Oh hell yea??

keisers1001

Registered User
Well, as I finish the rebuild, I have been reading about the fuel pressure needing to hover around 43 psi for higher flow injectors. Does this hold true for the Bosch green tops (42#)as well? I know that the stock setup runs about 39 psi. This entire engine project has been a case of the "Oh hell yea!!" syndrome. I was going to rebuild a stock setup, but then I was talking to a friend of mine who does head work, and it escalated from there. Here is where I am at...
fully ported/polished heads, larger chevy valves, 3 angle
ported lower/upper intake
.500 lift cam regrind
1.73 roller rockers
custom pushrods
73mm mass air
70mm tb
42# injectors
255 pump
10% pulley
raised top
modifed mac headers
custom exhaust: 2.5 - 3 - 2.5
arp head studs
bhj balancer

This is a case of one thing leading to another, without knowing exactly how smooth this thing will run in the end.

for this setup to run properly, am I going to need to have an adjustable fuel regulator, or a custom chip with stock fuel regulator? Are there any other potential problems that I need to be aware of?

Thanks for the help.....John
 
Do a search on the topic. But here is my two cents... It might run fine, still to make sure you are safe on the A/F ratio a trip to the dyno would be required. Or a really cool Wideband O2 Sensor ($350-$500).

After a trip to the dyno you could get a custom chip burned for best performance. With a chip you really don't need an adjustable Fuel Pressure Regulator. I have the Kirban adjustable Fuel pressure regulator but from what I read on here its just a matter of time before it fails...... The long time SC owners probably would reccomend just using the stock regulator with a custom burned chip or EEC tuner to get the A/F optimal for you mods.

So are you upgrading your intercooler too? It looks like that Intercooler would be the bottleneck in your performance gains.
 
Set it at 40 psi and dyno it there. You probably will need a chip, but more because of the cam than the larger injectors.

I haven't seen an adjustable regulator that holds up very long (except a universal remote mount) and after failing 3 adjustables I went back to a stock regulator. I had a Holley and two Aeromotives.

David
 
It'll run fine, but get it to a dyno and verify AF ratio. It will run better and make more power with some sort of tuning. My recommendation on that is biased. ;)
 
wezar said:
Do a search on the topic. But here is my two cents... It might run fine, still to make sure you are safe on the A/F ratio a trip to the dyno would be required. Or a really cool Wideband O2 Sensor ($350-$500).

After a trip to the dyno you could get a custom chip burned for best performance. With a chip you really don't need an adjustable Fuel Pressure Regulator. I have the Kirban adjustable Fuel pressure regulator but from what I read on here its just a matter of time before it fails...... The long time SC owners probably would reccomend just using the stock regulator with a custom burned chip or EEC tuner to get the A/F optimal for you mods.

So are you upgrading your intercooler too? It looks like that Intercooler would be the bottleneck in your performance gains.

I did a search on the topic and it seemed that all of the higher pressure discussion stemmed from running the Lucas injectors. I was not sure about the Bosch. I have also heard bad things about the kirban. I read somewhere that by modifying a motorcraft # EOSY-9C968-A regulator (tapping a 1/8" npt port and inserting a barb, then plugging the hole in the top adj screw) this will result in a leak free alternative.

I have not given the aftermarket intercooler much thought (pretty expensive)...I guess I can upgrade at a later date with no problems. I am using header wrap (primaries only) to try to cut down on the heat coming off of the header and being absorbed by the aluminum tube. I do not know how much this will help, but I feel there is some counteracting effects that can be helped without re-routing the tube. There is some controversy on the header wrap, but I was very careful to not overlap the wrap more than 1/8". I then sprayed it down with VHT. I will let you know how it works out.

John
 
ya set your pressure to 39psi for bosch style injectors. I have lucas injectors and they are rated at 42lbs at 43psi. They seem to run their best at 43psi, so thats where i leave them. But your bosch style is ment to run at 39psi static.
 
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