# Question: How could one achieve a flat torque curve on a VRT?



## Tom Long (Sep 21, 2007)

Particularly before 4000rpms.........
Domestics and Evos can do it..........
How can VRTs achieve this?...........


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## Southcross (Jul 2, 2004)

*FV-QR*

I was always taught that "Torque is related to airflow"... flow more air, get more torque (which leads to more HP). what I understand is the reason our torque falls off is our heads can't flow enough to support high rpms, unlike a K-series or an Evo. I supposed that with porting, or a head with more valves, the torque curves could be flatter/higher instead of dropping off


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## KubotaPowered (Jan 27, 2005)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Tom Long)*

If you wanna flatten out the torue curve, reduce piston stroke. With a long stroke comes "peaky" torque like you see in low revving engines and diesels on one extreme and on the other extreme you have engines like Honda and Ferrari with less torque and lots of HP that have small strokes that rev very high.


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## zwogti (Jan 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Tom Long)*

get a small turbo that will give you full boost around 3k rpm but than you will not have any top end, we go with big turbos for few reasons= more top end, more power, and some people try to stay way from torque, what are going to brake the transmission, my HP and TQ is kind of flat but start around 5400K to about 7400K but than again I have a big turbo and it spools up late, around 4800K


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## Southcross (Jul 2, 2004)

*FV-QR*


_Quote, originally posted by *KubotaPowered* »_If you wanna flatten out the torue curve, reduce piston stroke.

I didnt' realize that stroke would flatten a torque curve, I thought "short stroke" was a function of "reciprocating mass" that would limited the ability to Rev the **** out of an engine


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## KubotaPowered (Jan 27, 2005)

*Re: FV-QR (Southcross)*


_Quote, originally posted by *Southcross* »_I didnt' realize that stroke would flatten a torque curve, I thought "short stroke" was a function of "reciprocating mass" that would limited the ability to Rev the **** out of an engine


Yes that is partially correct but think if it in term of leverage. Decrease the throw of the crank, in essense moving the fulcrum point inward towards the main bearings, and you have less leverage than before which equals less torque. Couple that with a high flowing head and some boost and you have a nice recipe for traction and high end power. Only downfall is that the engine will be a dog off the line. BUT to make it work you have to essentially re-engineer the whole engine because your compression ratios will be off as well as the timing 

_Modified by KubotaPowered at 4:36 PM 7-6-2009_


_Modified by KubotaPowered at 4:40 PM 7-6-2009_


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## TBT-Syncro (Apr 28, 2001)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Tom Long)*

evos do not have tq curves any flatter than a VR. all building more TQ down low accomplishes is wheel spin, and more broken parts.


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## VOLKS-MAN (Oct 7, 2000)

*Re: Question: How could one achieve a flat torque curve on a VRT? (TBT-Syncro)*


_Quote, originally posted by *TBT-Syncro* »_evos do not have tq curves any flatter than a VR. all building more TQ down low accomplishes is wheel spin, and more broken parts.


Not much wheel spin if you have AWD...eh TBT


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## TBT-Syncro (Apr 28, 2001)

*Re: Question: How could one achieve a flat torque curve on a VRT? (VOLKS-MAN)*


_Quote, originally posted by *VOLKS-MAN* »_
Not much wheel spin if you have AWD...eh TBT









i can still get lots of wheel spin when i want.


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## Tom Long (Sep 21, 2007)

*Re: Question: How could one achieve a flat torque curve on a VRT? (EL DRIFTO)*

Anyone here spray with their VRT?.............


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## zwogti (Jan 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Tom Long)*


_Quote, originally posted by *Tom Long* »_Anyone here spray with their VRT?.............









no need for that, just go up on the boost control a bit, if you need NOS you may have a small turbo


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## jimivr6 (Feb 18, 2003)

*Re: Question: How could one achieve a flat torque curve on a VRT? (zwogti)*

twin turbos


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## Weiss (Jun 21, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (jimivr6)*


_Quote, originally posted by *jimivr6* »_twin turbos

5 turbos.


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## jimivr6 (Feb 18, 2003)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Weiss)*

2 small fast spooling turbos, hpa did it with 2 ko4's i think or gt28's.


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## Weiss (Jun 21, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (jimivr6)*


_Quote, originally posted by *jimivr6* »_2 small fast spooling turbos, hpa did it with 2 ko4's i think or gt28's.

Quicker power production will move the torque far more to the left. Think of it this way. This is how I was taught. Torque is the physical measurement of the force to move weight. Torque is the actual measurement of moving weight. Whereas HP is the rate at which it's delivered.


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## EL DRIFTO (Jul 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Weiss)*

sequential, inline biturbo
add a roots








i'm thinking the oe intake manifold yeilds the most area under the curve
if you have an unwanted torque peak, 
from an intake resonance that will always happen at the same rpm,
you could pull timing @ that specific rpm
which means you could add timing before and after it
since the VE is down there
has anyone advanced the cam timing, more than the HG, which is 1/2 degree i think
(9:1 HG vs mk3 HG)
or run 9.5:1?
_Modified by EL DRIFTO at 9:54 PM 7-11-2009_


_Modified by EL DRIFTO at 11:18 PM 7-11-2009_


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## zwogti (Jan 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Weiss)*


_Quote, originally posted by *Weiss* »_
Quicker power production will move the torque far more to the left. Think of it this way. This is how I was taught. Torque is the physical measurement of the force to move weight. Torque is the actual measurement of moving weight. Whereas HP is the rate at which it's delivered.

think like this >>>> more torque down low, fast spool, 2 turbos and full boost around 2k, 3k = to a lot of trannys you are going to buy near future


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## EL DRIFTO (Jul 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (zwogti)*

i was noticing the intermediate shaft having 32/18 teeth
offsetting that timing
could provide very small timing changes
http://forums.vwvortex.com/zerothread?id=4473543


_Modified by EL DRIFTO at 6:56 PM 7-12-2009_


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## EL DRIFTO (Jul 11, 2004)

*Re: Question: How could one achieve a flat torque curve on a VRT? (Tom Long)*

how many american muscle cars/evos have 1.8 rod ratio
i've seen 1.5 rod ratio (2.0 16v) rev to 8000 - torque
i'm guessing:
2.0 16v & 1.7 = 1.5 rod ratio - torque
1.8...............= 1.6 rod ratio - ok
1.6...............= 1.7 rod ratio - those things rev
VR................= 1.8 rod ratio - come on
makes for a smooth engine
but vr engine design needs long rods
i think the 1.8 ratio keeps things from breaking


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