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The mkiv Supra Owners Club

I need more power (VVTI)


MarkR

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Knock = Det.

Hot days and hot air = more prone to det especially with a blocked INTERCOOLER!!! ;)

 

Thanks Alex

 

I see... does water/alcohol injection etc help with that? I seem to remember reading something about it. Is it expensive?

 

aaaaaaaaaand I seem to remember several people telling me off for my number plate. Maybe I should make the plate outta mesh, or just drill holes in it ;)

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So.... 256 or 264 exhaust cam?

 

I've got an HKS FCON V but it's not a pro. Will it suffice or should I get rid of it and get something else? I bought it from Jezzy accidently a while back thinking it was the FCON V PRO... ooooops :(

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Get that 1st cat out! You'll be amazed how much restriction it is making, the VVti really comes alive de catted. Be aware the VVTi first cat is quite different to all the others, you need a VVti de cat pipe (and yes, I have some for sale... ;))

 

After that consider an ecu, as Pete says, Toyota, like all engine makers with big power turbo engines running cats, set them up to run mad rich under full boost to stop the substrates in the cats melting, or having very short lives. de catted you can lean the mixture and gain a lot of power, safely. You MUST use a decent ecu, and have it mapped by a true expert though!!!

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Get that 1st cat out! You'll be amazed how much restriction it is making, the VVti really comes alive de catted. Be aware the VVTi first cat is quite different to all the others, you need a VVti de cat pipe (and yes, I have some for sale... ;))

 

After that consider an ecu, as Pete says, Toyota, like all engine makers with big power turbo engines running cats, set them up to run mad rich under full boost to stop the substrates in the cats melting, or having very short lives. de catted you can lean the mixture and gain a lot of power, safely. You MUST use a decent ecu, and have it mapped by a true expert though!!!

 

Thanks Chris. Very useful info.

 

So, how much for the decat pipe? Also, while on the subject, where do you plumb in the sensor for the EGT? If it's in the Decat pipe, do you get pipes with a holder for the sensor already built in?

 

Any hints for the cam?

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I have found the VVti cat pipes slow moving of late, as few fresh VVti's are coming into the UK at the moment, so you can have one for 115 pounds plus 6.80 P&P. Fit a stock VVTi ecu for now. I'd leave the cams alone until you can get a proper mappable ecu in the car (which will be expensive). Water injection is a good idea, I sell and use the ERL Aquamist systems, some info on WI below, the first section written by myself, and a link to independent info is here:

 

http://autospeed.drive.com.au/cms/A_107970/article.html

 

Water injection serves 2 closely related functions on a turbo engined

car. Firstly it cools the charge air temperature by utilising an effect

known as the latent heat of evaporation. This property can be self

demonstrated very easily. If you pour something that evaporates quickly

like petrol on your hand it feels very cold. This is the rapidly

vaporising spirit removing heat from your skin and bloodstream by the

aforementioned process. By spraying a very finely atomised mist of water

into the inlet of a turbo engine when under boost conditions the

evaporation of the water into steam causes a temperature reduction in the air and

fuel intake charge. A cold charge is less likely to be subject to

detonation than a hot charge. A cool charge is also denser, able to

carry more air and fuel mix per unit of volume. These 2 properties of

water injection allow either less chance of detonation at a given boost,

maybe allowing lower octane fuel to be used, or to allow a rise in boost

pressure usage without detonation. These are very desirable goals for

any modifier of a turbo engine, or one using an engine mapped to run

on a higher octane fuel than generally available in the UK. Japanese

import turbo cars for example.

 

People ask whether squirting water into an engine causes corrosion. In

fact this is not a problem, the combustion temperatures under boost

ensure the water is turned instantly to steam and is ejected out of the

exhaust. The water mist is injected only when high boost is sensed via

a supplied pressure sensor switch. The basic combustion process of

hydrocarbon fuels causes LOTS of water to be generated anyway, which is why cars

not driven on regular long journeys will rust out a mild steel exhaust

system from the INSIDE out. If water is added in the correct volume, via

the supplied, calibrated jets, this is not a problem.

 

Even when used alongside a larger or more efficient intercooler, or

indeed when an intercooler is used in an application where one was not

present as standard, water injection can and does increase charge cooling

still further. Water can be stored either in the existing windscreen

washer bottle or in a separate, dedicated, container. In cold conditions

it is essential to add an anti freeze additive to the water to stop pump

damage through freezing. Windscreen washer additive serves this purpose

fine and the engine won't mind ingesting this solution at all. Or you

can add neat methanol, which is usually the anti freeze additive in

washer fluid anyway. Using a 50 / 50 percent by volume water / methanol

mix will actually help increase the octane of the intake charge, as an

added benefit. As a yet further advantage the latent heat of evaporation

of methanol is extremely high. A win / win situation. It is not however

obligatory to use methanol as an additive. All components of the water

injection kit that are in contact with the fluid are stainless steel or

able to tolerate water and methanol or screen washer additive without

degradation. A properly set up system does not use a vast amount of

water, in fact a modern car sized screen washer bottle used also for the

water injection reservoir will suffice admirably. A water filter is

included to keep any sludge out of the pump or jet. This should be

checked regularly for contamination and blown out if residue is

apparent within.

 

A more technical explanation:

 

Let us take a quick look at ignition. Those who have a Heywood can look it up

- mines on loan so going by memory. The first thing that happens is a plasma

cloud is formed by the arc consisting of super heated electron stripped atoms.

When this cloud "explodes" a ball of high energy particles is shot outward.

 

The highest energy particles are the hydrogen atoms - and they penetrate the

charge about 5 times as far as the rest of the particles. As they lose energy

and return to normal temps - about 5000 k - they begin to react chemically

with any surrounding fuel and oxygen particles. The effectiveness of spark

ignition is directly related to the availability of free hydrogen. Molecules

containing tightly bound hydrogen such as methanol, nitromethane, and methane

are far more difficult to ignite than those with less bonds.

 

During combustion - water - H2O ( present and formed ) is extremely active in

the oxidation of the hydrocarbon. The predominate reaction is the following:

 

OH + H ==> H2O

H2O + O ==> H2O2

H2O2 ==> OH + OH

Loop to top and repeat.

 

The OH radical is the most effective at stripping hydrogen from the HC

molecule in most ranges of combustion temperature.

 

Another predominate process is the HOO radical. It is more active at lower

temperatures and is competitive with the H2O2 at higher temps.

 

OO + H ==> HOO

HOO + H ==> H2O2

H2O2 ==> OH + OH

 

This mechanism is very active at both stripping hydrogen from the HC and for

getting O2 into usable combustion reactions.

 

Next consider the combustion of CO. Virtually no C ==> CO2. Its a two step

process. C+O ==> CO. CO virtually drops out of early mid combustion as the O

H reactions are significantly faster and effectively compete for the available

oxygen.

 

Then consider that pure CO and pure O2 burns very slowly if at all. Virtually

the only mechanism to complete the oxidization ( Glassman - Combustion Third

Edition ) of CO ==> CO2 is the "water method".

 

CO + OH ==> CO2 + H

H + OH ==> H20

H2O + O ==> H2O2

H2O2 ==> OH + OH

goto to top and repeat.

 

This simple reaction accounts for 99% + of the conversion of CO to CO2. It is

important in that fully two thirds of the energy of carbon combustion is

released in the CO ==> CO2 process and that this process occurs slow and late

in the combustion of the fuel. Excess water can and does speed this

conversion - by actively entering into the conversion process thru the above

mechanism.

 

The peak flame temperature is determined by three factors alone - the energy

present and released, the total atomic mass, and the atomic ratio - commonly

called CHON for Carbon, Hydrogen, Oxygen, and Nitrogen. The chemical

reactions in combustion leading to peak temperature are supremely indifferent

to pressure. The temperatures and rates of normal IC combustion are

sufficient to cause most of the fuel and water present to be dissociated and

enter into the flame.

 

As can be seen above, water is most definitily not only not inert but is a

very active and important player in the combustion of hydrocarbon fuel.

Ricardo and others have documented that under certain conditions ( normally

supercharged ) water can replace fuel up to about 50% and develop the same

power output, or that the power output can be increased by up to 50% addition

of water. This conditions were investigated by NACA and others for piston

aircraft engines. It is important to note that these improvements came at the

upper end of the power range where sufficient fuel and air was available to

have an excess of energy that could not be converted to usable pressure in a

timely manner.

 

As a side note - Volvo recently released some SAE papers documenting the use

of cooled EGR to both reduce detonation and return to a stoic mixture under

boost in the 15 psi range - while maintaining approximately the same power

output. Notice - they reduced fuel and still get the same power output.

 

When you consider that EGR consists primarily of nitrogen, CO2, and water ( to

the tune of about two gallons formed from each gallon of water burned ), you

might draw the conclusion that it also was not "inert". They peaked their

tests at about 18% cooled EGR - which would work out to about 36% water

injection and got about the same results under similar conditions that the

early NACA research got.

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Will I need a 1.2 bar restrictor ring?

 

If you have a none stock, free flowing, cat pipe back exhaust, probably. 15 quid, or 10 if you buy it with the first cat pipe. When / if you fit a stock ecu you will need a fuel cut eliminator (FCD) . I believe the FCON removes or raises this limit internally.

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Thanks for the info Chris. I'll read it in the morning when my eyes are semi open :) I'll also PM you about the decat.

 

I've still got the stock ECU installed, and I've already fitted a FCD (the Thor TRL VFCC). I never ever installed the FCON V as it had the old 3 plug harness and not the 5 plug jobbie that the newer ones had.

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I skim read your post and thought you'd had the 1st decat removed, but kept the second one in, but it's the other way around. Sorry about that.

 

Chris decatted mine and fitted a 1.2 bar ring, and yes it made a great difference.

 

It rarely goes above 1.1 and will hit 1.2 on cold days driven hard (if you believe the Blitz MD gauge). That's fine with me though as I don't drive mine like a loon and prefer longevity. :)

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So.... 256 or 264 exhaust cam?

 

HKS do the Valcon Plus Vcam Kit Pro for the VVTi Supra, this is a variable 264 intake cam and electronics to control the VVTi system. This coupled with a standard HKS 256 exhaust cam and ECU should give you a good increase in mid to top end power.

 

http://www.hks-power.co.jp/products/engine/valcon/img/valconpro_image.jpg

 

Another option could be to fit a combination of the GReddy V-Manage (VVTi controller) and GReddy E-Manage Ultimate.

 

http://www.greddy.com/featured/vmanagejdmopt.pdf

 

Give me a shout Mark if you'd like more details.

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If it were my car I'd do the following.....

 

First off: Get rid of the first cat, fit a restrictor ring, duct the intercooler and move the numberplate.

 

Then: Consider water/meth injection and look at ecu options be that EMU, Motec or Autronic.

 

Think about ecu choice carefully and be honest with yourself - are you looking to extract more power and stay with stock turbos? If so then a full standalone may be a little OTT. However I definitely would not get an airflow signal fudger like the EManage Blue - I would consider the EManage Ultimate as a minimum requirement as injector duty cycle can be increased/decreased without touching the airflow signal (which is good :) )

 

Then: Consider exhaust cam change to a 264.

 

If you are gonna start pissing around with cams, ecu, water injection then having a boost gauge, an exhaust gas temperature gauge (in the manifold) and a wideband are a good idea.

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HKS do the Valcon Plus Vcam Kit Pro for the VVTi Supra, this is a variable 264 exhaust cam and electronics to control the VVTi system. This coupled with a standard HKS 256 intake cam and ECU should give you a good increase in mid to top end power.

 

http://www.hks-power.co.jp/products/engine/valcon/img/valconpro_image.jpg

 

Another option could be to fit a combination of the GReddy V-Manage (VVTi controller) and GReddy E-Manage Ultimate.

 

http://www.greddy.com/featured/vmanagejdmopt.pdf

 

Give me a shout Mark if you'd like more details.

 

Nic, mate, you've written it backwards ;) :p

 

It's a variable intake which you mate to a standard HKS 264 exhaust cam.

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I skim read your post and thought you'd had the 1st decat removed, but kept the second one in, but it's the other way around. Sorry about that.

 

Chris decatted mine and fitted a 1.2 bar ring, and yes it made a great difference.

 

It rarely goes above 1.1 and will hit 1.2 on cold days driven hard (if you believe the Blitz MD gauge). That's fine with me though as I don't drive mine like a loon and prefer longevity. :)

 

Hi Pete... no probs :)

 

I don't have a boost guage but use the display on the SBC ID (the blitz boost controller) which is quite nice as it does a graph, so you can see your boost levels for the last few minutes. I think I will decat the front then.

 

Chris, expect a PM :)

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If it were my car I'd do the following.....

 

First off: Get rid of the first cat, fit a restrictor ring, duct the intercooler and move the numberplate.

 

Then: Consider water/meth injection and look at ecu options be that EMU, Motec or Autronic.

 

Think about ecu choice carefully and be honest with yourself - are you looking to extract more power and stay with stock turbos? If so then a full standalone may be a little OTT. However I definitely would not get an airflow signal fudger like the EManage Blue - I would consider the EManage Ultimate as a minimum requirement as injector duty cycle can be increased/decreased without touching the airflow signal (which is good :) )

 

Then: Consider exhaust cam change to a 264.

 

If you are gonna start pissing around with cams, ecu, water injection then having a boost gauge, an exhaust gas temperature gauge (in the manifold) and a wideband are a good idea.

 

Thanks Dan. I'd better get modding then :)

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and a flux capacitor!! :D

 

(Let me know when I'm helping.)

 

Great Scott Marty!!! ... 1.21 Gigawatts!!!!!!

 

"If my calculations are correct, when this baby hits eighty-eight miles per hour... you're gonna see some serious shit...."

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