2276 Draw through 'glass buggy. It's finally happening!

[slayer61]

After getting some new idle jets, I got it to start and idle,
Now tuning begins!
https://m.youtube.com/shorts/HKFugOIZB4k

[slayer61]

It's question time...

You guys who have run a draw through with a waste gate, should the waste gate be cracked open very slightly right out of the box?

Mine is/was and I think it might be the cause of my lean idle and jetting trouble

ETA the afr sensor and the waste gate are directly opposite each other on the collector

[panel]

Not sure how you would be able to have it cracked open a bit . The vacuum/pressure port would be the only way to open it. And your 02 sensor is in the wrong spot. It has to be on the exhaust after the turbo. Not pre turbo , not in the collector.

[slayer61]

That's information I can use. Thank you Sir.

Back to the drawing board!

[slayer61]

This is the waste gate just sitting on the bench. It is clear that the valve is open and leaking.



In an attempt to prove it was leaking, I removed the waste gate and replaced it with a blank plate. With the exhaust sealed up tight, i was able to get a steady, 1000 rpm idle at 14:1 afr. I have a leaky waste gate and an afr sensor in the wrong location

[Chip Birks]

This is the waste gate just sitting on the bench. It is clear that the valve is open and leaking.



In an attempt to prove it was leaking, I removed the waste gate and replaced it with a blank plate. With the exhaust sealed up tight, i was able to get a steady, 1000 rpm idle at 14:1 afr. I have a leaky waste gate and an afr sensor in the wrong location

Do you have the other part that goes with it? There should be a valve seat that clamps in there. It rests against the header flange, and the valve. If you are missing that, you are gonna lose a lot of exhaust energy out of that.

[slayer61]

Oh crap. I had no idea. I was recently contacted by Turbosmart USA and he asked about something called a "fire ring". Maybe I am missing something!

[slayer61]

This is the waste gate just sitting on the bench. It is clear that the valve is open and leaking.



In an attempt to prove it was leaking, I removed the waste gate and replaced it with a blank plate. With the exhaust sealed up tight, i was able to get a steady, 1000 rpm idle at 14:1 afr. I have a leaky waste gate and an afr sensor in the wrong location

Do you have the other part that goes with it? There should be a valve seat that clamps in there. It rests against the header flange, and the valve. If you are missing that, you are gonna lose a lot of exhaust energy out of that.

Thanks so much Chip! I saw that shiny new part in the waste gate box, but I didn't realize it was the valve seat. It's now installed, afr sensor relocated to the turbo dump pipe and I'm waiting on the rest of the neighborhood to wake up before testing commences.







Paul Toms

[slayer61]

Holy CRAP! This is a beast with a fully functional waste gate! Absolutely ridiculous.

[panel]

Right on ! Let the tuning begin !!

[slayer61]

Right on ! Let the tuning begin !!

Yes Sir. An assortment of new idle and main jets are due to arrive tomorrow.

Stay tuned!

[slayer61]

It's question time again.

I'm trying to understand why my 2276 goes dead lean at idle. Is the compressor portion of my turbo just an impedance to flow at "idle" ish speeds? At almost any idle (< 1000 rpm) I can watch the wide band go leaner and leaner until it stalls. If I manipulate the throttle, or screw the idle screw up, it seems pretty happy.

Is this just the nature of the draw thru beast?

[panel]

What carb , fuel pressure and what idle jets are in there now?

[slayer61]

It's a 45mm DCOE 152. Fuel pressure is 2 3/4 ish at idle and 55 idle jets.

I mention the 152 because it requires the mixture screws at 3 turns out, and that's about where they are right now.

[Clonebug]

It's not uncommon for a drawthrough to have a higher idle of 1000 rpm or higher.
At low airspeeds in the intake you will get fuel suspension dropout and it will go lean then once you crack the throttle it goes pig rich and you get a black cloud of smoke out the exhaust.
One of your videos showed that happening.
Mad Mike has a drawthrough setup running very good although he switched to I think a demon carb or possibly a Holley. He hasn't been active in a while and last I heard his turbo bug was for sale.
Try setting idle at 1100-1200 and try tuning from there......