4k-c Turbo Build!

[Jaydnisevil]

Ok was mucking around earlier to try and get this hesitation sorted out.

Now my suspicion was the carby was oversized for the engine, and it did not have the airflow to draw enough fuel at low RPM.

This was then supported by Weber performance Aus telling me something similar.

 

First thing was a test, I put a bit of cardboard 98% over the secondary throat.. Low and behold an idle to what throttle change had no hesitation what so ever! So its definitely a secondary fuelling issue.

A restrictor or disconnecting the secondary is not really a viable option it would be a last resort.

 

Next step, was to hook up the throttle nudger to a vacuum source (Just substituted it over the booster for now)

Then I proceeded to yank out the secondary jet, check the size and for blockages.

Well as a test I left it out to allow as much fuel as it could take.

Turns out this gave a considerable improvement in the hesitation (say 85%) Some hesitation from idle-what but the mid throttle-what was gone :)

 

I also re-jigged the vacuum source to my fuel reg, which is now tee-d off the vacuum advance so manifold vacuum does not effect the pressure. In doing so my base pressure has jumped up to a considerable 7psi :blinks:

I would really prefer to keep it at say 4.5-5psi, so not sure how I will approach this.

That pressure is just a result of my line back-pressure to the tank. I suppose I could shorten the spring, but ill keep thinking. Anywho, at least the pressure rises at a correct rate now and with boost pressure :)

 

Ohh and with that higher pressure (4.5-7) This again gave an improvement in the hesitation!

Its not perfect but now if I have given it a squirt, and try a idle-what jab soon after there is none at all. The only time it occurs is if I maintain a cruise RPM for a few seconds (when the mixtures settle back to norm) and I do the idle-what blip

 

My thoughts..

Check to see if restricting the air correction jet helps, if so..Get a smaller secondary air correction jet.

Fuel pressure issue.. Dunno, a little vacuum at idle would be perfect opposed to none. Cruising it will be fine, it sat back down to 4-6psi depending on the vacuum. But 7 is just too high for idle me thinks.

[Jaydnisevil]

Cable tie special gave me a chance to drive it today :) (well its hard when you have one wheel spinning)

I wanted to sort out what's happening with this carby before I proceeded any further. So I used a few ties to prevent the temp throttle bracket from flexing, and I supported the 'exhaust' also with ties :P

 

First drive:

Shit.. Leaning out, hesitating just crapola.

Still suspecting the secondary throat at fault, we remove the arm that pushes it down and cable tied it shut... TIGHT.

 

Well that gave a lovely improvement :) Enough to spin the wheels through 2nd and end up 40 degrees sideways down the street with half throttle (Admittedly it was unintentional, I overestimated the 165's in the wet lol)

Anywho mixtures were not bad at half throttle, but at wider throttle openings it still ran around ~17:1 At least it was on the scale this time and not hesitating. I think this is happening because it would have been jetted designed for the second to have opened by that stage.

Ima gonna try two things.. Block off the secondary throat by 95% (Plate with a few holes in it) and re-connect the throttle arm so we can draw more fuel in at higher throttle positions via the secondary 'jet' (which I will have to put back in). That or.. swap the bigger secondary jet to the primary and hold the secondary closed permanently. Ima trying option 1 first because its a better test, and its reversible.

 

Its gonna be trial and error untill its right, at which point I will continue with the de-ghetto process.

 

Ohh and I'm running around 6psi at the manifold (I think its Set to 10psi via the bleeder, but who knows)

Would be interesting to see the pressure loss from what its making at the turbo. Might hook the gauge up to the turbo outlet and check some day.

[Jaydnisevil]

Done a few small things since ^^ but can't really remember what else iv done

 

Turbo is off again.

Determined the reason I'm not getting over 7psi is turbo malfunction.

Came to that conclusion because I measured 7psi at the turbo and 6.5psi at the manifold. I then disconnected my waste-gate and it still stayed at 7psi, I then hooked it up in reverse (Pressure holding it shut)and it still stayed at 7psi.

I am fairly certain is due to the blades being out of balance, as the symptoms fit it perfectly.

 

Probably from when we welded the gate shut, or the oil that has clumped up on the compressor wheel from the draw through set-up.

That noise I was referring to in the initial video occurs all the time over 3psi of boost.

When I have some spare cash (About a week) ill send it away for inspection and re-balancing.

 

Iv put the larger LCA bolts in, didnt take too long (Free)

Iv also sourced a small muffler to quieten things up a tad, straight through design; and again a freeby from work :)

 

Iv changed the brake lines to the banjo fittings and re-bled, may have mentioned.

Ummm Still having leaning out issues, will need a larger main jet or smaller air correction jet.

 

Have a proper throttle cable bracket now :) I need to modify the carby bracket a tad, Its stiff off throttle.

 

But it works :)

 

Think thats it? :)

Edited November 4, 2011 by Jaydnisevil

[kickn5k]

Probably from when we welded the gate shut.

Really?? You didn't pull the housing off to do it?

[Jaydnisevil]

Really?? You didn't pull the housing off to do it?

 

Wanted to, tried.. and couldn't. Started damaging the core as we tried to separate them.

We covered the wheel with a small cloth and a plate on top of that. Nothing seems to be on it, the turbine looks perfect.. a bit of carbon but nothing unusual. Its the compressor side that looks suss.

[Taz_Rx]

Ct12's are classed as consumable turbos, ie no rebuild parts. Wouldn't be surprised if 9's are the same!

[kickn5k]

Wanted to, tried.. and couldn't. Started damaging the core as we tried to separate them.

We covered the wheel with a small cloth and a plate on top of that. Nothing seems to be on it, the turbine looks perfect.. a bit of carbon but nothing unusual. Its the compressor side that looks suss.

 

Hot shut down will usually cause the rear housing to tighten up. Welding might not have caused your issue, it might have been f'ed before you put it on. Considering your saying it's more on the front wheel.

 

Tazrx is right the ct stuff is real hard to get a hold of and can be well over priced if sourced through a turbo shop. Have heard of reco quotes for ct12 and ct26's being near $900. Considering it's a bushy and you can generally get a Garrett BB for a couple of hundred more that's what I'd be looking at.

[Jaydnisevil]

Hot shut down will usually cause the rear housing to tighten up. Welding might not have caused your issue, it might have been f'ed before you put it on. Considering your saying it's more on the front wheel.

 

Tazrx is right the ct stuff is real hard to get a hold of and can be well over priced if sourced through a turbo shop. Have heard of reco quotes for ct12 and ct26's being near $900. Considering it's a bushy and you can generally get a Garrett BB for a couple of hundred more that's what I'd be looking at.

 

 

I got the turbo for next to nothing, so not a huge disappointment. Balance is just shy of $100 Re-build is $300-$400 ish from what iv been quoted. Ill just get it balanced and that will hopefully do.

As for a nice BB turbos, ill invest in a good one with the new motor; I can't justify the money on this motor. Iv just gotten the cheapest parts available.

Looking at SR20's RB20 or 25's but no rush, ill get this one functioning correctly. Then piss the 4k off on eBay probably.. Again this was all for the experience. Its one thing to do an engine swap, but its another to manufacture a turbo kit :)

[kickn5k]

I got the turbo for next to nothing, so not a huge disappointment. Balance is just shy of $100 Re-build is $300-$400 ish from what iv been quoted. Ill just get it balanced and that will hopefully do.

Looking at SR20's RB20 or 25's but no rush, ill get this one functioning correctly. probably..

Yeah that sounds right if you haven't hurt either wheels or shaft. I do see what your saying.

IMO the rb20 isn't worth the effort. It's a big engine for the capacity and not known for making power. If you get a free rb25 it might be worth it but you really can't go past the SR. Light weight and will easily make good power. I'd try to find an s15 engine, get away with more mods before needing a "built" engine.

[Jaydnisevil]

Asking any decent torque of a 1.3 carby is like milking a dead cow, id rather spend the money elsewhere.

Agreed, and would more than likely be an easier swap.

Not to mention plenty around, and reasonably cheap.

The only bit that might be somewhat difficult, will be to find one that has not had the ass thrashed out of it :P

But Ill start a 'engine saving fund' while 4k is still running, would rather have everything ready to 'drop in'

[Jaydnisevil]

Long time since iv posted, but were back in action. Iv been on a holiday, moved house and will shortly be starting a new job. Lots going on so been busy. Any-who iv solved/discovered the cause to two of the issues that I was having.

 

The first was that strange noise on boost that sounded like a siren.

The second was the inability to make more than 6-7psi of boost.

 

What was happening was air was escaping out the bush where the choke arm goes into the hat, so iv had to remove the choke and plug it up. On boost it was just being forced out the slit like a kazoo :P

Ill see how it goes with a cold start, but I think I might be ok.

 

Now, the limited boost: That was the waste-gate at fault there. The pressure in the manifold it was pushing the gate open, despite me routing the pressure to the other side of the diaphragm. Solution, well a couple ideas come to mind. Stiffer spring, flip the entry and exit or use a plate and screw to wind the spring further down. I'm leaning towards the first, but $40 for a bit of twisted steel? Come on! :P

 

For the moment (Diagnosis) I just have the gate off and the plate blocked up.

I took a small test drive and managed to maintain 10psi at the manifold in second low speed before it started pinging. To be fair its a bloody hot day and I have not touched the ignition timing, nor are the mixtures what I want them at.

 

Remaining:

Look at new jets/air correctors.

Finish the exhaust.

Waste-gate Spring.

 

 

Edited January 2, 2012 by Jaydnisevil

[Jaydnisevil]

Did a basic wheel alignment with a tape measure today, it at least drives in a straight line now. Much less terrifying to drive :P

 

Removed, disasembled and restricted the max mechanical advance. Re installed and set base timing to 5-7deg for now.

 

Took for another drive but can't get more than 10psi below 50kph without hooning up the street. I'm not gonna tear down my street for the sake of testing. Itl have to wait till my exhaust is done and then I can take it down the main road.

 

That and my mixtures aint right, still leaning wayyy off up top. I drilled the main jet out slightly (From 140 to 155, the only drill bit I had) and I reduced the air correction from 160 to 155. By the way its behaving, I think I need a much smaller air correction jet. Ill see what I can do.

 

Still need to address

wastegate spring issue.

Exhaust

Mixtures

 

Niggly shit:

When stationary today for a while it was getting bloody hot, Ill look into getting a thermo fan.

 

Need to remove the mechanical pump and mount the fuel pump under the car near the tank.

[cianw94]

Loving this project man, fair play keep it up!

[Jaydnisevil]

Re-soldered the air corrector shut and drilled with a 1mm drill bit.

Mixtures appear exactly where I want them now :)

Again, cannot be certain until I go for a full road test at speeds above 50kph.

 

Still pinging it's head off in this heat, will do more testing/diagnosis when the temps drop.

I reckons its going to be the timing, but it could also be the fuel. I ALWAYS put 98 in my cars, however its been in there a while now and petrol usually starts to lose its anti knock additives from about 4 weeks. I may have the equivalent of 95 or 91 in there now :/

Still can't bring myself to drive to the servo given the amount of police about at the moment.

 

UPDATE:

Another test drive just now, much cooler.

Still sounds like its pinging (Hard to tell given the exhaust is so bloody loud :P)

I'm contributing that to the fuel and or timing. The A/F is pretty much perfect at loads and RPM in second below 60kph (Found a 60 road close to home)

Needs a full tank of 98 and an exhaust before I can correct this issue further.

Edited January 2, 2012 by Jaydnisevil

[Jaydnisevil]

Waste-gates fixed :)

Two piece problem

The first was incorrect hose setup (Well it was correct, but couldn't bleed off enough air)

Second: A ball valve in the Bleeder Tee

 

I originally had it set up so pressure was bled off from the lower part of the external gate. Meaning it didn't actually receive what was being produced. This was a nice, neat solution but clearly not working. My current thought is that it could not bleed the air off fast enough.

 

Now I have made it so the lower half get's a clean supply from the turbo, and a bled supply to the top.

I am able to open the bleeder to release some of the air holding the gate shut allowing me to customise my boost level.

When I first ran this setup, same issue.. 3psi and that was all it could muster.

So I removed the ball valve in the bleeder tee thinking it was restricting my supply to the top of the gate. Straight away (Bleeder shut) Full 10psi and all the pinging I could ask for :P

I really need to address that, Ill whack some fuel in it this weekend and see if she's any better. If not, I need to look into boost retard pods or getting it re-graphed.

 

I would like to see if simply using a smaller supply line (Or putting a restrictor in line) to the lower half and venting the top to atmosphere will have the same effect.

If I do indeed need a signal to the top of the gate to ensure it stays closed, then so be it..

But If I keep this setup, I will need more hose to neaten things up. Its still looks like a Thai telephone pole :P

Edited January 3, 2012 by Jaydnisevil