Turbo pics

[WideOpenThrottle]

Well,while the battery is getting charged for its first start since turbo,d i thought pic time so you you can see the progress,shoot me down! & give me some pointers of where to look for any potential problems.
Go easy as its my first attempt so its still in the evolutionary stage .
The intercooler,some piping,turbo & wastegate all came off a 323gti.
For now i will be happy if it starts & idles ok.
Also does anybody know if i need a check valve between the charcoal canister solenoid & the manifold as i keep reading about them but there doesnt seem to be one on the old 323 motor?

[WideOpenThrottle]

#2

[jif]

mmm... shiny :]



"as long as you're in there" ... you should seriously think about changing the radiator, even the $260 on trademe will handle the goods ok. An old stock radiator on the other hand has stuff all overhead to cope with clogged tubes, intercoolers in front of them and increased heat loads  In hindsight that's what I should've done.  Try and leave the undertray on , if possible.


The AFM situation has been covered already... try and get cool air for the intake as well - makes a noticeable difference.


Other than that, looks like fun - MX5s perk up nicely with a bit more spice under the hood !

[Posted via external email]

[WideOpenThrottle]

Yea for sure i can see a new radiator coming as there seems to be a minor crack in the bottom tank.

I have a custom undertray ready to go back on once its driveable.

[WideOpenThrottle]

Well would you believe it?
Started no worries, even the vertical AFM seems to be causing no idle/run issues.
Once warmed up & conviced nothing was going to disintegrate i took it for a test run--oh dear! under throttle, i looked like a cross between the Kingston-Flyer & a steam train
On closer inspection i could see oil dripping from under the turbo cast joint so the seal must be poked allowing oil to be burnt thru the exhaust as well.
Fun and games so out it comes.

[WideOpenThrottle]

Well as it turns out there is nowt wrong with the turbo.Steve from Motorsport engineering said it's more likely too much oil for the the turbo as well as perhaps the the rocker cover breather pipes.
I have since had the oil line restricted plus vented both breather's to atmosphere and capped the entry points to the pipe before the TB and the one to the plenum.
This appears to have solved the oil problem but now that i can properly test it i have an annoying [turbo lag?] when i floor it from lower revs!
After a few sec's or so it all catches up with itself and then it's like nitrous boost up to the red-line.
Otherwise if i gadually increase speed its not so noticable and seems to pull well.
Looks like i've got a way to go to get it performing better.
Might experiment without the 323 intercooler & reposition the AFM.
One things for sure it's such a better car even with its shortfalls!

[Timmo]

....but then how would the oil be getting into the exhaust if the seal was doing its job? Or would it simply be getting overwhelmed by too much pressure?

I would imagine the lag is caused by the mismatch in pipe sizes- There is a reason why the original inlets/outlets from the turbo and intercooler were kept small on the original set up: to avoid having to fill and compress large volumes with a small 'pump'.

Still, I bet it has transformed the car! (I do miss my MR2 turbo )

[WideOpenThrottle]

Apparrantly according to Steve the oil leakage is due to something like a balance of various things which prevent leaks thru the seal.
In my case i think i was pressurising the engine oilways thru the camshaft breathers which i suppose increases pressure on both the oil feed & drain at the same time which is obviously more than what the turbo seal could hold.
As for the mis-matched intercooler pipes does it not pay to go larger towards the thottle body from the intercooler? The outlet is the same as the turbo but needs to increase on the way from the IC to mate to the TB diameter.
Have i got it wrong or is the pipe work too long & bendy?
My logic for large pipe to the turbo inlet is because a smaller inlet would create more restriction for the turbo to suck in air???
Could you not have a turbo with the air filter fitted directly to the inlet side?

[WideOpenThrottle]

Also the 323 that this turbo came off had a bigger dia AFM then reduced to the turbo dia which then increased up to a bigger dia TB although it was perhaps a little shorter in length of the plumbing.Similar to what i've done.
I'm wondering if it might be fuel related as well!

[SLYDIT]

the lag you speak of is probably the wrong fuel mixtures below 4500 rpm or so. the factory computor runs in closed loop operation even at full throttle below about 4500 rpm, so even if you have big injectors in there the computor just tries to pull back the fuel all the time. what you need is an O2 clamp which tricks the ecu into thinking the mixtures are ok and prevents it from pulling the fuel.
basically its a simple circuit which feeds the ecu a voltage of about 0.39 volts on the Oxygen sensor circuit when on boost. you need a boost switch and a simple regulator and some resistors.

[WideOpenThrottle]

Okay! where can i get an 02 clamp?

[Timmo]

Apparrantly according to Steve the oil leakage is due to something like a balance of various things which prevent leaks thru the seal.
In my case i think i was pressurising the engine oilways thru the camshaft breathers which i suppose increases pressure on both the oil feed & drain at the same time which is obviously more than what the turbo seal could hold.

Yeah that makes sense- Seals are devices which are sensitive to pressure, not volume....and a turbo needs volumes of oil for lubrication, not necessarily pressure (although of course, pressure is a method for supplying volume)...probably not something you can predict unless you can somehow get hold of, or measure, the flow rate of the oil feed in a standard 323 setup and then restrict your pressure to match that rate.

As for the mis-matched intercooler pipes does it not pay to go larger towards the thottle body from the intercooler? The outlet is the same as the turbo but needs to increase on the way from the IC to mate to the TB diameter.
Have i got it wrong or is the pipe work too long & bendy?
My logic for large pipe to the turbo inlet is because a smaller inlet would create more restriction for the turbo to suck in air???
Could you not have a turbo with the air filter fitted directly to the inlet side?

Good turbo systems are about balance between the different components. No use putting a massive truck intercooler on a tiny turbo running low boost....assuming you are running, and intend to keep running, fairly standard (or below) boost, then I would think that there is no benefit to running larger diameter pipes. There is some downside to it as mentioned: Your turbo has to first fill and compress the air inside those pipes (and intercooler) before being felt as usable boost at the engine. This is turbo lag.

If, however, you intend to upgrade the turbo later and don't want to buy stuff twice then fair enough. But given that you are running standard internals (?), and therefore lower than standard 323 boost, there is no need for that extra pipe capacity (of course you will need to increase pipe dia at the intake plenum to make it fit!).

Increasing pipe diameter after the IC will possibly further reduce charge temps due to higher pipe volume (therefore lower pressure and therefore lower temp) but all you are doing is trading max potential power with drive-ability....and if the IC is correctly matched to the turbo (which it will be as its a standard 323 one?), then you wont be getting any more power anyway (since charge temps will be reduced as far as they can realistically be already).

In terms of air filter, you certainly can mount it and flow sensor directly onto the turbo inlet if it fits and if it is a good position in terms of incoming airflow. Pipe lengths and volumes on the intake side of a turbo don't have much impact on lag though so I would say the bigger the better here (although, ultimately it is going to be restricted by the size of the turbo inlet anyway)

What pressure relief/gas recirculation valve are you using?

[WideOpenThrottle]

For now while i am on this learning curve i will be keeping it 323 boost levels [whatever that was]! Seems like i will perhaps use smaller dia pipes between the IC & TB.
As far as pressure relief do you mean BOV or something? If so read heaps that they are not super critical for low boost levels around 5psi or so and less although i would like to fit one to atmosphere if my set-up will allow.

[sprsta]

i may have my flyin miatalink for sale soon
something like that would help you out with fueling

[WideOpenThrottle]

i may have my flyin miatalink for sale soon
something like that would help you out with fueling

cheers sprsta i will consider it when your ready

[Timmo]

Just wondering out loud- Do you think it would be possible to
a) re mount the radiator, keeping the same bottom position but slanting it back as much as possible (would need custom outlet pipe to thermostat)

b) placing intercooler in front of radiator at the top in the space left by the slanted radiator? That means you could have an even shorter intake tract?

The biggest issue would be how much you can slant the radiator back as that will determine how much vertical space you'll get for turbo piping (unless you could fit around the side?) and horizontal space for intercooler.

[WideOpenThrottle]

Hey Timmo-sounds complicated as well as reducing air flow/cooling thru a slanted radiator.I will probably be putting in a thicker race radiator at some stage so this lessons slantability.I am currently reconfiguring the piping set-up so will see if there is any improvement.

[WideOpenThrottle]

Well these flamin oil leaks are starting to get up my nose-i have just done the rear crankcase seal plus the cam angle sensor & they are both still leaking! The front crank case seal plus the turbo is leaking which untill i can get my head around whats going on i think i am gonna take up knitting!!!.
Anyone else had this sort of thing happen?

[Growler]

Hey Timmo-sounds complicated as well as reducing air flow/cooling thru a slanted radiator.I will probably be putting in a thicker race radiator at some stage so this lessons slantability.I am currently reconfiguring the piping set-up so will see if there is any improvement.

Check most race cars. They slant the radiator so that the air hits the cooling fins directly instead of passing through the radiator easily. It results in more efficient cooling of the radiator.

[WideOpenThrottle]

Thanks Gowler-i am repositioning the AFM so it might be in the way of a slanted radiator.Lets see how it turns out then i might put a slight slant on it if there's room providing the engine still has clearance for when the engine lurches forwards under hard acceleration.

[sprsta]

if all your engine seals are leaking check that you have plenty of crank case ventilation you may have issues with your pcv or rings letting boost into the engine
i cant see in your pics where the breather pipe goes (dont just block it off!)
go for a run and see if your dipstick has moved up at all
there was way more blow by after i put my turbo on
take it out and check you can blow through one way easy and not the other way
i would do away with it and use a breather/catch tank off both vents

[WideOpenThrottle]

I did have both breathers vented to atmosphere but i did reconnect the one to the plenum [looks like i will be taking it off again].It has been pointed out too by someone else that the main problem i have could be that fact that at nearly 300thou km the engine is leaking boost past the rings & pistons
Shame really as it really flies along for an old donk!
Maybe my plans for an 1800 motor might be implemented sooner than planned

[sprsta]

that would be my guess, she getting up there

you will need to make anoher exhaust manifold etc for the 1800

[WideOpenThrottle]

that would be my guess, she getting up there

you will need to make anoher exhaust manifold etc for the 1800

So an NA6c exhaust ports dont line up with an NA8c-funny i thought they were identical?

[sprsta]

no the 1800 is longer.
anything on the front or rear will fit but the side parts wont
these might help
http://www.flyinmiata.com/tech/1.8_conversion.php
http://www.solomiata.com/oneeight.html
http://www.solomiata.com/index.php

cheers

cole