harvey.searle Posted October 14, 2009 Share Posted October 14, 2009 *wavey*I bought a 1992 1700 x flow 4 speed supersprint 4 months ago. I would like to uprate it a bit and get a bit more poke, anyone got any ideas. Link to comment Share on other sites More sharing options...
Martin J Posted October 14, 2009 Share Posted October 14, 2009 Can't help you on that one but just saying welcome to your first day on Blat Chat Perhaps making sure the air filters are nice & clean would be a start! Martin Link to comment Share on other sites More sharing options...
jonboylaw Posted October 14, 2009 Share Posted October 14, 2009 Erm.. Zetec or Duratec? What budget? what spec do you have at the moment. What sort of power improvements are we talking here? For drivability and to keep costs down, maybe a megajolt 3D ignition will help improve the pickup and drivability. If you are looking for a big power increase then an Engine swap may be what you are looking for. Getting the head ported and cam upgraded then the likes of Burton or Vulcan can give you guidance. If you have an AX block (check the casting), then selling the engine maybe the best option (they are worth a fair bit) and using the cash to fund a new engine. Also worth considering is the Toyota 4AGE transplant. Jon Link to comment Share on other sites More sharing options...
Eugene Posted October 15, 2009 Share Posted October 15, 2009 Hi Harvey, welcome Herts, eh? Go have a chat with Chris at The 7 Workshop... He'll have loads of ideas, as will Dikko at the Herts area meetings. I originally had a 1700 crossflow (110BHP) and from there went to 135BHP (still the 1700 crossflow), and then to 165BHP with a Vegantune Twincam Head, but now have a Zetec with 5-speed conversion - much better 😬 Have a look at the images here. Small Boy - with Loud Toy! Co-founder of the BOG Club See Eugene here and see what I do here Link to comment Share on other sites More sharing options...
DohNut Posted October 15, 2009 Share Posted October 15, 2009 If you have a 4speed presumably you have a live axle which has its own power limitations - check the search function at the top of the page to look for more details. The Toyota may be a good engine, but very rarely used in Caterhams you would not for example be able to get an off the shelf exhaust for it as you can with the other engines mentioned. Link to comment Share on other sites More sharing options...
Eugene Posted October 15, 2009 Share Posted October 15, 2009 As posted elsewhere my Zetec still has an Ital live axle, but with an LSD - no problem with the power of thre Zetec - yet! Small Boy - with Loud Toy! Co-founder of the BOG Club See Eugene here and see what I do here Link to comment Share on other sites More sharing options...
Graham Sewell Posted October 15, 2009 Share Posted October 15, 2009 First thing tha I would do is get the car on a rolling road to see that you are getting the level of performance that should be standard (135bhp). If not, try to work out why. One of the most common issues is the dizzy that Caterham used does not have an optimal advance curve and this can be changed quite easily by sending the dizzy back to Aldon (assuming it is one of theirs) for a remap. Also, be quite fussy on valve clearances and ignition timing at idle - can make huge differences. Check the jets in the Webers. Caterham have always been slightly conservative on their choices. You can use Dave Andrews jetting program which is available from various sites on the web. Once this is done, and if you still need more power then look at an exchange head from Vulcan and possibly an uprated cam (Kent 244?). As others have said, for driveability, a 3D mapped ignition will help with mid range even if it does not give any more top-end power. Before you think about engine transplants, consider if it would be more cost effective to change the car as many people still like an original xflow car even if it is not the fastest car on the market any more. Cheers, Graham ------ Low tech luddite - xflow and proud! Link to comment Share on other sites More sharing options...
bstark Posted October 15, 2009 Share Posted October 15, 2009 Harvey, I have same spec as you, albeit tweaked around a bit to suit track and sprint use. The engine is still at 135bhp spec, though this seems plenty enough to scare passengers 😬. First thing I would do is take it to a xflow / 7 specialist who can check everything is setup correctly. Mine is very free-revving and pulls very strongly when everything has been properly set up. About to go the Megajolt route to widen the powerband further. Bob Stark Supersprinter Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted October 15, 2009 Area Representative Share Posted October 15, 2009 Hi Harvey Another name to add to your list of people who could help is Rob Morely at Ratrace/ProTune in Potters Bar. I too have a 1700 Supersprint (of 1996 vintage) and he breathes on it very nicely. The key thing is to decide what characteristics you are looking for... Democratic dissent is not disloyalty, it is a positive civic duty. Link to comment Share on other sites More sharing options...
OliverSedlacek Posted October 15, 2009 Share Posted October 15, 2009 The XFlow responds to all the old fashioned tuning methods. I've tried all of the following with success. 1. Head porting with bigger valves. The limit of valve size is reached when the bridge between the seats cracks. Bullet nosed valve guides also improve breathing. 2. Camshaft with more lift and duration. You need matching valve springs, machined seats and piston cutouts with some cams. 3. Forged pistons. These are much lighter than the cast pistons, and have an improved ring design. You will need them to get 1700cc or more in engine capacity. 4. Dry sump. The fact that the crank doesn't churn around in the oil increases power. 5. 3D mapped ignition. 6. Decent trumpets on the Webers. 7. Rolling road tuning. 8. Throttle bodies and injection. I haven't tried this myself, but it will give better breathing and fueling than Webers Link to comment Share on other sites More sharing options...
LesG Posted October 15, 2009 Share Posted October 15, 2009 I've just rebuilt my SS 1700, and with a rolling road set-up 3 weeks ago, my engine achieved 130bhp @ 5900rpm, with a max of 120lb/ft of torque. This is a freshly rebuilt engine, i.e., ZERO miles, and I told the operator to go easy. I've also converted to unleaded, and we just ran ordinary 95 ron fuel. The car is running the original 32mm chokes which could be swapped for bigger units, at the expense of low end torque. It was running fairly small jets, which we did swap. My plan is to run the engine in as it is now, then take it back to the rollers next year (when it's freed up a bit), and also fit the megajolt kit that's sitting on the shelf. Oliver; which trumpets do you recommend for the webers? Link to comment Share on other sites More sharing options...
millsn Posted October 17, 2009 Share Posted October 17, 2009 Check it does what it should, i.e. you can get lots of advance, it's jetted properly, carbs balanced etc. You may need different ignition (electronic) to get the right advance, I can't recall what that is, sorry. NB: unless it's been modified it'll not put out 135 brake at all that number is shall we say optimistic Add 3d ignition SPC long ratio first gearbox or similar The box is probably the biggest benefit, mappable ignition won't give you more power Other than that it's engine change time and or lose some weight somewhere / remove the screen for more speed. You might even find a tuned XF somewhere for less money than an engine swap if that's an issue? Link to comment Share on other sites More sharing options...
Terry Field Posted October 28, 2009 Share Posted October 28, 2009 I'm runnning a 1700XF built by Vulcan which returns 156 bhp at the wheels. This was a failry expensive rebuild, but I would suggest you give Steve at Vulcan Engineering a call (or drop in and see him in Ealing) and see what he recommends for the money / effort you want to spend. Terry 1700XF - Team Lotus with flares. Link to comment Share on other sites More sharing options...
cskip Posted October 28, 2009 Share Posted October 28, 2009 Terry are you sure? 156bhp at the wheels equates to 208bhp at the flywheel (presuming 25% tranmission loss). I thought 200bhp from a crossflow was uber expensive! 🥰 Skip. Link to comment Share on other sites More sharing options...
Graham Perry Posted October 28, 2009 Share Posted October 28, 2009 It is ☹️ I could have built two 210hp Duratecs with what mine has cost in the last 18 months Link to comment Share on other sites More sharing options...
OliverSedlacek Posted October 28, 2009 Share Posted October 28, 2009 Harvey, can you make it over to the Penn Sevens this Saturday? We could chat at length there. Link to comment Share on other sites More sharing options...
S47zz Posted October 28, 2009 Share Posted October 28, 2009 Easiest route is to bin the X flow and fit a modern Zetec in it's place, even a standard spec 2 litre with your existing webers or TB's and mapped ignition will give you 155-160BHP with total reliability. Oh and much better fuel economy Link to comment Share on other sites More sharing options...
Terry Field Posted November 5, 2009 Share Posted November 5, 2009 Skip Sorry about the delay but Yep 156 bhp, and I have the rolling road report to prove it. But it was very expensive compared to a Zetec conversion. Terry Link to comment Share on other sites More sharing options...
cskip Posted November 6, 2009 Share Posted November 6, 2009 Terry. I am interest in the spec. Can you Blatmail me a few details? Skip. Link to comment Share on other sites More sharing options...
guilleracing Posted November 6, 2009 Share Posted November 6, 2009 Had a chat recently with a fellow race engineer about the relative merits of the zetec engine against the crossflow. Neither of us has the desire to spend a fortune so that coloured the discussion somewhat. The engine is heavier and taller. That is the downside. Now for the up-sides A good low milage zetec can be found on e-bay for £250.00 or less. A standard 2 litre focus spec zetec, will make the same power as a very tuned crossflow. The difference is the Zetec will do 200,000 miles before it is worn out, the crossflow in 150 hp spec will last 25,000 to 30,000. Whilst it is nice to keep the old crossflow engines alive, we both felt that from a practical piont of view, the zetec makes more sense. I still have a very healthy crossflow but when it needs attention, I will fit a zetec and pop the crossflow under the bench for posterity. Link to comment Share on other sites More sharing options...
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