Author Topic: Turbo ABU. Am I nuts?  (Read 2681 times)

Offline cheys03

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Turbo ABU. Am I nuts?
« on: September 04, 2011, 10:01:47 am »
Ok....so... I've been running the turbo AAV for ~8months, 10,500 miles. So far no problems *touch wood*.
I need another project and the possibility of removing the AAV and running a low-ish boost 1.6ABU (9.3:1 compression?) wets my appetite. It may produce less overall bhp than the current setup, but the increased off-boost torque might be more suited to my driving style. In terms of physical changes I'd probably need a vernier pulley, intake manifold cut&shut to allow for the different bolt pattern and possible lengthen the down pipe slightly. I think the exhaust manifold would be ok?

I was thinking 5-10psi for boost. I don't want the expense of custom rods, pistons etc. I realise these engines are considered more fragile than the bullet-proof earlier short blocks, am I insane even entertaining the thought?

I value your opinions chaps. Many thanks

Offline Alexiskayak_7

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Re: Turbo ABU. Am I nuts?
« Reply #1 on: September 04, 2011, 01:36:19 pm »
Go ahead mate!

A friend had a ABU Golf 3,he rebuilt the engine, decreased compration ratio fitted g40 management, with g60 injectors, boosting up to 0,6bar he made 190hp. With just a 268 dbilas cam and a ported head...
When i first drove the car was so sweet of boost (comparing with my g40), and when you boost it up it has loads of torque.
I loved to see that block in a lightweight mk3 chassis.
abu engine components are much more frigile compared with g40 ones,it will be dangerous if you turn the boost up.

Offline cheys03

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Re: Turbo ABU. Am I nuts?
« Reply #2 on: September 04, 2011, 04:17:42 pm »
This is good information, thanks Alexiskayak. How did your friend lower the compression? When he rebuilt the engine was it just bearings, gaskets etc or did he replace the rods? Thanks

Offline Andy

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Re: Turbo ABU. Am I nuts?
« Reply #3 on: September 04, 2011, 06:10:34 pm »
I like your thinking! Are you just bored because the AAV hasn't broken yet? ;) ;D

Exhaust manifold should be okay, you will need to change the inlet as you said though - or cut and shut to suit.

Steve Morris (86C) always planned on building a G40'd ABU to see what happened, and I suspect that on low boost it'd do just fine. Given enough time it's something I'd like to do too, but wind the boost up 'til it shits itself, to fully explore the limits of the motor.

I probably wouldn't bother decreasing the compression, your AAV is okay, and my mish-mash of engine parts is 9.3:1 CR too. Once you start spending on spacer plates, 2 headgaskets etc. it stops becoming such a budget bit of fun.

Interestingly we've had someone ask us to map an AEE with decompression plate, K03 and G40 management recently - sounded like an interesting project too!

Offline Alexiskayak_7

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Re: Turbo ABU. Am I nuts?
« Reply #4 on: September 04, 2011, 06:47:59 pm »
He lowered the compration ratio using a custom thicker hg.
Yes, just bearings, piston rings and gaskets. OEM rods and pistons.
If i remember the CR was about 8,7:1. If you need further information, just ask!

Offline Yoof

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Re: Turbo ABU. Am I nuts?
« Reply #5 on: September 04, 2011, 07:57:04 pm »
Inlet manifold potential PITA- and possibly an expensive solution?


Offline cheys03

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Re: Turbo ABU. Am I nuts?
« Reply #6 on: September 04, 2011, 09:52:38 pm »
Thanks for the info Alexiskayak

Hehe, something along those lines Andy! :)
I get bored easily, so will probably always be tinkering with something. Good to hear others have been thinking the same, though I wonder why Steve never built it?

Yeah, you have a point with the inlet Yoof. It's certainly possible but could be costly. Carver on CP paid ~£120 to have his GT and ABU manifolds mated. I know a local fabricator who could do it, and hopefully it would be a reasonable cost. Luckily I've a spare GT manifold sat in the garage that cost me £5 so the parts would be negligible. Just thought, the sump would also need either 'adjustment' or (more likely because the oil return is already there) swapping for a Mk3 item to clear the subframe.

£250 should cover the engine and the manifold and I'd build the vernier to save money. Then just any bearings, gaskets, rings needed, depending on the condition of the engine. A fair amount of cash..... but there's a lot of torque..... 8)


Offline PeteG40

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Re: Turbo ABU. Am I nuts?
« Reply #7 on: September 04, 2011, 10:10:19 pm »
from what i can gather (from Steve 86c) you need to weld a mk2/3 mount to the later engines.  So you'll need an earlier block to cut up (which is what steve does) or make some cut/shut mounts

Offline cheys03

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Re: Turbo ABU. Am I nuts?
« Reply #8 on: September 04, 2011, 10:19:16 pm »
Aha! Forgot about that one. Cheers Pete. Though also forgot that I've an adapted engine mount and plate for the 3rd bolt in the garage (does anyone else find themselves forgetting about parts they're hoarding?)

Offline Yoof

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Re: Turbo ABU. Am I nuts?
« Reply #9 on: September 05, 2011, 06:44:57 am »
Clutch! Think organic helix is good for 250Nm?

It's a good idea, given that most of your current hardware will work, it's just being aware of the little bits like inlet, and possibly downpipe height change, that might be £50 here and there- all adds up!

Would be interesting to see, and deffo cheaper than a 1W/1341cc conversion, obviously need to think about knock sensor too...

Offline cheys03

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Re: Turbo ABU. Am I nuts?
« Reply #10 on: September 05, 2011, 02:29:03 pm »
Clutch, knock sensor...good point! Oil return might to be extended, but I think there's enough adjustment to cover it hopefully. Of course road tax will go up each year too. I think the project's a go-er then by the sounds of it - many thanks for your thoughts and input chaps. Timescale-wise I'll aim for the CP RR in Jan, there's no great hurry (yet!).
Thanks again

Offline Nick_S

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Re: Turbo ABU. Am I nuts?
« Reply #11 on: September 05, 2011, 06:01:43 pm »
Should be good to see, no replacement for displacement ;D

Its worth noting that on the thrust facing side of the pistons on two ABU engines i've seen had bad scouring marks. Probably neglected engines by golf owners though!

Offline cheys03

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Re: Turbo ABU. Am I nuts?
« Reply #12 on: September 05, 2011, 08:34:16 pm »
Thanks Nick. While we're on the subject, this will be my first time buying an engine from a (well-regarded) breakers. I plan to whip the head off once I get it home, but are there any checks I can do before buying? Maybe along the lines of:

- Check under oil cap and inside rocker cover with finger for any sign of mayo which may indicate a headgasket failure.  Although I'll whip the head off anyway it may be an indication of a possible warped head if any overheating got bad. Could be mayo from storage anyway though.
- Any major signs of oil leaks
- Mileage written on the top Vs flywheel wear
- Valve stems through the inlet and exhaust ports
- Cambelt not snapped or suspiciously new

That's all I can think or really... but should I look for anything else?

Edit:
- oh, and check for compression if possible
« Last Edit: September 05, 2011, 09:07:13 pm by cheys03 »

Offline Nick_S

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Re: Turbo ABU. Am I nuts?
« Reply #13 on: September 05, 2011, 09:35:17 pm »
If you are able to get a compression reading then do so. I'd also take off the breather on the back of the block, its pretty big on the ABU. A lot of 'cake' in there would be a sign its probably missed a few oil changes. Inlet manifold is completely different spacing and bore, so you'll need a cut and shut welding up. Engine mounting on the block is the same as the AFH type.

Offline Yoof

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Re: Turbo ABU. Am I nuts?
« Reply #14 on: September 06, 2011, 07:00:51 am »
Always a risk unless you can whip the sump off too and check everything.

Easy things to look at are:

Spark Plugs correct spec & reputable brand
Tensioner/Cambelt/Waterpump- OEM or not?
Usual under the filler cap check- whilst there take a good look at the cam (if not whip the rocker cover off) this is a good indication of oil quality used, mileage done, and general top end health.

Flywheel wear is questionable, I know some (women) drivers who could get through a clutch in a matter of weeks- this doesn't really have an effect on the engine's health.

Yoof