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The mkiv Supra Owners Club

Sucking & Blowing (bis)


Paul Booth
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Sorry to all those who didn't get to read the thread that disappeared and which has the background level-setting in it. I'll just *summarise* my goals/plans.

 

NB As before, if someone suggests something because it sounds/looks nice, I'm gonna be quite rude.

 

Now my 120MPH barrier has gone away I want to plan to move on.

 

I have no intention (and previously stated as much) of sticking everything in the catalogue on my car to 'see how it goes'.

 

I'm going to add little bits and get everything around that right and future proofed before adding the next 'bit'.

 

My next-steps plan was to fit a cat-removal down-pipe (NOT a full system yet) and something like the HKS air filter. I want to see what impact that has and what I can do to optimise that before changing to a 'boxed' induction system, FMIC and full exhaust system.

 

Questions so far:

What is the difference between Chris Wilsons de-cat and Shop!'s?

Should I fit a boost gauge if I'm only swapping out the cats? If so, which one and where from?

When does the FMIC become *mandatory* and not just *nice idea*?

When does the induction kit become *mandatory* (careful about talking about nice sounds here or I'm gonna get pissed off)?

Eric mentioned a low-cost mod which made a big difference. Eric, what was it and what peripherals are needed to be in place too?

 

I think I've remembered everything but if you think of a good point I forgot, slip it in.

 

I'm gonna start copying posts on here into a Word doc for the next time the thread disappears.

 

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From Eric:

 

Paul,

 

I would say that the first modification you should look at is ditching both cats. Chris Wilsons are made with the J spec in mind, and are 2.5 inch in diameter to sepcifically prevent overboost. The added bonus with ditching the cats is a drop in EGT's. Spool up time for the turbos is significantly quicker as well. That was my main gripe with the car in stock form, once on full boost it was quick, but waiting for the turbos to spool seemed to take forever.

 

If you still have the stock exhaust, you may still find that boost does not increase to the expected 18psi or so, as the Toyota system is still very restrictive. I know that Pete Betts was boosting to 14psi or so with decat pipes and the standard exhaust. I think the boost controllers are not really necessary on a J spec with decat pipes and exhaust, you should be able to hit 18psi. The UK specs have difficulty in getting above 15psi with this configuration, and need either a boost controller or bleed valve.

 

FMIC?? Hmmmm..... I think everyone agrees that 1.2bar (perhaps slightly less) is the max you want to go to with the stock IC, so again, with just the decat and exhaust I think you wouldn't really need to go that route, unless you wish to give yourself extra insurance. With a FMIC you are going to introduce more turbo lag. Water injection personally I didn't like the sound of, as there were too many stories of failures with the system. That's only a personal opinion though.

 

As Gavin says, a boost gauge is essential. It was amazing how much the boost varied from day to day with my car. On the hot summer days, I could set up my DSBC to hit 1.1 bar, come the evening when it was cooler, I was hitting 1.3 on the same setting, so definitely an essential piece of kit.

 

Air intakes?? I think that falls into both your categories of a)looks nice and b)sounds nice! If I did it all over again, I would have kept the standard Toyota airbox, then when I got a FMIC fitted, have the Ash solution of putting a HKS unit in the front air intake where the stock IC sits.

 

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Muchos apologias, problemas technicas

 

I'm also thinking of going the decat route - mine is a 93 and therefore it's not mandatory for the MOT to put them back on.  What's the best route to go for an N/A?  I've seen the loud cat-back exhaust in Shop!, but that'll only make the sound better, not make it go faster.

 

Oops, I've hijacked the thread.  Erm, how about nitrous Paul hehe.

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Quote: from Eric on 12:19 pm on Sep. 23, 2001[br]

 

Paul,

 

I would say that the first modification you should look at is ditching both cats. Chris Wilsons are made with the J spec in mind, and are 2.5 inch in diameter to sepcifically prevent overboost. The added bonus with ditching the cats is a drop in EGT's. Spool up time for the turbos is significantly quicker as well. That was my main gripe with the car in stock form, once on full boost it was quick, but waiting for the turbos to spool seemed to take forever.

 

If you still have the stock exhaust, you may still find that boost does not increase to the expected 18psi or so, as the Toyota system is still very restrictive. I know that Pete Betts was boosting to 14psi or so with decat pipes and the standard exhaust. I think the boost controllers are not really necessary on a J spec with decat pipes and exhaust, you should be able to hit 18psi. The UK specs have difficulty in getting above 15psi with this configuration, and need either a boost controller or bleed valve.

 

FMIC?? Hmmmm..... I think everyone agrees that 1.2bar (perhaps slightly less) is the max you want to go to with the stock IC, so again, with just the decat and exhaust I think you wouldn't really need to go that route, unless you wish to give yourself extra insurance. With a FMIC you are going to introduce more turbo lag. Water injection personally I didn't like the sound of, as there were too many stories of failures with the system. That's only a personal opinion though.

 

As Gavin says, a boost gauge is essential. It was amazing how much the boost varied from day to day with my car. On the hot summer days, I could set up my DSBC to hit 1.1 bar, come the evening when it was cooler, I was hitting 1.3 on the same setting, so definitely an essential piece of kit.

 

Air intakes?? I think that falls into both your categories of a)looks nice and b)sounds nice! If I did it all over again, I would have kept the standard Toyota airbox, then when I got a FMIC fitted, have the Ash solution of putting a HKS unit in the front air intake where the stock IC sits.

 

 

This is the kind of truly excellent response which keeps me hooked on this BBS.

 

The only thing about my car which *really* pisses me off is the turbo lag.  What, if any, would be the arguments for going with a larger bore de-cat pipe ('none' is a valid answer)?

I don't think I could stand even more lag so I need a solution to the FMIC. I'm going to try increasing the air-flow into the standard air-box.

I could do with suggestions as to a portable air-temperature measuring kit so's I can measure it before and after.

 

So, I think my next step is confirmed: de-cat pipe, stock exhaust, HKS air-filter for stock air-box, boost controller and boost gauge.

I'll also test my modded air intake on the car as-is, before I add the pipework.

 

What boost controller? Where from? How much?

What boost gauge? Where from? How much?

Any idea what Cris Wilson charges for his de-cat pipery?

 

Oh yeah! Where can I get an A-pillar instrument pod from? How much?

 

 

 

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Paul, I think boost controllers are very much a personal preference. Some people prefer the Apexi AVC-R, although I thought it was WAY too complex, and not the easiest unit to locate in the car without looking messy. I went for the Blitz DSBC with the chrome finish and blue LCD panel. I then located it in the bottom half of the double din stereo unit space in a plate made to house it (my stereo was only single din). I liked the DSBC for its simplicity, and the fact it did exactly what I needed, ie 4 different settings you can assign a boost level to. I really didn't need to plot my boost on a graph or anything like that.

 

I think the standard DSBC is about £350 and the chrome unit about £400. Might be cheaper now that their new unit is on the market.

 

Boost gauge: I went with HKS as everyone agreed they make quality kit (CW, Leon, Ash etc). I too looked at getting an A pillar mount, but generally they all seemed to be for LHD cars, and the ones that were available in the UK had a pretty shoddy finish and involved screwing it into the A pillar which I did not want to do. As I wasn't really planning on adding any more gauges, I got an HKS pod to house the boost gauge, this then stuck to the top of the instrument binnacle on the far right hand side. Looked very neat and didn't involve making holes anywhere. I think the gauge was about £120 and the pod maybe an extra £20.

 

I got all the above bits supplied and fitted by Leon.

 

CW downpipes - about £300 for the pair, or £150 each.

 

Regards

Eric

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Well thats that sorted then. We can close this thread now as well. :)

 

I decided to use one of those indoor-outdoor battery powered temperature gauges for measuring the air temperature in my airbox. Any comments from anyone (i.e. a better solution)?

 

Chris just told me he charges £280 for both cats (£140 each).

 

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Paul

 

If you want to see a nice clear image of the HKs boost guage that I have (Eric had the same guage too) then look at the photos under my name (member 16) in the members directory.    There's 2 shots : I showing the general location etc., and one showing a close-up of the guage.

 

I agree with Eric that the de-catting the car, adding a boost guage and then ditching the stock exhaust will make a *dramatic* difference to the performance.    you'll need a FCD if you haven't already got one too.

 

cheers

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Paul it was my post last night that screwed the thread. I don’t know how?

 

I was suggesting FCD as the stock system has a fuel cut if 15 psi is exceeded. Pete's unit feed a false belwo 15 psi until 18psi is reached.

 

Fuel cut seems to be a variable from car to car, but with the increased boost the mods will give FCD has to be a must, very good value at  £70.

 

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What you need to do is junk the cats, fit an HKS Super Drager exhaust together with PB's FCD. This will give you a useful and safe increase in power and the turbos will spool quicker too. If you are not into noise then it's not worth playing with the intake.

 

Boost controllers are a bit gimmicky on a stock turbo'd car. They only really come into their own when bigger turbos are fitted. The ECU will only map to 1 bar (14.5 psi) anyway and you can get in this region without a boost controller with the cats are removed and a straight-through exhaust.

 

People fit boost controllers and talk about running 1.2/1.4 bar with the stock turbo setup. But as long as it's not MY engine.................

 

BTW... I'm now beginning to get a steady stream of people who have had all kinds of weird and wonderful things fitted to their MKIVs by various tuning companies and none of which work properly.

 

Latest was a MKIV that had a boost controller fitted and the tuning company concerned piped the new Apexi boost control-valve in series with the stock wastegate VSV. Upshot of which, no matter what boost pressure was set on the Apexi unit, the car would still run stock boost.    

 

The HKS electronic 60mm gauges are very good. They have peak hold and warning zone alert. I would suggest the fist gauge you fit is an EGT gauge followed by oil temp.

 

Greddy do a RH-drive pillar pod but it sucks IMO.

 

Yours,

J

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Ash

 

Are you saying that the ECU has no fuel mpa over 14.5 psi ?   i.e. it either doesn't *know* that the car is boosting to 17psi, say, or it *does know* it's boosting to 17psi but can't add any extra fuel cos it's got no fuel-map at that level ?    

Everything i've read suggest that the mkiv can provide sufficient fuel at 17psi or so not to be in danger of running lean.   A lot of people here are running 17-18psi and they don't seem to be having problems.

 

Can you confirm your understanding of the situation here ?

 

 

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Paul,

 

I believe the only way to gain a real improvement in BHP using an induction kit would require a box like the Max-Air box system which basically puts your induction cone inside a compartment which is sealed off from the heat and air of the engine bay, yet still able to draw in air from the outside world.

Putting an induction cone in the area of the stock IC when you replace it would lead to problems in bad weather so if your Supra is your second ("occasional") car then it is the best solution. If not then you should keep it withing the engine bay.

 

On a quick note Paul Waite who sold his old car to Ian C tested all the induction cones out at the time he was prepping his engine and found the Apex'i Cylindrical Filter to actually flow air better than the competition, AT THAT TIME.....

 

Once you cave de-catted the exhaust you will quickly want to put on a better cat back system. The Super Drager is inoffensive but it sounded sweet going through the Dartford Tunnel last night! :) I must admit I have had a complaint about the noise when its sat idling in the drive way but the old codger just loves an excuse to moan so I discounted his view!

 

After making sure that the air flow in and out of the engine is ok then the best bet after that is to replace your J-spec camshafts....the j-spec ones are very mild and don't really allow for a fully free breathing engine. 256i and 256e will do but to leave slightly more flexibility in the system you may wish to use a 264e cam.

 

As everyone before me stated make sure you get a boost gauge and a TRL FCD (pete betts) which caps the boost to 18psi instead of 14.5.

 

If you wish to make sure your EGT's stay low it may be worth while considering the ERL Aquamist system as at a 1/4 of the cost of an FMIC it will give you limited protection whilst you save the cash you need to spend on the FMIC... Once you have the FMIC combine it with the aquamist and have a very well protected car.

 

The Injector system is probably the weakest point in the J-specs armour...maybe worth thinking about...(440cc injectors J-spec, 550cc UK-spec)

 

Hope that was helpful.

 

Laters

 

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Quote: from Ash on 10:10 am on Sep. 24, 2001[br]

 

What you need to do is junk the cats, fit an HKS Super Drager exhaust together with PB's FCD. This will give you a useful and safe increase in power and the turbos will spool quicker too. If you are not into noise then it's not worth playing with the intake.

 

Cats are already on the way out. I've arranged the cat-removal pipes and Pete's FCD (both from Pete as it happens - he has a set of used downpipes he's letting me buy). I'm not going to fit the Super Drager *yet*, until I've seen what's going on with the boost (not breaking my beloved engine). I will fit it, later, but for now 'softly softly catchee monkey'.

 

I was only going to fit the HKS filter element to the stock airbox.

Other than that, I really don't like the 2 intake ports into the airbox. One is restricted by the headlight and the other sucks air over a hot radiator from a semi-sealed chamber behind the front bumper. I'd like to see that arrangement improved with a small amount of bodywork.

 

Quote: from Ash on 10:10 am on Sep. 24, 2001[br]

Boost controllers are a bit gimmicky on a stock turbo'd car. They only really come into their own when bigger turbos are fitted. The ECU will only map to 1 bar (14.5 psi) anyway and you can get in this region without a boost controller with the cats are removed and a straight-through exhaust.

 

OK, I can buy that. What about boost limitation, or as I see it, 'damage limitation'? I guess this could be achieved with the FCD, nes pas?

 

Quote: from Ash on 10:10 am on Sep. 24, 2001[br]

People fit boost controllers and talk about running 1.2/1.4 bar with the stock turbo setup. But as long as it's not MY engine.................

 

Nor mine, back to boost limitation.

 

Quote: from Ash on 10:10 am on Sep. 24, 2001[br]

BTW... I'm now beginning to get a steady stream of people who have had all kinds of weird and wonderful things fitted to their MKIVs by various tuning companies and none of which work properly.

 

Latest was a MKIV that had a boost controller fitted and the tuning company concerned piped the new Apexi boost control-valve in series with the stock wastegate VSV. Upshot of which, no matter what boost pressure was set on the Apexi unit, the car would still run stock boost.    

 

Why, after seeing what I have on my speed conversion, am I not the teeniest weeniest bit surprised?

 

Quote: from Ash on 10:10 am on Sep. 24, 2001[br]

The HKS electronic 60mm gauges are very good. They have peak hold and warning zone alert. I would suggest the fist gauge you fit is an EGT gauge followed by oil temp.

 

Greddy do a RH-drive pillar pod but it sucks IMO.

 

I've heard about the nice electronic HKS instruments but do they retain an analogue display. Human perception is relative and digital data has to be converted to a scalar value in your mind's eye before it's meaningful, a slow way to absorb information.

 

I couldn't decide whether the EGT or oil temp was more important but I'm surprised you don't list the boost gauge.

 

I'd heard that about the A-piller pod but what's the alternative?

 

Alex, I really appreciate your input but a bit too aggressive for my short term goals.

Ash has captured the flavour perfectly and something like the Super Drager is destined, just not immediately, i.e., before I've got the cats out, cleaned up the airbox generally and it's all being measured/controlled/limited and *safe*.

 

 

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Guest Martin F

I have the Greddy A-pillar pod (waiting to go in) and i really like it.

 

As far as i can see it is the only way of fitting extra gauges in a neat OEM type fashion, other than the Blitz DIN panel, or the HKS airbag panel.

 

But the screws that go all the way through do look a little tacky, so i'll be looking for another way to try and attach this panel.

 

I think it's all back down to personal preferences, and whether you like your clock and air vent the way they are.

 

Martin

 

Am i the first person to say something looks nice ??? :biggrin:

 

 

 

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:biggrin: let you off this time, it's relevent to the assembly. I don't care if the exhaust front pipe doesn't look pretty but the dashboard doesn't want to look like a floor pan either.

 

Eric had his mounted on the main instrument bulge. Leon supplied a mounting pod which fitted there, I believe.

 

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Yep, quite a tidy job. Don't understand why anyone would want a pillar-mounted version.  It also looks good at night too - competing for my attention with the electro-blue dials and the cool-blue DSBC :cheesy:

 

P.

 

 

(Edited by Peter Howe at 5:18 pm on Sep. 24, 2001)

 

 

(Edited by Peter Howe at 5:19 pm on Sep. 24, 2001)

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After reading Martin F's post, I just realised why you might want a pillar mounting! Definitely a personal preference though. Some people may not want a gauge slapped on top of the dash...

 

P. (with slapped wrists, must read all replies before posting, must check all posts before submitting, FFS!)

 

 

(Edited by Peter Howe at 5:20 pm on Sep. 24, 2001)

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Paul..........

 

The HKS electronic gauges are analogue display. The electronics come into play more with the actual sensors. For instance, with mechanical oil pressure or turbo boost-pressure gauges, one has to route an oil or air pipe to the the back of the gauge. Unlike the electronic gauges where a sensor is placed at the appropriate point on the engine which sends an electrical signal to the gauge. Plus, as I say, the electronic gauges have peak hold and warning mode settings which can be very useful.

 

Yours,

J

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Mein Gott, are they *still* running pipes to the back of gauges?

 

OK, I'm sold, electronic gauges it is then.

 

Many thanks, in fact thanks to everyone for being so helpful (I'm having a warm fuzzy moment over how helpful and knowledgeable the people on this BBS are).

 

OK, I also got home early too, which helps with the mood.

Just time to start measuring up for a discrete air intake from the radiator 'hole' into the airbox intake. Life just doesn't get any better.

 

 

 

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Doughie.......

 

The MKIV cannot supply any more fuel beyond the point at which fuel-cut would ordinarily operate. Which is about 14 psi give or take. Which is just below the maximum sensing pressure of the MAP sensor of 14.5 psi (1 Bar). Which, engineering design-wise makes sense.

 

You say people are running without problems. But I would suggest, in all seriousness, the people that do this aren't really pushing their cars to any great degree. I would argue that the only person on the list that *really* and *truly* DID push his car 10/10ths (with the stock turbo setup) was Justin.  

 

His engine was virtually shot after just a few thousand miles.

 

Okay, it's running VERY sweetly now - after JF became a number of thousand pounds lighter. :)

 

In any kind of venture, myths abound. The tuning business is no exception.

 

In the publishing and direct marketing business, for example, the myth is you can write some mailshot and send it to xxx thousand people and receive an xxx% response that'll make you a millionaire overnight.

 

But anyone (who is anyone) in the direct marketing world knows that creating a successful promotion is a very delicate balance of many, many different factors.  

 

In the car-tuning business, the myth is that you can buy all this bolt-on gear that'll send you powering into the stratosphere in one giant leap.

 

In reality, to my way of thinking, that is tantamount to believing some dodgy, junk-mail chain letter that virtually all of us would instantly file in the bin...

 

Ah, but call it a Super-Power something or other.

 

Suddenly those power greed-glands start flowing (particularly if it's pitched as power on the cheap).

 

As I say, myths abound.    

 

Yours,

J

 

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OK this is good stuff.

 

If i may further pick your brain here.

Is the stock fueling running at stoichiometric i.e. 14.7 air-to-fuel ratio at 14.5psi ?     if this is so, and the mkiv does not supply any more fuel over this level then, by definition, as soon as you go over 14.5psi the engine is running lean.    not by much initially, but lean nevertheless.

OR if not, then the engine is running rich at 14.5psi (which i've heard may be the case) and therfore it slowly leans out the more you push the boost beyond this level.

If the air/fuel ratio is LESS than 14.7 at 14.5psi (i.e. rich), then at what boost level does it actually reach stoichiometric ?

Also is Jap-spec fueling the same as UK-spec fueling ?   I know the injectors are smaller, but i'm talking about air/fuel ratios at the same level of boost.

 

thanks in advance

 

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Ash,

I sat here for 5 minutes trying to think of another market sector which has the same problem but I can't think of one, everything else I could think of failed to pass the key test; that being, the customer makes up more hype than the salesman did in the first place.

 

It used to be the cigarette-smoker's siren song, "come on in, the water's lovely".

 

 

(Edited by Paul Booth at 9:51 pm on Sep. 24, 2001)

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Running lean or running rich are not necessarily relative to a figure of 14.7 A/F. An engine should be running different A/F ratios depending on conditions of operation.

 

If, say, under a certain condition of operation the engine should be running an A/F ratio of 12.0. If it is actually running 11.5 then it could be said to be running too rich. If it were running 12.5 then it's running too lean. Technically, it is still running rich overall, but running too lean for the conditions of operation.

 

A turbo engine only ever should read 14.7 A/F under light cruise conditions. To this end, manufacturers design the engine ECU to switch to running in what is called: Closed Loop Mode.

 

Under any other engine circumstances, the management system switches to Open Loop mode. In other words, it ignores the oxygen sensor and decides appropriate fuelling and ignition in accordance with a stored fuelling and ignition map. The basic sensors used are the MAP sensor, RPM and CP (crankshaft position).

 

Under Closed Loop conditions, fuelling is measured by an oxygen sensor located in the exhaust manifold. Also, the fuel injector system can switch to Sequential Operation, i.e. timing the squirting of the fuel with the opening of each respective the intake valve(s). As opposed to Batch Firing the injectors, i.e. all the injectors opening and closing at exactly the same time.

 

Closed Loop mode is used in order to give the highest fuel economy with the lowest possible emissions.

 

Open Loop mode can also be used to reduce fuel consumption, for example, on the overun it leans out the mixture considerably (sometimes switching off fuel delivery altogether) so as to save fuel and eliminate exhaust popping.

 

Open Loop mode is also used under high load conditions. With a turbo motor, at the point of vacuum-to-boost threshhold, the A/F should be 13.1. The mixture should further richen to the point where, under full load conditions at wide-open throttle, the A/F ratio should lie between 11.9 to 12.2 A/F.

 

The MKIV is blind, boost pressure-wise, beyond the point of fuel cut which occurs at around 14 psi. Beyond which point I cannot fathom how the ECU can possibly provide more fuel.

 

There are two major questions that arise, which are, 1) How does the engine know what the boost is? And, 2) Why would Toyota engineers program fuelling and ignition maps beyond the boost pressure at which fuel-cut would operate?  

 

To my mind, simply attaching a fuel-cut device (without considering any other fuelling provision) and running more than 1 Bar boost (14.5 psi) is sheer madness. But, as I keep saying, provided it is not MY engine............  

 

Yours,

J

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The advantages of sequential injection, i.e. slightly better fuel economy and correspondingly lower emissions, tail-off the higher the RPM. It only really works well at lower RPM, where the inlet-valve open time is long and the injector open time is short.

 

Yours,

J

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