Jump to content
SAU Community

Recommended Posts

I have wound up the boost in my GTST R33 to 10psi with a turbosmart manual boost control valve and now it has a big flat spot and sometimes hesitates.

I have changed the plugs to 0.8 gap ones and have tried resetting the ecu. The ecu reset sometimes makes a big difference but only for that run and goes back to running like a dog when i turn it back off and on.

Any suggestions?

cheers

nick

96 GTST r33

cat back exhaust

sports panel filter

and stuff.

You've encounted the flatspot that everyone hates :D;)

From what people have found is that it's the ECU either retarding the timing heaps for some reason, or the AFM is maxing out for a spit second.

I know what your feeling, and it's damn frustrating. From what I've read a S-AFC helps with the problem. Not much else can be done sadly :D :D

Otherwise it's a replacement ECU.

Everyone will encounter this characteristic unfortunately.

It's S-AFC or PFC etc to get rid of it and also increase power by leaning out the mixtures at the top end as the std ecu richens the fuel when it detects a boost increase.

Cheers

does the factory ECU actually richen the mixture when it detects increased boost at the top end/high rpm only or does it richen the mixture evenly across the rpm from the moment turbo spolls up?

is this flat spot that bad and does everyone encounter it - I was about to install a blled valve next week to take it to 10psi but now.......????

Should I if it means I will have a big flat spot??? Will installing the bleed give me an increase in performance???

thanks guys

Originally posted by -Joel-

Slap a bottle of Octane Boost... Nulon Pro Strength.. 7 Points.. :) for around $20 or $16.95 at KMart.

Joel, don't waste the money on the 'so-called octane boosters' when they say upto 7 points they reffer to an octane increase maximum of 0.7 RON based on the lowest octane unleaded fuel it's boost is less on ultimate 98 and others. Toluene is a real octane booster:D

Originally posted by Black33

is this flat spot that bad and does everyone encounter it - I was about to install a blled valve next week to take it to 10psi but now.......????  

Should I if it means I will have a big flat spot??? Will installing the bleed give me an increase in performance???

thanks guys

Most people will encounter some sort of flat spot when the boost is increased.

But believe me - the flat spot isn't really that bad compared to the increase in performace you get :uh-huh: :uh-huh: :burnout:

Mine Doesn't.. :)

But thats because its an R32.

What are the differences between the RB20DET's ecu and the RB25DET's ecu to make the RB25det's take out so much timing and over fuel so much.. I really can't understand this.

Or is it because of the crappy fuel in Aus and the RB25det's higher comp ratio doesn't run as well as the RB20det's.

Joel,

I'm really not sure about that one. I know that the R32 ECU has bad ignition maps (for the RB20det), I'd say this is partly becuase of the lower quality fuel we use here. And the R33 ECU has bad ignition and fuel maps (for the RB25det), again, partly becuase of the fuel we use.

But I also read somewhere that Nissan made the maps to overfuel while on full boost to keep everything cool (piston tops etc.) So maybe it is due to the factory maps and us using lower RON fuel just makes it worse???

Not sure

J

Yes you have to re-write it to suit obviously.

You can do the same with the RB20DET ECU for the R33 but you also have to make up a circuit to read the rpm and switch the solanoid on/off for the vct.

There was a discussion either here or on SDU about it.

I think it was in a Microtech discussion. Freebaggin was discussing (hehe) with the bloke.. Can't remember his alias but.

Originally posted by -Joel-

Yes you have to re-write it to suit obviously.

You can do the same with the RB20DET ECU for the R33 but you also have to make up a circuit to read the rpm and switch the solanoid on/off for the vct.

There was a discussion either here or on SDU about it.

I think it was in a Microtech discussion. Freebaggin was discussing (hehe) with the bloke.. Can't remember his alias but.

Yepp - I understand that it needs rewriting. But what about the wiring??? Any ideas if the plugs and pinouts the same??

Thanks

J

I also intend to increase boost to 10 or 11psi but my exhaust is limiting so can't go more than 9psi at the moment. Secondly my boost bleed valve setup was not very correct. Nigel from ICE told me I had to block off the solenoid(?? is it correct) so that it's somewhat isolated from the new system, otherwise the ECU will keep hesitating.

However I've just got the HKS dragger back exhaust now, and next do I have to get a hi-flow cat to attach it? Here's a info phrase from Taka-kaira "They are designed to integrate into the factory exhaust system by bolting up to the factory b-pipe".

What's this b-pipe? Is it the section with resonator after the cat?

Originally posted by Black33

is this flat spot that bad and does everyone encounter it - I was about to install a blled valve next week to take it to 10psi but now.......????  

Should I if it means I will have a big flat spot??? Will installing the bleed give me an increase in performance???

thanks guys

I wouldn't worry about it, I have a bleed on mine set to 10 PSI and it goes great. I have not noticed any flat spot at all and the performance increase at 10PSI is well worth it.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • The speedo's can be very conservative, when my Mazda NC MX5 speedo is showing 118kph, the GPS, and a calibrated radar.... cop mate.....hits me at around 110kph +/- 1 or 2 kph, and that is on a 215/45 17, stock tyres size is 205/45 17 as well, so weirdly conservative with stock tyre size When my Commodore speedo red 116kph GPS had me at 110kph After doing some offset and clearance measurements to see what can fit the NC on 17x8 +40, without guard rolling or rubbing anything at my current ride height, I've decided that when my tyres are toast, I'm going to fit 225/45 17 and see where that gets me IRT actual speed of my speedo and GPS/radar From the online calculator I should be still be doing around 5kph under an actual 110kph when the speedo is showing 110kph My ADHD requires that when I'm doing 110kph on the speedo, that the actual road speed is actually really close to that, and not alot slower And going from 205 to 225 still keeps the car within the %/mm allowable in the NSW vehicle rules and regulations, which is nice, as long as I'm looking at the latest version that is.....LOL https://www.nsw.gov.au/sites/default/files/2021-02/RMS-13.464-Light-vehicle-modifications-Vehicle-Standards-Information-No-6-November-2013.pdf
    • Take the value it measured as, and pick the closest range available that is above the reading on the screen.   Also, no point just testing the coils. Read what has been said again. You need to test all your wiring, everything.
    • Does the scanner do all the CUs in the car, or only the ECU?
    • @666DAN sorry to bring you and old thread.     I've got my de+t done and it's all running great other than 1 small issue.    Car has remained auto with the na auto and tcm, I've used a stagea ecu with. NIstune board and everything is great other than my gear selection on the dash. It illuminates park, reverse, neutral, 3rd and 2nd when selected . But nothing when in  drive or what gear your in when you pop it into tiptronic. I'm sure there is maybe 1 wire in the ecu plug I need to move to rectify this. Do ya have any ideas?     Cheers man
    • Well I recently changed my rear axles and was thinking if I bumped anything, I have been driving the car for a while now though... But it has been raining today so everything is wet under the wheel arches. Brakes feel fine and can't hear any of the metal screamers, I had a squeak coming from one of the handbrake drums but that seems to have gone away a while ago. I was going down a hill when it lit up and I did feel the abs bite for a second and question why it did it?
×
×
  • Create New...