# Info on high-compression stroker ABA's?



## secondgen (Jan 9, 2004)

Researching, almost all the stuff in the archives is related to stroked low-compression ABA's.
If you have solid answers/insight please share!
Looking to yield ~11:1CR. Will be running a worked counterflow head, TT 276 or 288 camshaft, standalone and 40mm ITB's. And this will be a street driven car. So if what I'm after will not be doable on 93octane, I'll reconsider the CR.
What combination of parts will be needed. Will oil squirters on the OBD1 ABA block become an issue with the longer stroke? I have both OBD1 and 2 blocks at my disposal. 
Thanks in advance, I'd start a FAQ/Info/Build page as i collect information. http://****************.com/smile/emthup.gif


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## all-starr-me (Jul 14, 2003)

*Re: Info on high-compression stroker ABA's? (secondgen)*

You want 11:1 get custom pistons or mill/deck a little off the block/head. A stroker crank like a TDI one will give you a 14:1 at least, of course if you add a 16v head it will drop it down to a usuable 11-12 and have a ton more flow and potential. If you have already worked and 8v I gues you are set that way but will be limited to 130-140hp, where a 16v could see 170+.
Here is a good page for info: http://www.not2fast.com/turbo/...shtml


_Modified by all-starr-me at 10:32 PM 10-1-2008_


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## secondgen (Jan 9, 2004)

*Re: Info on high-compression stroker ABA's? (all-starr-me)*

Thanks! A 16V head is out of the question right now, I've got too much time and $ into this 8V head to start over with a stock 16V head.
That calculator's handy... http://****************.com/smile/emthup.gif


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## antichristonwheels (Jun 14, 2001)

*Re: Info on high-compression stroker ABA's? (secondgen)*

My machinist milled the mounts for squirters 1,2,3, to match the height of #4 to make room for the 95.5 crank.


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## richanddanger (Jul 31, 2008)

*Re: Info on high-compression stroker ABA's? (antichristonwheels)*

does anyone know what kind of displacement using the deisil crank adds? and how to acheive a lower (around 11.5) with an 8v head as compared to what all star me said of 14. will the length the rods and pistons work with large cams? interested in doing a build like this and would like as much info a possible any help would be appreciated!


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## vwpat (Oct 25, 2000)

*Re: Info on high-compression stroker ABA's? (richanddanger)*

The TDi crank adds ~1 point of compression so it, a shaved head and maybe a thinner headgasket may get you to 11.5:1 but watch your clearances.


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## ABA Scirocco (May 30, 2001)

*Re: Info on high-compression stroker ABA's? (vwpat)*

What, nobody remembers how to do grade 6 arithmetic?
Here's the info you need. 
The stroke on a stock ABA crank is 92.8mm, on the 1.9L diesel crank it's 95.5 so the diesel crank pushes the piston (95.5-92.8)/2= 1.35mm further into the head chamber. That reduces the combustion chamber volume by 7.72ccs 
The bore of the ABA is 82.5mm and the compression ratio of the stock ABA is about 9.7:1 (Yes, I know most of the published figures say 10:1, I've cc'd several of them, never had one come in at 10:1 yet) so that makes the total chamber volume about 57.0cc. With the 95.5 crank, you need to subtract 7.72 from that and recalculate the compression ratio and you come up with 11.35:1. The compression numbers are based on the stock ABA cylinder head chamber volume of 32.5cc, with your worked over counterflow head the volume's probably smaller so you'd need to redo the calculations with your numbers.
Personally, I wouldn't use the stock pistons with a 95.5mm crank in spite of the fact they might give you a reasonable compression ratio. The reason for this is that the clearance between the piston and the head becomes very small and that altered the quench and squish characteristic of the combustion chamber, likely making the engine more susceptible to detonation and/or pre-ignition. Instead, I'd order new pistons they'll cost you about $500.00 but you can get them made to your specs so you know they're appropriate for your application. Get them so that they have zero deck clearance with the 95.5mm crank and a dish volume sized to give you the compression ratio you want.


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## secondgen (Jan 9, 2004)

*Re: Info on high-compression stroker ABA's? (ABA Scirocco)*

Thank you, that's the kind of info i've been waiting for. http://****************.com/smile/emthup.gif


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## reggie2fast (Dec 12, 2004)

you may also want to look int using 2.0 16 valve pistons they have a 1mm smaller wrist pin it will drop the piston top into the bore using stock aba pistons they hang out of the block slightly .. unfotuneately the 16 valve pistons are flat top and will up the compression ratio those pistons in a aba stock stroke yield 10:1 so im thinking with a stroker crank you probally will get around 13 


_Modified by reggie2fast at 5:56 AM 11-2-2008_


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## vwpat (Oct 25, 2000)

*Re: Info on high-compression stroker ABA's? (ABA Scirocco)*


_Quote, originally posted by *ABA Scirocco* »_What, nobody remembers how to do grade 6 arithmetic?
Here's the info you need. 
The stroke on a stock ABA crank is 92.8mm, on the 1.9L diesel crank it's 95.5 so the diesel crank pushes the piston (95.5-92.8)/2= 1.35mm further into the head chamber. That reduces the combustion chamber volume by 7.72ccs 
The bore of the ABA is 82.5mm and the compression ratio of the stock ABA is about 9.7:1 (Yes, I know most of the published figures say 10:1, I've cc'd several of them, never had one come in at 10:1 yet) so that makes the total chamber volume about 57.0cc. With the 95.5 crank, you need to subtract 7.72 from that and recalculate the compression ratio and you come up with 11.35:1. The compression numbers are based on the stock ABA cylinder head chamber volume of 32.5cc, with your worked over counterflow head the volume's probably smaller so you'd need to redo the calculations with your numbers.
Personally, I wouldn't use the stock pistons with a 95.5mm crank in spite of the fact they might give you a reasonable compression ratio. The reason for this is that the clearance between the piston and the head becomes very small and that altered the quench and squish characteristic of the combustion chamber, likely making the engine more susceptible to detonation and/or pre-ignition. Instead, I'd order new pistons they'll cost you about $500.00 but you can get them made to your specs so you know they're appropriate for your application. Get them so that they have zero deck clearance with the 95.5mm crank and a dish volume sized to give you the compression ratio you want.
I came up with 11.1:1 using my "Grade 6 arithmetic" which is why I said ~1 point higher than the "advertised" comp ratio of 10:1. ABAs I have seen (and the value I used) are usually around 9.6:1 so it is ~1.5 points higher than the "true" comp. ratio.


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## ABA Scirocco (May 30, 2001)

*Re: Info on high-compression stroker ABA's? (vwpat)*

Apologies Pat, I should have acknowledged that you were in the right ballpark.


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## mudanddust (Oct 24, 2007)

*Re: Info on high-compression stroker ABA's? (secondgen)*

this is some good info


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## Col-Buddy-Greenleaf (Jun 27, 2007)

*Re: Info on high-compression stroker ABA's? (all-starr-me)*

"If you have already worked and 8v I gues you are set that way but will be limited to 130-140hp, where a 16v could see 170+"
Wait a minute, all of that work for only 140hp?
Please tell me this isn't right.


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## mudanddust (Oct 24, 2007)

*Re: Info on high-compression stroker ABA's? (secondgen)*

what do you think about using stock pistons and a head spacer?


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## wantacad (Apr 4, 2003)

*Re: Info on high-compression stroker ABA's? (mudanddust)*

Just leaving a mark here so it's in my watched topics.
Awsome info... http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## CanadianCabby (Sep 1, 2006)

*Re: (reggie2fast)*


_Quote, originally posted by *reggie2fast* »_you may also want to look int using 2.0 16 valve pistons they have a 1mm smaller wrist pin it will drop the piston top into the bore using stock aba pistons they hang out of the block slightly .. unfotuneately the 16 valve pistons are flat top and will up the compression ratio those pistons in a aba stock stroke yield 10:1 so im thinking with a stroker crank you probally will get around 13 

_Modified by reggie2fast at 5:56 AM 11-2-2008_
... dont use 1
_Quote, originally posted by *reggie2fast* »_you may also want to look int using 2.0 16 valve pistons they have a 1mm smaller wrist pin it will drop the piston top into the bore using stock aba pistons they hang out of the block slightly .. unfotuneately the 16 valve pistons are flat top and will up the compression ratio those pistons in a aba stock stroke yield 10:1 so im thinking with a stroker crank you probally will get around 13 

_Modified by reggie2fast at 5:56 AM 11-2-2008_
 this set up would require differnt/ modded rods... and would not be streetable


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## 91redjetta (Aug 28, 2006)

*Re: (CanadianCabby)*

my math sucks.. I'll be the first to say it. So.. I have a early aba block and a aaz crank(1.9 diesel). When a was taking the aba crank out I grabbed sommething that I could look at piston height with. With stock aba crank the piston was about a razor bblades thickness below the deck.. 
pulled all the stuff out of the block. Put the 1.9 crank in. First off the counter wieghts hit the piston squirters. All but #4. It's down father then the rest. Took squirters out.. #1 counter wieght rubs the back outside corner( inside of course). Rubs as in stops the crank from spinning. (this why people knife edge the crank I'm sure.) now to me it looks like there is lots of metal in this spot. Enough I believe you could take metal out of the block. Save the crank from being knifed..(i like counter wieghts!)... So I put #4 aba piiston and rod back in with the aaz crank. Nothing else hit. Just would have to take care of the piston squirters and the #1 counter wieght to block problem.. So far... At top dead the aba piston is what I would say is a stock head gasket thickness out of the block. I'm sure this would cause high compression problems. 

maybe a thicker head gasket could be put on it. Or the stock aba pistons machined down to zero deck? Maybe both? 
just my way of hill billy messuring.. Sorry to bother anyone..


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