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Phil Wall
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Yes, it is not a good thing to keep hitting fuel cut repeatedly. I can say that Pete's FCD works very well on the MKIV as I've had the chance to test one thoroughly.

 

Yours,

J

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I'm really confused, does fuel cut always come in at 15psi?

Mine will boost to 18+ (I know, I know it's bad & I try VERY

hard not to) but I have never come across fuel cut. Does this mean I must have a FCD fitted? If so where - would I know? I am getting a tad worried about turbos, running lean etc - hardly dare put my foot down at the moment! What's that about a little knowledge being a dangerous thing..!

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I know, that's what I'm concerned about. Assuming the boost gauge is reading correctly it has definitely shown up to 1.3 (about 18.8psi?) & that wasn't absolutely flat out. I don't dare push it any further. I also have a leaky old type Blitz dump valve at the moment which starts to lift the piston at around 4000rpm, which I assume would restrict boost pressure to some extent - is that correct? (the theory I mean!)

I had the car serviced at Option Motorsport, they didn't mention FCD, I assume they would be able to tell me if there was one?

 

 

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Francesca..................

 

The only FCD I can recommend for the MKIV is Pete Betts' unit.

 

Now and again, you come across some add-on gizmo that actually works well. Pete's unit is one of these.  

 

Pete's unit first allows the pressure signal to connect to the ECU unaltered. Which keeps the sequential turbo transition and the air/fuel ratios *exactly* as Toyota intended. Then, just as fuel-cut is about to be initiated, the unit clamps the pressure signal voltage.

 

Once the voltage is clamped, however, it *will* affect the fuelling. The "saviour in disguise" is the fact that come 15psi boost, the stock turbo setup is operating very inefficiently. Which does not appear to be the case on the EVO which goes lean *very* rapidly.

 

One thing I'd like to do (if I ever get time) is to data-log the MKIV and EVO A/R signal with a "before and after" comparison. Then, rather than me keep explaining it, I could simply point people to a website address where you could see a graphical representation of exactly what I mean in the way the A/R ratio is leaned out.

 

Yours,

J    

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Guys........

R U saying the HKS fcd is cr*p, and should be replaced with one of Mr Betts????

If so ......... how cr*p r they....... and have any listers had probs with the HKS version??

I ask 'cos I've just fitted a HKS .. ...... and I wouldn't like to think a superior solution was available .....and only 60quid!!!!

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thats a difficult question to answer, the HKS one does the job and is used extensively by the guys in the states, but Pete Betts one works in a better way as it was specifically designed for the Supra. It also has the boost cut raised to 18psi so it still retains some safety margin where I think the HKS one just totally removes it.

 

I would talk it through with Pete Betts and find out his views, I wouldnt want to recommend removing the HKS unit unless somebody can really prove that the HKS one is inferior to Pete Betts one.

 

JB

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I dont think the HKS is cr*p.

 

However I spent along time reading about  both units and decided to go for Pete's as it still offered 18psi protection.

 

I could not find anything to say that the HKS unit  offered this level of protection.

 

Also  I understod that Pete designed this unit just for the Supra.

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Hey Guys

   I am interested in the 18psi protection of the Betts model as I seem to be gettin false (ie too low) readings from the gauge....... I have never seen more than 0.9bar on the gauge with a cat replacement pipe and FMIC as the only mods, yet I hit fuel cut on stock exhaust (with cats) and only the FMIC fitted.

   Now I only fitted the FMIC to replace the stock IC which unexplainedly popped off an endcap shortly after I got it....(this was on a completely stock import)

I have replaced the gauge with a Blitz mechanical one , and it is plumbed as per the mkiv.com info . I have checked the integrity of all pipes etc and looked for evidence of previous bleed valves etc ....... the pipe work is all original (bar the hoses in the FMIC kit)

  Any Ideas????............... could it be Turbo hoses expanding...... do I need hard pipes??

    Any help would be appreciated..........  TIA

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Are you sure you were hitting fuel cut?

 

This sounds unlikely with standard exhaust and cats in.

 

Fuel cut is very scary and almost feels like you've hit a brick wall, I thought I'd blown my turbos the first time it happened to me.

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Hey Phil......Yeah........... I'm pretty sure it was fuel cut ..... it went away after fittin the fcd.........

I know it sounds odd.......... I'll get it into someone to check the boost level on a known gauge (I can't trust this one without checkin, even tho' this is the 2nd)

    I had put down the blowin of the stock IC as bad luck and a Friday afternoon job........especially as every1 I spoke 2 had never come across this b4.....

.......But now  I'm wondering if it was overboosting then.

 

 

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u gotta b from the black country with that accent :wink:

 

........ but I'm sure I hit fuel cut.......sudden loss of go, wait for boost to drop and off it goes ??  Brick wall is a bit far......I hit it passin an impreza and it allowed him 2 gain somewhat...........

 

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No, you get a really violent bang and the red triangle comes on in the centre of the dash, you would certainly drop the throttle out of fright.

 

I can't see that you would get from 11psi to 15psi just by fitting an FMIC, this should just lower the intake temperature and make the turbo more efficient.

 

If it was in 1st or 2nd it may have been you TC?

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Maybe it wasn't fuel cut then............. I didn't get the warning light on the dash, although it was a severe sensation....... (I have in the past hit a brick wall and this was rather less disturbing :wink:)

....but it has gone away with the fcd fitted

 

Any thoughts?????

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