Murf SuperShark - Supercharged US-Spec 1981 completed - fun way to spend a weekend.
#61
Three Wheelin'
Join Date: Mar 2006
Location: San Diego / Las Vegas
Posts: 1,813
Likes: 0
Received 0 Likes
on
0 Posts
ya, don't tune down the fuel, turn UP the boost
those really are great #s for an 81tho, seeing as tho there isn't much 'modifications' out there for them! Im anxious to see the 10psi results!
those really are great #s for an 81tho, seeing as tho there isn't much 'modifications' out there for them! Im anxious to see the 10psi results!
#62
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
It's going to be a while since July is a very busy month for me. No more car wrenching (knock on wood.....) just a lot of driving and trips to Road America.
10psi with proper air / fuel and SS manfolds should exceed 350rwhp.
With 2:73 rear end 5-speed - this damn thing is a tire shredder
10psi with proper air / fuel and SS manfolds should exceed 350rwhp.
With 2:73 rear end 5-speed - this damn thing is a tire shredder
#63
Inventor
Rennlist Member
Rennlist Member
Git 'er dun!
#67
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
Originally Posted by toofast928
I the believe 4.5L is capable of 400 HP.
#68
Captain Obvious
Super User
Super User
impressive number!
Sounds like you running an FMU to controll fuel under boost. To bring the final pressure down you can switch out the spring and the diaphram for a smaller ration. This should bring down the fuel pressure under boost. Going with higher boost and having the FMU with the exisitng ration will make the problem even worst.
Sounds like you running an FMU to controll fuel under boost. To bring the final pressure down you can switch out the spring and the diaphram for a smaller ration. This should bring down the fuel pressure under boost. Going with higher boost and having the FMU with the exisitng ration will make the problem even worst.
#70
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
We know how to dial in better air / fuel - This is the Corky Bell unit which is easier to adjust than the standard Vortech units (no need to swap out any disks). If we turned town the unit for less fuel up top, it was too lean down below. There are a few different ways to adjust this unit - it was getting late so we "settled" for what I posted here.
We set it at the happiest setting for overall driving. Sure I could have cranked out an even more impressive top end number playing with the timing and top end fuel pressure (or the old dry ice on the intercooler trick). It wouldn't have been realistic.
We set it at the happiest setting for overall driving. Sure I could have cranked out an even more impressive top end number playing with the timing and top end fuel pressure (or the old dry ice on the intercooler trick). It wouldn't have been realistic.
#71
Addict
Rennlist Member
Rennlist Member
Nice Numbers!
With the 2:73's that car must be a blast to drive.Might want to use a different ratio boost:fuel disc in the SFMU (if that is what you guys are using)-but you guys already know that.
Jim
With the 2:73's that car must be a blast to drive.Might want to use a different ratio boost:fuel disc in the SFMU (if that is what you guys are using)-but you guys already know that.
Jim
#72
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
Originally Posted by Jim R.
With the 2:73's that car must be a blast to drive.
Originally Posted by Jim R.
Might want to use a different ratio boost:fuel disc in the SFMU (if that is what you guys are using)-but you guys already know that.
So now that I know everything is 100% good to go, I can go back, rethink the setup, go from there. I might try putting the vortech unit back in.
So this is not a SFMU like Tim has on his 88 - it's the sliver space ship looking FMU made by Corky Bell. They pretty much do the same thing, I think.
#73
Rennlist Member
Nice numbers Hacker !!
Bet the manifolds alone will help significantly to let 'er breeeaaath.
Gotta imagine that thing is rediculous when you shift --> 321.7 rwtq @ 3,915rpm, with 2:73 rear... 2nd gears done, clutch to 3rd a-n-n-d neckbrace please !! That's a serious E-ticket ride !!!
Bet the manifolds alone will help significantly to let 'er breeeaaath.
Gotta imagine that thing is rediculous when you shift --> 321.7 rwtq @ 3,915rpm, with 2:73 rear... 2nd gears done, clutch to 3rd a-n-n-d neckbrace please !! That's a serious E-ticket ride !!!
#74
hacker - think clearly now - Rick can ship you steel MSDS 2V headers for 425-450 - he discounts them for me the last two times.
#75
Race Car
I have a spare one of those "spaceship" FMUs..uninstalled, intended for boost referenced applications. Cartech/Begi. Email if interested, retailed around $250 I think.