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

[slayer61]

Absolutely!

[slayer61]

But MORE importantly, I do believe that is the last of the empi parts to come off the buggy from the first generation of the build.

[Clonebug]

Didn't you buy the turbo from RAD????
Why not ask him for advice....He has a pretty good rep and if he recommended that turbo he must have a tune that you can work off of......

[slayer61]

I did buy it from Rodney, but it was one of 4 he suggested, and it was the one at the lowest price. At that point, I don't believe he knew i was going to feed it with a 45 DCOE.

[slayer61]

So the engine is coming down, again... and oil comes out of the turbo piping to the engine inlet. I'm sure this is a large part of my tuning problem.

[slayer61]

I thought this was going to be a simple turbo and head swap...

Then I found this...




Yup. Cylinder cracked in 5 places and the copper head gasket/spacer ruptured. Dammit again

[panel]

To much boost or pre-ignition/detonation/pinging ? What do you think caused it?

[slayer61]

To be quite honest, I'm not sure my boost controller has never been set higher than 7 pounds, and my MSD has timing set at 32 degrees and it pulls 1 degree of timing per pound of boost to a maximum of 8 degrees of retard, or 24 degrees total advance. Now mind you, I've never gone on a test drive with the laptop plugged in, and I don't have a data recorder. Unless somehow the oil puking into the combustion chambers, or something else caused "pre-detonation".

Keep in mind that this motor has/had massive deck height due to the 55cc combustion chambers. <shrugs/>

[Clonebug]

Are You running a boost gauge???
Have you tested the pop off of the wastegate with air pressure????

Excessive deck should not really affect the turbo setup........Mad Mike on STF has been running .120 deck on a 2276 for many years with good results.
You need to verify the timing you are running when in cruise and on boost and make sure the boost retard is working correctly.
That is one of the great things about an ECU based timing control setup. You can log a run and even see what' happening in real time if desired.
Make sure you have a boost gauge and it doesn't go over 6-7 lbs until you get the tuning perfect. Once that area id=s good only then should you increase boost and tune it further.
Also make sure your AFR gauge is calibrated and mounted correctly. The sensor should be on the outlet side of the turbo and needs to be far enough away from the end of the exhaust pipe that the readings don't get contaminated by fresh air.
I recommend running a muffler to quiet the engine enough that you can easily hear when detonation occurs and you can let off immediately......it doesn't take much detonation to damage an engine as you already found out.

[slayer61]

It occurs to me now, that there was a short time (1 test drive) that I drove it without a waste gate at all....

[slayer61]

Hi CB. I don't have a boost gauge, but I do have the display of the Turbosmart boost controller. It's an LED display, and I can sure hear when the waste gate is open

[Clonebug]

It's challenging enough to tune a turbo let alone tune one without feedback info. There is not enough time to look at a gauge or anything other than the road when you are in higher boost ranges. Therefore....it is important to have some way to log the important readings like boost level and even ignition timing instead of guessing.
If you don't know what's going on it's difficult to know what part of the tune to adjust.
My buggy will go thru three gears to 90 mph in about 7 seconds and there is no way I want to be glancing at any gauges when I need to be watching the road. I get this info from my logs off my ECU.....it is soooo nice to have it and once you get addicted to the boost you need to step up the game.
I bought crankfired ignition the 2nd week I had a turbo......I've never looked back and now am on my 4th ECU.
Even if you get a gopro and video the dash and gauges.....at least you can go back and see what is happening.......
You really should invest in a boost gauge....even a cheap 30 lb vacuum/pressure gauge can work as a boost gauge. I use a Turbosmart boost gauge I bought from Marty many years ago...... I can't remember what I paid for it.

[slayer61]

Hi again CB. I have bigger issues than I originally thought. I spent an hour or so in the shop this morning removing the remaining pistons and cylinders. In addition to the cracked number one cylinder, i found shattered top rings in numbers 3 and 4. This explains the difficulty i had trying to start it the last few times.

When I first added the turbo, i removed all the rings and gapped the top rings at 0.022" and the bottoms at 0.023- 0.024". I have no idea why the rings broke into pieces.

I just need to look at starting the turbo up like starting a power plant up... one system at a time. Check ignition timing advance. Use a bicycle pump or something to simulate Boost to the map sensor before I go crazy out on the street. Thanks again for your insight

Paul

[Clonebug]

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 load area......timing is critical until rpm gets up.
My engine is sensitive between 3000-3800 rpm and when ramping up boost to 21 lbs. or higher.

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 that the Wife didn't mind the noise even traveling to California and back.

[Piledriver]

One usually runs more top ring gap than on second/3rd, esp boosted, but I'm going to stay out of this one as someone with long experience is helping you...

Y'all have motivated me to finally get back to work and install the J&S Safeguard I picked up for my rig.