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Converting to SVT from standard Zetec?

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  • Converting to SVT from standard Zetec?


    Who's gone down the road of converting from the standard to the SVT Zetec?

    I called Caterham USA a few years ago after they introduced the SVT engine kit, and they tried pretty hard to discourage me from doing the conversion myself. Can't recall what they said was tricky about it, but they emphasized that there were problems to be solved. They weren't willing to sell just the parts required because they were trying to recoup their investment through kit sales.

    It seems if I could get to 185-200hp on 91 octane fuel with Ford ECU, it would satisfy me and be pretty cost effective.

    I talked to Quicksilver and they want nearly $10K for a 220hp, 91 octane rebuild of my (non-SVT) Zetec, including $3K to convert to Pactel T2 and required sensors and software. That got me thinking maybe I wasn't aiming for the sweet spot... maybe I should set my sights on less.

    Thanks for any insight,


  • #2
    I did my own conversion from stock Zetec to SVT. If you can find a stock SVT with stock engine wiring harness I don't think the conversion is that difficult. Mechanically it bolts right in. I don't know how they get the stock intake to fit but I did not really try. You may need to offset the engine a bit which might mean different motor mounts. You'll have to adapt the engine harness to mate with the Caterham Chassis harness. The intake fit and the harness are the only issues I can think of.

    I did not use the SVT ECU or intake manifold. I actually started my conversion before Caterham USA was selling an SVT option.

    I've done things a bit different than they do.

    Jenvey Throttle bodies: I did not think the stock intake manifold would fit, Obviously Caterham USA figured out how to do it. Another reason was I wanted to get a cold air intake from outside the bonnet. The intake under the bonnet costs you 10-15 HP because of the hot air, ~+30آ؛ F over ambient. I checked this on a dyno. Intake track is shorter and you loose the variable length.

    Intake manifold: I did have to match it to the SVT ports which are much larger than non SVT. Again not hard but then I've been a machinist in a past life.

    Pectel T6 ECU (used ~$1500): I made my own wiring harness. Not easy but not too difficult if you can follow a schematic and crimp connectors. I used this because it will control the VCT. (The T2 may do this as well.) I still have not implemented it but use a VCT delete kit. Some gent on the Turbo Focus forum was selling them. Part of the reason was at the time it was difficult to find the cam map for the SVT to program the T6. The stock ECU has these problems solved but at the time the tools to reprogram the stock SVT ECU were not available and I wanted that flexability. I don't know if they are now but I think so. Pectel makes a great product as my 10 year old+ T6 has more capabilities than some of the newer competitors. Their support is virtually non existent. We aren't the market they are selling to so I sort of understand that.

    There are companies that will make the wiring harness for you, ~$1500. If you don't have the time, skill, cheapness, and stubbornness, pay the money.

    I'm getting about ~175 HP at the rear axles. Measured by a hub dyno so no wheel slip. See the first 'dyno day' for the results.

    If you compare the dyno results you'll see that I give up lower end torque for the peak HP. Compare mine to soareyes who has a stock non SVT intake. Part of this is the shorter intake track of the Jenveys, part is the VCT which I keep saying I'll get around to turning on and figure out the map. This may mean more dyno time. Peak HP is sort of just a bragging right as do you really run it at 7000 RPM all the time? I think the lower end torque would be more useful. On the other hand it's quite quick as it is.

    Given that they no longer make the SVT my advice if you really want more power, convert to the Duratec.

    A stock Duratec will give you almost as much power, probably better torque and an engine still in production that has everything you need to get to 260HP+. When I bought my car the Duratec was a truck motor with nothing available to install in a Caterham let alone get more power out of it. If you want the VCT, get the Mazda version that has it. Plus you loose another 20 to 40 lbs unless you dry sump it then you might break even weight wise.

    Magnus can tell you exactly what he bought for his conversion. The biggest expense is probably the headers unless you go the dry sump route.

    I've been happy with what I have as the power is not yet my limiting factor on turning faster lap times on the track.

    If I win the lottery or find some other big source of income I'd get the Hartly V8. 400 to 500 HP and less weight than the Duratec. Maybe detune it to 300 hp as the 280+ HP cars have reported breaking the chassis where the diff mounts.

    Send me a PM if you have questions.

    Last edited by Doug Liedblad; August 18, 2010, 05:17 AM.


    • #3
      What benefit is there to doing an SVT conversion Doug? My car is also making 175hp (205 crank) and it is a non SVT motor (as far as I know)

      The funny thing is my wife goes " What is that car a Morgan ? " and I said "No that's a Caterham but there is a Morgan driving it " -delise


      • #4
        For me it was the cheaper way to get close to 200HP. Otherwise you do head porting and cams at least.

        The SVT comes stock with larger intake ports,hotter cams, heavier valve springs, lighter pistons, forged connecting rods, and a higher redline.

        To take a stock Zetec and do those things was a lot more than what I spent for the engine and ECU.

        Did you ever post your dyno curve?




        • #5
          I see. I believe my Zetec was sold as part of the Caterhams superlight performance package and has the cams and other stuff, the PO did have the head milled a bit and added the throttle bodies.

          Yes, dyno curve was posted in the dyno thread


          The funny thing is my wife goes " What is that car a Morgan ? " and I said "No that's a Caterham but there is a Morgan driving it " -delise


          • #6
            The intake manifold is a tight fit on the standard chassis. The chassis is notched to allow the intake to clear the frame so an older chassis would have to be modified if using the stock intake. I have a template that came with my build guide for making the notch but my car is a 2006 and came notched from the factory. The wiring harness to mate the SVT to the chassis was made up by Caterham USA


            • #7
              My car has the notch as it was made for the stock Zetec intake manifold. I don't know if they made the notch larger for the SVT, probably not.

              You can do the wiring harness mods yourself. Not too difficult if you can read a pin out diagram.

              Be advised that my dentist tells me I have a high pain tolerance and this may apply to wiring harnesses too.

              Perhaps because the Zetec was replaced by the Duratec no one has really developed cams for it. In the focus they just tubo charge it.

              Caterham USA does sell a Kent cam for $1000, reported ~220 hp. You can get cams reground to your spec for less.

              Do we have enough SVTs for a group cam buy?


              • #8
                220 hp is a fantasy on an SVT, unless you go forced induction. I have the Kent cams, the mods, the dyno charts, and the bills to prove it! The SVT is a great motor and uses the factory ECU, reprogrammable now with a couple of aftermarket products (I used Diablosport). I am currently prototyping a cold air intake that does not require cutting the bonnet to remedy one of the 2 major shortcomings of the SVT set up, namely the intake location. The other major problem with the SVT package is that the Caterham exhaust is COMPLETELY wrong for the engine. The primaries are much too long, as well as too big. After the collector, the exhaust is way too small, all the way to the end. A stock SVT Focus exhaust uses 18" long 1-5/8" primaries, a 4-2-1 collector, and a 3" outlet. The net result is a hole in the torque curve around 3000 rpm, and who knows how much hp loss at higher rpms. One of these days, $$$ permitting, I will have a custom exhaust made for the car. As to the Kent cams, they are only of value IMO if the ECU's VCT values are reprogrammed. Kent makes absolutely no representations about theses cams, either. In fact, they would not even talk to me about the cams, other than to say that the specs were Caterham USA's, and they only ground them the way they were told. I do have a neat torque bubble on my power curve from 4000-6000 rpm that a stock SVT motor does not have. The stock SVT makes 170 hp/145 lbs-ft torque at the crank. My car makes 160 hp/148 lbs-ft at the wheels on a Dynojet dyno, and I have not seen a normally aspirated SVT dyno chart, in either a Focus or a Seven, that is any higher.

                I agree that the SVT is not a good candidate as an upgrade motor, as it has not been built since 2004, and new motors don't exist (in 2007 the only one I could find was $7000 with no harness and no ECU!).
                2013 Boss 302 Mustang
                2005 SV Roadsport (gone but not forgotten)


                • #9
                  I'd go Duratec.

                  Cosworth will sell you either a complete engine or the bits and pieces to build your own. Once you have the engine with intake, Caterham can sell you almost everything else (exhaust manifold, engine mounts, bell housing with oil tank, etc). I went my own route and clobbered together my own solution around a CSR260 specced engine.

                  252 hp at the crank.

                  I believe I paid about 13K for the engine, plus another few K for the various bits and pieces needed to get it in place. Money well spent (although my wife may disagree).

                  See for a build diary.

                  /Magnus F.


                  • #10
                    I saw this the other day and thought it might be of interest regarding Zetec engines. Check out the Roush - Yates Engines web site:
                    Standard new crate motor Zetecs (only 130 HP) are $1150.00 + freight:

                    A new Focus Midget engine is listed at $8995 list plus freight:

                    I wonder how much power the "midget" engines make? Check out the throttle bodies.

                    '62 Lotus Seven
                    '84 Turbo Esprit (x2)
                    '14 Evora
                    '77 Esprit S1 (RIP) :(

                    "A man must keep a little back shop where he can be himself without reserve. In solitude alone can he know true freedom." -Michel De Montaigne 1588


                    • #11
                      I saw a Focus midget engine on a Dyno a while back, the guy said about 180 HP.

                      Note that they run methanol.