Jump to content
SAU Community

Recommended Posts

Ever seen a compressor map? they're not exactly linear.. what someone was trying to say earlier is that even at 4psi and 2k rpm, the stock turbo is probably still flowing enough air to open the bov. I'm no expert, but that makes perfect sense to me.

I'm no expert either but last time I looked the whole theory of a BOV Blow off Valve was that when it senses VACUUM in the Intake manifold when the throttle is closed between gear changes on a MANUAL,

it dumps the compressed air in the piping from the compressor thru to the closed throttle plate to stop the air backing up on the compressor wheel.

A BOV is NOT actuated by PRESSURE but VACUUM.

A BOV on an AUTO is used to shorten the throttle response by bypassing the longer inlet tract as well as venting after sudden throttle closure when on boost.

My GTS4 AUTO is also experiencing similar symptoms after a new upgraded turbo and I intend to move the AFM to after the FMIC before the TB to see if that solves this issue.

  • Replies 60
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

It is very very laggy. On the stock ecu on 11 psi, any gains are not noticeable due to r+r (i.e. power output is probably similar).

It wasn't a direct bolt on, had to bend the lines, and rotate the housings.

Is it worth the money? I'll pm you

1) Get some cams; it'll bring the boost on earlier... or get some cam gears... with my Slide turbo I was making 1bar by 4k RPM so laggy? NO!

2) My turbo sounds like a jet-engine; I would double check all your fittings... want proof?

3) Of course the lines will have to be bent; you're no longer fitting a R33 turbo. Didn't you order the biggest RB25 highflow you could get from Slide? From memory of installing mine, the centres are different.

4) Rotating the housings? I'm not sure if Aaron still does this but I was given CLEAR instructions to tighten the bolts on the comp cover when i got the turbo as he had deliberately left them a bit loose to allow for installation "play". We never had to move it; just tightened it.

Ive got the basic Stage1 Slide RB25 highflow.

fitted up no probs, used a braided oil line.

very very loud, I have a pod in a cai box with a heap of sound deadening foam in there, very loud tho.

and thats with a restrictive exhaust (muffler), cant go past 14psi as it has too much backpressure

get the blowoff sounds but I dont believe I have any flutter

at 14psi she only has 190kw but goes very very nicely, very happy with the turbo; price / quality / result :(

My thoery is, that the flutter has something to do with the plumback. The slide turbo is probably sucking more when you are backing off, so when the bov causes the air to go back to the intake, it causes reverberation hense you get flutter.

That is my theory anyway.

Edited by Thunderbolt
1) Get some cams; it'll bring the boost on earlier... or get some cam gears... with my Slide turbo I was making 1bar by 4k RPM so laggy? NO!

2) My turbo sounds like a jet-engine; I would double check all your fittings... want proof?

3) Of course the lines will have to be bent; you're no longer fitting a R33 turbo. Didn't you order the biggest RB25 highflow you could get from Slide? From memory of installing mine, the centres are different.

4) Rotating the housings? I'm not sure if Aaron still does this but I was given CLEAR instructions to tighten the bolts on the comp cover when i got the turbo as he had deliberately left them a bit loose to allow for installation "play". We never had to move it; just tightened it.

You have clearly diverted from the aim of this thread. As you are not the one that installed your turbo or any of your mods, clearly, you are unaware of fitment of the turbo. It is easy to be a backseat mechanic and look at a part and go oh yeh, you undo some bolts, undo some lines, take it off the manifold. Installing it is a totally different story.

My aim of this thread was to attempt to develop theories on the topic. I.e. hoping that information would be shared for the benefit of all to see. However, as the thread keeps getting diverted and people are arguing on other topics, that's fine. I'm going to stop replying to this thread, and i'll discuss this topic over pm. As a result, information is no longer shared.

Edited by MANWHORE

Ok few ideas from this corner.

1) The compressor wheel is larger, and made of different material... (i think the stock R33 wheel isnt steel)

This in itself is going to make a fair difference. Its like going to a plastic or metal casing pod filter. One makes more noise than the other :cheers:

2) Sounds like the VAC line to the BOV should be increased. Use a larger line so the BOV knows whats going on.

If that doesnt work, just bolt on a GTR BOV (one of the pair), should cost you around $150 at the most.

3) As for the lag, this is due to the stock ECU. So it is relevant that the car needs to be fully tuned

I've got a GT2876R, standard bov at the moment until i buy inj for tune etc. but it doesn't flutter at low rpm, still makes the pchhtt noise... so this is really weird especially if its happened to more than one person... i'd like to see the explanation of this..

EDIT : I think ash's explanation of the vac line seems reasonable, i changed mine straight away to a 6mm one, maybe thats why i don't get the flutter...

Thanks guys, there have been a lot of good replies in this thread amongst the threads about other things.

Gazee, that's exactly what i'm talking about. Spot on the money.

My aim was to understand what it was about this turbo that does that, whetehr it was compressor maps etc etc. This is not my first turbo change, nor is it my first turbo car. I've actually had more experience with 1JZs, and i haven't seen this (just as a matter of interest). but yeah, that's what i'm talking about - i haven't seen other similar turbos do the flutter at low rpm. I have seen flutter at high rpm - because the stock bov can't release air quick enough, so some goes back through the turbo, but just hadn't seen it at low rpm.

Edit: Gaz, my car came stock with a 6mm one, not the 4mm one. No there aren't any holes in it (if anyone asks)

Edited by MANWHORE
My aim was to understand what it was about this turbo that does that, whetehr it was compressor maps etc etc.

Do you have one of those modified standard rb25 bov's? that doesn't let it bleed off air whilst coming on boost or something or other?

lol

I don't know where the break down in communication was Chris.

The larger turbocharger is obviously going to have different characteristics to the standard.

As Paul has said the flow rates of the turbocharger are extremely different and the airflow at different boost pressures is also.

You just have to think about this as to where in the rev range it will be different which to my understanding of this thread is not understood by most people, It is different everywhere, It is a larger turbocharger.

It is not a phenomenon, you will find that once the car is tuned it is vastly different again, It is the nature of the beast.

If you do not understand how a turbocharger works there are many aids that can help.

www.howitworks.com

If you want to see how a journal turbocharger is made you can even see that here:

http://www.biagioturbos.com/ing/process2.asp

The standard blow off valves are still useful and not useless.

After market adjustable blow off valves are simply better as they are designed to cope with most sized turbochargers not just the standard one like Nissan intended.

Regardless of the fact it may be working properly or not its simply not up to the task of being able to do so with the new turbocharger.

This is the same for any after market turbocharger.

You have an OP6 Stage 3 Sliding Performance Highflow?

If not then its characteristics will be different as stated, The car is also not tuned and running this size turbo on an untuned car is not only dangerous but also not being used the way it was intended.

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

    • That is the serial number of your block
    • best advice yet.  so between the elite and the nexus... much of a difference?  cost is damn near identical (only $170 difference).  thank you!!!
    • Hi everyone, I've found some free time to write up my "build thread" which is 10% 'build' and 90% fixing problems of a skyline that has endured a lifetime of abuse. I will start with the backstory & get everyone up to speed. Ever since I was just a teenager in high school I have had a spot in my heart for the shape of an R32 rivaled only by the look of an S13, my mates & I all having overly ambitious dreams as one does about having the sickest car in the school carpark. Unfortunately I started my journey of cars down the path of the Silvia and after spending years of putting up with the underwhelming SR20 life I dipped my toes into the 1J Toyota pool for a small moment until my true compass brought me back to that incomplete dream of an R32. At this point the trawl through marketplace, gumtree, carsales etc. starts looking Aus wide for an affordable example in the current economy which was extremely barebones compared to the good old days of sub 10k cars everywhere. Out of the handful of cars in the budget at the time I settled on a 1992 R32 GTS-T that was located in Adelaide. It had caught my eyes as it was similar price to the others on the east coast and had been RB25DET NEO converted and an open door respray in a custom colour based off TH1. It was also a stand out to me because it already had some NSW registration left which saved me the hassle of getting it on the road in my state. As for mods I was told it was pretty stock other than the motor swap, a nistune to run it, and an unknown fuel pump. My first mistake was trusting the seller blindly that the car was in good condition in all aspects and decided to purchase the car unseen other than some walkaround videos & pictures as the flights down there were very expensive at the time. The price of getting it transported to my door from Adelaide from Sydney was surprisingly cheaper than the flights at the time. I was told the few issues it apparently had was only 1 speaker not working, some cracked or missing trims, and it had been rear ended at some point but had been all professionally repaired (this is all foreshadowing at this point). I paid for the car, and then booked the interstate transport. Now at this point save your criticism as I already know how stupid I sound in hindsight, this was a major lapse of judgement and I accept the problems that followed. I spent the next 2 weeks in a crazed excitement knowing I am finally the owner of an R32 & that it was on its way. I started preparing as when negotiating with the seller I opted out of the Lenso wheels as they aren't really my style & I wanted a set of genuine wheels, and the bucket seats in the car as I am 6ft5 and not the skinniest guy so I had my predictions that I wouldn't fit in them anyway. Due to this the car was put on a set of R33 stockies and some average condition R33 seats that he had laying around. While I waited for the car to arrive I went and picked up a pair of R32 seats and some R32 GTR wheels to fit nicely on it once it had arrived. Being the first time I had done anything like this or had a car transported interstate I had no clue how the logistics of it were, I chose my work as the delivery address assuming it would arrive at some point in the middle of the day. You can imagine my surprise when I wake up to a call from the truck at 5:30am telling me his about 20 minutes away. When I tell you that was the fastest drive to work I have ever done, I managed to catch up to the truck before it even got there. Spent the hours before work taking in the car and living my first experience with one, I had never even been inside one so I spent some time getting familiar with the interior before doing the seat swap. Here is my first proper photo of it as the sun rose in the background. I also noticed it had the switch for the electronic front lip which was a pleasant surprised but sadly upon looking it didn't actually have the lip or the motors or even any wiring behind the switch. As I swapped the seats, the extremely questionable history of the car started to show itself starting with some really dodgy seatbelt buckles that had been extended for some reason with horrendous welds. This was followed by me noticing the drivers side front was quite bent up to which the owner then decided to let me know it had been hit in the front at the same time as the rear end. It also had a pretty leaky power steering rack and the pump was screaming for its life. By now I was a little on edge but I had to get to work for the day, I sent the car down to my mechanic to get the fluids changed and a general check over as I started to question what I had got myself into. I packed the GTR wheels into the car to get put on while it was there as I ran out of time which was a struggle because the handle to release the fuel door/boot was non-existent and just had the end of the cable tied to a bolt. It wasn't much of a surprise when I got a call saying that it looked like the fluids hadn't been done in quite some time. Although that didn't come as a shock, it did catch me off guard when I was told he couldn't open the boot which had the wheels in which I just had open not long before. Mission #1 was to squeeze through the back panel and open the boot from the latch while loaded with a set of wheels which to my amazement he pulled off after a bit of a struggle to reveal there was nothing holding the cable mechanism in place where it sits at the fuel cap. After that dilemma was solved the mechanic did an inspection over the car while on the hoist with nothing too interesting being found other than the expected crushed frame rails. It seems to have had some bilstein shocks installed at some point and judging by the AWD sump that has been sealed up I suspect the NEO is out of a stagea. By the time I got the car back and was ready to have my first drive home in it I was still excited but now quite anxious with the car already. First stop was to the servo to get a nice fresh tank of fuel as I had no idea how long it may have been sitting around for before I bought it. It sat quite nicely on the GTR stockies I must say. Now my drive home from work is short only being a 15-20 minute commute so the chances of anything going wrong is quite small right? WRONG. As I go over a speed bump only 100m from home I start to smell the dreaded smell of electrical burning and my lights drop out and shortly after the car dies. I am in extreme panic at this point thinking the car is going to burn down on its first drive before I have even had a chance to insure it. I move to the bonnet as quick as I can and lift it up, and as I go to grab the bonnet prop my brain is in such a frenzy that it takes me a second to realise my hand is being burnt to a crisp. This is where I notice that there is no plastic clip for the bonnet stay and when I have gone over the speed bump it has knocked the stay onto the positive terminal of the battery welding itself there. Levering it off with a nearby stick I sat there for a few minutes making sure nothing was going to burn down while waiting for a mate to come jump start me. My main stress was that I could've absolutely cooked the ECU or any other electrics. I was relieved when the car started fine with jumper leads on it but it would die as soon as the headlights were turned on so I carefully limped it home with no lights and decided it was a tomorrow task. You can see here where the stand sat on the positive terminal. Thankfully with a new battery the car behaved and seemed healthy. It was pretty smooth sailing for a little while getting to enjoy dailying the car. Interior wise it was pretty much as the seller described except for the the lack of working speakers, the digital controls had no power, and the headunit would randomly turn off & on. I installed a quick release I had laying around from an old car to help with getting in & out of the car and a nice momo wheel. I bought some oem side skirts to match the rear pods that were on the car already, who said a skyline can't be a practical parts mover. Test fit looks good! Found a good deal on a GTR wing & boot that I couldn't turn down. At this point the skyline was being too good to me and had to throw the spanner in the works again. First incident was as I was coming off the motorway and heard a bang and an awful grinding noise. As I pull over down a side street to investigate I notice my whole exhaust has basically fallen off and is dragging on the ground. After waiting around to let it cool to the touch I managed to get it back on its hangers. Thinking it was a weird 1-off instance I didn't think much of it until it happened to me again a few days later to which I see this time the middle hanger has snapped in half and the rear hangers have snapped at the welds. I manage to get the car in to a shop to get the hangers welded and while there I notice that my intercooler has broken its brackets and was being held up only by the piping. Quickly got that sorted and got some thicker brackets out of steel plate to support it all. Just when you thought at this point the car might give me a break, I fill the car up on my way home from the fabricators shop and after I pay I walk back to a good portion of my liquid gold on the floor. I just shrug it off at this point in exhaustion and call it a job for another day. The car had other plans for me though as the next morning on my commute to work, I am halfway there when I notice I am struggling to shift gears. I get lucky with a run of no red lights to work and find some time on my lunch break to investigate the problem. The slave wasn't leaking and the master still had fluid so I was left confused until I contorted myself under the dash and noticed the whole pedal moving loosely side to side when pushed in. Upon pulling it out of the car I found it to be multiple snapped spot welds on the clutch pedal bracket and the actual face of the pedal that sits against the firewall had snapped in half. I jerry rigged it with nuts & bolts at the spot welds but I will need to come back to this in the future and replace with one of the strengthened nismo brackets available. I then got to enjoy the car for another 2 months of cruising and dailying it, peep the obnoxious fireballs it would shoot every shift on the dodgy tune that was on there. On a sunday drive in that period of working car, I was on my way home on the motorway when I heard a slapping noise on my front left to which I pulled over to find my indicator had ejected itself from the car. Nothing a bit of tape can fix lol. I then bought some smoked indicators but after I realised I didn't like the look I found some damaged series 1 indicators. I repaired the tabs with some cut up cards and they looked good to me. My next venture was the hunt for some wheels, I test fit my mates Work Equip Spinning that were tiny 15" and I wasn't sold on the small wheel look. I ended up finding a killer deal on some Rays Volk Racing Group C in 17x8.5 & 17x9 that had been rebuilt many years ago and not ran on a car. I am still yet to get these on the car as they require some specific adapters and shank style lug nuts but I think they will look awesome. At this point my 2 months of reliability had ran out and on a cruise with some friends I suddenly lost the ability to shift gears again and thankfully could get it home by taking main roads and not having to stop. This time my master cylinder was bone dry and the culprit was the clutch slave that had decided to let go. It was a quick and fairly easy fix, but in my luck bad things always come in waves. Only a few weeks later I am on my way home from World Time Attack when the car completely shuts off while coasting down a hill, I try crank it while I still have momentum but no luck. Thinking I might have killed the fuel pump from running it low or maybe killed a CAS because the symptoms seemed to line up somewhat, I opt to get the car towed to a workshop to get fixed up on the Monday. When it gets there they get stuck into diagnosis and the CAS wasn't sending a signal to the ECU, and the fuel pump was also dead so it was comical for a small moment there. They replace the dead fuel pump when one of them notices some smoke coming from the passenger kick panel. Boy oh boy this is where it gets very bad and very expensive. I am not sure who wired the car when the NEO swap was done originally but I hope they never attempt auto electrical again as I am lucky that this handywork only managed to short and kill the ecu and engine loom and not do more damage. This is the point where you could say the 'build' started but not by choice. After some deliberation with my bank account I opted for a Haltech Elite 2500, RB terminated loom, and WB1. While I wish I stopped there and did the minimum of get the car running and leave it at that, I slipped into the rabbithole and decided I wanted to make the most of getting a retune and throw some bolt ons at it and see what it would do. I then threw together a bit of a mix n match build of marketplace deals starting with a GCG GTX3076R, a turbosmart FPR6, 980cc injectors, walbro 460, jackspanian ffp, throttle & fuel rail. At this point it was coming along nicely, the shop was making quick work of it and the bay was looking a lot nicer without the stock crossover intake. I also got them to replace the noisy centre bearing while it was off the road. Then we couldn't get an OEM CAS to talk to the haltech so ended up getting a PRP Street Trigger Kit for it.   While the car wasn't playing nice it decided to kill the stock alternator too so went with an LS1 alternator conversion kit. By now the car was pretty much done and ready to go but come tune day the car kept throwing the timing out every time it would warm up. Upon further investigation it seemed to be warping the PRP trigger bracket when the metal would get hot and expand which would cause the sensor to lose timing as it moves. Herman advised that they have seen the issue a few times now and don't know what the cause is. At this point I decided to switch to the PRP Pro kit with the crank trigger and considering the whole timing belt would have to come off I decided to get a new timing belt kit with water pump fitted. The car would now run fine with no issues and it was finally tune time. It ran up a healthy 275kw but ran out of boost due at 17psi to the rear housing being undersized. At this point the clutch also started slipping and due to it still being a weak RB20 box the tuner set it up to ramp from 8psi up to 17psi with the revs so that it wouldn't load up the clutch and box as hard. Car drives like a dream now. With the car back on the road I could return my focus to the smaller details, starting with getting a set of badges for the hood and quarters. I was struggling to drive with shoes on and I noticed that my accelerator pedal sits higher than my brake and clutch, if someone could confirm how it should sit that would be great. Next little changes was a killallwipers rear windscreen wiper delete, I also got some interior bits I was missing such as parcel shelf speaker covers, wiper trim cover, and boot floor and trims. Finally made it to a SAU NSW event which was awesome to cruise with a bunch of likeminded individuals. Another creature comfort I decided to look into was my lack of A/C. Since the Haltech got wired up the digital climate would power up now, and would blow but no cold air. First issue noticed was the lack of belt on the A/C compressor. After sorting that to no avail, it also had no A/C gas in it, but turns out the condenser has a huge leak. We are almost caught up on the story so far, but at the start of this month while coming into a driveway I heard a huge clunk in the front end to which I got out to witness whatever dodgy camber arms someone installed in this at some point decided to snap in half and I feel very lucky that it didn't happen at speed. Managed to get the car fixed the next day with some replacement GKtech arms. Next problem to address was the leaking gas tank from months ago. Checked the pump hanger seal first but that was fine, stuck my camera up after filling up to try scope out the leak which looked like the breather hose. Got the car up on a hoist prepared to drop the tank when I reached up to feel with my hand and I could feel that the hose clamp was missing and soon after felt that there was a gaping hole in the top of the hose. Replaced and tested and the car holds its liquid now and doesn't give me a fume headache whenever I drive it now. Finally have caught up and now onto fixing my latest issue which is the lack of dash light when driving at night, checked fuses first, then when searching I found the common problem of the headlight switch burning out but mine looks fine. Next test will be plugging a known working headlight switch into my car to tell if my switch is dead. Sorry for the long read but I wanted to be thorough, so if anyone made it this far I salute you soldier. Enjoy the rest of your day and I will keep this updated with issues I find/solve and any cool mods I can do inbetween. Merry Xmas!
    • can someone tell me what information a block number of 330680a on a rb25det engine specifies?
×
×
  • Create New...