Jump to content
SAU Community

Recommended Posts

I was going to say 28mm :rofl:

Near enough!

I cant remember 100% but i think someone here got it machined out to around a 32-34mm size and them changed the flapper as it wasn't sealing perfectly.

Was a while ago now, i'll have a search later and see if i can find something. I can't remember for the life of me who it was at present

The bigger the hole is. The harder it is to hold boost up the top. Best to not drill it out too much. Most Garrett IW housings had the hole match machined refer to the CHRA at the sort of perfect size.

well force = Pressure x area

Means there is greater force transferred to the actuator while its trying to pull the wastegate flapper shut.

So at high RPMs back pressure over comes actuator's spring load and force the gate open it self.

Once that happens you will have a boost drop. and that is not due to boost controller.

How ever on the other hand the turbo will boost unlimitedly if wastegate whole is too small. So best is to run a external gate. Lot better boost control, and steady power to red line.

I'm currently working on a project, which allows screamer pipe to plum back into certain area of the turbine housing. So we can have a externally gated turbo that bolton without any modifications to dump pipe or manifold.

Ye ok so force = P x A

However with...

1x heavy duty actuator

1x upgraded flapper

1x decent EBC to aid in control and

1x correctly set pre-load...

I'm really not seeing how this would be a major problem for a GT30 internally gated (with some porting should someone so like to do so). It certainly was not a problem for the user who ported their int gate (still looking for the thread)

You are already bleeding air as well to control boost so there is not the absolute max pressure being realised either.

The only time i've heard of internal gates blowing open was on the GCG OP6 hi-flows, and the reason for this was not supplying an upgraded actuator and preload being poor.

Meaning the gate was flapping open before boost was even being created and thus resulting in boost coming on around 4500rpm give/take.

ANYWAY - A proper Garrett IW rear does not need porting.

In my searching for the porter... i found a person i'd forgotten... Darren has GT35, 350rwkw if memory serves me correct... internally gated, don't get much better

http://www.skylinesaustralia.com/forums/Ga...porting+turbine

http://www.skylinesaustralia.com/forums/Gt...porting+turbine (last post)

GT35's are 32mm

correction, 36mm. i checked lol.

on the topic of wastegate sizing, even porting it out to 38-40mm, surely this wouldn't cause an issue with top or low down boost control? aren't most external gates that are recommended around that size anyway? i can however understand the theory behind going too big on the port size of the wastegate, in either blowing open early or "bouncing" when first opening.

Edited by QWK32

The internal and external gates do operate a tad differently with regards to how they open.

Only is like a door hinge, one is pure up/down valve.

So ye, you could see some issues in that regard once open you have a lot of force on the outside side of the flapper (int gate), where external is far more distributed/uniform

also, if you think about it, one becomes a straight through tunnel with no restriction, in the other the air has to flow around the poppet valve and stem. Looking at both designs, an external wastegate is always a bit larger [they generally start at 38mm] because it has to overcome more turbulence. Just looking at the wastegates, not how the air gets there or what happens once it passes through the wastegate. No proof, just my thoughts??

Strictly from an actuators point of view the larger the diameter of the can/diaphragm/spring the better .

Note how external wastegates are generally not small in this area .

Also as mentioned the external has no swing valve arm to multiply force against the actuator .

A lot depends on boost and exhaust manifold pressures , if the exhaust (turbine inlet) pressure rises markedly faster than boost pressure then the pressure/area force eventually overcomes the waste gate actuator and forces it to open . Its trying very hard to tell you that the system is not running in regulation . Just another indicator that high boost pressure does not guarantee reliable high horsepower .

A .

Just wanted to know as a reference really......

So many ppl are getting probs with boost control i just wanted to know what was the average size of the internal gate and if using an ext 38mm will still be too small and cause creep

As mention before we know ext gates are more efficient because of its larger diaphragm, ability to change springs,valve type etc. but i think factors like exhaust manifold pressure,type of manifold and turbine a/r also has a significant part to play when it comes to boost control

So i don't believe the concept that if Fred gets good results using a 38mm ext gate that means Larry will have good results too using a 38mm ext gate even though they are using the same specd turbo on the same engine but on different manifolds, have different dia exhaust, same type but different sized a/r turbine etc. etc...

And for sake of this discussion lets use........and u guessed it........ the Gt3076 :)

Well the example of Darren's car, making over 300rwkw, with a larger GT35... would all seem to point it should be OK.

What most people have drama's with is when they go with Garrett housings, but machined ones - not the ones designed for the turbo in quesiton.

The GT30-IW rears so far all seem to be fine, same as the GT35 ones.

Well the example of Darren's car, making over 300rwkw, with a larger GT35... would all seem to point it should be OK.

What most people have drama's with is when they go with Garrett housings, but machined ones - not the ones designed for the turbo in quesiton.

The GT30-IW rears so far all seem to be fine, same as the GT35 ones.

That was what i was lead to believe too until i went with a GT3076R 0.82 IW on my 2JZ...boost crept up to 18psi by redline...2 dump pipe designs and 1 slightly restrictive catback later...i finally managed to get it to settle at 16.5psi at redline...

You are talking about a factory 3 Liter engine there and a 0.82 A/R GT30 turbine housing is not big by 3L standards .

Rather than me guessing where did in come on boost with the 2JZ . May have been a case for the larger 1.06 A/R GT30 IW housing .

A .

That is true...and i remember us speaking about it too...however the rb30det boys seem to run the same turbo without much hassles...if anything they had issues with the standard actuator not holding boost...

On the 2J it made 18psi by 3200rpm with the 0.82 rear...i did consider the 1.06 at one point but the issue seems to be under control now...

What most people have drama's with is when they don't go with Garrett housings, but machined ones - not the ones designed for the turbo in quesiton.

The GT30-IW rears so far all seem to be fine, same as the GT35 ones.

I think u left out a word there....

I wouldn't say that is entirely true however.... kinda which made me start this topic in the first place

This was posted in a thread recently

http://www.nissansilvia.com/forums/index.p...t=270&fcat=

100% Garrett....ext gated, and still having creep issues

Not sure what size the turbine a/r is tho.....

Reads ok to me...

Just because a car has gate creep, does not mean its the housing. Infact that's pretty much the late port of call in my book (if its the correct housing)

Likely too soft of a spring/actutor, poor manifold design and similar issues.

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

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...