Engine Need Some Serious Help Guys!! Dyno Results Are Pathetic!

Discussion in '1994 - 1995 Specific Tech' started by N8sGT, May 6, 2012.


  1. N8sGT

    N8sGT New Member

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    Just got done rebuilding my '94 GT. Car had only 89k miles and ran great! These are the mods I put on the car in total. We had a nice car show at my work with a FREE dyno. I figured I should be around 300hp with the mods I put on the car.... Not even close, something is WAY off. I know the dyno is working perfect so no mistakes there. My car dyno'ed at a whopping 176 rwh and 278 ft tq. Looking at the graphs (which i didn't get a print out) the car pulled strong until 4000 rpms and fell on its face after that. I mean the graph showed a complete nose drive after 4000. I don't even think i can keep up with my wifes lexus SUV. LOL. I am noticing the car runs rough and pops when cold and it does it sometimes when the engine is warmed up. I adjusted the rockers and valves this way. Zero lash while twisting the push rod then tightened the rocker 1/2 turn and then tightened locking screw. Car is set as 12 degrees advanced, rockers are riding on the valve tips perfect, there is some noise still coming from the rockers from both banks (was told that is sometimes normal for larger roller rockers), Car idles and sounds great. Vacuum is at 18", compression is between 135-150 between all 8 cylinders. Very very minimal leak down in a couple of cylinders. I was told that the stock injectors SHOULD be able to handle this setup just fine. Reading other forums i was told that the MAF from the '94-95 GT and Cobras are the same and that the ecu has the tune for the 24# injectors not the MAF. Honestly guys i'm lost as to what to do next. I know my way around an engine but I'm mostly used to old school carb engines. Really any help would GREATLY be appreciated! Here are the list of mods i have done to the car. PLEASE someone help me figure out what went wrong with this build. I have all complete pics of the engine tear down and rebuild.

    '94 stock block with stock pistons,rings and lifters.
    stock 19# injectors and MAF with stock computer (NO TUNE)
    new crank and all new bearings and high pressure oil pump
    B303 cam (cam was degreed to spec)
    Ford Motor sports double roller timing chain
    Avenger Aluminum Heads (CNC ported and polished, 2.08 in 1.6 ex, 1.72 rollor rockers with 6.4" holly push rods and using AutoLight 3910 plugs)
    '93 Cobra intake with lower intake ported and polished, 1" trick flow spacer to clear valve covers.
    Trick Flow 70mm elbow with EGR delete
    BBK 70mm throttle body
    Cold Air intake.
    MSD coil, 9mm ford racing wires,
    New Distributor,new cap and rotor.
    smog pump removed,egr removed
    4:10 gears
    2 1/2 inch ex. no cats and H pipe into 40 series flows.

    I do understand that 24# injectors will help and that a tune will help as well. But I can't see them adding the 100+ HP that this engine should be making.

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  2. revhead347

    revhead347 I have face herpes.

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    Those heads are a total mismatch to everything else there. The intake valves are way too big. If it falls flat at 4000 rpms, that usually means it's blowing out the spark. How big of an ignition coil are you running, and what is the plug gap set too.

    Bottom line is that you are going to need a bigger intake and cam to feed those heads. No doubt a chip of some kind too.

    Kurt
     
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  3. N8sGT

    N8sGT New Member

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    Its the MSD street fire coil, I'm pretty sure the plug gap set to 35.
     
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  4. revhead347

    revhead347 I have face herpes.

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    Give us some back ground on how you ended up with that combination. I'd say get a chip burned, but I think with those heads you'd be ****ing into the wind. I'd try and get a different set of heads. You just don't have the valve clearance to make those work properly. I can tell just from the pictures that someone has gone ape with the port work. I wouldn't be surprised if those heads aren't flowing 315ish/215ish at .600". That's where I would start. I have no idea what an Autolite 3910 is suposed to be for. With those heads, you should be running a 3924 or a 3923.

    Kurt
     
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  5. N8sGT

    N8sGT New Member

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    I thought the heads would be to big but i would go with a charger later down the road, I didn't expect to have such a loss in HP in the mean time. I bought the heads from a guy who had them on a 408w. I figured bigger was better, but I'm guessing bigger in this case isn't better. I do have a set of GT40 iron heads that i bought and can bolt them up later in the week. I have some of the specs of the heads
    Avenger Cylinder Heads/Ford Performance Solutions.
    215cc intake runners.
    Have 2.08/1.60 Manley Stainless Steel.
    64cc chambers.
    Springs are set up for .700 lift.
    with 7/16th guide plates , screw in studs, and 1.72 roller rockers.

    I was told the autolight 3910 plugs were the main plugs guy are running with the aluminum heads.
     
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  6. N8sGT

    N8sGT New Member

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    I also have a new set of blue top 24# injectors, I had read that the '94-95 GT and the Cobras use the same MAF and that the ecu has the program for the injector size. Is this tru? If so has anyone bought a cobra ecu and used it on the GT?
     
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  7. 94blackcobra

    94blackcobra Member

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    The Cobra's EEC is programmed for the 24's. No matter what, you are going to need a custom tune at this point. Swap out those heads and get a tune.
     
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  8. revhead347

    revhead347 I have face herpes.

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    Your logic is correct on the Cobra computer, but I'm not absolutely positive on that one. the GT40 heads would work ok, but I'm not a huge fan of iron heads. Depends on what you want to do with them. The good news is those Avenger heads are worth a good bit of money. They aren't particularly better than any of the other big heads available today, but they don't make them anymore. That head used to be the cat's meow back in the day, and people pay big money for them. You could easily sell those and get a set of TF 170s or AFR 165s.

    Kurt
     
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  9. 95Vert383AOD

    95Vert383AOD Active Member

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    I had the same problem with my 383. I made about 285hp @4200rpm & 500Tq @ 2500 and the car kept crapping at 4000RPM. First off if you swap a MAF Ive noticed that the 94/95's Maf is closer to the 96+ maf than it is the 87-93 fox maf. So i went with an SCT. It was night and day difference. Also theres a big difference between the auto computer and the manual one. (manual computer worked better for me) Another issue is you need an adjustable fuel pressure regulator. Get a gauge on the rails and see how much pressure you have there at WOT. Also leave your timing at the factory spec. which i believe is 10-12deg.

    Also do you have a tuner chip or programmer?
     
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  10. Venom351R

    Founding Member

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    Yeah those heads are deff your issue. Hell I dont even have intake valves that big on my hogged out and ported trickflow heads on my 351 and to put a head like that on your 302 its going to be taking steps backwards. Sell those bad boys and get a head better suited for that combo and that will still give you room to grow and it will wake that car up immensely
     
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  11. N8sGT

    N8sGT New Member

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    I'm taking the heads off this week and putting the gt40 ones on. I'll prob switch over the 1.72 rockers on the gt40 heads also. As far as the heads i'll probably put them on Craigs List and sell them on there. I do have a guy that has a fuel rail with an adjustable reg. and fuel pressure gauge already on. Its a shame on the heads as they are pretty BadA** but i don't seem to have enough engine for them. I won't mind trading down for a set of AFR's or TF's either.
     
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  12. N8sGT

    N8sGT New Member

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    Forgot this on the heads also if it matters. They flow 315@.700 and 238 on exhaust.
     
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  13. Venom351R

    Founding Member

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    Throw them on corral.net if you want them gone quick if craigs list does not work out. Mine flow 334/236 at .700 but I also have a custom cam and a Victor 5.8 intake and more cubes so to throw a head like yours on your 302 is asking a lot.
     
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  14. revhead347

    revhead347 I have face herpes.

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    Yeah, you pretty much have to have a 4 bolt main block to spin up to 7500rpms to get the engine to suck enough air through a head like that. Those are awesome flow numbers. They ought to sell pretty quickly.

    Kurt
     
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  15. N8sGT

    N8sGT New Member

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    Just posted them on Corral.net. Only take me an a couple hours to remove them and clean them up. Asking $1,200 free shipping.
     
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  16. revhead347

    revhead347 I have face herpes.

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    I think you could even do better than that.

    Kurt
     
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  17. N8sGT

    N8sGT New Member

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    Yea I probably could Kurt, but I'm really just looking to get rid of them fairly quickly. The buyer is deff. gonna end up with a set of killer heads!
     
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  18. revhead347

    revhead347 I have face herpes.

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    With my history of selling used parts I'd be lucky to get $50.

    Kurt
     
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  19. Venom351R

    Founding Member

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    Ive always had good luck selling stuff just not good luck finding stuff at a deal. Throw up a link to your thread on the corral, I cant find it.
     
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  20. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor
    Admin Dude

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    ... or that valves are floating.
     
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