I am looking to make some changes to my engine to boost the bhp up as much as i can without changing the engine, I have already got a straight through exhaust and a induction kit. Any ideas would be very good
Cams would set you back about 300-400 probably. You could get headwork done for about 300 (depending where you go)
dbilas do inlet manifolds and injector systems but there are varying opinions on the quality and they cost over a grand.
You could slap throttle bodies on for about £1500
A supercharger would need to be done entirely by yourself unless you can find somewhere that does it (i haven't). You would probably need to rebuild the engine replacing most internals and it would be rather time consuming and cost thousands.
If a supercharger doesnt float your boat, you could put on a turbo. But I wouldnt even want to think how much hassle and cost that would be.
A new exhaust manifold would help, costing around 300 quid.
And if you up the power by a bit you'll probably need new brakes and suspension.
How much bhp would a new manifold make, a allready have v6 brakes so they should be ok, and also what bhp would high lift cams make.
Inlet or exhaust?
On an x18xe (115bhp) dbilas claim an extra 35 bhp from their inlet manifolds, but I think they come with cams.
Exhaust manifold wont make much (sometimes claimed up to 10%). Better used as a complement to other mods.
Courtenay cams say from 15bhp gains.
As with any mod, the gains will be quoted as best gains, probably in conjuction with other mods. Cams are best chosen to suit your particular engine configuration. I think courtenay cams are best for stock engine.
Have a poke about their website http://www.courtenaysport.co.uk/default.htm
Regal are the uk dealer for dbilas www.regal-shop.co.uk
and most of all, none of the above mods are gonna go down too well with the standard ecu (dbilas say their stuff is designed to work with standard ecu) so you might wanna invest in a unichip or new ecu. You will need big bucks to seriously improve a 1.8 though. You will be cheaper just getting a V6!