MarcNS Posted January 16, 2006 Share Posted January 16, 2006 I have a standard engine with 135bhp How can I improve the bhp in the most cost effective way 🤔 I'm looking for about 145bhp. Regards, Marc Link to comment Share on other sites More sharing options...
Manxseven Posted January 16, 2006 Share Posted January 16, 2006 Buy my engine which is about to come up for sale (150bhp, brand new, never run) Caterham Bike Engine here Link to comment Share on other sites More sharing options...
ashaughnessy Posted January 16, 2006 Share Posted January 16, 2006 How old is it and how many miles has it done? You might find if it's old that any kind of dismantling will result in a lot of expense, even more so when you want to stress it more highly with more power. Is it totally bog-standard supersprint spec, cast pistons, 40DCOE webers, 234 cam? What exhaust do you have? Anthony Link to comment Share on other sites More sharing options...
ashaughnessy Posted January 17, 2006 Share Posted January 17, 2006 Does anyone have some really old copies of low flying at home? Many years ago (early nineties) SPR used to advertise standard crossflow upgrade packages every month on the back page and, what's more, put prices on them. I know SPR don't exist anymore and that's a long time ago but it might be useful to get a ballpark figure for their cheapest upgrade package. Anthony Link to comment Share on other sites More sharing options...
MarcNS Posted January 17, 2006 Author Share Posted January 17, 2006 As far as I know it was a standard Supersprint, What do I need to do for just 10bhp more. The CarThe Club Built Vvvrrrooomm Link to comment Share on other sites More sharing options...
Manxseven Posted January 17, 2006 Share Posted January 17, 2006 Cheapest way is to remove some weight from the 7. Caterham Bike Engine here Edited by - Manxseven on 17 Jan 2006 12:57:38 Link to comment Share on other sites More sharing options...
Robster Posted January 17, 2006 Share Posted January 17, 2006 Fit 34mm chokes in the webers, larger main jets and a 244 cam (and new followers). Adjustable cam sprocket will help you time it properly which will improve driveability as well. Standard pistons are not safe for high revs though..keep a limit of 6500 unless you go for forged which is quite a bit more money..although worth it in the long run. You could use standard and see..if they break go forged then! Porting the head is also worth doing..around £350 upwards. You really need to do this to get the most from the cam. Link to comment Share on other sites More sharing options...
ashaughnessy Posted January 17, 2006 Share Posted January 17, 2006 Marc, I've sent you a mail. Robster, how much benefit would you get from 244 cam and larger chokes without going above 6500 rpm and without porting the head? Not disagreeing, just asking. Also, my supersprint (before upgrade) started to sound distinctly rough from about 6000 which I put down to the valve train. Would the rest of the valve gear stand regular running at 6500 in order to get the most out of the 244 cam? When working out costs it's probably worth remembering things like the rolling road setup afterwards, which I guess would be necessary for any breathing-related changes. Anthony Link to comment Share on other sites More sharing options...
MonkeyBoy Posted January 17, 2006 Share Posted January 17, 2006 If you have a standard 1700XF, does it have a rear exit exhaust ? An upgrade there is likely to be a good fairly cost effective start i would imagine, don't know how many bhp you're likely to get with say a Raceco exhaust - anyone ? Link to comment Share on other sites More sharing options...
Graham Perry Posted January 17, 2006 Share Posted January 17, 2006 I can't remember the exact adjustment required but you can re-time the standard 234 cam to give more revs at the top end. If you either rechoked the 40's or fitted 45's and maybe changed the dizzy to leaded advance curve anther 10hp should be attainable but ideally some headwork should be done. How long it lasts though would be a moot point as there are other changes that are really needed to add to longevity and safety e.g. Dowelled flywheel Steel rocker posts Forged pistons Duplex chain new bottom pulley There is plenty in the archive about tuning crossflows Link to comment Share on other sites More sharing options...
Phil Posted January 17, 2006 Share Posted January 17, 2006 A new 4-1 exhaust was costly at £900 pounds including the 7 inch box but worth every penny as it changed the feel of the engine, power comes in early and it sounds great. I would recomend a Caterham 4-1 mated to a 7 inch RACECO box. X/FLOW 1700 DD 1990 ROAD USE ONLY..SO FAR Link to comment Share on other sites More sharing options...
Robster Posted January 17, 2006 Share Posted January 17, 2006 The 244 cam works very well from 4K upwards, so you would feel it at 6500rpm limit. Stiffer valve springs would be cheap to fit though if you are worried about valve bounce. It's hard to guess the benefit without porting the head though. With hindsight, you may be better timing the standard 234 cam properly, fiting a lightened flywheel (revs up much better)...and go on from there. Really depend on budget. 244 cam is popular though and very driveable. R7RDC and home to the full Gulf Liveried Midget...as seen at Le Mans 2005! Link to comment Share on other sites More sharing options...
JampJ Posted January 17, 2006 Share Posted January 17, 2006 If you've got the standard Caterham distributor fitted, it will be worth sending it to Aldon to be rebuilt with a better advance curve, There are already quite a few relevant threads if you can find them. Or get a Lucas Competition Ignition System. Found one! If you search for the last year for: cheap upgrade xflow you will find a thread by Graham Sewell, regarding getting his distributor rebuilt by Aldon. Cheers John JFDI (Just F*****g Do It) Edited by - johnjulie on 17 Jan 2006 23:27:33 Link to comment Share on other sites More sharing options...
Nigel Riches Posted January 18, 2006 Share Posted January 18, 2006 ....and get your car rolling road power checked before and after the modifications, thus verifying the 10bhp improved power, use the same rolling road for both checks..........opens a can of worms.. 1982. 5 speed, clamshells. B.R.G / Ali. The True Colours. Link to comment Share on other sites More sharing options...
mikes Posted January 18, 2006 Share Posted January 18, 2006 I have emailed as well. What I have learnt is much as the others say - there is no one change which will give you thre result you want AND last! Once you start improving one component, if you want to utilize it to its maximum, you have to upgrade a number of other components as well. I was faced wiht this decision a few years ago (because the pistons were starting to disintegrate) and initially went for forged pistons, unleaded head, uprated valve gear, electronic ignition, tuftrided crank and rockers, high capacity oil pump etc Good luck Mike Link to comment Share on other sites More sharing options...
DaveMorris Posted January 19, 2006 Share Posted January 19, 2006 MArc, a couple of questions - 1/. How much do you want to spend (or have to spend) 2/. Why 10bhp increase ? - Is this a magic number (i.e. linked to insurance costs). Comment made above about increasing performance by losing weight is well valid. 10bhp up from 135 is 7.5% increase in power (and hence I presume in power/weight ratio if no increase in weight for improved performance - this not always the case !). Assume car+ driver comes in at 620kg then to achieve 7.5% increase in p/w ratio would need to get weight of car +driver to 575-580kg. Not that easy - but removal of spare tyre gets you a SUBSTANTIAL part of the way there, and running max.1/4 tank fuel gets quite a bit more. Then it all gets a bit messy and expensive (from what I've heard). Anyway that's my 2p worth Dave. Oh yes - my x-flow currently away being re-built. It's not cheap Link to comment Share on other sites More sharing options...
MarcNS Posted January 20, 2006 Author Share Posted January 20, 2006 Thanks everyone, I have around £800 to spend on the car, I thought 10bhp may be more easy to achieve and within budget. The engine is on 3000miles+ I think had 6K when installed it has a 4 speed box. I would be interested if anyone does upgrades but will probably upgrade to an unstressed engine and 6 speed in a few years. I will probably now change the rubber,roll bar, fit rev limiter and have cash to spare ready for some track days. 😬 The CarThe Club Built Vvvrrrooomm Link to comment Share on other sites More sharing options...
ashaughnessy Posted January 20, 2006 Share Posted January 20, 2006 I don't think £800 will go far to upgrading a supersprint. I think another ten horsepower will be expensive. Mine were. Stickier tyres will make a bigger difference and be a lot cheaper. Anthony Link to comment Share on other sites More sharing options...
Phil Posted January 20, 2006 Share Posted January 20, 2006 As I suggested, the exhaust, should give a reasonable upgrade in power but a great increase in the use of the power available making the car more drivable. X/FLOW 1700 DD 1990 ROAD USE ONLY..SO FAR Link to comment Share on other sites More sharing options...
Manxseven Posted January 20, 2006 Share Posted January 20, 2006 Marc, I'll e-mail you over the weekend with reference to the engine I have for sale, in case you are interested? Caterham Bike Engine here Link to comment Share on other sites More sharing options...
MarcNS Posted April 11, 2007 Author Share Posted April 11, 2007 I Posted this a while back, I went for tyres last year and some minor mods so I would still like a small power increase but I would like to keep the power it has also The car feels slow at the moment and could probably do with points and carbs etc looking at. I have been working my way round the engine but how do I get to the distributor? I want to try and do most jobs myself and probably need something better than my Dads AA Book of the Car from the 1960s/70's ! Any ideas for books and whats the most suitable 'upgrade' exhaust for a Xflow and what ignition should I go for? Cheers, Marc Link to comment Share on other sites More sharing options...
MonkeyBoy Posted April 12, 2007 Share Posted April 12, 2007 i went for the Powerspeed exhaust on my X-Flow - highly recommended *thumbup* I got it as part of a bulk buy a while ago, it made a big difference. I've also started replacing the standard ignition with a mapped megajolt system (though this has been a slow project over the last year 😳) - some people on this forum have recommended this upgrade. Alistair Link to comment Share on other sites More sharing options...
alextangent Posted April 12, 2007 Share Posted April 12, 2007 I have been working my way round the engine but how do I get to the distributor? With small hands, and from the front. It's possible with some jiggery pokery to get the cap off a std dizzy, but the Lumenition is more difficult, as the rotor is actually a beam cutter, and it's bigger than a std rotor. It's certainly possible to do the timing; just watch out for moving components 😳 and don't wear a tie 😬 Alex McDonald A loud 1700 SS Link to comment Share on other sites More sharing options...
New Cat Posted April 12, 2007 Share Posted April 12, 2007 Roughly how much is the Powerspeed exhaust? (just the side exit silencer)? Others have suggested in the past that one of the most cost effective performance upgrades is to replace the clutch bellhousing with an aluminium one - no idea of the current cost but should be well within budget. The other cost effective upgrades are likely to be a tune up - how many 'Supersprints' are really producing 135bhp? Certainly switching from a Lucas to Bosch 'Valencia' distributor improved the timing and performance on mine. Also, £800 worth of driver training would go a long way... Jon 1994 1.7 Supersprint De-dion X-Flow. Yellow with black cycle wings Link to comment Share on other sites More sharing options...
Leadership Team Midas Posted April 12, 2007 Leadership Team Share Posted April 12, 2007 FWIW I had a similar train of thought, and this is what I identified - all points made by other already, but in my case I have done it so can comment on the results. In order of priority: 1. Remove rear wheel - amazed how much difference it made. Cost £7 for a can of sealant 2. Install Lucas Constant Energy Ignition system - gives an extra 10 bhp, available form Burtons and other specialists. Fit and forget. About £400 3. Replace tyres - quicker through the bends, even if BHP stays the same. About £350 4. Replaced the standard Bilsteins with a FReestyle Handling Kit. Again, no greater power but the car handles much better leading to greater speed carried down the road. About £400. Link to comment Share on other sites More sharing options...
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