Scubadude
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| posted on 18/11/07 at 09:16 AM |
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1600 Crossflow power -- Calling Kent buffs
Greeting from sunny South Africa!
Just bought myself a Seven which is a home-built copy of a Birkin which is a South African "copy" of a Caterham which is a reproduction of
a Lotus ...
Anycase, it is fitted with a mildly tuned 1600 Crossflow and 4 speed Escort Mk II box. "Mildly tuned" means twin Weber 40 DCOE's,
gasflowed head (standard valves), 1300 pistons, mild cam ("one notch up from GT spec" ) and 4-into-1 freeflow exhaust. Compression tests
perfect but timing and carbs are out of tune.
When properly tuned, what sort of power should this engine be making? How much further can I take it economically and reliably? What would be the
next mod/mods and at what price?
Thanks!
[Edited on 18/11/07 by Scubadude]
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rusty nuts
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| posted on 18/11/07 at 09:34 AM |
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Slightly different spec , my x flow has a Kent BCF2 cam , a Vulcan 11A head with large valves, Kawasaki ZZR1100 throttle bodies (35mm bore?) on a
home made manifold with h/m airbox and an aftermarket ECU . Smallish bore exhaust . That lot developes 127BHP and 115ft/lbs torque. Should give you
some idea what can be done. Even though it's not as powerful as it could be with a few more changes I'm happy with it.
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David Jenkins
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| posted on 18/11/07 at 09:48 AM |
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I think Rusty's about right - I have a similar spec'd Kent engine, but with a Weber down-draft carb, and that makes a gnat's under
100BHP.
These old engines improve hugely when the old dizzy is replaced with something like Megajolt, or even an ex-Fiesta mechanical dizzy with electronic
pickup (LINK). Not significantly more power (1 or 2 BHP) but a
huge increase in maintainability and will also keep its settings indefinitely.
The next step up would be throttle bodies with a good ECU - either Megasquirt if you like to tinker, or something off-the-shelf like Emerald (like
Rusty's).
This is probably as much as can be done without doing stuff inside the engine.
Although many might disagree, personally I think 120 - 130 BHP in one of these cars is more than enough for a heap of fun, without too many unexpected
surprises when you go a bit wrong.
I do like the Kent engine though - it is old, always drips a little oil here and there, and is limited in ultimate power, but it is fun to use and
makes a lovely noise!
David
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thunderace
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| posted on 18/11/07 at 06:04 PM |
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you get a 2l xflow in africa
i would say 130bhp
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Scubadude
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| posted on 18/11/07 at 07:08 PM |
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Thanks guys!
Well it sounds like 120-130 bhp is the average estimate ... around 100kW. That's more than I expected! I thought it would be max around
105-115bhp, which is about a third up on the standard 84bhp.
On performance, though, your estimates sound about right. I haven't done accelaration tests but I suspect a good run will give 0-100km/h
(62mph) in the low sixes (if I could lay down the power with the bum 205/60 R13 tyres fitted). And that is at an altitude of almost 5500 feet!
Are there any other quick wins to be had, or is this where the price / performance graph starts tapering off?
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David Jenkins
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| posted on 18/11/07 at 09:04 PM |
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You can get more power - the racers reached 175BHP or more - but at the cost of lousy tick-over (i.e. non-existent) and no pulling power below 3000 -
4000 rpm. Not practical for road use!
To be frank, if you really want a load of extra power, you'd have to look at a more modern engine. After all, a stock Toyota 4-AGE engine gives
130 BHP unmodified, and a fair bit more when tuned. A newish Ford engine like the Zetec or Duratec will also give excellent power out of the box.
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MikeRJ
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| posted on 18/11/07 at 11:15 PM |
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quote:
Originally posted by Scubadude
Thanks guys!
Well it sounds like 120-130 bhp is the average estimate ... around 100kW. That's more than I expected! I thought it would be max around
105-115bhp, which is about a third up on the standard 84bhp.
With a mild cam and standard sized valve I think your initial estimates are far more likely. Rusty's has throttle bodies, a big valve head and
a reasonably "warm" cam to reach his 127bhp.
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Marcus
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| posted on 19/11/07 at 12:37 PM |
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I agree with Mike - I've got a 1700 X-flow - Piper 270 cam, 32/36 carb, modified GT manifold, Ported head with Std valves, Valencia Dizzy -
dynoed at 112bhp.
Got an engine ready for rebuild with kent 244 cam, GSXR TBs, 1300 pistons (+90), Megasquirt - using same head and expecting 125bhp.
Marcus
Because kits are for girls!!
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Scubadude
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| posted on 19/11/07 at 01:34 PM |
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quote:
Originally posted by Marcus
1700 X-flow - Piper 270 cam, 32/36 carb, modified GT manifold, Ported head with Std valves, Valencia Dizzy - dynoed at 112bhp.
@Marcus: 112bhp at the flywheel I suppose?
@David: Nope, engine transplant not foreseen. I LIKE the idea of a Kent egine in a Seven, because it is "authentic", even if my car is a
copy of a reproduction of a reproduction. It looks and drive's like a late 60's Seven, and I want to keep it that way. And I'll
probably sh!t myself in a car as nimble as this with a lot more power  Just thought there may be a cost effective way to improve power output
without shredding the wallet ...
Not that power output is THAT important to me in any event ... if it was I'd have the car on a dyno in no time rather than making chit chat
about what power it may be producing. I only use the car for weekends. And two toddlers plus baby is not very friendly conditions for track days, so
there won't be any for some time. Racing is also out of the question at the moment. 
[Edited on 19/11/07 by Scubadude]
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David Jenkins
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| posted on 19/11/07 at 07:49 PM |
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I have a heap of fun in my sub-100BHP car, especially as I didn't go for silly wide tyres. It accelerates as fast as I want or need, corners
like it's on rails, and I can hang the tail out on roundabouts if I'm in the mood. 
And I love the sound of a Kent engine being used energetically...
The electronic ignition I recommended only because it makes life easier - the car won't go 'off-tune' as it would with an ordinary
points dizzy.
[Edited on 19/11/07 by David Jenkins]
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Marcus
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| posted on 20/11/07 at 12:05 PM |
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quote:
@Marcus: 112bhp at the flywheel I suppose?
Yes - I'd love that at the wheels, but without spending a fortune, it ain't going to happen
Contrary to many on this forum, I'm still having fun on a shoestring budget - scrounging bits wherever possible, making others and sticking to
the Locost ethos. ('cos I'm skint!)
Marcus
Because kits are for girls!!
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Scubadude
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| posted on 20/11/07 at 12:19 PM |
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Shoestring budget is my motto too! Single income and three little ones do not mix well with expensive hobbies!
Just too make you a little jealous, my car is a 2001 build with 20000miles and lots of nice bits ... engine specs as above, louvred bonnet, Caterham
headlights, racing harness, etc, etc. You can follow my car hunt on ...
http://www.locost.co.za/phpBB2/viewtopic.php?t=683
and
http://www.locost.co.za/phpBB2/viewtopic.php?t=724
It needs some work, but looks ver authentic period Lotus and goes extremely well. And I paid the equivalent of GBP 2400 for it here is SA ... Guess
you can't buy much in the UK for that sort of money?
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stretch
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| posted on 21/11/07 at 11:01 AM |
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AH eaHE aHE AEH
orsm, i'm from capetown
i've got a kent 1.6 as well, twin 40' dellorto's BCF3 cam, ported head + bigger valves, electronic ignition, 1.3 pistons, etc etc
i haven't been for a dyno run recently - but before the ported head and oversized valves and on std 1600 pistons was doing 87kw
i'm hoping with all the mods done now i should get over 100killerwhats
its ALOT of fun to drive, the noise is just so orsm!
i have a performance meter, i'll do a 0-100 and 1.4mile run over the weekend sometime and let you know the results
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