randybugger Posted August 18, 2009 Share Posted August 18, 2009 I have a Roger King 155 x-flow in my car which is a brilliant engine but I've got to the stage (as everyone does) that I would like a little more power. My problem comes when pulling out to overtake, at certain revs the car takes a while to really pull away, when it does it goes well but sometimes I'm stuck between needing to use a lower gear and reving the nuts out of it, to bogging down slightly and not clearing the car fast enough. My first upgrade will probably a BGH box, not sure which one to go for? Another idea would be to fit some throttle bodies etc, what extra could I expect if i did this? and how hard is it to do? and If I ever went to a zetec would they fit on? Sorry for so many questions all at once Tony Link to comment Share on other sites More sharing options...
DohNut Posted August 18, 2009 Share Posted August 18, 2009 Tony, are you going to Dunsfold? I am booked in with my injected x-flow if you want to compare. Nick Link to comment Share on other sites More sharing options...
jonboylaw Posted August 18, 2009 Share Posted August 18, 2009 Nick, Just a question, what TBs are you using and what ECU ? Tony, I take it you have an AX block Xflow? Maybe the Megajolt could help with the mid range responsiveness, I noticed a big difference on this, a lot smoother delivery with improved torque. If you are looking for power gains then things start to get expensive (Steel Cranks and Rods etc...) so I would consider another engine (I like the 4AGE Toyota lump) and sell your x-flow to fund it. Jon ----------------------------------- She is back in my garage, ready for a re-build. 1992 LA, Xflow, Ford axle Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted August 18, 2009 Share Posted August 18, 2009 Tony, what is your exhaust system ..... is it 4 separate primaries coming through the sideskin, connecting to a 4:1 before the silencer ? I had this arrangement, and changed the collector to a 4-2-1 ... which improved the mid-range torque nicely. Link to comment Share on other sites More sharing options...
randybugger Posted August 18, 2009 Author Share Posted August 18, 2009 Hi Nick, no not booked in for dunsfold but thanks for the offer, will quiz you on it next time we ride. Ian, yes I have 4 into 1 collector, perhaps a 4 2 1 will be worth a try, I'm hoping some re giggled ratio's in the gearbox might help jonboylaw, I have some kind of electronic ignition but don't know what kind (it was on the car when I bought it) Tony Link to comment Share on other sites More sharing options...
DohNut Posted August 18, 2009 Share Posted August 18, 2009 Jon It is a Weber Alpha ECU with Weber 40mm TBs It was one of the few options back in 1992 🙅🏻♂️ My only complaint is that I would like to access the map to tweak the cold start, other than that is has been faultless. Link to comment Share on other sites More sharing options...
jonboylaw Posted August 18, 2009 Share Posted August 18, 2009 Tony, Is it a 3D system, I.e do you have a TPS sensor on the end of the carbs or is it just an Dizzy based electronic ignition ? The Megajolt maps the advance vs engine revs Vs load (throttle position) so you get the ideal ignition timing for any load/speed for a fairly low cost (say £250 all in). Nick, Shame the Weber system is not programmable, makes it difficult to optimize or alter if you change things :( ----------------------------------- She is back in my garage, ready for a re-build. 1992 LA, Xflow, Ford axle Link to comment Share on other sites More sharing options...
randybugger Posted August 18, 2009 Author Share Posted August 18, 2009 Thanks for that, I think the megajolt is the way to go, anyone got any advice on the gearbox ratios? Link to comment Share on other sites More sharing options...
millsn Posted August 18, 2009 Share Posted August 18, 2009 TBs might give you more power if you're on 40s at the moment. You could afford to go to 45s on TBs which would relesase a bit. Otherwise the swap won't give you any more power but driveability and fuel consumption would improve. I'm pretty sure Roger used to do greater than 155 options also. There are some people out there with 220 bhp XFs but they're just daftly (is that a word) tuned. Ps: I'd recommend the long ratio first sstyle boxes they do make a big difference. Generally most noticeable when pulling away though and when in fifth which gets usefully shorter. Edited by - millsn on 18 Aug 2009 20:43:44 Link to comment Share on other sites More sharing options...
DaveMorris Posted August 18, 2009 Share Posted August 18, 2009 Tony, of the many thousands (sorry dear, hundreds) of pounds I threw at my (originally)1600cc x-flow, the biggest change in driveability was moving to a BGH (well actually SPC) long first , semi-helical, heavy duty gearbox. Get the longest first gear you can - I don't reckon it makes much difference with something as light as a Caterham unless you go for the Quaiffe 2.08 (or 2.04) 1st gear in their straight cut box. With closer ratios you will not be dropping out of the power band, so might not need to go for the injectors just yet. Having said that - my next job, after rebuilding the car completely, will be to inject the engine. Not because it needs it, though nor does it need a thru-the-bonnet exhaust, - it's just because it can be done. Link to comment Share on other sites More sharing options...
Area Representative dikko Posted August 18, 2009 Area Representative Share Posted August 18, 2009 just a quick mention re steel cranks. It makes sense to create some insurance/longevity t your crossflow, they are about £600. The Formula Fords of UK went over to them at the beginning of the year and are getting them in bucket loads for all the racers therefore keeping the cost down. It's an an American made (Scat) unit and it's a copy of the standard unit so you won't get it in superlightweight format but it will be well balanced (but double check with your flywheel) and last forever with ARP big-end bolts. You can get them from a couple of suppliers. One is Bob Yarwood www.yarwoodeng.co.uk or the official FF suppliers who do (for a 7) an unecessary official ID stamping for racing at Hemel Hempstead, Sky Ford. Create a bulk buy and Bob will reduce the price I'm sure. Link to comment Share on other sites More sharing options...
Graham Perry Posted August 19, 2009 Share Posted August 19, 2009 Personally I would stay away from building highly tuned crossflows at the moment, keep to the level you are at or go for a different engine. The engine builders are having problems with components that are not being made to the spec they once were and this is from the well known makers. I have been a victim of this as my 185 hp crossflow has hardly run for the last two summers due to various engine components failing because they were poorly made. Its currently having its 5th full rebuild in 18 months due to cam/cam follower/oil pump / valve spring failures over that time. Cam followers have given loads of trouble from several suppliers as they are not being hard faced sufficiently. The longest my engine has run in the last two years is 40 minutes before its lunched itself due to component failure ☹️ Link to comment Share on other sites More sharing options...
DohNut Posted August 19, 2009 Share Posted August 19, 2009 40mins RE Gearboxes I had a quaife straight cut box which I changed out because it was a) LOUD - in a really annoying way b) had a 2.04 1st gear which a x-flow struggled to get away from standstill briskly, the novelty of doing 0-65 in 1st gear is shortlived. Now have a BGH gearbox without long 1st and regret not spending the extra £75 it would have cost at the time. Link to comment Share on other sites More sharing options...
JampJ Posted August 19, 2009 Share Posted August 19, 2009 I guess the person to ask for advice is Roger himself! Cheers John JFDI (Just F*****g Do It) Link to comment Share on other sites More sharing options...
andy couchman Posted August 20, 2009 Share Posted August 20, 2009 I love the sound of the S/C gearbox. 🥰 In 4th (top) it's 1:1 so is quiet (noisier in the other three gears though). You also get a marginal power benefit due to less friction on straight cut gears. My 1st is 2.50:1 from memory and it seems to get off the line OK. That said, BGH boxes have a great reputation too (Brian built my Quaife box too). Maybe try each and go for whatever you prefer/ Andy Link to comment Share on other sites More sharing options...
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