i'll cut to the chase. i want to know how much boost i can run with my current setup.

415 cc/min injectors
S-FMU with the 2.72" disk and the hard spring (yeah, i know, it's the wrong disk. i need to put in a smaller one, but i don't know exactly what size...)
walbro in-tank
HRC "raped pig" inline
1g SMIC
fully built bottom end

i'm guessing 12-14 psi safely. i know i need to get a FMIC, i'll be doing that over the summer. then i think i need to get some type of ignition controller, then i can do lots more... i'll probably need to do the 8 injector setup around then too.

what do you guys think?

well i think that intercooler get unefficient aroun 15-17psi not positive though...

ignition is not of conern yet unless your tuning witha afc...

armond is running 18psi with no ignition control and likes it better considering his msd was the cause of the last rebuild...

the only thing your limited with is how u tune the car and your intercooler at this point so u should be able to do 14psi or so if tuned properly

8 injector setup would be a good route to go...

Bill

Can you explain why he had to rebuild? What happened with the MSD?

i thought that was Dave_FL, who had to rebuild his already fully built engine because he killed 3 pistons due to detonation. i think that he DIDN'T have a way of retarding timing and he was using an AFC... can't really remember exactly what happened, but i remember that he was pretty upset and was all like "if you want a fast car just buy a f'n corvette"

I think you can run 14psi easily. Im an avid believer in the 1G SMIC, and it should hold up around that boost. I think youre injectors are more than enough to handle 14psi. You might want to move onto an aftermarket SMIC or FMIC if you want to run more boost. Id think that youd want to get an SAFC in order to have better fuel control, im not sure if you really need any ignition mods when running 14psi. Are you running the 255lph walbro?

How much boost could the rebuilt bottom end take? I figure rebuilt 4g63's can take upwards of 20-30psi, can the 420As do that too?

It really all depends on how much money you waist on that bottom end.

With the Howell bottom end i believe that with good timing retart and good tuned maybe some 22 psi on race gas.

With the HRC they are doing i believe 25 -30 psi on race days. Of course will nice mods to back up stand alone and timing retard.

The HRC setup is really tight that is waht i wanaa go with but 9.0 compression instead of 8.8

laterz

>It really all depends on how much money you waist on that
>bottom end.
>
>With the Howell bottom end i believe that with good timing
>retart and good tuned maybe some 22 psi on race gas.
>
>With the HRC they are doing i believe 25 -30 psi on race days.
>Of course will nice mods to back up stand alone and timing
>retard.
>
>The HRC setup is really tight that is waht i wanaa go with but
>9.0 compression instead of 8.8
>
>laterz
Why would you say that howells bottom end could hold less than HRC's? Also why would it be a waste of money to rebuild the bottom end?

yeah, i have the walbro 255 in-tank. my goal is to not use the AFC at all, it's just there to correct things a little at low throttle and low rpm's. right now i'm using it for eliminating fuel cut in vacuum at low throttle because i'm so rich and haven't had a chance to find the smaller S-FMU disk.

Using 415's, you have plenty of fuel and pressure available to run quite a bit of boost. If i can push 12-13 psi on 310's, then the 415's you can boost to at least 17-18 psi. Upping the fuel pressure with the SFMU on the 415's, you should be able to boost much more than 14 psi.

Dave_FL did have to rebuild because of detonation. What caused it was likely the safc. As I recall, he was running fuel pressures around 40 psi with these injectors and using a lot of correction from the safc to reduce fuel flow. The problem with this is that the safc alters the MAP voltage to lean out the injectors. Well, the cars computer uses the MAP voltage to calculate other numbers such as engine load and ignition timing. What was happening was that the computer would think that the car was at partial throttle when it was actually in boost, so his timing was advanced around 25-30 degrees when it should have been around 15 degrees. This is the reason why I chose to go with the 8 injector setup (doesn't mess with the MAP sensor signal).

Please get rid of that as your sig pic.....that piston is just scaring me...

hahaha it's so good... i cleaned it off and now it's a nice paperweight on my desk!

i got one of those guys hanging out in my block! x(

Yea I have 5 of those hanging around too :)