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    Ford 4ltr Turbo

    hello all, i have an issue with a 4 ltr ford EB engine , it has a gt35/82 turbo 3 inch exh, 450x300x76 iC , link ecu, 218@50 cam 112LC . after making a few changes which i though were for the better it, revs up very well to 4000rpm then hits a brick wall so to speak it doesn't die just build revs at a dramatically slower rate after 4000 , It has good AFR timing is good , changes i have made since last time when it used to be fantastic,, went from 212@50 cam to a 218 running 125 LBs seat pressures before it had about 100, changed from a water to air intercooler , to air-air and also added a HV oil pump as i had engine out. My question would relate to the IC im getting 2.2 psi drop from comp cover to centre of inlet manifold , not ideal but not the worst i have seen, or would a HV oil pump cause such drag on the engine but the brick wall it hits is very defined any help would be great .

    Dean

    Thanks

    #2
    What does your ignition curve look like from 4000rpm onwards? You say it is fine but have you confirmed that nothing has changed?
    Boost curve is the same?


    Last edited by Greasystick; 12-10-21, 08:54 AM.

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      #3
      Hows the cat look?

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        #4
        holds 12psi boost and timing is at 15 degrees i will do another log on weekend to double check as i havnt driven it in a while as it was driving me crazy . AFR at 11.2 , when i log it nothing obvious changes. i will inspect cat and i might even make up a pipe to by pass IC
        Last edited by Kassan1973; 12-10-21, 10:39 AM.

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          #5
          Cat. (remove it)
          Valve springs? I had an issue with valve springs once and a new set of doubles fixed it.

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            #6
            Originally posted by ed40 View Post
            Cat. (remove it)
            Valve springs? I had an issue with valve springs once and a new set of doubles fixed it.
            i will inspect cat all this has happened suddenly but you never know i guess, engine previously had 95lb singles seat springs and was perfect never missed a beat now in running 125 doubles 7333 i would have thought it wouldnt be an issue, thnaks for all the suggestions ill try one thing at a time and post my findings
            Cheers

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              #7
              Exhaust restriction, intake restriction, cam phasing, assuming timing is ok. Although stable AFRs, assuming the link is MAP tune might suggest otherwise. What does the fuel map look like?

              It is manifold air pressure based tune or mass flow sensor? Unless you are doing some weird turbine engine stuff with very slightly too tight valve clearance which only bypasses at higher revs as heat load increases you would expect it to go rich on MAP tune with a flow restriction if it has started suddenly.

              what triggering arrangement has it got? Is it dizzy, wasted spark or sequential?

              Plug gaps? What coil(s)?

              Just to be clear, has if ever pulled hard to redline with the new cam or this is first pulls with the cam? (Would point to cam phasing or valve clearance)
              Last edited by Slides; 12-10-21, 07:46 PM.

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                #8
                cam is 1 degree advanced, triggered by a dual pick up hall dizzy although did the same when using EF crank trigger and cam sensor as i have a ef crank and timing cover on it ! , cam is hydraulic, sequential injection multi coil LS1 x6, plug gap 22 it doesnt missfire at all , if i nail it in first gear and let it break traction it will go to 6200 but as soon as you hit second and revs drop any where near 4000-4200 it just feels dead. i will go over tune in ecu to make sure i haven't missed anything .

                This week i will delete intercooler and exhaust to rule them out , and go from there thnaks for the suggestions start with the basics i guess.
                Cheers
                Last edited by Kassan1973; 12-10-21, 09:23 PM.

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                  #9
                  How different is the new cam in terms of valve overlap? Only 6 degrees different in duration but if the overlap is too big it could be blowing your boost straight out the open exhaust valve. Wheelspin in 1st gear would hide the rate of acceleration you are feeling because of the lack of load allowing the engine to essentially free rev
                  Last edited by F3ARED; 13-10-21, 06:44 PM.
                  1978 Gemini Sedan - Powered by i change my mind every week - R.I.P
                  1980 Gemini Sedan
                  1987 Range Rover Vogue
                  1996 TF Holden Rodeo

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                    #10
                    From the information presented, one would have to direct most suspicion at the camshaft.
                    " Racing cars don't have doors. Toilets have doors" : Keke Rosberg

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                      #11
                      Is the timing locked at 15deg?
                      2017 Ford Ranger XLT (Jeep Wrangler recovery vehicle)
                      2007 KTM 250 SX

                      Originally posted by Monza
                      I've never considered myself the type of guy to eat arse but I am currently reviewing that policy

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                        #12
                        Originally posted by F3ARED View Post
                        How different is the new cam in terms of valve overlap? Only 6 degrees different in duration but if the overlap is too big it could be blowing your boost straight out the open exhaust valve. Wheelspin in 1st gear would hide the rate of acceleration you are feeling because of the lack of load allowing the engine to essentially free rev
                        Yes makes sence old cm was a 114LC new one is 112LC i have had another one made same specs as old one i never thought of it that way to be honest , Cheers again

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                          #13
                          Originally posted by Greg Rust View Post
                          Is the timing locked at 15deg?
                          NO not locked looking at logs ecu isnt doing anything wierd but i can try locking it at 15 to try . i will do that before anything else as its quite easy .

                          Cheers

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                            #14
                            I wasn’t advocating that you try that, I just couldn’t see in any comments what the ignition curve was.
                            2017 Ford Ranger XLT (Jeep Wrangler recovery vehicle)
                            2007 KTM 250 SX

                            Originally posted by Monza
                            I've never considered myself the type of guy to eat arse but I am currently reviewing that policy

                            Comment


                              #15
                              Originally posted by Greg Rust View Post
                              I wasn’t advocating that you try that, I just couldn’t see in any comments what the ignition curve was.
                              All good thanks yes its a mapped curve just high lighted timing at that point, Cheers Dean

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