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Problem with flat spots with higher boost

GunMetalR33

By GunMetalR33,
in Engines & Forced Induction

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GunMetalR33 Mentor

GunMetalR33

Posted
Posted

I have a 1994 R33,

I just turn my boost up to 11 pound using a single stage turbo smart boost controller. Since then I am having a problem with flat spots between 4,000 and 5,000 rpm. A mate of mine said that the R33's have factory boost limiters maped into the computers?

An suggestions would be helpfull.

Thanks...

predator Grand Master

predator

Posted
Posted

Super AirFlow converter.. by Apexi.. it hooks into the oxygen and air flow meter sensors of the car and into the ECU .. basically a correction factor so the ECU "sees" less or more air than actually going in for each rev range. With a different reading "seen", the ECU adjusts the fuel mapping accordingly resulting in a richer or leaner mixture than factory. This generally can be used to give the car a 20-30% power increase with the right tuning.

Its what you use when you don't have a full aftermarket computer (around $1000 more) where the fuel maps (and other things) can be adjusted internally a lot more accurately. Hope that helps.

GunMetalR33 Mentor

GunMetalR33

Posted
  • Author
Posted

Thanks for your reply,

I was going to buy an after market computer. By reading your post above it looks like that will solve my problem.

Ps, Is it true that the standard R33 computer has a over boost restricter? because the problem only exists at 10 pound and over

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi GunMetalR33, the issues and solutions are;

1. Over boost protection, the ECU cuts fuel and ignition when boost goes over 11 psi. Solution device called boost cut defeater. Cost a couple hundy.

2. 180 kph speed limiter, the ECU cuts fuel and ignition when the speed goes over 18o kph. Solution device called speed limit defeater. Cost a couple hundy.

3. Fuel mixture enrichment, the ECU increases the fuel supply as boost increases. Solution device called SAFC as explained above. Cost a few hundy.

4. Ignition timing retard, the ECU retards the ignition timing as boost increases. Solution device called ITC similar to SAFC except it modifies the timing signal such that the ECU does not retard the ignition. Cost a few hundy.

So if you add all these together you will find that the total cost ends up more than a Power FC. Particularly if you can pick up a used one. If you want to fix all of these issues we always recommend the PFC, if you are happy missing out on more than one fix then maybe the SAFC is worthwhile.

Hope that helps

Jay95R33 Grand Master

Jay95R33

Posted
Posted

Andrew (Jayson here :) ),

I was just thinking, it could be the gap in your plugs !!!

Damn, if I would've thought about that last night we could re-gapped them then :P

Seems your car is one of the rare ones that are totally stock, I'd say your plugs are still gapped at 1 or 1.1mm !!

Damn (hitting myself in the head), I should've thought about that !!

Cool, we can re-gap your plug's a little on the weekend and see how it goes?

J

  • 3 years later...
gts-4 dreamer Mentor

gts-4 dreamer

Posted
Posted

my car was stock.. but shite, after putting on exhuast and fmic... YOU CNT GO BACK !!!, soooOOOo much more efficient, seriously that smic is sooOOO shithouse its not funny....

GunMetalR33 Mentor

GunMetalR33

Posted
  • Author
Posted
Sorry I am new to forums & Skylines, what does SAFC mean?

ha ha ha, I cant believe I asked this type of question :)

Its amazing how much you can learn from this forum... I went from "What does SAFC mean" to installing after market ecu, turbo, injectors and clutch etc :)

man, this takes me back to the first couple of weeks that I had the car :)

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