# ABA rev limit



## Rallymech (Mar 5, 2007)

Does anyone have any thoughts on how fast an ABA can be spun? I am getting ready to bo an ABA bottom end swap in my Digifant GTI. I need to figure out what chip to use, the Digifast with the stock rev limit or the Techtonics with the higer limit. Thanks.


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## ABA Scirocco (May 30, 2001)

*Re: ABA rev limit (Rallymech)*

It'll spin pretty good, well beyond the stock rev limit. What's the rev limit on the TT chip?


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## Jettaboy1884 (Jan 20, 2004)

*Re: ABA rev limit (ABA Scirocco)*

I take my stock bottom end ABA to 7200 RPM without any trouble. Anything beyond this, and the hydraulic lifters start to float. (I have HD springs)
I would imagine that a fully balanced ABA bottom end could rev to 8k with no issues.
Keep in mind, the ABA is not exactly the ideal motor for high revving, as it has a long stroke crank. However, it is quite strong and will certainly rev if you want it to...


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## Rallymech (Mar 5, 2007)

ABA Scirocco: I have been told that the TT chip will rev to 7200.
Jettaboy: I am going the ABA route because of the long stroke torque. How is your motor in the higher rpm range? I assume that you are running a chip?


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## ABA Scirocco (May 30, 2001)

*Re: (Rallymech)*

At 7200 rpm, you shouldn't have any issues with the bottom end.


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## Rallymech (Mar 5, 2007)

Thanks, ABA.


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## Jettaboy1884 (Jan 20, 2004)

*Re: (Rallymech)*


_Quote, originally posted by *Rallymech* »_
Jettaboy: I am going the ABA route because of the long stroke torque. How is your motor in the higher rpm range? I assume that you are running a chip?

Yup, the ABA is a nice torquey motor. However, if you really want to get into details, a motor with a shorter stroke crank will like to rev more quickly. Ideally, a motor thats stroke is shorter than its piston diameter will rev the best (oversquare)
I'm running an ABA in my '83 GTI on the stock CIS. There is no rev limit. It pulls pretty hard up to about 7200, and can spin a little more, but at around 7500 I get quite a bit of vibration, and I believe the valves begin to float. It's a stock Bottom end, with no balanced internals.


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## Andrew Stauffer (Oct 2, 2000)

*Re: (Jettaboy1884)*

This amounts to internet racing and splitting hairs. Truly. The whole rod length vs revs is true if you compare John Deer to Honda S2000. For the purposes of VW engines, it's BS. 
The ABA revs *beautifully*. I took a stock bottom end to 8300rpms while warming the tires at the track, she never blinked. Not a factory head, however. 
Quarter mile runs to 7300rpms, the bottom end never blinked. They *sing* at those rpms. Have you seen the pistons? Practically Mahle race stuff. 
Nate Romero-most don't remember Nate anymore- took an ABA bottom end WITH A 95mm TDI CRANK- to 240whp, normallly aspirated. Granted, 20v head. But as a pro stock racer, he would not have gone that route if the bottom end was fundamentally flawed for revs as the interweb would lead you believe. 
The torque is the flow characteristsics of the head, cam, management, NOT the bottom end. Make em breath and they sing....


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## Jettaboy1884 (Jan 20, 2004)

*Re: (Andrew Stauffer)*


_Quote, originally posted by *Andrew Stauffer* »_This amounts to internet racing and splitting hairs. Truly. The whole rod length vs revs is true if you compare John Deer to Honda S2000. For the purposes of VW engines, it's BS. 
The ABA revs *beautifully*. I took a stock bottom end to 8300rpms while warming the tires at the track, she never blinked. Not a factory head, however. 


Well, that's definitely an interesting spin on things. (Pun intended







)
So, you're right that it comes down to splitting hairs. I'm sure you have seen this thread: http://forums.vwvortex.com/zerothread?id=3472422
I was just taking what I have learned in that thread and applying the bottom end discussion to the OP's question. Note, that I wasn't trying to say that the ABA Can't rev. I take my unbalanced ABA to 7500, and at that point it is the cylinder head that keeps it from revving higher.
You really brought up a good point though. VW cylinder heads are lacking in the CFM department, which is what making power really comes down to. Even the VW 16v head is poor in comparison to other makes...
I didn't know that someone made 240 NA Hp with a 20v head. That's pretty impressive, and goes-to-show that it really comes down to breathing.
Do you have any dyno plots for this motor? I think it would be interesting to see the power curve. http://****************.com/smile/emthup.gif 
If you haven't checked out the thread that I made about making Naturally Aspirated Horsepower, come and take a look, and share what you know. 















Mike.


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## chois (May 12, 2000)

Yep, it will rev fine. Without a big cam, it will just be making more noise at those rpms. I assume that you have some sort of head and cam if you are wondering about reving it out.


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## Murnau (Oct 29, 2007)

*Re: (Jettaboy1884)*

Mike:
The URL for "The Professor" Nate Romero is http://www.race101.com/ . The 20/20 "project" page is here: http://www.race101.com/project_2020.html
No dyno sheets or any technical data, really, but still very cool nonetheless.
Nate Romero is also one of the 8v drag racing heroes. 
http://****************.com/smile/emthup.gif


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## Rallymech (Mar 5, 2007)

chois: Yes, I am planning a torque focused street motor. The rev limit question really had to do with the chip. I am debating building a Performance Trends EZ Flow flow meter to develop my counter flow head. I have an Autotech 270 cam that I will continue to use.


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