PDA

View Full Version : 5.8 ford efi/cobra performance mods



rastadr
12-17-2006, 10:16 PM
are there any easy bolt on true hp mods out there, short of heads? please let me know. and if so, can the cobra gearcase handle it..

turbo2256
12-18-2006, 08:21 AM
I can port a set of E7 heads and pull 400+ HP out of a 302 at 6000 RPM in a FI car. Cost to up grade the FI to do it properly around 4000.00. You need bigger fuel lines bigger, fuel pump, bigger fuel rails, adjustable pressure regulator, aftermarket or reprogramed ECU, bigger throttle body the list goes on.

For most swapping to a carb is best. Your heads ported sticking with your cam. A 650 carb and a Vr Jr intake or Torker II would net you around 400 to 450 HP with gobs of low end peak HP around 5600 to 5800 in a 351. Cost for head work as low as 550.00, marine carb 500, intake 200 something, Fuel lines pump and fittings around 400.

Guy B
12-18-2006, 10:06 AM
I just built one of these. Did it as an EFI motor first. Built it with a 393 stoker, Comp Cam all roller, World Products AL heads, 10.5/1 CR. Had complete data logging and software control. As the motor it is a speed density EFI set up I was just unable to get an idle that I was happy with. Needed some software mod for better idle control that was not that easy to get to.
Anyway with that set up the motor would run my 18 at 64 MPH. The cam profile was not long and I wanted a motor that would pull right up to 5500 RPM. Cam was 224in and 230ex at 50. Also did not like the idea of 2 bank injection and that it may not work as good as the old carb. Did figure out how to install an Innovate wide band O2 system so I could tune this hole mess up.
Well I took the motor out and put in a cam with 230in and 236ex at 50. Installed a Torker II manifold with 1 inch spacer and a complete MSD set up. Put a Barry Grant 650 CFM carb on it. Just started bebug and have run 66 MPH so far. That's about 5200 rpm, but don't have the data logger so just working from the dash and GPS now. Have some issue at this rpm but have not had time to work it out at this point. Goal is 70 mph.
IMHO don't do much to your stock motor or you will get into ECM problems. The speed density system cannot change it's setting that run the motor like a MAF system can. A small change to anything could move you the wrong direction.
As noted on this thread a few weeks ago, it's big money for each one of the MPH. My stock set up ran 60 mph and the motor ran like a Swiss watch. I have done the $1k per mph and now have the fun of dealing with a boat with a carb again.
If I can help you with anything please let me know. Not alot of us Ford boy's around. We did get the boat right - Go Donzi

MOP
12-18-2006, 12:57 PM
You fellas need to ask "Pretty Please" of Mario for some inside info, his 18 with maybe 305ci runs "a guess 67-68! Mine GPS's at 65.5 he just slides by me.

Phil

turbo2256
12-18-2006, 03:45 PM
I just built one of these. Did it as an EFI motor first. Built it with a 393 stoker, Comp Cam all roller, World Products AL heads, 10.5/1 CR. Had complete data logging and software control. As the motor it is a speed density EFI set up I was just unable to get an idle that I was happy with. Needed some software mod for better idle control that was not that easy to get to.
Anyway with that set up the motor would run my 18 at 64 MPH. The cam profile was not long and I wanted a motor that would pull right up to 5500 RPM. Cam was 224in and 230ex at 50. Also did not like the idea of 2 bank injection and that it may not work as good as the old carb. Did figure out how to install an Innovate wide band O2 system so I could tune this hole mess up.
Well I took the motor out and put in a cam with 230in and 236ex at 50. Installed a Torker II manifold with 1 inch spacer and a complete MSD set up. Put a Barry Grant 650 CFM carb on it. Just started bebug and have run 66 MPH so far. That's about 5200 rpm, but don't have the data logger so just working from the dash and GPS now. Have some issue at this rpm but have not had time to work it out at this point. Goal is 70 mph.
IMHO don't do much to your stock motor or you will get into ECM problems. The speed density system cannot change it's setting that run the motor like a MAF system can. A small change to anything could move you the wrong direction.
As noted on this thread a few weeks ago, it's big money for each one of the MPH. My stock set up ran 60 mph and the motor ran like a Swiss watch. I have done the $1k per mph and now have the fun of dealing with a boat with a carb again.
If I can help you with anything please let me know. Not alot of us Ford boy's around. We did get the boat right - Go Donzi



Most speed denity systems dont like anything under 17 inches of vacuum at idle. They dont like hot cams. They do respond well to increased air flow.

My guess with your current set up Brodex street heat heads or track 1s would have been a better choice. How many CCs are your heads?

How big is your fuel pump, fuel lines? You might be better with a 750 carb .650 is a bit small for a stroker. Good bet your running lean at top end if you havent upgraded your fuel supply system. Should have 3/4 inch lines from the tank to the pump. at least 1/2 inch to the carb and min of 3/8 inch to each end of the carb.

rastadr
12-18-2006, 08:13 PM
well this thing is definately stock and when i took it for a ride before buying it i brought my hand held gps and it was at 62.5 and it felt like it needed more trim but i wasnt driving it. if i was going to port heads and go with a carb/manifold/msd id be crying if i didnt get more than 70 out of it. im gona meet with poodle and play with props, then send the best one out to tweak it. ill be super happy with 65 all day long at 4600. i did get the set of original manuals from ebay and the plugs it calls for are outdated. i went with ngk's as that is what was in it and they looked great. where do i buy a new water pump and impeller for the outdrive? ill post pics next weekend but the boat i bought was the white one with black stripe on ebay. the joker who was selling it said it was a fresh water boat with 20 hours on a new motor. funny, after i ran the fl #s and called the original owner she laughed and said it was never in fresh water its entire life and only the exh and risers/ oil pan were new. its in my garage and im enjoying the hell out of cleaning it. getting the oil out of the pan with my ten dollar sears motor driven pump was a pain. there has got to be a better way. looking foward learning from you guys and sharing pics of my beautiful new toy. rastadr

sweet 16 1966
12-18-2006, 09:06 PM
My motor is stock and cheap. I like its dependbility though. I can hold it at 4800-5000 for some time and it does fine. I have wanted to build another 302 with some HP. FI is too expensive though. Sounds like
lots of knowledge here. Currently a 79 302 torker and 600 holley only.

turbo2256
12-18-2006, 10:40 PM
Wouldnt a 3/4" fuel line feeding off of a 3/8" pickup be a waste??

Yea it would if thats all the bigger the tank pick up is. Of course bigger lines would be like having a larger fuel bowl. Just wouldnt run lean as fast.

Guy B
12-19-2006, 10:27 AM
Yes, I think I will be looking at the fuel pretty soon. Just need to make sure the MSD rev limiter is not coming into play. Not much time for boat testing this time of year.

Flow tested the present set up and it looked ok for 450 Hp ( based on a BSFC of .5). Have found that the Barry Grant carb is very sensitive to float level, so if the pressure drop is large this could be an issue. Also see a hit to the A/R from 12.7 to 13.1 and back. That looks like a sure sign to me. Just have to take the easy shot's first.

Thanks for everyones idea's. I think everything is coming along fine. I will be back for help with the prop. Thats an art that I sure don't understand!

Guy

BigGrizzly
12-19-2006, 06:44 PM
I have 690+ hp and a big block with a blower and I use aq 1/2 inch from the tank and my releaf valve is always going. There is no way that that small an engine can use that much fuel at 7000rpms let alone 5500rpms, unless you have a hole in the float bowl the size of a dime. Our 1100hp motors don't use that much fuel. You won't be able to use speed density or mass air without O2 that don't get wet! I would go with a carb on that motor but it is your let us know the out come I'm sure someone wants to do the same thing