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68 Dart initiated into Boost Land
https://slantsix.org/forum/viewtopic.php?t=45187
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Author:  Dart270 [ Mon Jul 18, 2011 4:38 pm ]
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Depends on what I would get offered for it... :roll: :wink:

Lou

Author:  turboram [ Mon Jul 18, 2011 7:57 pm ]
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Glad to see you made it home ok Lou, who needs a truck when you have an old mopar :wink: :wink: :wink: thanks again I can use the extra to finish the valiant

That boost sure is addictive next thing you know you'll be turning it up and picking on Those porsche's and beamers on the weekends :D

Author:  Dart270 [ Tue Jul 19, 2011 6:08 am ]
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Yeah, thanks for the shop/projects tour too. I wanna see that Valiant at a race!!

Lou

Author:  Dart270 [ Mon Sep 05, 2011 9:13 am ]
Post subject:  First "fuse" blown

Well, I knew this would happen eventually. After about 40 drag passes, 6k street miles, and countless full boost runs, I got a bit overconfident about the tuneup on the car and blew a head gasket. For the record, I have never had a head gasket problem of any kind on a Slant 6 - ever.

Recent history: I made 10 passes on Sat at Bristol and ran a best of 15.10 @ 94 in 95 deg humid heat - not bad. AF gauge said around 11:1 on the passes, with some dips into the 10s, total timing was at 18 deg under full boost. Again, 9 psi max boost, achieved at about 4000 RPM. Makes about 2 psi at 2000, WOT.

Relevant engine specs: 8.8:1 static comp, MP 244 cam at 103 deg centerline, 160 psi cranking pressure, Felpro head gasket with stock bolts.

Tuneup changes: I moved the timing up to 20 deg, and dropped about 6-8 % fuel to bring things into the ~ 11.3 range of AF. Immediately felt better and I did a few pulls on the street. Had to have been at least 0.5 sec faster... Last pull was going up that big hill before the track entrance, and it started to sputter around 80 MPH and I let off. Crested the hill and it was chuggin when I got back in it a little. Coasted/drove down to the pits and saw no smoke of any kind, but felt just like 2 dead cylinders.

Diagnosis: My initial guess appears to be right: It must have blown between 4 and 5 cyls. Gary Bruner lent me a comp tester (and helped) and it showed 30 on those 2, and 160 on all the others.

Getting home: Seemed like it would be fine driving home on 4 this way (plus I was curious), so went ahead and did it, with Brian Mimken following behind. Averaged about 50 MPH and probably could've done more. Did one 30 mi stint on I81 averaging 65-70, but felt that was enough straining. All I did was unplug #4 and 5 injectors and take the valve last out of those 2 cylinders (I and E) to hold the valves open a bit to help with pumping losses. Idle was still fine (bit higher) and no overheating or other negatives. It still wanted to go into boost at higher RPMs (where it ran smoother and had more power), but I was careful not to let it do this more than 2 psi on a few occasions. Made the uphills a bit slow, but fine.

Acknowldegements: Big thanks to Jack Everhardt for offering to bring gaskets AND/OR tow me home - what a guy! Also thanks to Brian Mimken for following me home.

Next up: head studs, knock sensor, intercooler... Possibly use a different gasket - opinions???

All part of the adventure!

Lou

Author:  turbo66valiant [ Mon Sep 05, 2011 11:17 am ]
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Hussey copper gasket and o-ring the block. Haven't blown a gasket since...he he

Author:  Dart270 [ Mon Sep 05, 2011 12:07 pm ]
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Thanks, Ryan. I was pretty sure you'd been through a few head gaskets. I'll be contemplatin'...

Lou

Author:  turbo66valiant [ Mon Sep 05, 2011 1:58 pm ]
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Only when my boost was in the twenties and leaned her out though. Not when I had good A/F. Two were blown out into the lifter area and others were in between cylinders. You have more cyl pressure than me. I'm only at 105 - 110. Later

Author:  Dart270 [ Tue Sep 06, 2011 5:08 am ]
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Yep, I may drop cyl press some, but also going after mileage...

Lou

Author:  slantzilla [ Tue Sep 06, 2011 2:26 pm ]
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You found your weakest link. Now off to the next one. :D

Author:  Rug_Trucker [ Tue Sep 06, 2011 7:10 pm ]
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Quote:
You found your weakest link. Now off to the next one. :D
The voice of eggspeareeunse! :lol:

Author:  Dart270 [ Sun Mar 18, 2012 5:51 am ]
Post subject:  feeling like a doofus, now enlightened...

Sanity has returned to (entered?) my boosted world. After getting this car running in June, 2011, I have never understood why it makes the boost number it does under different conditions. First fire up, open head pipe - 12 psi, after hooking up 2.5 exhaust - 8.5-9 psi, after plugging some leaks in the intake tract between turbo and TB - 11 psi, after running new 3" exhaust - 18 psi!

I could never rationalize why it was changing so much since that stupid spring (6 psi spec) in the actuator should be limiting it.

Now I know. I thought the WG had malfunctioned somehow when I had it off for the exhaust work in December, and was not regulating at all. So, I took the actuator/diaphragm/spring housing apart and could not see any damage or irregularities. HOWEVER, I did find a somewhat hidden 1/8 NPT port in that housing that was not plugged! Man, what a dork I am... So, I plugged that and went for a drive - now 11-12 psi max. Progress, but still confusing. After feeling around a little more, I found ANOTHER PORT. OK, still a dork. Plugged that and finally am getting 6-7 psi max. These were two big leaks in the sensing circuit for the WG, so plugging them gets us the spec'ed boost. I can't believe it.

I have learned some very useful things by this mistake, actually, like how I can change boost under different situations by introducing leaks/bleeds. I simply had never sat down and thought about this.

One lesson here is that boosted motors are NOT like NA motors. When you have an intake tract leak in an NA motor, the car won't run right! Not the case with leaks on a boosted motor outboard of the TB/manifold. Those can affect boost dramatically.

I hope someone else can learn from my mistakes.... For now, I am very happy to have increased the understanding and control over my system!

Lou

Author:  Turbo Toad [ Mon Mar 19, 2012 2:14 am ]
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Lesson learned keep us posted
Lou I see your running T60-1 Turbo what's your exhaust housing size I changed my first setup and upgrade to the same Turbo with a .67 exhaust housing trying to get the car back together now
Thanks Aaron

Author:  bmimken [ Sun Apr 08, 2012 1:38 am ]
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Don't worry Lou, I have a feeling you will have some company soon figuring out this boosted stuff!

Brian

Author:  slantzilla [ Sun Apr 08, 2012 6:56 am ]
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As Johnny Heyworth used to say, "If a man weren't supposed to make mistakes, they wouldn't put erasers on pencils". :D

Author:  Rug_Trucker [ Sun Apr 08, 2012 7:53 am ]
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Quote:
As Johnny Heyworth used to say, "If a man weren't supposed to make mistakes, they wouldn't put erasers on pencils". :D
Or divorce lawyers..........



Or shallow graves in your back yard............ :shock:

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