50 replies to this topic

[daggles]

I'm from the old school of people who tuned engines on the 'every little helps' principle by matching, porting, grinding, polishing and pretty much anything else that would get metal powder up your nose. Having an exhaust driven air pump ramming the stuff in is a bit of a luxury but old habits die hard..

Ever since I swapped my turbo I've wondered why the inlet pipe to the compressor has a thick squared cutoff end and not a nice smooth entry, surely the last place you want lots of turbulence is just before the air arrives at the compressor blades?

Anyway while I was tinkering making myself a nice little fairing for the top of the pipe as an experiment (yes I was really bored cos it's been raining for a month and I can't find my dominoes), I noticed where the big rubber pipe from the air filter had hose clip dents from years of fitment to the original turbo. Some zealous technician had made sure the pipe was properly on by pushing it well down on the turbo inlet pipe and I'd put it back on the new one the same way. There isn't much of a straight bit to the rubber pipe and if you push the pipe well on you get something like the result in the RH pic below (or worse). Having sussed this I pulled the pipe back up leaving only about 20mm still on to get the hose clip onto as in the left pic.



Took it out for a quick test and was gobsmacked by the difference! Slightly more max boost (just over 1/2 pound) but it comes up much, much faster, the whole drive is a lot more responsive, surely my little bit of aluminium fairing couldn't make that much difference? And I was right.. after a bit of experimenting it turned out to be the position of the rubber pipe and yes it really does make a shed load of difference.

Doubtless anyone who fixes these things for a living knows this already and I guess it's obvious really, but if you've had that rubber pipe off and given it an extra shove for good luck when you put it back, go and take another look at it. It's not often you get a decent improvement for free but this could be one of them.

[joshua]

Nice tip - will check out my pipe tomorrow

[siztenboots]

Done this is on mine, and all turbos I fix faults on. It will also give you a bigger air gap between the hose and the heat shield.

[cheeky_chops]

will pull mine out, good idea!! Some people on the astra forums also knife edge the metal inlet pipe on new turbos. Though you have to be very careful that the waste doesnt get ANYWHERE near the turbo!!!

[l14mha]

great call..... had mine off lots recently lol liam

[daggles]

will pull mine out, good idea!!

Some people on the astra forums also knife edge the metal inlet pipe on new turbos. Though you have to be very careful that the waste doesnt get ANYWHERE near the turbo!!!

I had the same thought so I made this instead



it just stands on top of the inlet pipe and does the same job, no risk of junk in the turbo and you can do it with the turbo fitted

[cheeky_chops]

will pull mine out, good idea!!

Some people on the astra forums also knife edge the metal inlet pipe on new turbos. Though you have to be very careful that the waste doesnt get ANYWHERE near the turbo!!!

I had the same thought so I made this instead



it just stands on top of the inlet pipe and does the same job, no risk of junk in the turbo and you can do it with the turbo fitted

Can you knock any more up??

[daggles]

will pull mine out, good idea!!

Some people on the astra forums also knife edge the metal inlet pipe on new turbos. Though you have to be very careful that the waste doesnt get ANYWHERE near the turbo!!!

I had the same thought so I made this instead



it just stands on top of the inlet pipe and does the same job, no risk of junk in the turbo and you can do it with the turbo fitted

Can you knock any more up??

If I can find any more material, this was the end of a solid bar

[Sambo1]

For an engine newbie like me how hard is it to check this ? is it a simple case of poking your head and hand down there when the engine is cold ? Cheers Folks

[cheeky_chops]

If I can find any more material, this was the end of a solid bar

Plleaaaase! - Reckon you could flog loads of these on ebay to the astra lot

For an engine newbie like me how hard is it to check this ? is it a simple case of poking your head and hand down there when the engine is cold ?

If you put you hand down the turbo inlet pipe when its not hot(!) you can undo the clip and pull the pipe up. If its all the way down, it is like the right hand pic. Put it back with a few inches of pipe only

[l14mha]

great advice, did this this evening and what a differance it has made

[daggles]

will pull mine out, good idea!!

Some people on the astra forums also knife edge the metal inlet pipe on new turbos. Though you have to be very careful that the waste doesnt get ANYWHERE near the turbo!!!

I had the same thought so I made this instead



it just stands on top of the inlet pipe and does the same job, no risk of junk in the turbo and you can do it with the turbo fitted

Can you knock any more up??

This one was for a VXR turbo, if you have a standard Z20LET turbo and can accurately (digital caliper idealy) measure the inside and outside diameters of your inlet pipe I'll see what I can do with offcut I have left.

[cheeky_chops]

I am 99% certain the housing is the same, just the internals differ. Will measure

[Cookies220]

If I can find any more material, this was the end of a solid bar

Plleaaaase! - Reckon you could flog loads of these on ebay to the astra lot

For an engine newbie like me how hard is it to check this ? is it a simple case of poking your head and hand down there when the engine is cold ?

If you put you hand down the turbo inlet pipe when its not hot(!) you can undo the clip and pull the pipe up. If its all the way down, it is like the right hand pic. Put it back with a few inches of pipe only

Can this be reached without taking the wheel / liner off?

[lee_VXT]

Can this be reached without taking the wheel / liner off?

yes, iv just had a looksy, its pretty easy to undo the jubilee clip and pull it up and inch or two
shame the jubilee clip wont tighten properly for me

[lee_VXT]

oops

Edited by lee_VXT, 14 September 2008 - 09:57 AM.

[Jimsan]

What a great advice Daggles! It´s even work here in Sweden Did this last night and even if it was a week or two since I drove the car I could feel the difference, much better response when I hit the gas pedal.

[VXT Tim]

Checked mine at the weekend and it is as far down as it can go. Will shift it when i have time. Thanks

[Sambo1]

I undid my clip and couldent pull it up, im not weak my dad and mate tried too. Ended up not being able to do the silly clip Vaxuall put on there and had to go and buy a decent jubilee clip.

[Tolksee]

Can someone post a piccy of exactly what and where I should be looking in the engine bay for this?