pulling my engine soon for its freshen up.got forged pistons,gt525s,555injectors and chip.divorced dump pipes and de cats oh and a front mount.im hoping for around 400 -430rwhp.are there any mods in the engine i can do to get me up to the 450 mark.would polishing the ports in the lower plenum give me any noticeable gains?.

Yes it would cams and lifters are another good way of unlocking BHP.

thanks for the reply mac.are the jwt stage ones good for this?

I would say so. JWT have had a lot of experiance with Z tuning.

so along with the cams.are there any other mods i can do ie headwork etc to help me gain a few more gee gees.

How about removing the sound equipment from the boot !! it won't give you more BHP but with the car then about 100kgs lighter, you should certainly notice the different. (He He)

manifolds:

 

 

http://www.z1motorsports.com/product_info.php?products_id=1818

thank you for the input guys.would love to spend on manifolds and camshafts but dont think i could stretch to that yet the missus would have my guts for garters and she is a reasonable woman!!!.has anyone had much success porting or polishing the heads.im going to do the lower plenum myself.

must say there a bargain for about 550 quid ish

thank you for the input guys.would love to spend on manifolds and camshafts but dont think i could stretch to that yet the missus would have my guts for garters and she is a reasonable woman!!!.has anyone had much success porting or polishing the heads.im going to do the lower plenum myself.

i ported my own heads with a carbide tip tool on a dremmel type drill, you need to match all inlet/outlets to the gaskets. its a real pain and time consuming but well worth it, you wouldnt believe how much metal you take out.

i ported my own heads with a carbide tip tool on a dremmel type drill, you need to match all inlet/outlets to the gaskets. its a real pain and time consuming but well worth it, you wouldnt believe how much metal you take out.

 

Where abouts are you mate?

 

Im only down the road in marston moretaine :)

thank you for the input guys.would love to spend on manifolds and camshafts but dont think i could stretch to that yet the missus would have my guts for garters and she is a reasonable woman!!!.has anyone had much success porting or polishing the heads.im going to do the lower plenum myself.

 

shes already had my guts for garters :p

Where abouts are you mate?

 

Im only down the road in marston moretaine :)

i know marston well, i am in houghton conquest!!!

Small world mate :)

 

Im from london but have been up here about 4.5yrs now, Have to meet up one day, be nice to meet a ZED owner that close.

 

My cars in my rides, say hello if you see it about :)

shes already had my guts for garters :p

not you as well greg.as long as your paying like the rest i dont mind. :slap:

i ported my own heads with a carbide tip tool on a dremmel type drill, you need to match all inlet/outlets to the gaskets. its a real pain and time consuming but well worth it, you wouldnt believe how much metal you take out.

ive got a die grinder and have just ordered a 10mm belt sander so im gonna go for it.

not you as well greg.as long as your paying like the rest i dont mind. :slap:

what do you think paid for your turbo's :wack:

ive got a die grinder and have just ordered a 10mm belt sander so im gonna go for it.

dont hold me to it but it tried a belt sander but they clogg up cause aliminium is soft. carbide tip with slow rpm is what you need.

fair shout mate as long as my face is smiling longer than yours was i dont mind. :p

dont hold me to it but it tried a belt sander but they clogg up cause aliminium is soft. carbide tip with slow rpm is what you need.

will have to try both,my bluepoint die grinder only does fast and faster.might have to put a pair of molegrips on the airline!!!.

will have to try both,my bluepoint die grinder only does fast and faster.might have to put a pair of molegrips on the airline!!!.

that exactly what i did!!!!!!

great minds think alike.are there any areas where the material is thinner because of waterways.i have 2 pairs of spare heads but id prefer to use the ones on the car now.better the devil you know hey!

great minds think alike.are there any areas where the material is thinner because of waterways.i have 2 pairs of spare heads but id prefer to use the ones on the car now.better the devil you know hey!

just have a good look in and around, dont think the heads are too bad just got to be careful not to catch valve seats. i would thoroughly recommend porting out the exhaust manifolds aswel because there even more restrictive than the heads. if you look inside them youll see what i mean, lumps and bumps everywhere. you can use the same tip for them but high speed as its cast iron. also trim up the gaskets for the new bigger ports when you fit them otherwise it will all have been a waste!!!!!! give us a shout if you want to ask anymore.

thanks for that bud.much obliged.

Also, try not to match the exhaust ports exactly to the manifold. Ideally you want the manifold at the top edge to be a few mm bigger than the port to kill any reversion.