Jump to content
SAU Community

Loss Of Power under Hi Boost

Robo's

By Robo's,
in Engines & Forced Induction

 Share

Recommended Posts

Robo's Mentor

Robo's

Posted
Posted

Ive upped the ante on the 2530, raising it too 17psi, and now i get a sudden total loss of power in the mid range. As i accelerate hard in 3rd from 3000rpm, i get 1 or 2 sudden losses in power for a split second and then it comes back, its between 4000-5000rpm. Im thinking its the standard AFM to Turbo rubber pipe being sucked in fully and then re-opening under hi boost.

Opinions?

Link to comment
https://www.sau.com.au/forums/topic/55916-loss-of-power-under-hi-boost/
Share on other sites
Robo's Mentor

Robo's

Posted
  • Author
Posted
I heard SAFC-II does not correct/modify your ignition timing and so that may be the cause??

Your right it doesnt alter ignition timing, but still doesnt explain total power loss. Im not meaning a slight surge, i mean no power.

I think its the AFM

If i reduce the boost by 1psi, it doesnt do it

paulr33 Grand Master

paulr33

Posted
Posted

17psi and stock ecu cant be good, it will just cut the timing and limit stuff

get a remap, check for sale section, $350 swap in swap out, rev limit change, boost remove and speed cut remove, change of timing, ignition and other stuff you may need

Cubes Grand Master

Cubes

Posted
Posted
Your right it doesnt alter ignition timing, but still doesnt explain total power loss. Im not meaning a slight surge, i mean no power.

I think its the AFM

If i reduce the boost by 1psi, it doesnt do it

I tried to run the RB30DET on the stock RB20T ecu, the fuel cut was hitting with the AFM reaching 60% at 2000-2500rpm & about 8psi of boost.

The AFM wasn't maxing out, but the injectors appeard to be, just before the fuel cut the afr's would go dangerously lean in to the 14:1 AFR.

The ECU was freaking out because the fuel requirements were out of its map (I assume) Either that or the injectors were at 100% duty cycle which is possible as the RB30DET makes more power on 6psi than the rb20det did at the same rev's etc at 11psi due to the much larger valves & ports.

The ECU has to try to raise the duty cycle to get the required fuel in, not as much fuel pressure is being run due to less boost being required to make the same power.

This would also apply to running a larger turbo because the airflow is greater at any given boost pressure compared to the stocker.

If the new turbo makes 200hp at 5psi and the old one made 150hp at 5psi then you will be lacking fuel pressure for that extra 50hp as for the old stock turbo to make 200hp it may need say 8psi which will increase the fuel pressure via the rising rate regulator for that extra 50hp. Hence the injectors don't need to run as much duty cycle.

The base maps are designed around the rising rate fuel pressure regulator & stock turbo (airflow per psi) etc.

As soon as you throw out this airflow per psi and make the car much more efficient be it cams or bigger turbo it will throw things out quite bad as I found out.

lol If that makes sense.

I had the SAFC adjusted to max everything, as much fuel as it could pump in and the AFR's still would not pull in line. It only made the fuel cut hit much much earlier.

It seems to be related to the amount of air the car is sucking (nothing to do with boost) at that particular RPM. The ECU thinks some thing is wrong and first begins to play with the ignition timing (mine dropped from 22degree's to 8 degree with a big power dip at ~6psi) then it fuel cuts if you start sucking even more air (by ~8-9psi).

EVEN if the AFM hasn't maxed out yet.

lazza Enthusiast

lazza

Posted
Posted

Get it on a dyno (if you havent already), to check the fueling. It could be the spark plugs, what gap are you running? At that boost it could be that the spark is being blown out, although that would occur more at high rpm? Try plugs one colder than standard and with a maximum of 0.8 gap.

I would say if the ECU hasnt been remapped it will need to be to run 17psi on a bigger turbo.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      Chris' Toyota Mark ii JZX110

      By Duncan · Posted

      Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
    • Duncan
      Jacks that fit under GTR lips that can reach the subframe?

      By Duncan · Posted

      BTW I measured the jack I have, it is 70mm at the saddle but you only have about 700 until it returns to 150mm high at the cylinder so it is good but no magic bullet.
    • hoodedreeper
      Chris' Toyota Mark ii JZX110

      By hoodedreeper · Posted

      My experience with Rising Sun Exports Before agreeing to the sale I tried to do as much research as I could (obviously), his Facebook reviews are 98% and he goes Live at least once or twice a week. I contacted 2 people in the UK who had used him for their imports, both had positive feedback. His explanation and talk through of the import process was thorough, answering any query no matter how stupid it was. It felt as soon as the money was sent, communication dropped off. I asked for shipping updates every 2 weeks or so, not wanting to pester him, he never had any updates. I wasn't informed the car had been dropped off at the port, I only found out by his Facebook story. I asked for the photos taken at the port, knowing he would need some for insurance purposes. I received a few 5 second clips and that's it. When asked again, he said his staff had them. Weeks later I asked again, he tells me he doesn't have any, but does have 50 photos from the original advert. I never received them. I eventually got the documents sent via WhatsApp after I mentioned the port was requesting them. I purchased a CarVX report, to find out the vehicle is a Grade R with recorded accident damage, first recorded in 2017 when it was first auctioned. He never told me the grade, then again I didn't ask. His response was "Grade R means nothing, it wasn't chassis damage". Still, I would have liked to have been informed about it. Jon prides himself on being open and honest when it comes to inspecting cars, it's his main job doing so at the auctions for customers. When the vehicle arrived in the UK I noticed a few little cosmetic issues. It's a 21 year old car so it wasn't going to be mint condition. The side skirts are cracked on each corner and the sealant is failing. The front grill on the bonnet/hood isn't secured very well, mounting studs are missing. Both minor things, but again, it would have been nice to be told. During a Facebook Live walk around video of the vehicle, he mentioned it has a front Whiteline anti roll bar/sway bar. While on the inspection ramp, I noticed the stock item has been installed. When first questioned, his response was "the ARB? Switched? Since when, it never had them". Since sending video and photo evidence I've not received a response. I'm probably being over critical of the overall condition of an old car, but all I wanted was honesty (which he claims to have). I'm aware I wasn't his only customer, he's busy doing XYZ but other reviews praise him for great communication with regular updates and photos, I felt I didn't receive the same treatment. 
    • hoodedreeper
      Chris' Toyota Mark ii JZX110

      By hoodedreeper · Posted

      I was able to get some underside photos while the car was on the ramp The suspension is all Altezza/IS200/IS300 so getting part's will hopefully be less of a headache
    • hoodedreeper
      Chris' Toyota Mark ii JZX110

      By hoodedreeper · Posted

      Welcome to my 2004 Toyota Mark ii IR-V Fortuna (series 2) With a 1JZ-GTE powerplant under the bonnet (hood) it'll give me plenty of scope for power upgrades. For those who aren't familiar with imports, the 1JZ-GTE is a 2.5L 6 cylinder VVTi engine with a single turbocharger. This has the factory R154 5 speed gearbox, along with a aftermarket 2 way LSD differential (brand unknown). Under the arches are a set of CST Zero 1 alloys, 18x9 +30 225/40 up front and 18x9.5 +15 265/35 on the rear. The car was quite low in Japan and there's evidence of the wheels catching the rolled arches/fenders. The tyre's aren't great so I'm in two minds whether to replace both or just the tyres and put up with the wider wheels on the rear. The car still uses stock brakes with the addition of some braided hoses. The exterior is stock with the exception of a BN Sports front bumper and a replacement Fortuna grill  Moving to the interior, the steering wheel has been replaced with a dished MOMO steering wheel (which will get swapped for my Momo Tuner for the time being) Defi Link Gauges are mounted above the climate controls and on the A pillar, the Oil Temp,Oil Pressure,Water Temp and Boost gauges should help with spirited and track driving  The stock seats have been replaced with some retrimmed Recaro bucket seats. Being a larger build these are a little snug, unfortunately the orange isn't for me so I'll look into replacing these down the line. Other modifications include a twin plate clutch, Blitz intercooler, Evolve alloy radiator, a stainless exhaust with decat, HKS EVC-S boost controller and coil overs
×
×
  • Create New...