 = CID

RPM = Engine Speed (MAX)

VE: Volumetric Efficiency
Aproximate VE numbers
2V = .85
4V = .90

PR: Pressure Ratio
14.7 + Boost /14.7 = PR

 

[4pointslow]

Fuel Pump Size

To get Fuel Pump flow size needed use this formula
(HP x BSFC) / 6.0584 = GPH

To get GPH to LPH
Gallons x 3.78541 = LPH

Notes
HP: Horse Power (At crank)
BSFC: Brake Specific Fuel Consumption
BSFC = .5 to .65 (aprox)
Weight of 1 Gallon of gasoline = 6lbs
Weight of 1 Gallon E10 = 6.0584

Note: If using HP from dyno run, add 20% HP to make up for drive train loss?
Add a % for HP to drive supercharger. 50-70HP ?

 

[Dono]

I used 36lb injectors on mine.
I believe my pump is a treperformance 255 lph unit.

 

[4pointslow]

4.0 ohv

Shaggy101,
What is your max rpm, and is the engine bored larger?
Desired horse power at crankshaft?

 

[shaggy101]

not to sure what the max rpm is as i havent got the motor yet but it has been bored out .030 over and my desired hp at crank id like it to be about 300-320 this motor is also an OBD 1 comp

 

[vroomzoomboom]

you may want to think more about your horse power numbers. its going to take a lot of money and mods to get to that....lots.

 

[4pointslow]

Injectors

Shaggy101,

CID 244 x RPM 6000 x VE.85 x PR1.48 / 3456 = 533CFM

533CFM x .44298 = 236 / 4.8 =
49 lb hr injectors

If you use smaller ones you will have to raise fuel pressure quite high and/or make rather large adjustments to the MAF transfer function in the tune which could throw out the load calculations and other things.

I had 30lb injectors and raised fuel pressure to 65psi, still had to adjust the maf too much. Now I am running 60lb injectors with 14 lbs of boost at aprox 40 psi fuel pressure. According to calculations I should have 67.5 lb injectors. If I did my math right.....

 

[Dono]

Yup, 250 to 300 rear wheel hp on a 4.0 ohv with 4x4 and a m90 isn't as easy as one would like to think. You will make a fun truck with tons of bottom end torque, but not a high hp motor.
I did a ton of work to mine and was never able to achieve your goal. I did learn/am learning a ton from some very smart people tbough. That stuff is priceless. I'd call my 4.0 ohv m90 build a success, and would encourage anyone to do it.

See jd4242`so ranger build and the work he's doing with his heads. Larger valves will really help the motor your working on.

 

[shaggy101]

well ok sofar the motor i am buying has the biggest cam comp cam offers, bored .030 over, p&p, ducked heads to up the compression a bit, and upgraded valve springs n push rods, claims to be making 250-275hp i call bs n say maby 225 if hes lucky and thats with stock tune and stock externals such as maf, injectors, and such so thats why i figure if i add the m90 kit that i am also buying from him that i could achieve the 300hp mark with 5-7 psi like i know the motor is awsome as is but ive wanted to have that m90 sc on that 4.0 forever so i got a motor i can put on a stand and add and do work to it to be able to add the m90 but thing is i want it to run right but have no idea about these forced inductions and what they need

 

[Dono]

Thats ok, neither did I. That's why my thread on my build is so long.

How do you feel about cutting a hole in your hood? The hot intake temps seem to be the real limiting factor on making good power up top in the rev range.

Sounds like your build will be a fun one. I'm looking forward to it.

Can you find an odbI tuner in your area? Maybe start with that.

 

[2000StreetRod]

dyno tuning

Unless you upgrade your PCM to OBDII your tuning will have to be done on a dyno. The advertised rate for my local dyno is $105 per hour just for using the dyno and someone to operate it. That does not include any tuning expertise. It may be less expensive for you to upgrade to OBDII. That way you can record data and send the data to a tuner for analysis and PCM calibration changes. See this thread for more information: Custom tune by Henson

 

[shaggy101]

im not too keen on cutting a hole in my hood tbh maby a cowl hood to get some more air in there but id sooner be inclined to make a custom intake that uses stock air box with a bigger tubeing and bigger opening beside the rad sattle to get the outside air only vs engine bay air

id like to keep my odb 1 comp just cause its a unique thing plus then i can keep all the stock harness n such nbd if it cost me some cash to get it tuned right i am more curious as to what exact parts i need to hunt down and buy so that tuneing can be done easily and she will perform how she should

 

[shaggy101]

ok so i did some numbers based on stock rpm of 5200 and i came up with 42lbs for the injectors and only 121.84 LPH for the fuel pump based on 300 hp also where abouts did you purchase your injectors ive been looking online for 36lbs injectors and cant find anything more than 26lbs

 

[jd4242]

well ok sofar the motor i am buying has the biggest cam comp cam offers, bored .030 over, p&p, ducked heads to up the compression a bit, and upgraded valve springs n push rods, claims to be making 250-275hp i call bs n say maby 225 if hes lucky and thats with stock tune and stock externals such as maf, injectors, and such so thats why i figure if i add the m90 kit that i am also buying from him that i could achieve the 300hp mark with 5-7 psi like i know the motor is awsome as is but ive wanted to have that m90 sc on that 4.0 forever so i got a motor i can put on a stand and add and do work to it to be able to add the m90 but thing is i want it to run right but have no idea about these forced inductions and what they need

If he is telling you its making 250-275 hp NA, I would question every and anything he says..if and if its 2wd,5 speed the most your be lucky to make with EVERY bolt on and GOOD port work would be more in the 220ish hp range..even with 7psi you be lucky to make those numbers he is claiming. .

Now if your auto and 4x4 your be lucky to break 220hp even with 7 psi

Get a 255 pump and 36 will be PLENTY for only 7psi, probably get away with 28.also for tuning you better set aside probably a good grand...your need to buy a SCT Eliminator chip and have it custom dyno tuned..NOT CHEAP..

 

[jd4242]

O and anything over 5 psi you better be looking into a intercooler or water/meth setup