# Best way to build an engine for ITB



## vwscotty (Jun 1, 2012)

Ok, before anyone freaks out, I know this is not a cut and dry topic and that there is no single "best" way to build an engine. I'm just looking for some opinions and guidance

Currently I'm running a completely stock ABA in my mk2 and I'm looking into starting a ITB project. I want to run a 16v head with jenvey ITB and megasquirt.

I know the 16v head is going to drop my compression ratio way too low. It looks like the most common solution to this I saw was using the 'ABF' pistons to raise the cr back up to around 10:1 IIRC.

Here is where I'm getting confused - Some people said that because the ABA has a longer stroke than the 16v engines it is not ideal for an ITB setup. However I see some other people using 'stroker' engines which (correct me if I am wrong) caused the stroke to be even longer than stock.

So my question to you guys is, what do you think is the better way to go? Short stroke high rpm, or longer stroke higher displacement? Or something else entirely? 
If you could please back up your opinions that would be appreciated. opcorn:


Also, this is not a track car, just a fun project that I want to do the right way.


And yes, I am aware I will be broke forever. :screwy: :beer:


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## rhussjr (Aug 7, 2000)

There is nothing wrong with using an ABA/ABF setup with ITBs. As stated, this will not be a track car and revving isn't a major issue. Years ago, I built one of the first forced induction 16V ABA using ITBs on the Vortex. I am currently in process for building a new motor for my 92 GLI, which will feature a Mk4 2.0 block with 2.0 FSI crank, DM Forged rods and 12.5:1 compression pistons and Borla ITBS managed with VEMS.


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## -RalleyTuned- (Nov 17, 2008)

The ABA/ABF bottom end is a good idea, but you should go to the next step further and use a TDI crank in the aba bottom, with the stock rods (or go h-beams) and 9a 16v pistons. The tdi crank will give you massive torque, couple that with a ported 16v head and some 288 cams and you will have a engine which would truely see the benefit of ITB's

also one that would put out nearly 200whp NA


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## vwscotty (Jun 1, 2012)

Thanks for the responses! So if I'm thinking about this correctly, since its not a track car and higher rpms aren't an issue, I should do the TDI crank to get the extra torque? Almost 200hp sounds really nice too. With the 9A pistons what is the compression ratio? I still want to keep it on pump gas.

Also rhussjr, just out of curiosity, what kind of numbers did you get with that turbo ITB setup?


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## rhussjr (Aug 7, 2000)

450 hp to the wheels with low boost on 9:1 compression. I wouldn't do the TDI crank.


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## bonesaw (Aug 8, 2004)

I'd consider using a mk4 2.0 block. You should be able to pick one up relatively cheap. You would have the internal trigger wheel for megasquirt on crank. And retain the rod length of the 9A motor. So you can get off the shelf 11:1 wisecos or wossner makes 12.5:1. You will need to get custom headbolts and new accessories but I think it will be worth it. Issam from INA has a thread about it. It's titled like 06X-16V


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## vwscotty (Jun 1, 2012)

damn rhussjr, that thing must have been a beast! Why wouldn't you recommend the TDI crank?

Thanks bonesaw, I didn't even consider that, Ill definitely look into it


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## bonesaw (Aug 8, 2004)

I've been looking into tdi crank for increased displacement. People talk about rod ratio. And also many of the cranks being trashed from the high comp of diesel. You can make a pretty fun car without breaking the bank. My personal setup is mk4 2.0 block. Wossner 12.3:1 pistons. 20v head ae111 throttles. Header and Lugtronic. Makes about 200whp and is a blast to drive.


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## rhussjr (Aug 7, 2000)

vwscotty said:


> damn rhussjr, that thing must have been a beast! Why wouldn't you recommend the TDI crank?
> 
> Thanks bonesaw, I didn't even consider that, Ill definitely look into it


It was a beast:










High revving and long stroke do not go together. Just adding the extra stroke does add torque, but not enough to warrant the cost. Diesel cranks are strong, but they have a use, in diesels with low revs. 92.8mm is just fine. If you really want a screamer, build a Mk4 block with a 83 or 83.5mm bore and the lightest piston and rod combo you can get with a set of 268-276 cams.


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## vwscotty (Jun 1, 2012)

rhussjr said:


> High revving and long stroke do not go together. Just adding the extra stroke does add torque, but not enough to warrant the cost. Diesel cranks are strong, but they have a use, in diesels with low revs. 92.8mm is just fine. If you really want a screamer, build a Mk4 block with a 83 or 83.5mm bore and the lightest piston and rod combo you can get with a set of 268-276 cams.


I realize they don't go together, that was where my original question started. Which is better for an ITB setup, long stroke or high rev? I saw some people saying high revving is better and some saying the TDI crank is the way to go


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## rhussjr (Aug 7, 2000)

High rev works best for making good HP.


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## -RalleyTuned- (Nov 17, 2008)

i wouldn't say either one is "better" than the other. They are just options and make a different engine in the end. I am building a NA ABA/16v for a friend who wants gobs of torque and good hp, so the TDI crank is the way to go for his engine. Its a daily driven car that won't see much high rpm, so building an engine for high rpm is sort of silly for a street car. 

Street engines are all about reliability and torque, no one runs around at over 6000rpm all day. You also don't put a long stroke crank in an engine you intend to build for high rpm. Building an engine for a street car is all about matching up a nice package that will retain daily driveability and have good power, without sacrificing longevity and running race gas. 

the 9a piston/tdi combo puts the compression right around stock 10:1 iirc the thread correctly, but the actual compression would need to be measure with the engine put together. 

I love the mk4 block/16v head setups, they are reasonably cheap, you get a solid bottom end with a trigger wheel and those bottom ends are getting really easy to find. 

ITB's function is to provide fine tuning of each cylinder, so higher compression and large cams will be the most matched setup to run ITB's. I have found them to me more of a pain and expense than they are worth for anything short of a full race engine. I have talked countless people out of ITB's on daily driven street cars and I have never had any issues making a really fast car with a factory 16v intake, just food for thought. You can save yourself a whole heap of $$ and still make really good power using the stock intake setup and you won't loose any torque down low. Most people just like the thought of them and they do sounds sweet :laugh:

IMO it is better to figure out what you want from the engine, and then build the engine that best suits what you need instead of wanting a certain component and trying to make that work for you. In the end every person ends up building the engine that suits the purpose, and most of them want or had ITBs and no longer run them on street engines. This is just my opinion based on my experiences though :beer:


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## vwscotty (Jun 1, 2012)

Thank you RallyTuned, rhussjr, and bonesaw for your help. This is exactly the kind of help I was looking for :thumbup:


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## Sycoticmynd29 (Jan 17, 2011)

For someone aiming for High revs, would you guys suggest an ABA, or AEG block?

Going dry sump is also a possibility, but not definite, so if one has a better oiling system than the other, would that be the main factor?


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## rhussjr (Aug 7, 2000)

Personally, I have built and ran about every VW motor available. My GLI will be running an AEG block with an FSI forged crank. The intent is not to be an extremely high revver, though it could be, but this is a budget build car. If I was building it for competition, I would stick with the AEG block and use a Eurospec 4130 crank and Pauter Titanium rods with a JE FSR piston similar to the units that I will be running. It all comes down to budget when you start planning a motor and its intended use.


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## -RalleyTuned- (Nov 17, 2008)

Sycoticmynd29 said:


> For someone aiming for High revs, would you guys suggest an ABA, or AEG block?
> 
> Going dry sump is also a possibility, but not definite, so if one has a better oiling system than the other, would that be the main factor?


What is your definition of high revs? and what is the motor being built for?


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## Prof315 (Jan 5, 2009)

Stock Volkswagen oiling systems (both old school 058 and the newer 06A based blocks) are good to 8000 rpms reliably. Yes, I know, people have turned their motors higher than 8K on stock oiling but if you have ever seen a VW engine that came apart at high (8500+) rpms you'll know why I say 8K is a SAFE limit.


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