20 replies to this topic

[John Faulkner]

Hi guys, its getting closer & closer to the point of the Astra VXR engine going in, so i was wondering if any of you lot knew any mods for the turbo engines that you would class as worth while doing? the clutch & flywheel are staying put for now, as they have only covered 700 miles! and im not sure it would be needed on the 6 speed box.... so far my list consists of: -Pre-Cat Pipe -Uprated Actuator -Aluminium Underdrive Pulley thanks john

[Freedo]

Erm, the top hat perhaps?

[vocky]

don't fit the engine unless you fit a courtenay lightened flywheel first, you WILL regret it

Edited by vocky, 17 January 2009 - 10:41 AM.

[MEAGY]

don't fit the engine unless you fit a courtenay lightened flywheel first, you WILL regret it

Yeh its a pig of a job with the engine in & the clam on!

Cam belt? Also a pain in the ass with engine in lol

[John Faulkner]

unless i've missed it, they don't sell one for the M32, 6 speed box? and cambelt!? it's a 2008 engine with 700 miles on the clock!? john

[slindborg]

C20XE inlet cam + venier pulley with half a tooth of retard on.

[vocky]

unless i've missed it, they don't sell one for the M32, 6 speed box?

you need to give Jon a ring as it's not on their website

[cheeky_chops]

i didnt think anyone did a lightened fly as its dual mass??

[Duncan VXR]

Interesting thread as I have taken my leaky turbo off today and to start the day off to a bad start there was a manifold threaded bolt and nut still attached sitting on the undertray for me that would be the leaking manifold issue and excessive fuel consumption issue manifold is also twisted so even though no cracks it may be going in the bin Head off to get the rest of the stud out so while I am there a bit of head work and change of cams, then do the cambelt while there with the underdrive pulley. Guess I will do the rods at the same time and then fit my new hybrid turbo and see how it gets on at the predicted 340bhp Mark at CS does not think the crank needs to worry at that power - anything else to do while the engine is in bits? Maybe look at removing the dual mass flywheel and convert to std type and maybe change the clutch also. So far it has not been an issue but suspect it can be improved upon (maybe get a diff while its out?) Guess I should get a 3" exhaust also and finish the 80mm intake system also, hope to make a nice curve and power.......? Got some pics to upload soon but may start a fresh thread instead of hijacking this one

[joshua]

Your VXR engine already has uprated rods capable of more than 340bhp

[MEAGY]

Your VXR engine already has uprated rods capable of more than 340bhp

Just the bolts i would think he`s changing?

Also can you not just use a bolt extractor to get it out Duncan

[MEAGY]

unless i've missed it, they don't sell one for the M32, 6 speed box?

and cambelt!? it's a 2008 engine with 700 miles on the clock!?

john

I`d still do it mate, the belt could have been nicked in the crash. Just for piece of mind!

[Duncan VXR]

It may be able to come out with a bolt extractor? - light stopped play today. It is in the head by about 2.5mm Either way as the car will no be my 2nd car now I am thinking of what is needed to run more power from the new turbo on track without early failure of the engine until today I was just going to detune a bit to keep the power down rods are prob only needed for high revs or missed gear changes lol

[siztenboots]

Your VXR engine already has uprated rods capable of more than 340bhp

afaik , the rods are same as C20let , pistons are different due to valve position and cutouts. 350bhp is typical for a stage3 clet , but its the torque and mileage on the rods , 350lb-ft @ 5252 gives you that 350bhp , but its the even bigger overboost torque around 3000 to worry about

Hence , limit yourself on the mid range torque to 350 becuase of rods and go for more rpms with ARP bolts

plus bigger fuel injectors

Lets just look at the cycle of an engine for a few seconds.

right, lets start with the explosion, lots of pressure pressing down on the piston, which pushes on the rod which pushes on the bearing which pushes on the crank, the rod bolt is under negligable strain at this stage, little more than just the weight of the rod cap.

piston reaches top bottom centre, the crank then starts pushing it back up, the crank presses the bearing, which presses the rod which presses the piston, the rod bolt is under no strain

piston reaches the top of the exhaust stroke, the crank rotates and pulls down on the bearing, this presses on the rod cap, which pulls on the rod bolts which has to yank the conrod and piston down against all the momentum they have (proportional to revs)

piston carries on down to bottom dead centre, the crank then starts pushing it back up, the crank presses the bearing, which presses the rod which presses the piston, the rod bolt is under no strain

Piston goes back up and we are back at the explosion.

Edited by siztenboots, 17 January 2009 - 07:39 PM.

[John Faulkner]

cheers guys, any more simple mods out there too? not planning on stripping the engine just yet, i want to get it running first! cheers john

[John Faulkner]

Erm, the top hat perhaps?

if it was a better flowing one, then maybe, but utterly pointless putting a tophat on thats bigger than the inlet, all IMO of course!.....

[Nev]

John,

Definietly do the airbox mod (remove the 2 silly trumpets in it) and possibly drill holes in the back of the box where there is very little room for the air to pass trhough the filter. I did this and though you get a lot of induction noise, it drops the torque curve down about 1000 revs and makes the engine a lot easier to drive at low revs and most probably helps at higher revs too. This costs £0.0 so do it !

Also consider inscreasing the bore of your inlet pipe that run from the AMM to the turbo. The std ones are just rubber and when they get hot they have a habit of semi colapsing! And also they are only 2.25 inches I think, so airspeeds in them will be upto 200 mph. This costs approx £50 to £100 if u insert a solid aluminum 3" pipe. Pro-alloy sell a kit for a bit more than that, but a good improviser like you acan do it for a lot less ;o)

Lastly do the top hat. Its worth doing this becuase it reduces to approx 44mm and additionally is a bend. When I did it I noticed a difference. For a 1/2 finished kit, ring Jack on 07793711686 and ask for his VX220 kit and lok at my Pics . This will cost you about £70 and again helps torque and possibly throttle response. Also rotate the TB by 90 degrees to align the outer apex of the tophat to be inline with the downway side of the buttlerfly valve in the TB.

These 3 mods will make QUITE a diff to the cars performance, so worth doing IMO.

Nev.

Edited by Nev, 18 January 2009 - 09:07 AM.

[cheeky_chops]

manifold is also twisted so even though no cracks it may be going in the bin

Give you a £10er for it? Just want to take it apart, see what all the fuss with these thrust bearing etc is about...

[Duncan VXR]

Paul will get a load of pics both my turbos and manifolds are in the post Ok so based on the following info; "Hence , limit yourself on the mid range torque to 350 becuase of rods and go for more rpms with ARP bolts plus bigger fuel injectors" Which bolts need changing? Head is prob going to come off or engine out so may just get a bit of head work done anyway my drill is too big to drill the snapped bolt with engine still in the car I take it the vxr injectors cannot cope? What about the fuel pump? Cheers

[Winstar]

Ok so based on the following info;
"Hence , limit yourself on the mid range torque to 350 becuase of rods and go for more rpms with ARP bolts

plus bigger fuel injectors"

Which bolts need changing?

The ARP's are the big end bolts.