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Posted: Fri Sep 19, 2008 5:30 pm
by superchargedfool
a supercharger comes in gracefully and builds up where as a turbo comes in hard.
superchargers tend to be kinder to old engines
Turbos cause a lot of heat in the intake charge but superchargers only add a little heat due to compressing the volume of air.
Superchargers are rarer on old school modded cars and its good not to be a sheep.
Having said that a turbo minor isn't exactly common though.
Posted: Fri Sep 19, 2008 5:50 pm
by bmcecosse
As above - the supercharger gives power all the way up the rev range - you don't need to rev it like mad! Much kinder to the engine, and much much nicer to drive with. As long as reasonable (ie moderate/low) boost is used and 'full bore' driving is sensibly limited, a supercharged engine will last far better than a turbo engine.
Posted: Fri Sep 19, 2008 7:20 pm
by superchargedfool
lets hope my 140 plus bhp 10psi lasts as said.
will prob be driven very hard to over 7k.
go on turbo a 1275, forced induction is costly, troublesome, annoying, unreliable, full of problems to solve but hey its good fun and different!
Posted: Fri Sep 19, 2008 11:04 pm
by bmcecosse
" will prob be driven very hard to over 7k. " BANG!
Posted: Sat Sep 20, 2008 9:08 am
by superchargedfool
forged pistons, lightened and balanced, better studs and nuts, sorted crank and built by autosprint (mainly build competition and trackday engines).
I have had other a series that where happy to nearer 8k on the road. You just have to build them right.
Posted: Sat Sep 20, 2008 9:22 am
by bmcecosse
Sounds good !
Posted: Sat Sep 20, 2008 9:52 am
by jonathon
I'd have thought that adding a turbo or old school/type turbo reduces the need to make a high reving engine as the peal torque is much lower down the rev range making reving past it pointless.
The K series motors can rev to 7600rpm if using aftermarket management but the turbo version produces all of its torque from 1500rpm to 5500rpm so no need to stress it by high revs.
The more modern superchgargers such as Rotrex units are designed to enhance the original engines characteristics ie high reving Toyota 20V motors but add huge amounts of torque throughout the rev.
range
I'd have thought a high reving A series and turbo/superchrger is just asking for trouble and weekly rebuilds. One of our customers has just had a 1293cc motor built with the V Max Scart injection supercharger fitted. Reasonable revs 6000 and between 125-130 bhp low boost and long engine life.
Posted: Sat Sep 20, 2008 10:26 am
by superchargedfool
yes but I have sort of been there and done that and am now thinking of going further (or was that too far?).
When you say an engine build is built to be able to rev to high 7's that doesn't mean you are going to change gear there every time. It means you can sometimes.
I will be changing gear in the 6's but knowing I can take it further if I want.
Posted: Sat Sep 20, 2008 11:12 am
by jonathon
Well you did say 'will prob be driven very hard to over 7k.'
But really even reving to 6's will not be required as your torque will be lower down the rev range. My 16V turbo diesel can rev to 6500rpm but if you do you gain less acceleration than if you short shift at 3-4000rpm.
I'd go supercarger and turbo if you need to be different, or just start with a cheaper more powerfull/reliable engine in the first place, unless the project is more about an engineering excercise rather than the ultimate end product and its use.

Posted: Sat Sep 20, 2008 11:23 am
by superchargedfool
I will one day build a modern engined minor but for now I want to see how far I can go with an oil dripping a series up front.
Posted: Sat Sep 20, 2008 11:42 am
by jonathon
Posted: Sat Sep 20, 2008 8:34 pm
by jonathon
SCF,
I remember one of the engineering companies we used to use, building an EVO turbo motor , but with a twist, no big turbo but instead four small ones from the Smart car, now that would be a different take on the A series, if you could work it out, nice 8 port head etc !!

Posted: Mon Sep 22, 2008 3:18 pm
by aussiemike
right just got the dizzy and the exhaust manifold sorted.
now al i need is the rest of it!
cheers, updates on the way.
Posted: Mon Sep 22, 2008 4:57 pm
by bmcecosse
Has this to be ready for big attack on the Mull Rally in 4 week's time ???
Posted: Mon Sep 22, 2008 7:26 pm
by aussiemike
ha ha ha...no, i am off ot oz in a wee bit under 6 weeks so at the moment I am just collecting all of the bits and bobs i will need. The car already has an escort axle, disc brake front end, telescopic ear shocks, bigger radiator etc.........are you coming up for the rally?
cheer,s michael.
Posted: Mon Sep 22, 2008 11:26 pm
by bmcecosse
Sadly no Mike. Mate Chris Paton (vauxhall nova )will be there as usual - he has started every Mull rally except the very first one - when we both spectated!