Jump to content
SAU Community

Recommended Posts

Hey Guys,

I've been searching High and Low for the answer to my question..... Why don't I have any boost, even spooling until over 4000rpm or more?

I'm very new to turbo's and i've only had the car for around 2 weeks. One of my mates came for a drive with me (him being in previous skylines before) and said It just didn't have the same kick back as previous ones. Then I picked up my car after getting a front and rear wheel alignment, and the fella asked if I was running the car with minimum boost? or none at all? He said It didn't feel like any of the other ones he has been in!?!?

The car has a pod filter and after market intercooler installed. Along with yellow jacket coil packs.

My questions are,

Should it have some boost even when cruising? in all gears?

Should the first stage kick in or around 2500rpm in most gears?

Should I just buy a boost tap (Manual or electric)?

Does anyone have any other ideas on what and where I should start to look? I'll post up a video of my driving it, viewing the stock gauge. Also I'll post up a picture of the vacuum hose setup near the boost solenoid (think thats the name). The red hose goes into the charcoal filter? is that right?

Cheers in advance peoples.

P19-11-10_18181.jpg

http://s49.photobucket.com/albums/f296/ske...-11-10_1810.mp4

Sorry for the crap video

Link to comment
https://www.sau.com.au/forums/topic/344858-r33-94-gtst-nolow-boost-help/
Share on other sites

the stock guage on the dash (turbo icon inside RPM tacho) should swing past 0 mmhg on the guage (which is half way) after about 2 seconds of accelearting

anything past 0 is "boost" it should goto around 3/4 which is around 0.75kgcm2is after 4500rpm and before that it should be around 0.5kgcm2 if its a manual gtst

the stock guage is in MMHG but its close to kgcm2 so its ok as a base measure

post-2054-1290248508_thumb.jpg

ok so the guage is in MMHG

-7 is vacuum

0 is basically absoute pressure

+7 is 760mmhg which is 1 bar or 1kgcm2

when you drive it will be around -500 ish

when you floor it, it will build pressure to 0 (all cars do this, even N/A)

then it will go past zero and start building boost pressure

3/4 up the guage is +5 or +500mmhg which is around 11psi ish

the green area is vacuum

blue line is around stage 1 boost - 0rpm to 4500rpm approx 5psi on manual GTST

pink line is around stage 2 booost - 4500rpm to redline, approx 7psi on manual GTST

the auto runs approx 5psi on stage 2 boost

I fixed a R33 for a guy a while ago were the line to the map sensor was cracked after Autobarn put a boost guage on it. He thought the turbo was blown but it was the car not sensing boost so it wouldn't boost up. Check the map sensor line for cracks! It effects the ecu and boost gauge.

It was/is some sort of vacuum leak. Where ever the stock gauge line is. I installed a DEFI boost gauge today, and there we have it. Positive boost. It shows no issues at all. Spool time might be a little out but not very much. There is def. positive boost. As far as I can tell, the boost is a smooth process, so I kinda didn't notice it.

Does anyone know where abouts the line is to check for the stock boost gauge?

its just behind the firewall, where the steering column goes

its a little light brown box with a single vac line into it and 3 wire plug

it might be disconnected, therefore it never goes boost and will always sit around -600 ish on the stock dash

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

    • I know this one’s the BB one. My tuner did make mention about the actuator. I am curious about the VCT as well
    • Might also needs a stronger actuator with the right preloading. With older 2019 built bush G3 units, BB upgrade or 21U housing down size makes a pretty decent gain in response as well. 
    • Hey lads  so im finally putting together my rb30 forged bottom end and ran into an issue. I measured my main bearing clearance with arp main studs torqued to 60 ft-lbs using ACL H series STD size bearings and standard, un-ground crank shaft journals and got an oil clearance reading of about 1.3 thou measuring straight up and down and about 2.8 thou measuring at a 45 degree angle (just above and below the parting line). My machine shop said they measured the main tunnel and it was all within spec (they didnt say the actual measurement) and to go with a standard size bearing, which i have done and the clearance is too tight, I'm guessing because of the extra clamping force from the arp studs distorting the main tunnel. I was wanting to run about 2.5 thou main bearing clearance.  My questions are: 1. could i just use the HX extra 1 thou clearance ACL bearings? that would fix my straight up and down clearance making it about 2.3 thou, but then would the side to side clearance be too big at around 3.8 thou? 2. what actually is the recommended main bearing clearance for measuring near the parting line / side to side. i know its supposed to be bigger as the bearing has some eccentricity built into it but how much more clearance should there be compared to the straight up and down measurement? at the moment there is about 1.5thou difference, is that acceptable or should it be less? 3. If i took the engine block + girdle back to the machine shop and got them to line bore the main tunnel (like i told them to do the first time, but they said it didnt need it) what bearing size would i buy? the STD size bearing shells already slide in fairly easily with no real resistance, some even falling out if i tip the girdle up-side-down. If im taking material out of the main tunnel would i need a bearing with extra material on the back side to make up for it? this is probably confusing af to read so if something doesn't make sense let me know and ill try explaining in a different way. My machine shop doesn't come back from christmas break until mid January, hence why i'm asking these questions here. TIA for any help or info 
    • I bought the model back in Japan in Feb. I realised I could never build it, looked around for people who could build it, turns out there's some very skilled people out there that will make copies of 1:1 cars or near enough. I'm not really a photo guy... but people were dragging me in a group chat for the choice of bumper as someone else saw the car before it was finished as they are also a customer of that shop. I took the photo in the above post because I was pretty confident that the lip would work wonders for it. Here's some more in-progress and almost-done pics. It gives a good enough idea as to what the rear looks like!   I have also booked in a track day at the end of January. Lets all hope that is nothing but pure fun and games. If it's not pure fun and games, well, I've already got half an engine spare in the cupboard 
    • Well, do ya, punk? Seriously though, let's fu<king go! The colour and kit looks amazing on the car. Do you have any shots from the rear? I don't quite follow how the model came around. You bought the white kit and he modified it to match your car? Looks nuts either way!
×
×
  • Create New...