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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 1994 - 1995 Specific Tech

30 or 36 pound injectors

  • Thread starter Thread starter jromeo
  • Start date Start date Nov 9, 2009

jromeo

New Member
Mar 5, 2006
16
0
0
charleston sc.
Nov 9, 2009
#1
  • Nov 9, 2009
  • #1
I have a 347 with AFR 185s , holly intake,70mm tb ,and a custom cam , 1 5/8 long tubes .The cam is good to about 6000 to 6400 rpms. I'm thinking the car should make 380 to 400 rwh.
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
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Acworth, GA
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#2
  • Nov 9, 2009
  • #2
30s will be fine.

Kurt
 

jromeo

New Member
Mar 5, 2006
16
0
0
charleston sc.
Nov 9, 2009
#3
  • Nov 9, 2009
  • #3
will my 190 fuel pump be good or do I need to go bigger ?
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Nov 9, 2009
#4
  • Nov 9, 2009
  • #4
36's for sure. I had 100% maxed out 30's in my old 347..appx 400rwhp on a dynojet (made 370 on a Mustang dyno)
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,297
1,641
214
Acworth, GA
Nov 9, 2009
#5
  • Nov 9, 2009
  • #5
Grn92LX said:
36's for sure. I had 100% maxed out 30's in my old 347..appx 400rwhp on a dynojet (made 370 on a Mustang dyno)
Click to expand...

I got to go find that link for the injector table. 400rwhp should not max out a 30lb/hr injector.

Kurt
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,297
1,641
214
Acworth, GA
Nov 9, 2009
#6
  • Nov 9, 2009
  • #6
Here's one. If you are putting down 400hp, you'll be ok with a 30lb/hr injector.

http://z31.com/software/injector.pl

Kurt
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Nov 9, 2009
#7
  • Nov 9, 2009
  • #7
I would like to mention

All of those inj size programs I've seen relate to fwhp

Most of us gearheads of today think in terms of rwhp

Another thing is if you are runnin a centri charger .......
those programs don't take into account the drain of the sc as well

If you are gonna tune it
I just can't see a reason not to have a bit of breathin room

Just somethin to think about

Grady
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
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129
New York
Nov 9, 2009
#8
  • Nov 9, 2009
  • #8
revhead347 said:
I got to go find that link for the injector table. 400rwhp should not max out a 30lb/hr injector.

Kurt
Click to expand...

I don't go by internet calculators, I go by real world tuning devices. I was seeing 96% duty cycle before the shift light came on with my PMS. Car NEEDED 42's but I decided to sell it before doing more changes.
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,297
1,641
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Acworth, GA
Nov 9, 2009
#9
  • Nov 9, 2009
  • #9
When I was doing aprox 370rwhp, I was seeing about 78% duty cycle.

Kurt
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,297
1,641
214
Acworth, GA
Nov 9, 2009
#10
  • Nov 9, 2009
  • #10
final5-0 said:
All of those inj size programs I've seen relate to fwhp

Grady
Click to expand...

The one I posted was crank hp. Wheel hp is really immaterial when you are calculating injector size.

Kurt
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Nov 9, 2009
#11
  • Nov 9, 2009
  • #11
revhead347 said:
When I was doing aprox 370rwhp, I was seeing about 78% duty cycle.

Kurt
Click to expand...

Right..now the new owner of my car dynoed it on a MUSTANG dyno like I mentioned. So your 370 dynojet hp would be appx 400ish for my old car on a dynojet. What rpm were you turning? My old car would go to about 6,800-7,000.
 

revhead347

Apparently my ex-husband made that mistake.
20+ Year Stangneter
Jun 14, 2004
9,297
1,641
214
Acworth, GA
Nov 9, 2009
#12
  • Nov 9, 2009
  • #12
Grn92LX said:
Right..now the new owner of my car dynoed it on a MUSTANG dyno like I mentioned. So your 370 dynojet hp would be appx 400ish for my old car on a dynojet. What rpm were you turning? My old car would go to about 6,800-7,000.
Click to expand...

Well, that would explain it I guess. I was doing that pull on a dynojet, and I make peak power at about 5500rpm. I let out on the dyno at about 6300rpm.

Kurt
 

nmcgrawj

Advanced Member
Sep 28, 2003
3,651
4
68
Indianapolis, IN
Nov 9, 2009
#13
  • Nov 9, 2009
  • #13
I'd rather have too much injector that i can tune down then have not enough injector that i have to up the fuel pressure for to squeek by.

I've seen some h/c/i 302s run 30s....
 

final5-0

Mustang Master
Apr 6, 2003
6,817
12
79
DFW Texas
Nov 9, 2009
#14
  • Nov 9, 2009
  • #14
revhead347 said:
The one I posted was crank hp. Wheel hp is really immaterial when you are calculating injector size.

Kurt
Click to expand...

How do you see it that way when the op said he was lookin for 400rwhp

I mean ... That equates to about 475 fwhp

You gotta tie one to the other

If I am missing something here

I guess I need someone to enlighten me

Grady
 

Black95GTS

Active Member
Jan 8, 2004
1,644
3
38
Marlborough, MA
Nov 10, 2009
#15
  • Nov 10, 2009
  • #15
final5-0 said:
How do you see it that way when the op said he was lookin for 400rwhp

I mean ... That equates to about 475 fwhp

You gotta tie one to the other

If I am missing something here

I guess I need someone to enlighten me

Grady
Click to expand...

36s, if you can find them. I understand they are hard to come by these days. The standard 42 pound injectors and 90mm LMAF would work fine in this situation, especially if you don't want to crank up the fuel pressure past the stock setting. If your cam can make power to 6400 you will be shifting around 7000. Another advantage of the LMAF is that a lot of people have experience with it so you'll find good support if you self-tune. You'll also want the 255 in tank pump.

Your 70mm TB is likely too small. If you have it already keep it, but if you have the chance, step up to at least a 75mm unit. Not sure if you have to modify the Holley intake to accept that size, but you'll likely be using the trickflow adapter elbow and thats setup for 75mm anyway. Don't worry, it won't "hurt your low-end grunt" WTF that means. [hides from keyboard dragracers]

Adam
 
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