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The mkiv Supra Owners Club

What Is The Best Fuel Cut Defenser?


Mid_lifecry_sis

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Running 1 bar with HKS air, Hyper and first CAT still in > Buying colder plugs than the current Toyota ones 2.

 

Have a Greddy which was purchased incorrectly for what I want out of the SUP for now.

 

I hear that there is a 19PSI programmable one available. Second Q. What is 19PSI! 1.2 BAR??

 

Appreciate any comment > always learning.

:D ;)

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Hi,

 

Forgetting what you have been told for a second, can you have a look at the unit and see if there looks like there is any way of adjusting it. Any little pots or screws, maybe with the word 'cut' somewhere? It will just be a single adjustment, thats all.

 

Have a look in the instructions....OK, they might be in Japanese but they will usually show diagrams.....anything in there relating to an adjuster inside the box maybe?

 

I'd be really surprised if this was a fixed unit. It would then be vehicle specific- unusual for a product of this nature. The HKS/TRL etc. units have adjustment not only to give the user whatever fuel cut point they want but also because they can be used on other cars where say 1 bar would be the limit.

 

I don't want to see you buying another unit if you don't need to!

 

Cheers,

 

Nathan

TDI PLC

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Guest Martin F

The Greddy unit is the one that all the Yanks recommend.

 

Take a look here for fitting instructions.

 

http://www.mkiv.com/techarticles/bcc/bcc_install/bcc_intro.htm

 

I'm not saying this unit is any better or worse than Pete's (TRL's) unit, it's just why go through all the hassle of selling the unit and buying another when the one you have is perfectly good enough ?

 

Unless you like hassle of course, in which case please supply name and address and i can send you some of mine. :D

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:) THAT'S the one.... think it's in teh car, which John has aka Dude for a bit or garage - lost for ever!

 

Was told that this was not adjustable ie 1.2 bar and cut? Would read tech detail on web link but don't do technical given that I'm only an IT Security/COMMS/ISP/Voice/CITRIX Internet fraud FSA regualted & Data protection educated consultant LOL!:p

 

Of course now all I do is sit and play with the BBS!

 

Work in verification/people tracing world now kind'a...

 

so - if you need to find anyone let me know, in return please assit with the FCD:D :) :D :p lol!

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I think the major difference between the HKS, Greddy and TRL fuel cut devices is the TRL VFCC has an adjustable OVERBOOST setting. i.e. it can activate fuel cut at a new higher adjustable level.

 

So the HKS and Greddy **ARE** ADJUSTABLE fuel cut removers

 

BUT

 

the TRL VFCC is an ADJUSTABLE Fuel Cut RAISER. (It can raise the fuel cut threshold and also (with the correct setting) just be an ordinary remover as well.

 

I think that's what they meant.

 

regards

Pete

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So the HKS and Greddy **ARE** ADJUSTABLE fuel cut removers

 

BUT

 

the TRL VFCC is an ADJUSTABLE Fuel Cut RAISER. (It can raise the fuel cut threshold and also (with the correct setting) just be an ordinary remover as well.[/b]

 

Hi Pete,

 

I'm not sure I follow here. The HKS unit, being adjustable, means that you can 'move around' the fuel cut point. So you CAN raise it, but it doesn't just go away. You still get fuel cut protection. I've got the impression from you before that the HKS unit removes the fuel cut altogether, but it doesn't, so still provides overboost protection.

 

Does that make sense?

 

The only difference I was aware of with your unit was that it was a clamper (like the Greddy unit) rather than a scaler like the HKS unit. Other than that I thought they did exactly the same thing.

 

Cheers,

 

Nathan

TDI PLC

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I don't want to get into a war of words.....but

 

Yes, the HKS FCD does have an adjustable voltage clamp but also a proportional scaling as well. (coupled to the clamping level)

This has the effect of compressing more of the MAP input into the same area as before. (Scaling) This DOES have the indirect effect of raising the fuel cut threshold as well as clamping.

 

The TRL VFCC maintains the standard MAP range but monitors the increase in MAP output beyond the stock fuel cut threshold and when it hits the overboost threshold it unclamps the output, causing fuel cut.

 

A graph would be easier to show this.

 

We've said before that it's a matter of opinion if you choose to scale all the MAP signal to compress a larger deflection range into the same space as before or just allow it through without modification. I'm not arguing one way or the other.

 

So yes, I had forgotten that the HKS FCD does in effect raise the fuel cut threshold by scaling and maybe the only difference is the TRL VFCC has seperately adjustable fuel cut and overboost settings where the HKS FCD have just one fuel cut setting a fixed scaling relating to that setting.

 

I hope that settles that point.

:baa:

 

The Greddy is just a voltage clamp as far as I can remember.

 

Pete

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hope this helps from mkiv.com

 

III. Precision Adjustment of the BCC Output Voltage:

 

Inside the BCC shell is a screw that provides adjustment of the peak voltage output. Since the ECU uses the TPS V data for many functions, you want this set only as low as needed to avoid fuel cut, and not unnecessarily lower. The setting as it comes from Greddy is usable but lower than necessary, and varies from unit to unit. You could roughly set it by just repeatedly driving your car at max boost and slowly turning the screw counterclockwise to reduce the peak voltage output until you no longer hit fuel cut. But this is a crude method compared to adjusting it precisely by measurement with a volt meter, as follows:

 

1. The Connections for Voltage Tune assume your BCC is uninstalled. To Volt tune after the BCC is fully installed, you will need to disconnect the BCC's green and white wires to proceed, but may leave the red and black wires installed.

 

2. Red BCC wire to any 12V source such as car battery +

 

3. Black BCC wire, and negative probe of your voltmeter, to ground of same battery.

 

4. White BCC wire to any automotive voltage source of 5-12V. Simplest is to use the 12V source same as red wire. Others have used the 6V output of a battery charger, doesn't matter because any Input of 5-12v to the BCC will give the same Output for a given adjustment screw setting.

 

5. Green BCC wire to the positive probe of your voltmeter.

 

6. Turn screw to provide voltmeter reading of Nearly but Not More Than: 4.3 V for 93-95 cars; 4.1 V for 96-98 cars.

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Guest Martin F

Sorry, nobody told me people had an inability to click on the links that i post.

 

Next time i'll cut and paste the articles from MKIV.com.

 

:moo:

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Originally posted by TRL Performance I don't want to get into a war of words.....but

 

I hope that settles that point.

 

Pete,

 

No war of words! It wasn't a case of getting words mixed up. I just wanted to clarify a very important area. I have been getting the impression for quite a while that people feel that the HKS FCD removes the fuel cut point altogether, thus making it a 'non-safe' option compared to others (in an overboost situation).

 

I had no idea where this suggestion had been coming from and to be honest wasn't too bothered anyway but this thread came up and gave me the opportunity to clear it up. It had nothing to do with scaling V clamping, who should fit what FCD or any war of words whatsoever.

 

The HKS FCD DOES NOT remove overboost protection. Thats all I wanted to get accross.

 

 

The Greddy is just a voltage clamp as far as I can remember.

 

More importantly, an adjustable one at that, by the look of it.....

 

Glad the Greddy issue has been cleared up too. Mid'lifecry'sis, personally I'd use what you have.

 

Regards,

 

Nathan

TDI PLC

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