fuel pump size to injector size

[trav_19]

well i think i am going with 30lb injectors for the 347 build...what size pump should i get?? 255? also what happens if i put the pump in before i build the motor? would it send to much fuel to the engine...not to smart in the fuel delivery part lol any help is appreciated.

 

[HGFireHazard]

Put in a fuel pump that you think will fit as far as you plan to upgrade your car. Our fuel system is a return style, meaning that fuel that doesn't get used gets sent back to the fuel tank. A lot of people (including myself) use the Walbro pumps and seem to have very little trouble with them. They have a 255 and a I think HP 255, I suggest the latter of the two. If I remember correctly the pump is literally named GSS 347, or something similar.

 

[Grn92LX]

What parts are you using for your 347? 30's may be too small. 255 pump is perfect now and later

 

[scorpion95]

+2 on the 255lb pump but if you're going with a 347 you might want to consider 36 or 42lb injectors

 

[MattZ281LE]

(Max HP x BSFC )(.50 in most NA cases) / (8 (# of injectors) * .80 (Duty cycle) )= Injector size in LBS per Hr.

So in your case....

450 MAX crank HP (382rwhp approx) = 225/6.4 = 35.15 Injector.

You have room to play up or down with FP and tuning.


Unless you are running a VERY healthy combo then a 36# should be plenty

 

[trav_19]

wow and i was worried 30 would be on the large size for a n/a combo haha hummmm i will more then likely be hooking up bottle to so maybe larger injectors are in the future...what do you guys suggest or a maf then?? never seen one calibrated larger then 30?

 

[MattZ281LE]

I used to use the Pro-M77....was always my fav. I suppose you can find them still

If your having it tuned which you will have to. I would get a lightning and be done with it. The tuner can map the CPU to your MAF. When he datalogs your pulls he can adjust the tables to work with the voltage output of your MAF. In some instances it is possible to peg a MAF, which I have done a few times. But NA you should have no issues.
The calibration thing is if your not doing a custom tune IMHO, just bolting stuff up at home.

 

[trav_19]

well i was looking into the hp 255 pump and what im coming up with it says for turbo or supercharger applications only?? i dont understand what could be different if they are both 255?...

also i will be installing everything at my house...? but after its all installed i want to take it down to paul's high performance....about 10 mins away....never been there do they do dyno tunes and everything there?

 

[final5-0]

Well Trav

It used to be like this

They offered a 255 high volume
and
a 255 high pressure

Now this info is from several years ago
but
the some boys on the power adder forms reported

They could not get their pressure down low enough with the hp choice

I saw that on more than one occasion
so
I went with the high volume choice
and
All has been good for several years now

Grady

 

[HISSIN50]

As I recall, the HP version is supposed to keep pressure up at highest demands, where the HV pump starts to fall off.

That's some good stuff from Grady - I didnt know that.

 

[trav_19]

so would a high volume or high pressure be what i want to go with ..it will be on bottle?

 

[HGFireHazard]

The HP one as hissin stated.

I had my stang tuned at PHP, I wasn't aware you were so close to where I live Trav. I paid almost exactly $1,000 when I went, if I remember correctly the rates were $425 to burn a chip and $150 per hour on the dyno, and I had them bracket up and touch up a couple of things dealing with my S/C.

 

[trav_19]

1000 are you messing with me???....im goin to be so completly broke after this build lol....my old lady is goin to kill me lol yea i had no idea you were so close either lol...im going to have to start looking at where everyone one else lives too

 

[trav_19]

well i want to know if either of these are good buys...both in the classifieds at corral brand new 38lb injectors 200 to my door, and 42lb 200 to my door but it dosent mention if the 42's are new

 

[final5-0]

well i want to know if either of these are good buys...both in the classifieds at corral brand new 38lb injectors 200 to my door, and 42lb 200 to my door but it dosent mention if the 42's are new

I've seen talk lately about not being able to find FMS 36# (Bosch) injectors

I'd be more comfortable with a name brand
or
common type/size inj's most use

Don't know about 38# inj's

Might be a good idea to talk to your tuner

When you run off brand or different parts than most ..........
Thats not always a bad thing
but
Sometimes ... asking for support can be difficult
because
Peeps can't relate as others have not used them before

Grady