# VRT WAI questions..............



## instg8r (Sep 22, 2003)

i have a 91 b3 wagon witha 95 vr6 swap.
custom turbo kit
t3/t4 .63, clipped exhuast wheel and hogged out internaly.
xs power "evo" fmic good to "600whp"
2.5" piping
c2 obd1 chip
36# injectors
3bar fpr
9:1 headspacer........
this chip tune is good for 15psi......just looking to improve on this setup.

just curious, looking into WAI, but really dont know where to start.
i know that the benifits are cooling and octane boost. i was reading other threads in this forum, just wondering what to use, what size nozzle? also im thinking single nozzle set-up placed for general improvements on both cooling and octane boost.
any advice, info and direction would be great.
Thanks in advance
Matt


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## [email protected] (Jan 13, 2005)

*Re: VRT WAI questions.............. (instg8r)*

Matt, nozzle sizing is a function of 3 main variables: fuel injector flow, fuel pressure, and boost pressure. Other factors involved in setting up a system are compression ratio, fuel octane level, altitude/barometric pressure, ambient air temperature, intercooler type, and certainly the manner in which the vehicle is used.
Since you've already clarified the main points here, I can make some suggestions. Since VR6Ts generally have very long intake piping, you'll benefit from a dual nozzle set up in a big way. If you go with that configuration, I'd use a 175cc just after the intercooler and a 100cc at the throttle body. Run it at ~165psi and you'll be good to go.
A single nozzle set up is going to be a bit more challenging given available nozzle sizes... I can certainly figure something out, though. I'd probably place it 1/3 of the way from the IC discharge pipe. But, it surely depends on what size we'd end up implementing. So, that's just general advice.
If you have more questions, please ask. This is a set up that will benefit greatly from some WAI! For max benefits you'll want to run full 15psi boost. http://****************.com/smile/emthup.gif


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## instg8r (Sep 22, 2003)

*Re: VRT WAI questions.............. ([email protected])*

interesting, you suggest dual nozzle. i didnt think about that, i did keep the stock intake mani, its 2.9 clone.
i will research again
i was looking at a devils own kit, but noticed that the pump is only rated @ 150psi, will that be a issue with 2 nozzles?


_Modified by instg8r at 10:52 AM 8-16-2008_


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## [email protected] (Jan 13, 2005)

*Re: VRT WAI questions.............. (instg8r)*


_Quote, originally posted by *instg8r* »_i was looking at a devils own kit, but noticed that the pump is only rated @ 150psi, will that be a issue with 2 nozzles?

It depends on how much nozzle that pump is trying to feed, how much boost you're running, etc. As for doing more research... I'm more or less the guy that put WAI on the map within the VW enthusiast space. If you've got a question chances are pretty decent that I've got the answer. Just ask. http://****************.com/smile/emthup.gif


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## therealvrt (Jul 21, 2004)

unless you are getting high egt's you won't see much gain by adding this unless you have a way to add timing, so gains will be there but will be minimal


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## [email protected] (Jan 13, 2005)

*Re: (.therealvrt)*


_Quote, originally posted by *.therealvrt* »_unless you are getting high egt's you won't see much gain by adding this unless you have a way to add timing, so gains will be there but will be minimal

Unless we're talking about EGTs so high that the impeller is about to melt down and fail, high EGTs = more energy to spin the turbo. How are you linking EGT to gains from WAI?
Adding timing is an excellent means to extract more power. Increasing boost is another and leaning the mixture is yet one more way. Of course, one can also run lower octane fuel, too. The more volatile fuel will increase cylinder pressures more quickly -similar to increasing timing. The WAI will make this safe. There are many ways to skin a cat.
The accurate part of your statement, however, is that WAI by itself will do little compared to a properly tuned set up. But, that's the case for almost any mod.


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## therealvrt (Jul 21, 2004)

*Re: ([email protected])*

i am linking the egts and wi to the same reasons that richening up the mixture in the cylinder lowers egt's


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## [email protected] (Jan 13, 2005)

*Re: (.therealvrt)*


_Quote, originally posted by *.therealvrt* »_i am linking the egts and wi to the same reasons that richening up the mixture in the cylinder lowers egt's

WAI will certainly lower EGTs. There's no debate there. However, you state that running WAI on an engine without high EGTs will do little to improve performance (unless timing is increased). I'm challenging your claim and am saying that:
a) You can use other means than advancing ignition timing to optimize a tune with WAI. Implementing the changes that I described previously can produce substantial gains even if timing is held steady.
b) Dropping the EGT will not generally improve engine output.
c) The primary reason to run a fat mixture or to use WAI is to suppress detonation. The lowered EGTs are merely a byproduct.
d) It is easy to *raise* EGTs with an overly rich air/fuel mixture and retarded ignition timing.


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## instg8r (Sep 22, 2003)

*Re: ([email protected])*

Scott, you know your sh!t.
i was just thinking that even though the lower egt's wont help, but having cooler intake, more octane will allow the ecu to run more timing, thus recreating some of the egt loss......no?
school me please http://****************.com/smile/emthup.gif


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## [email protected] (Jan 13, 2005)

*Re: (instg8r)*


_Quote, originally posted by *instg8r* »_Scott, you know your sh!t.

Thanks for the complement, sir.

_Quote »_i was just thinking that even though the lower egt's wont help, but having cooler intake, more octane will allow the ecu to run more timing, thus recreating some of the egt loss......no?

Well, first let's distinguish between combustion chamber temperatures and exhaust gas temperatures. They're not the same thing although there's an obvious relationship. What we want during a combustion event is complete oxidation (burn) of the fuel. The flame front in the chamber will be intensely hot if/when all fuel and air are consumed. However, once the event is finished, the exhaust will cool very quickly.
If, however, an overly rich mixture is injected into the chamber, or if the ignition timing is overly retarded (in both cases to save the engine under heavy stress) it is unlikely that all fuel will be burned until it reaches the exhaust system. The result is often hotter EGTs than would be experienced with a leaner mixture that burns completely.
Now, what we want is for the rapidly expanding chamber gases to exert a steady shove on the piston. What's undesirable is an uncontrolled "detonation" of air/fuel. The sharp pressure wave that results is what wrecks piston crowns, ring lands, rods, etc. 
As you know well already , WAI raises the air/fuel charge's octane rating. That means that the energy from the combustion event will be released over a longer period of time. So, then, by the time the combustion event is finished, the piston will be positioned relatively farther past TDC. Thus, the piston will "sit" at a greater distance from the crank centerline. Since the energy is transmitted via a steadily larger torque arm over more time, the result is more twist on the dyno chart -usually across a wider rpm band! 
Since the energy is released in a controlled and longer shove versus that aforementioned "bang", the engine's mechanical parts will be less stressed. SO, now, let's finally address your question:
*Answer: *With nothing else changed (timing, boost, octane, etc.), the EGT's will drop. Some gains will be had coming largely from the torque effect described just previously. But... if boost is added, for instance, then more fuel and air can be burned to release even more energy in the same time. Yes, EGTs will climb -possibly to previous levels. Let it do so. Who cares? You've got lots more power to enjoy with no more or less stress on the engine!
THAT is wassup.


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## instg8r (Sep 22, 2003)

*Re: ([email protected])*


_Quote, originally posted by *[email protected]* »_
THAT is wassup.










damn skippy


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