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

[Chip Birks]

What fuel are you running? That magic 24° number is a race fuel number from what I remember. If I were you, I'd take a ton of timing out of it, get your fuel dialed in first and then start adding that timing back in, a degree or 2 at a time.

[slayer61]

Texas premium pump gas with some off the shelf octane enhancer. Don't some of the more "basic" ignition setups involve just locking an 009 at 24 degrees and calling it a day?

[slayer61]

On a more positive note... my new carbon sealed turbo arrived from Ron Lummus today. Too bad cylinders are still another week and heads 5-7 weeks

[Chip Birks]

Texas premium pump gas with some off the shelf octane enhancer. Don't some of the more "basic" ignition setups involve just locking an 009 at 24 degrees and calling it a day?

That's what I did on my old draw through setups, but I ran 114 octane leaded race fuel. Split cylinders happens from detonation. Causes are too spicy of ignition timing, or too lean, too much boost, or all of the above. If you're only seeing 7psi, then it's probably not too much boost. What did you set compression at?

Like I said before, turn down the timing, get the fuel right, then add the timing back in. Get the fuel right.
Back in my EFI turbo days I went through a cylinder splitting era, it sucked. I had to go through the same process.

[slayer61]

Hi Chip. The compression was set at 8.4:1.

I will be starting from scratch all over again. New pistons and cylinders, obviously, set with a nice tight deck height. New turbo heads from Greg Tims to work with the tight deck height. And really slow, delayed timing, I guess, until I sneak up on the tune.

[slayer61]

Detonation will cause the cracked rings and cylinders.... It's really hard to hear when you have a short pipe right off the turbo.
My engine with a two foot straight pipe off the turbo sounds wicked but it is a cop magnet and gets annoyingly loud in a short amount of time. It's very difficult to converse at idle with someone standing next to you. I have to shut it off to talk.
When we pushed my engine to the limit on the crank dyno in 2020 we ran over 40 pulls in a couple days. at 26.5 lbs. boost it said "enough" and gave a puff of steam through the vent tube. It had two broken pistons, cracked rings and was pushing compression past the head and cylinder. It did put out 226 hp and 255 lb. ft. of torque before it went though. All before 5000 rpm.
WE never could hear any detonation while dynoing it but it took the piston skirts right of two or three of them. When an engine is on that much boost it just sounds different and it's hard to differentiate between hard pulling and detonation.

You need to know exactly the amount of boost you are running and preferably what the timing is at when boosting. That way you can cut boost, cut timing or add fuel........whichever is needed or maybe all three. I would think with draw through you intake temps should be good till about 12 lbs depending on timing but since you have no way of knowing it is just a guess.
The critical area is when you are around 3000-3500 rpm in the high

Put new P/C's on it,,,,maybe fix the deck while you're at it and make sure you check your bottom end for possible pounded rod bearings or shifted upper rod bushings. Put it back together and set it for a max of 6.0 lbs boost and set timing for 25 degrees.
I would also build a two foot long turbo outlet and either run a decent muffler or get one of those Resonators in the exhaust diameter you have. They will at least take the bite out of the sound and keep the fresh air from getting to your O2 sensor and giving false readings.
I had limited room and stuffed an 8”long Cherry Bomb muffler on my turbo. It toned it down enough

CB I've taken your advice to heart. When you talk about timing at 25 degrees, are you meaning Locked at 25 or limited to 25 degrees? Either way it's just key strokes on the computer.

Paul

[Clonebug]

I would limit it to 25 degrees and retard more after around 8 lbs. boost.......It's difficult to recommend timing since every engine is different.
When I was blow thru without W/I or intercooler I was down to 20 degrees timing or less trying to control detonation in the summer at 13 lbs boost.
draw thru and blow thru are two different animals. With draw thru you get intake cooling from the venturi of the carb. How much is the question.
I read that there can be 100 degrees cooling in drawthru but it was on the internet so who knows.

[slayer61]

Thank you Sir. I will add that to my notes, and make it happen when the time comes.

[slayer61]

More new parts are starting to arrive. New pistons and cylinders showed up this afternoon!

[slayer61]

The boost gauge has arrived and been installed. When the motor was NA, and the first version of the turbo, I used NGK D7EA plugs. Should I be using something different in a boosted application? I'd like to have a couple boxes of whatever before start up time comes.

[slayer61]

Quick update... I did find most of a box (8 plugs) of D8EA left over from a motorcycle project, if there's an advantage in running a colder plug on the turbo

[Piledriver]

Quick update... I did find most of a box (8 plugs) of D8EA left over from a motorcycle project, if there's an advantage in running a colder plug on the turbo

It can be... extended core/nose helps cooling at high throttle, and most EFI setups have load/time enrichment, which is useful on any ACVW, even moreso boosted. Even Cadillacs use that run 1:1:1 or richer AFR under extended boost to keep from melting the plugs.

Too cold will just get fouled with carbon.

[Alexander_Monday]

I use NGK DR8EA with IGN1a coils, but you will have to find which heat range works for you. Too hot and the plug ceramic will look glazed and or speckled, too cold it will look black and sooty, correct and it will be a light brown.

[slayer61]

Reading through the instructions for the boost controller, I saw that it has a "tattle tale"! Cool! What was my maximum boost, I wondering. Seems it's a volatile memory and lost after you shut it off.... dammit. I did see that the factory Over Boost Shut down was still set at 7 pounds. I did see that display, at least once.

[slayer61]

While we're talking "tuning", I'm in central Texas, so we do have some heat. The car isn't a daily or long distance driver, it's just a toy. I was running oil through the intake manifold as an oil cooler. Would i be better off deleting that circuit and letting the intake charge be cooler? FYI it has a factory dog house cooler and an aux cooler mounted to the torsion housing without a fan right now.