4722 replies to this topic

[SteveA]

TBH I found the difference between 250 bhp & 300bhp in these cars is very small in 1st and 2nd gear. It's when you hit 3rd and onwards it becomes noticable (maybe due to boost limitation in low gears) I have R888's and 250bhp and I find it very difficult to spin in the dry unless I do a (very rare) full launch start.

Edited by SteveA, 02 February 2010 - 12:55 PM.

[VXT Tim]

I've never experienced the grip of these semi slicks. I'm sure it makes a world of difference

[Whiteboy]

TBH I found the difference between 250 bhp & 300bhp in these cars is very small in 1st and 2nd gear. It's when you hit 3rd and onwards it becomes noticable (maybe due to boost limitation in low gears)

I have R888's and 250bhp and I find it very difficult to spin in the dry unless I do a (very rare) full launch start.

On an astra vxr the full boost doesnot come in until 3rd to protect the gearbox from all the torque, so I would imagine the vxt is the same.

Steve.

[tangerine_sedge]

Nipper is gaining some fans - I've had a work colleague forward on a link to your blog. He'd received it from another friend....

[Nev]

Thanks Tangerine, I wonder who contacted who?! I guess you are still working Orange (assuming that you survived the annual kull!)

[Nev]

Have added a little known and interesting section on piston selection and calibration/measurement here:

[Nev]

Ferrea came back To Steve Milton with a quote for making 4 sets of inlet and 4 sets of exhaust valves (all +1mm on OEM size). Because of VAT, import duty, markup by their suppliers (Colesport), weak GBP etc etc the prices are: Inlet (each): £53 + VAT Exhaust (each): £ 57 + VAT This means a full set of 16 valves would be just over £1000.... Too much for what may yield 5 to 20 BHP, so I am going to retain the OEM valves. If I wanted say an extra 60 BHP, I could simply pay an extra £100 and put a 76mm housing on the turbo instead - far better value for morey (though more lag).

Edited by Nev, 09 February 2010 - 07:59 PM.

[cheeky_chops]

This means a full set of 16 valves would be just over £1000....

fook me!!

any reply from the guy in AS?

[Nev]

Yet another fickle change to the valve saga. Steve has now found another US company that will make up some valves at the following prices: Inlet, £20 Exhaust, £36 (made of nemonic 80 or 90)

[Nev]

Well, it's been a long time since my last update, but the project just hit another benchmark today... I have parked the car up on axel stands in the garage and started taking the rear clam off in anticipation of extracting the current engine. I spent approx 1.75 hrs doing this and had to stop once my semi-broken back started aching too much . Hopefully I will complete the clam off phase tomorrow, but as this is my first time taking a clam off I am doing the job slowly I expect. Thankfully all my nuts and bolts seem to be coming off easily enough and I have Italian Ricky to thank for his usefull guide.

The new engine's valves are now being made and are due for delivery at the end of May 2010, and hopefully this won't get put back any more or I will simply have to abandon trying to put larger valves in. Once the valves are delivered, this means the head and then be assembled with its heavy duty springs, modified Audi valve guides , Audi valve stem seals, solid lifter set and brand new cam with their mechanical cam profile. This in turn will be followed by a full engine assembly in mid to late June (hopefully). The swages for strengthening the block have arrived from a chap called Chris Reay (an ardent Vauxhall fan usually found on the MIG website) and the block awaits machineing to allow these to be inserted.

All in all I have started getting excited about the whole project again and am keen to get cracking. After hearing the amazing power output of 451 BHP from Chris Randals engine, my engine with the additional benefits from all the head work/mods I am doing may (and I stress MAY) make even more power, just from a humble GT30R71. I am aware that Chris's engine has a bespoke and seemingly very compentant mapping whereas mine will be done at Courtenays by Klassen and Shield, retaining the less advanced Bosch Motronic 1.5.5. However, I will be happy with anything from 420 BHP with reliablity being more important than power as I can't imagine how depressing it would be to have to re-extract the new engine out of the car if it has serious internal problems

Edited by Nev, 22 May 2010 - 10:08 AM.

[Cookies220]

Good stuff Nev

[siztenboots]

did you ever find out the static compression of c20let mahle pistons vs standard. I take it your head is z20let not an leh?

[Nev]

I've added a small update and several pics of taking the clam off and some other interesting bits under it...

LINK HERE

Steve, I didn't work out the SCR of the C20LET piston chambre, just the volume (in CC) of the piston crown to top of the block, which turned out to be 14 CC. I would never measured the volume in the head, as I don't need this for my calcs on a Z20LET head. Sorry.

Edited by Nev, 17 October 2010 - 08:10 AM.

[cheeky_chops]

Whats the timescale on this now Nev?

[Nev]

Ug, Im not sure about timescales - I've learnt not to make any foolish predictions ! Progress so far: a) The bespoke +1mm oversize valves have been fabricated and supplied (by 2 diff companies). b] Valve seats have been ground out to accomodate the new valves. c) Solid lifter cams with 10.5mm inlet valve lift and 9.5mm exhuast valve lift (!!) have been ground and supplied. d) The head has been hand machine by a professional head specialist (who works on Prodrive heads). e) Block strengthening dowels have been supplied but not machine in. f) All other internal parts are awaiting building up. My old engine is ready more or less for extraction from the car. I still have lots of other major tasks ahead though... 1) Buy turbo. 2) Fabricate an exhaust manifold (with Dave hopefully) from 3mm thick steel. 3) Fit new engine. 4) Get old exhuast pipe to mate with new turbo. 5) Fit larger pipework for charge throughout (this may not happen if I feel lazy). 6) Run engine in with old map. 7) Remap at CMS or elsewhere.

Edited by Nev, 18 October 2010 - 11:27 AM.

[Nev]

Well, after another hour or two in my garage and the engine is now ready to be lifted out. I will be scouring eBay for an engine hoist.

[Dynamo]

Hi Nev,

We've not met, but I do a few trackdays in my VX and like the sound of the engine you're building .

I was looking at your blog (v. good by the way) and noticed in one of the pictures that your turbo actuator bar is a two part bar with a brass joiner on it. (it's shown in the photo with caption "Turbo area (nearside POV)" on this page: https://sites.google...odywork-removal )

I had the same two part bar and managed to heat up the brass joiner enough that it stripped the thread whilst on a trackday at Le Mans a couple of year back. They effect was that the wastegate was fully open all the time, so no boost and car down to about 50% power. I remember spending a day in baking hot sun trying to fix it whilst the other cars whizzed by. The issue occured because the actuator rod is right next to the turbo, so lots of heat in that area.

After my problem, Courtenays fitted an uprated actuator with a single piece actuator rod (no joiner). Given the engine power / heat you will be generating, you might want to replace the actuator/bar too?

Good luck with the car...really looking forward to seeing it once finished.

Adrian

[Nev]

Thx for the tip Adrian, I can see your point. I will be using a diff actuator on the new engine + turbo anyway, as it will be sprung to open at 1.8 bar of boost.

Edited by Nev, 31 October 2010 - 09:03 PM.

[darronwall]

i also had a similar actuator and sure enough the bar ended up snapping on a trackday,the collar around the bar i think was brass so i would think the heat did it in

[edwards]

nev, how long would you need an engine hoist for? if it would be easier for you you could borrow mine for a day or 2? think im a couple hours away from you......then you could borrow again when you need to put it back in.....just a thought anyway