[Mk2 Turbo] Boost cut / fuel cut?

[neilg1977]

OK, please could someone help me understand all this.

I have a basic knowledge of how all this works but I have some questions....

My car recently had a downpipe and mongoose fitted. It then started to cut out at about 5500rpm (the engine light on the dash would blink). I rang Millway and we agreed that it was about time I took the Dastek option (I have a GReddy IC so was confident to turn the boost up).

Millway did a good job fitting and mapping the dastek (273bhp and 265 lb/ft, enough for my monthly track days) but im hitting the 5500rpm cut again.

Is this boost cut or fuel cut? The car was mapped to just over 1 bar.

I dont understand the difference and am worried that damage could be caused.....

Thanks in advance,

Neil

[Al-sw20]

Theres a speed limiter at 5500rpm in 5th gear, which means you are going rather fast

Otherwise theres a boost cut around ~18psi in a gen3 motor'd car like urs.

[Peter Gidden]

Theres a speed limiter at 5500rpm in 5th gear

Is there?? I never knew that.......

[nikfarmer]

Theres a speed limiter at 5500rpm in 5th gear, which means you are going rather fast

Otherwise theres a boost cut around ~18psi in a gen3 motor'd car like urs.

how does it know what gear youre in..? or do you mean the equivelant speed at 5500 in 5th..?
ive hit boost/fuel cut in my rev3 mk1.5 and can confirm it feels like hitting a brick wall...though i couldnt tell you exactly what speed it was..think it was somehwere around 130mph but your cut speed may be different due to wheel sizes..

[JekylandHyde]

The turbo MR2 has a fuel cut, not a boost cut.

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[screech205]

Do you have a speedo delimiter fitted?

[Rogue]

Theres a speed limiter at 5500rpm in 5th gear, which means you are going rather fast

The speed limiter actually comes in at 180kmh (~112.5mph), and is triggered by the speedo signal into the ECU. This is a requirement of Japanese law.

Of course, it may be that 180kmh is achieved at 5,500rpm in 5th gear...

Modifying the speed signal is the normal way to remove the limit, but simply cutting the speed signal wire to the ECU will also do the trick (although it will light the engine management light during normal driving). Contrary to popular belief, this will not force the ECU into limp mode or affect the engine's performance in any way.

Rogue