rebuilt motor MAF / fuel requirements

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
Preparing to install newly rebuilt engine in 99 Cobra few questions on supporting items that I may still need. This is going into an NA open track road race car designed for 20-45+ min sessions

03 marauder block
04 Mach 1 crank
03 Cobra Rods
JE Pistons forged
GT 500 oil pump with boundary forged gears
03 Marauder heads, 5 angle valve job with mild port and polish (west side performance in Houston)
98 Cobra intake cams, stock exhaust timing set to 110/114 with adjustable gears
ported stock length lower intake with a spacer
ported stock 03 throttle body
bassani mid length headers with cat less xpipe and 2.5" cat back
10.5 : 1 compression

with this set up I expect to shift at 6Kish and have a fairly broad power band suitable for road coarse use. Based on reading other similar combinations I expect this to 370 rwhp ish. Hopefully higher but goal is for a broad power band to power through and out of corners not peak #. I tried to stay with factory items for durability.

Who still ports lower intake manifolds?
I saw that stiegmeier list lower porting on his site but didn't find anyone actually using his lowers during searching.

Will this combo peg my stock MAF?
I'm fairly certain this will peg my stock 24lb injectors.

Will my stock fuel pump keep up? (couldn't find a definitive answer on this through searching)

thanks in advance
 

black4vcobra

Well-Known Member
Established Member
Premium Member
Party Liquor Posse
Joined
Feb 22, 2009
Messages
4,460
Location
Cottage Grove, WI
I'd lean on the side of being safer than sorry so I'd pickup a lightning MAF, Focus pump and 39 lb injectors.

Not sure who still ports the lowers but @na svt would know.
 
Last edited:

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
thanks for the replies.
Will an 03 MAF work? it should also be a draw through type MAF...
If yes, I can harvest the injectors and MAF off my 03 to up grade those at same time.
any thoughts on 99 fuel pump potential?
 

Brutal Metal

Well-Known Member
Established Member
Joined
Feb 2, 2009
Messages
10,571
Location
Largo Florida
An SVT Focus pump is a drop in replacement, that and 39's will be plenty. Your 03 MAF would be the most cost effective but you'll need to tune for it.
 

99COBRA2881

Piss on Fox Sports1
Established Member
Joined
Oct 10, 2003
Messages
6,307
Location
Kansas
I have a similar setup on my AI race car. With an FR500 intake with the butterflies removed my car put down 389/326 iirc.

I also use 90mm L maf, 39s and a focus pump. Have your tuner pay attention to fuel pressure from wot to off throttle, that’s not the correct term but you will kill the diaphragm in the FRPS from the pressure spike.

Best bet is to go return style fuel system and eliminate the FRPS it’s given me a lot of problems on track with an off throttle to full throttle hesitation.
 

black4vcobra

Well-Known Member
Established Member
Premium Member
Party Liquor Posse
Joined
Feb 22, 2009
Messages
4,460
Location
Cottage Grove, WI
I have a similar setup on my AI race car. With an FR500 intake with the butterflies removed my car put down 389/326 iirc.

I also use 90mm L maf, 39s and a focus pump. Have your tuner pay attention to fuel pressure from wot to off throttle, that’s not the correct term but you will kill the diaphragm in the FRPS from the pressure spike.

Best bet is to go return style fuel system and eliminate the FRPS it’s given me a lot of problems on track with an off throttle to full throttle hesitation.

Have you ever heard of this? My tuner recommended it when I installed my Vortech and a FGT/BAP fuel pump - https://www.ebay.com/itm/KENNE-BELL...T-FUEL-RAIL-PRESSURE-DISC-2V-4V-/391561579393
 

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
thanks for the replies, sounds like a new fuel pump will be needed. Is the SVT Focus pump a play?

Regarding the '03 MAF, would I be able to "tune it enough" with an SCT4 to get it to my tuner?

Regarding the FRPS, did 03-04's have these as well?
I have tracked my 03 dozens of times with no issues. I'm assuming that higher strength disc will solve this
 

99COBRA2881

Piss on Fox Sports1
Established Member
Joined
Oct 10, 2003
Messages
6,307
Location
Kansas
I have the kenne bell washer installed it helps but doesn’t solve the issue.

The focus pump is plug and play.
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,126
Location
Cali
Your tuner should be able to send you a start up tune for that MAF and injectors.

The fuel pressure can be tuned so it doesn't blow the FRPS. There's three values that need to be adjusted.

Misspelling brought to you by Tapatalk
 

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
Thanks for all the replies. Good idea about the start up tune.


Sent from my iPhone using svtperformance.com
 

32vApe

Not Fast Enough
Established Member
Joined
May 20, 2008
Messages
227
Location
Wisconsin
370whp is optimistic. More like 340. All the little stuff adds up though. Ported lower and a 90mm maf.
 

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
bringing this back up, in the midst of install now.
I just got an extra 03 cobra MAF housing (with out sensor) as part of deal with a local guy.
I know that the 03 maf is 90mm vs. 80mm on the non SC 4V's. is that the only difference?
Can I just plug my 99 MAF sensor into the 90 mm housing to extend its air flow potential via tune?
thanks
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,126
Location
Cali
You can put your 99 sensor into the 03 housing. The MAF transfer will need to be tweaked I'm sure. I couldn't tell you how much room it'll give you. But it could be worth a shot.
 

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
bring this back up again, this install is taking longer than expected...

I just dropped my 99 tank to swap in an 03 cobra tank with baffle.

I planned on using the 99 basket with aviator pump, but just realized the 03 tank has no means to attach a 99 style bottom mount fuel basket. (03-04 were hat mounted)

ideas on how to mount the 99 basket? I'd feel safer if it were firmly attached to something

thanks
 

Brutal Metal

Well-Known Member
Established Member
Joined
Feb 2, 2009
Messages
10,571
Location
Largo Florida
bring this back up again, this install is taking longer than expected...

I just dropped my 99 tank to swap in an 03 cobra tank with baffle.

I planned on using the 99 basket with aviator pump, but just realized the 03 tank has no means to attach a 99 style bottom mount fuel basket. (03-04 were hat mounted)

ideas on how to mount the 99 basket? I'd feel safer if it were firmly attached to something

thanks
Every person I know including myself went with either a 03/04 Cobra oem twin pump hat or aftermarket (Fore/Divison X) when switching to an 03/04 Cobra tank.
Why did you feel you needed to switch out the tank?
 

Dave.O

Active Member
Established Member
Joined
Apr 14, 2014
Messages
502
Location
Houston
for the baffling, this car will open tracked for long sessions, 40min or more.
I need to ensure no fuel starvation during high g corners or heavy braking when fuel is low.
03-04 twin pumps are over kill for my application and more difficult to install.
I am considering drilling the welds out the 99 tank to remove basket mount and epoxying that in 03 tank bottom... just wanted to see if someone else has done this mod yet
 

01yellercobra

AKA slo984now
Established Member
Joined
Oct 5, 2005
Messages
21,126
Location
Cali
Tons of people have tracked with the 99/01 tank with no issues. A friend of mine being one of them. The baffling in the 03/04 tank is for the twin pump set up. Keep it simple. Put the 99 tank back in.
 

Users who are viewing this thread



Top