Xflow upgrades

[Mat Norris]

I'm trying to find out more about upgrading a xflow to outputs of 170+BHP and what exactly is needed to make this possible and reliable. I know most people would want to bin the xflow for something modern, but I like it! If there is anyone out there with who has done such an upgrade, whats it like and was it worth it?

Cheers!

 

[John E]

Mine is not upto the BHP that you are looking for but the man that you should talk to is Roger King at rkingeng@aol.com

or 01992 421111

 

He will tell you the top and bottom of what is involved.

[Graham Perry]

Roger King will probably be along in a minute, to explain further but you are on the edge of a 'steel' engine with those sort of BHP figures. ie Steel, con rods Crank and flywheel as well as a few other choice bits such as dry sump. Cost is likely to be in the £ 6K + region if someone does the work (All steel engines are always expensive).

However, if it can be made to produce that sort of power without going all steel(perhaps an 1800 cc version with a 254 cam ?) then the costs will be about £2500-3000 less. Cross flows, although basic still need to be made properly if you want big BHP and are not a DIY job if you want reliability.

I have a 1700cc 180 BHP steel engine that is timed in for torque rather than power. The modifications on mine are from memory

 

Big valve ported head with steel rocker posts, forged pistons, steel flywheel,rods, flywheel,264 cam and top quality cam followers , dry sump,Cosworth bolts all round, double dowelled flywheel, race clutch, duplex timing gear, fancy water pump, 45 Carbs, small bottom pully, hand-built one-off exhaust system etc etc. A headgasket alone is about £60 if you want one that lasts. It produces max BHP at a surprising low 6900 RPM but will rev to 9100 quite happily. Its not let go yet despite 3 years of motorsport use and uses no oil. I would recomend that you consider 3D ignition mapping as well as it will be much more drivable.

 

I will be changing it in the next couple of years for something with lots more power though, as it isn't really possible to squeeze more than about 190-195 BHP from one without a 2.2 Aluminium block and then we start to talk serious money..........

 

I would think very carefully before going down the high BHP X-flow route with so much easy power to be had in modern engines.

[Graham Perry]

Mat, I have just realised that I only answered half your question yesterday. In terms of if the upgrade was worth it, I would say it was at the time it was done. I was fortunate enough to win two regional Kit car sprint championships with it last year in spite of the fact that a few hot 'K' series cars were about, but this year I knew it would be outclassed by newer machinery. I really like the car, and inspite of its tune I personally believe it is more tractable than when it started life as a humble supersprint.

 

This year though I have found that I can still hold off Vauxhall and 'K' series cars up to about 200-205 BHP but it has meant quite substantial mods to the car have had to be made and this winter another 15-20 kg will have to come off to remain nearly competitive next year. If you come across another Caterham producing any more than 200 BHP, even with a really top cross-flow then you don't have a chance, as big BHP is always quicker in the right hands.

 

Having said the above, I am more in love with the Car than the engine and a new sixteen valve will have to be installed in the next couple of years to provide the power needed to give the go I need. I am hearing some almost unbelievable BHP/litre figures are being obtained by Fords with their Zetec SE engine so that may be the way to go, but they are not yet very common. Having said that I love the noise of a 2.1 BDG, and the 'K' series has bags of torque so it will be a difficult decision when it has to be made.

 

If you do decide to go all steel be very careful when buying secondhand Steel Crossflow parts, I would recommend you have them crack tested before instalation as they can prove a false economy otherwise, and I know I said it previously but the single part that bought the most improvement of all on my car was the 3D Emerald mapped ignition. Although 500 quid, it is worth every penny as the car will be so much more civilised with the more cammy engine.

[Mat Norris]

Thanks there,

You have given me lots to think about and even more ways of spending my dosh!

[Eugene]

Mat,

 

Look at http://freespace.virgin.net/shaw.clan/vegantunespec.htm

 

I have over 170BHP from this Kent based engine and love it!

 

Steve