Jump to content
SAU Community

Who Stole The Boost?

mad082

By mad082,
in Engines & Forced Induction

 Share

Recommended Posts

mad082 Grand Master

mad082

Posted
Posted

yesterday we stuck my mates 33 on the dyno. it has a fmic, turbo back exhaust, pod and a 3076r (IW, 0.63a/r). we were tunning the boost controller at 16 psi and it made 290hp but it was bleeding off boost back to 12psi at redline. it was making max power at 14psi at about 5500 rpm.

we thought it may have been the boost controller so we disconnected the hose to the wastegate to run open boost. no real change. it went up to about 18psi but then bled off back down to 12psi and there was about 1hp difference in power.

now we know there is a restriction but we aren't sure where. we know the cat is a bit screwed, but not sure how bad and it is on the 'to do' list. i'm also thinking it may be the fmic as i don't think it flows very well. it uses the stock piping but the core doesn't seem to be that good IMO. the air comes in the top (from the side) then has to do a 90 degree turn into the core, then has to do another 90 degree turn at the bottom to exit out the same side it came in. i think a cross flowing cooler would be an improvement. we are going to put a boost line in before the cooler to measure the difference in boost pressure between the 2 sides.

we know it isn't the pod, because we took that off and lost nearly 10hp, but i think that was more to do with heatsoak.

so any ideas you have would be welcome.

Link to comment
https://www.sau.com.au/forums/topic/179344-who-stole-the-boost/
Share on other sites
Gazee Grand Master

Gazee

Posted
Posted
no hadn't thought of that.once we have a look at the cat we might have another run and try and restrict how far the wastegate can move to see if that makes a difference.

if your cats blocked, boost will continue to rise and if your wastegate can't open all the way to expell the exhaust gasses, boost will rise

the only time i've seen it taper off at redline is when i had a bleed valve, i put the ebc in and it held to redline no prob

have you thaught about a air leak or something along the lines of that?

mad082 Grand Master

mad082

Posted
  • Author
Posted
if your cats blocked, boost will continue to rise and if your wastegate can't open all the way to expell the exhaust gasses, boost will rise

the only time i've seen it taper off at redline is when i had a bleed valve, i put the ebc in and it held to redline no prob

have you thaught about a air leak or something along the lines of that?

if the cat is blocked the boost won't continue to rise. the air in the system will back up so the turbo won't be spining as fast. that is why people get a boost increase when they put a turbo back exhaust on.

Gazee Grand Master

Gazee

Posted
Posted

have a read of this marc

http://www.skylinesaustralia.com/forums/in...20cat&st=60

or maybe you already did, its pretty much the same sheit that your mates going through

but at least your mates not getting infinite boost like what i was getting :down:

UCD15R33 Experienced

UCD15R33

Posted
Posted

ok well a bit of an update (it's my car that mad082 is talking about). we just took the cat off. that is looking to be our problem. the rear honeycomb had turned sideways, so the holes were flowing sideways rather than from front to back, so effectively the cat was only flowing through about a 1" x 2" hole. mad will post up a pic of it on monday, and we are putting a new cat on next week (we just punched out the rear honeycomb for now, but the front honeycomb is still intact.

we will post up our findings later on.

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

    • Turbodoc
      Noobie Stagea owner..

      By Turbodoc · Posted

      Hey Dave, welcome aboard! Good to see another soon-to-be Stagea owner here. The wagons are awesome — plenty of space, still got that Skyline DNA, and loads of potential if you’re into mods. Definitely post up pics when you get it, everyone here loves seeing new builds. What model/year are you looking at?
    • GTSBoy
      Duncan's V37.......race car?

      By GTSBoy · Posted

      See if you can thermal epoxy a heatsink or two onto it?
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      The other problem was one of those "oh shit we are going to die moments". Basically the high spec Q50s have a full electric steering rack, and the povo ones had a regular hydraulic rack with an electric pump.  So couple of laps into session 5 as I came into turn 2 (big run off now, happily), the dash turned into a christmas tree and the steering became super heavy and I went well off. I assumed it was a tyre failure so limped to the pits, but everything was OK. But....the master warning light was still on so I checked the DTCs and saw – C13E6 “Heat Protection”. Yes, that bloody steering rack computer sitting where the oil cooler should be has its own sensors and error logic, and decided I was using the steering wheel too much. I really appreciated the helpful information in the manual (my bold) POSSIBLE CAUSE • Continuing the overloading steering (Sports driving in the circuit etc,) “DATA MONITOR” >> “C/M TEMPERATURE”. The rise of steering force motor internal temperature caused the protection function to operate. This is not a system malfunction. INSPECTION END So, basically the electric motor in the steering rack got to 150c, and it decided to shut down without warning for my safety. Didn't feel safe. Short term I'll see if I can duct some air to that motor (the engine bay is sealed pretty tight). Long term, depending on how often this happens, I'll look into swapping the povo spec electric/hydraulic rack in. While the rack should be fine the power supply to the pump will be a pain and might be best to deal with it when I add a PDM.
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      And finally, 2 problems I really need to sort.  Firstly as Matt said the auto trans is not happy as it gets hot - I couldn't log the temps but the gauge showed 90o. On the first day I took it out back in Feb, because the coolant was getting hot I never got to any auto trans issues; but on this day by late session 3 and then really clearly in 4 and 5 as it got hotter it just would not shift up. You can hear the issue really clearly at 12:55 and 16:20 on the vid. So the good news is, literally this week Ecutek finally released tuning for the jatco 7 speed. I'll have a chat to Racebox and see what they can do electrically to keep it cooler and to get the gears, if anything. That will likely take some R&D and can only really happen on track as it never gets even warm with road use. I've also picked up some eye wateringly expensive Redline D6 ATF to try, it had the highest viscosity I could find at 100o so we will see if that helps (just waiting for some oil pan gaskets so I can change it properly). If neither of those work I need to remove the coolant/trans interwarmer and the radiator cooler and go to an external cooler....somewhere.....(goodbye washer reservoir?), and if that fails give up on this mad idea and wait for Nissan to release the manual 400R
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      So, what else.... Power. I don't know what it is making because I haven't done a post tune dyno run yet; I will when I get a chance. It was 240rwkw dead stock. Conclusion from the day....it does not need a single kw more until I sort some other stuff. It comes on so hard that I could hear the twin N1 turbos on the R32 crying, and I just can't use what it has around a tight track with the current setup. Brakes. They are perfect. Hit them hard all day and they never felt like having an issue; you can see in the video we were making ground on much lighter cars on better tyres under brakes. They are standard (red sport) calipers, standard size discs in DBA5000 2 piece, Winmax pads and Motul RBF600 fluid, all from Matty at Racebrakes Sydney. Keeping in mind the car is more powerful than my R32 and weighs 1780, he clearly knows his shit. Suspension. This is one of the first areas I need to change. It has electronically controlled dampers from factory, but everything is just way too soft for track work even on the hardest setting (it is nice when hustling on country roads though). In particular it rolls into oversteer mid corner and pitches too much under hard braking so it becomes unstable eg in the turn 1 kink I need to brake early, turn through the kink then brake again so I don't pirouette like an AE86. I need to get some decent shocks with matched springs and sway bars ASAP, even if it is just a v1 setup until I work out a proper race/rally setup later. Tyres. I am running Yoko A052 in 235/45/18 all round, because that was what I could get in approximately the right height on wheels I had in the shed (Rays/Nismo 18x8 off the old Leaf actually!). As track tyres they are pretty poor; I note GTSBoy recently posted a porker comparo video including them where they were about the same as AD09.....that is nothing like a top line track tyre. I'll start getting that sorted but realistically I should get proper sized wheels first (likely 9.5 +38 front and 11 +55 at the rear, so a custom order, and I can't rotate them like the R32), then work out what the best tyre option is. BTW on that, Targa Tas had gone to road tyres instead of semi slicks now so that is a whole other world of choices to sort. Diff. This is the other thing that urgently needs to be addressed. It left massive 1s out of the fish hook all day, even when I was trying not too (you can also hear it reving on the video, and see the RPM rising too fast compared to speed in the data). It has an open diff that Infiniti optimistically called a B-LSD for "Brake Limited Slip Diff". It does good straight line standing start 11s but it is woeful on the track. Nismo seem to make a 2 way for it.
×
×
  • Create New...