Jump to content
Click here if you are having website access problems ×

Xflow - 1600 vs 1700 - Extra 35HP for 100cc?


Recommended Posts

Just wonderin' like.


For what seems 100cc, gives you 35HP between the two cars.


Are the only differences

1) 100cc

2) Bigger valves

3) Plugs

4) Comp Ratio ie. 1300 pistons

🤔 🤔


If so, then can I 'convert' my 1600 to 1700 sprint spec, by changing the head, pistons & plugs? And would that provide say, 20hp?




Edited by - tim_H on 25 Apr 2005 11:33:21


Edited by - tim_H on 25 Apr 2005 11:47:56

Link to comment
Share on other sites

1600 with GT cam 100 HP

1600 with A2 cam 110 HP


so only 25 HP more


1700 Super sprint 135 HP with Kent 234 cam

140/145 HP with 244 cam ( uprated)


larger valves

but a 1700 reliable need forged piston



Link to comment
Share on other sites

If I were you

I ll stay with 1600 + a good unleaded head stage 2

cam Kent 234

for road you will have something like 125 / 130 HP


very good engine, very flexible lot of power

lot of torque

no trouble, sound as a beast for a little money


If you go 1700

more money spent

for road useless





Link to comment
Share on other sites

If it a road car


you can stay with the cheap solution


keep the GT cam (same as the historic formula ford in france

about 115/120 HP with the 32/36 webers


use a good unleaded head stage 2 or 3

stay with mechanical fuel pump (I stay with a 1600 Burton ul stage 2 head

A2 cam)

2 webers

you should have 120 HP


You have time to take off the engine

Normally the caterham Flywheel is about 5.7 Kg or 5.3

with is perfect on escort it was 7.6 kg




Link to comment
Share on other sites

Ok, - confused now.


As it is : Standard Sprint Spec.


1600cc, twin 40's, GT cam, Aldon (std) distributor, lightened flywheel (std), 4-2-1 side exit s/steel exhaust.


I'd like to retain the 1600 block, - but putting 1300 pistons in raises the CR. - apparently? Bigger valve head? - Different Cam? Ignition curve?



Link to comment
Share on other sites

1300 pistons not strong enough

aldon with ignitor perfect

just change the head


and if you want to get off the engine

cam kent 234



if you want to spend more money

forged piston and conrods


if you want to spend more

forged steel crankshaft




Link to comment
Share on other sites

The question is, what are you trying to achieve? If it's "most bang for your buck", there are a number of cost effective options, some of which can be combined.


1. Rebore and new pistons. I can't think of any reason not to go to 1700cc in that case, as the cost is much the same irrespective of the size of overbore.


2. Forged pistons. These give more power and are essential if you hope to exceed 135 bhp at any stage.


3. Hairy cam. A 244 is sufficiently tractable in a car as light as a seven, but is more expensive than a 234 because you need to machine the spring seats. Either cam will need the pistons machined for valve clearance.


4. Ported big valve head. You'll need to do this at some stage anyway, but bear in mind the issue of spring seats.


5. 4 into 1 exhaust.


Is that any help?


SEP field working, not spotted in 103,300 miles. Some photos on webshots, updated 25 Jan

Link to comment
Share on other sites



As Eric, Oliver and others suggest there are so many things you can do.


I have a similar spec. engine to you - some possible 'food for thought' discussed on previous threads here & here


* A Caterham supplied 1700SS engine produced somewhere in the region of 120BHP, not the 135 quoted.


* Mapped 3D ignition is good and there are cheaper alternatives to Weber Alpha.


* .........or junk the crossflow and fit a Duratec 😬. Seems to be the way forward!






Edited by - Gavin on 27 Apr 2005 10:57:55

Link to comment
Share on other sites

Sorry to say that power is not the best thing to have on a road caterham


Because it is more important to have less horses at high rev

and more at low revs for a road car

torque is also important

and the differences between a 110 caterham and a 150 hp

with the kent are not so important on the road


the mileage you can do with 110 HP is higher than a 150 hp


and the cost is less


it will leave you some money to une the car

and not leave it at the garage


Sorry not to be agree with all power fans

Link to comment
Share on other sites

As it may be one of my last posts, I'd like to put the case for BEC's again.


No problem with only having 130ish bhp at the top end with beggar all torque, and as you are never driving it anywhere near the max, the 'blade engine lasts and lasts. The same goes for the R1, except it has a little more poke (around 150-160bhp).


OK perhaps not the cheapest way to upgrade, but possibly the cheapest way to go sub 4 secs 0-60 *wink* at around £3.5k (less money back from selling your existing engine and box, etc.). And if it does go wrong it won't be a king's randsom to fix it *thumbup*



Link to comment
Share on other sites

BB comes in from the dark side again. *tongue*


Can you really get sub 4 sec out of a Blade 7? The weight comes down to 450kg with creature comforts but I understand that it's hard to approach 400kg.Say 420kg without too much effort, will that see sub 4 sec? I suppose the seq box helps the shifts, all one of them required up to 60. 😬

Link to comment
Share on other sites

I'm sure with the right tyres, diff and a blatant disregard for the mechanical wellbeing of the machine, you won't be far off the magical 4 secs in a 'blade car, I'm convinced that an R1 version would breeze it. However, I have my doubts about the n/a 'busa versions. In a small skurmish with a westfield 'busa in my striker 'blade, he wasn't doing any better until we got into third, then he buggered off into the distance!!! *eek* 😳




BB *thumbup*

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...