92 replies to this topic

[Nev]

Ummm, you can get cam regrinds from Piper that will suit your needs for approx £250. Their 'VXR' regrind adds 1mm of lift to the inlet which will be totally safe for you with the Cometic 1.9mm gasket. In fact, if you have bought Courtenays/PECs (Cosworth) forged pistons with the deeper pockets, you could even ask for 1.5mm to 2mm of extra lift (though these are more expensive as they require blanks to grind from), though you will likely incur a lump idle. If you have bought these pistons you will find it impossible to get exact info about them, I tried on 3 occasions to different people in vain and gave up. Std valve springs will be fine, so long as you dont rev beyond 7500 RPM (which you turbo wont want to do anyway). What exhaust + downpipe will your car have? Hopefully 3" at least or you will be bottleneck your exhaust gases and might melt your head/hot side with too much back pressure. Stage 6 tune?! What is their stage 5 tune?! LOL You will end up with whatever Klassen pulls out of the bag unless you specify how you want your setup to work. If I were you, when you go there for the map, I would specify that you want as flat a torque line as possible (at the expense of power). Also, take the car out for an extended drive (ie at least 50 miles) before paying and make sure the partial throttle mapping has been done well enough (both at low and high revs).

Edited by Nev, 08 October 2011 - 02:31 PM.

[craigb78]

Ummm, you can get cam regrinds from Piper that will suit your needs for approx £250. Their 'VXR' regrind adds 1mm of lift to the inlet which will be totally safe for you with the Cometic 1.9mm gasket. In fact, if you have bought Courtenays/PECs (Cosworth) forged pistons with the deeper pockets, you could even ask for 1.5mm to 2mm of extra lift (though these are more expensive as they require blanks to grind from), though you will likely incur a lump idle. If you have bought these pistons you will find it impossible to get exact info about them, I tried on 3 occasions to different people in vain and gave up.

Std valve springs will be fine, so long as you dont rev beyond 7500 RPM (which you turbo wont want to do anyway).

What exhaust + downpipe will your car have? Hopefully 3" at least or you will be bottleneck your exhaust gases and might melt your head/hot side with too much back pressure.

Stage 6 tune?! What is their stage 5 tune?! LOL You will end up with whatever Klassen pulls out of the bag unless you specify how you want your setup to work. If I were you, when you go there for the map, I would specify that you want as flat a torque line as possible (at the expense of power). Also, take the car out for an extended drive (ie at least 50 miles) before paying and make sure the partial throttle mapping has been done well enough (both at low and high revs).

Ok so who do I contact with regard to cam regrinds.? Piper them selves? So that sounds just about ideal really. Yer I'm also considering going to RS tuning for the mapping as I have heard a lot of good reviews about those guys and they have also mapped speckys 600+ bhp tigra so they must know there stuff so I need a flat torque line then when I get it mapped why is this? The exhaust is going to be a full custom 3" built by a company near me who build exhausts for formula Renault so shud be good quality.

[Nev]

Just give Piper a ring and talk to them about your spec, they are quite approachable. A flat torque line (once you get over the initial turbo 'hump') will help you control the power delivery. The flatter it is, the more linear the power delivery and more controllable it is. A bespoke 3" exhaust pipe will be excelent. Try and get them to make the curves of the down pipe (and rest of the exhaust) as wide a circumferance as possible to help flow. Make sure you wrap it too. Also get them to add a mount point from the downpipe to a spare block bolt hole uder the turbo (there are several in that area). This will stop all the weight of the turbo + manifold + downpipe levering downwards on the head studs which can shear with all the load (particularily when you drive over bumps etc). I am not sure that getting your head ported and gas flowed will be worth it for your budget. At best you will gain about 2% or 3% more power, so for the cost I would not recommend it. I'd save the money and spend it on a LSD or something else if I were you.You can port match your new Nortech manifold to the head yourself very easily - it's not rocket science, you just need a blueing/engineering pen and a die grinder and some patience.

Edited by Nev, 09 October 2011 - 05:39 AM.

[craigb78]

And I have now taken delivery of my Nortech manifold

[Duncan VXR]

As per when I did the cams I would shim the oe springs by 1mm - I made some to suit but never used the oe VXR regrind of the piper stuff and went for the most I could get from a regrind. Basically has more on the exhaust side. Springs seem to be fine but never bothered with lowering the compression and was stock oe kit with no issues - any reason why you would want to lower it further? The cams def help loose low down torque - cant remember what the std cams become a restriction but its high! So could help if you want a bit of extra top end in exchange for low down response DG

[craigb78]

After having a long chat with a few people I am going to leave the head as it is tbh as I don't fee anything is needed because a long chat with George lockerby the guy with the 488bhp corsa c which was at 10 of the best. He hasn't had any head work done and said for the power I want there is no need and also standard springs should also be fine for the power I want and he is using the klassen cams which are 600 but he said all in all they are worth it as they are the dogs dangelers as he had a set if regrinds before them and he said they are now worlds apart. With apposed to the lowering compression I thought I would lower it a little using the bigger head gasket just to be on the safe side as I would rather be bait over cautious now than after it's all back together and realise it's too high. The biggest desision I need to make now is weather or not to send my manifold back to nor tech and to get him to put a external waste gate flange on it and go external as apposed to internal to avoid boost creep best as possible

[danger7]

Hi all, Not to be a bringer of doom or gloom, when I installed my first Z20LEH engine the block let go in a spectacular style. The power output was in the region of 330 bhp and 1.6 bar boost pressure from a 2871rs Garrett. Investigation of the block showed the bore had cracked around the water jacket between cyinders 2 & 3, the wall thicknesses on the LEH have been deliberately reduced compared to a Z20LET block. There have been reports of block failures in a number of tuned VXR and OPC astras & I'm not saying it will happen when power outputs are pushed, just dont want anyone to spend a lot of money for the same thing to happen which befell me. In my case the LEH fitted now is not technically an LEH its an Z20LEH/C20LET combination, i.e. all internals and head are retained standard LEH the block is a modified C20LET with thicker walls between the cylinders. Regarding pistons, replacing the standard LEH mahle squeeze cast skirted piston is really a waste of money if you are aiming for 350ish bhp. The piston is very very good and can cope with 350-375 bhp no problem. Hope above helps - pm if you need more info Cheers Ian

[siztenboots]

coscast c20let block?

[danger7]

Hi sizeten, Coscast (Cosworth process Worcester) is the aluminium AlSi7Cu3 head, the block is GG Cast Iron - Tupy Brazil manufactured for GM major quality issues and now safely back to Eisenwerke Bruhl, Cheers Ian

[craigb78]

I see what your saying matey I am using standard pistons you see then I know lots of people running way over 330bhp with standard leh for example klassen is on a standard leh block withna 600bhp vx220 and also his Newley built astra Vxr which will be 900bhp on standard leh block One off my good mates Lee also has courtenays project car when they where developing the leh in to the mk4 astra in hiss 888 ands he been running 380bhp for 3 years with no issues so it's abit of gamble That you hopefully have a good block also I will be fitting my h beam steel rods Did you have standard rods in yours?

[danger7]

Hi, Yep been running standard internals now for 3 years and 20,000 miles with various states of tune highest power output was @360 bhp at 1.62 bar with 390 Nm torque, now I've settled for 320 bhp and 335 Nm at 1.41 bar. Had the head off once at 15,000 miles and all was well with pistons and rings - head was also showing no issues. Regarding blocks just my bad luck I guess Cheers Ian

[craigb78]

Another present to myself....Thankyou to myself :



Just a shame about the bill that came with it......

[craigb78]

Now to take my engine on the stand and the rebuild bits to my father along with the tools and he can get on with doing it

[Nev]

Hi all,

Not to be a bringer of doom or gloom, when I installed my first Z20LEH engine the block let go in a spectacular style. The power output was in the region of 330 bhp and 1.6 bar boost pressure from a 2871rs Garrett. Investigation of the block showed the bore had cracked around the water jacket between cyinders 2 & 3, the wall thicknesses on the LEH have been deliberately reduced compared to a Z20LET block.

Wow, I never relaised the water jackets failed so easily on the LEH block and at such low power/compression.

To avoid this issue you can have dowels inserted into the water jacket. I did this this as I knew I wanted lots of power. Previously I had though it only necessary on 400 + BHP engines, but your experience shows otherwise (abeit with a slightly weaker LEH block compared to my LET block).

[craigb78]

Now had a change of plan again the nortech I have just bought is up for sale and I am now going to get Jay at nortech to me me a new manfold with a vband fitting and external waste gate to try and eliminate as much boost creep as I can. So the new job sheet for Jay is: New manifold with vband and external waste gate Supply gtx3071r with vband fitting Supply tail 38mm external waste gate Make down pipe and screamer pipe Make full exhaust system So then my new rebuild engine should be built around the same time. Still unsure in the cams to go for yet but have bought a set of 875cc injectors to cope with the power so the car will then be mapped to 400bhp with the potential of more if 400 isn't enough

[Nev]

Now had a change of plan again the nortech I have just bought is up for sale and I am now going to get Jay at nortech to me me a new manfold with a vband fitting and external waste gate to try and eliminate as much boost creep as I can. So the new job sheet for Jay is:

New manifold with vband and external waste gate
Supply gtx3071r with vband fitting
Supply tail 38mm external waste gate
Make down pipe and screamer pipe
Make full exhaust system

So then my new rebuild engine should be built around the same time. Still unsure in the cams to go for yet but have bought a set of 875cc injectors to cope with the power so the car will then be mapped to 400bhp with the potential of more if 400 isn't enough

Ugg, not speccing the manifold correctly was a bit of a mistake

Also, I'm afraid that your injectors you've bought are far too big, your mapper will not be able to do as good a job with them. 875cc injectors would be capable of fueling a 700 BHP engine.

Lastly, a GTX 3071R is too large for just 400 BHP. You should get something smaller IMO if you only want cira 400 BHP, as it will lag less and will require a smaller/cheaper (possibly internal if you can) wastegate.

Not doing any head mods is the correct thing to do IMO for 400 BHP

Edited by Nev, 16 October 2011 - 04:00 PM.

[craigb78]

well after speaking to RS Tuning who are the people doing my mapping which are proven mappers by george lockerbys corsa c and speckys tigra, they have told me i will need 875cc injectors for 400 bhp as they will be better than a set of 630s at full capacity. also the GTX3071 is also the turbo of which i was told by rs tuning to go for i also kniow wa guy who is running 330bhp on a astra with 875cc inectors and his car is on a gt3071 not a gtx and he doesnt suffer with any lag what so ever and he was the guy who went to rs tuning too so tbh if worst comes to worst and the injectors and turbo are too big for 400bhp i will then go for 450bhp and deal with the fact i cant get all my power down all the time lol. and as for the head work i am not doing anything as i think its pointless for the power i want as a standard head has been proven by george lockerby on his corsa to make 488bhp. also i have now bought a TTV L&B Flywheel.

Edited by craigb78, 16 October 2011 - 04:08 PM.

[Nev]

well after speaking to RS Tuning who are the people doing my mapping which are proven mappers by george lockerbys corsa c and speckys tigra, they have told me i will need 875cc injectors for 400 bhp as they will be better than a set of 630s at full capacity. also the GTX3071 is also the turbo of which i was told by rs tuning to go for i also kniow wa guy who is running 330bhp on a astra with 875cc inectors and his car is on a gt3071 not a gtx and he doesnt suffer with any lag what so ever and he was the guy who went to rs tuning too so tbh if worst comes to worst and the injectors and turbo are too big for 400bhp i will then go for 450bhp and deal with the fact i cant get all my power down all the time lol.

and as for the head work i am not doing anything as i think its pointless for the power i want as a standard head has been proven by george lockerby on his corsa to make 488bhp.

also i have now bought a TTV L&B Flywheel.

My engine make 500 BHP with 630 cc/min injectors. I did the calcs myself and double checked them and they run at a max of 80% duty cycle, though mostly way below 80%. It might be that the RS mappers use a higher BSFC figure to keep their map very safe and help with cooling and hence want the larger injectors for that. The knock on effect is poor fuel economy and possibly worse granularity of partial throttle mapping.... this will manifest itself when trying to feather the throttle when on boost. That guy you mentioned with a 330 BHP Astra using 875CC injectors seems rather extreme to me however (seeing as a Klassen/Courtenay map happily uses 435 cc/min for the same power). However having said that RS may map them really well for partial throttle, have you have a chance to drive one of their mapped cars? Remember that drag cars (like Specky's) aren't really interested in partial throttle drivbability as they just floor the accelerator every time, but in your case your car has to be driven on the road without launching into the rear of the car in front of you !

BTW, another tip for you to save some money: If you buy an external wasted turbo (like a GTX30R71) just get a 0.3 or 0.4 bar spring in it, not a 1.0 bar spring like I did (which meant my turbo couldn't make less than 450 BHP).

You probably know this already, but you have to be a bit careful about comparing one dynos BHP figure to anothers. A car rated as 500 BHP on one dyno can be as low as 375 BHP on another, so you have to take peoples BHP quotes with a pinch of salt. I went to a dyno meet for VXes about a month ago and even on the same dyno, the same car was making +/- 10% 5 minutes later (not ACT related either) !!!

Keep us posted with developments, sounds like you are cracking on nicely.

Edited by Nev, 16 October 2011 - 04:29 PM.

[craigb78]

Yer I see what your saying georges corsa c is usd a as daily driver not really overly fussed on the fuel economy as I'm not building it for that. I'm just doing injectors as to what the people who are going to map my car have said. My mate with the 330bhp astra is a daIly drive and georges corsa which is 488bhp is doing quarter miles In 11.6 so I would imagine that figure is pretty close a guy who also made a bhp run of 590bhp at regal went there and couldn't make over 420 on there rolling road so i think there rr reads low is anything Ok mate thanks for the advise on the waste gate Jay at nortech is supplying so I assume he knows what spring will be needed but I will take that in to consideration when it comes to ordering it.

[craigb78]

Injectors and TTV Lightened and Balance flywheel have now arrived will get pics up soon. all parts are coming now to get it built