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NA to turbo conversion - questions and answers...


mikeatrpi

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Head bolts are torque to yield. If you restretch them you're going to risk breaking one, and I don't have to tell you why that's bad :D

 

ARP head studs are reusable, convenient, and awesome.

I've read here and elsewhere that the factory turbo bolts can safely be reused, but this would suggest that's not the case. Do you know for sure about factory turbo bolts?

 

Also, why can the ARP studs be reused? Aren't they also torque to yield? (Not trying to challenge you, just trying to clear this one up. Thanks!)

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Hey Mat -

 

Nope, I have never had the head off the car. I ordered two head gaskets and intake / exh manifold gaskets from MSA. Two, so that I'd have spares 'next time'. You know, like carrying an umbrella when the forecast is 50% rain...

 

Why does everybody say the ARP studs are so great? I'm tempted to re-use the head bolts that came with the car. Unless somebody tells me that's a seriously bad idea.

 

Did you read attworth's thread about having three bolts break off in the block? Thats why :)

 

I wouldn't re-use bolts simply because I've had to dig exhaust studs out of a head, I couldn't imagine the hassle of digging a head bolt out.

 

Lazy question - what size are the MSA gaskets? 1.5?

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OK, fine... :)

 

Like most things in life, "do it right the first time" is a sound philosophy. I ordered an ARP stud kit off EBay last night for $131. A hundred here, a hundred there - oh well, right? I'd hate to break the head bolts, or have it blow again and have to re-do this job.

 

Size of the gaskets - you mean thickness? No idea. I'll check it out for you when they come in the mail.

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Hi Mat, the gaskets came today. The head gasket measures 1.58mm thick at the metal ring between two cylinders. I'm sure my measurement isn't terribly accurate for a variety of reasons, so in my opinion its OK to call the MSA gasket 1.5mm thick.

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  • 2 weeks later...

I finished the head gasket job earlier today. It was easy enough to remove the manifolds, turbo, and the associated parts, and just as easy to put them back together. Removing the head wasn't so bad; none of the bolts broke, and I didn't drop the chain. I used a soft handle screw driver as a wedge to lock the timing chain and keep it from falling.

 

The ARP studs worked well- it was super easy to line up the head and slide it into position. Yes, I waffled a bit over the price but I'm glad I bought them. I installed the MSA head gasket dry, but I did copper-kote the manifold gasket. In about 100 miles I'll re-torque the intake and exhaust manifold bolts, and I'll probably check the torque on the head too for peace of mind.

 

100_0360.sized.jpg

 

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100_0373.sized.jpg

 

100_0399.sized.jpg

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I forgot to mention, you can see my new fancy Magnecor wires in the last pic. They're supposed to suppress noise. You can't use a timing light with them - I tried.

 

Also, I installed a 160 degree thermostat and BRP7ES plugs at .032" gap - both are colder than stock. It should help with the pinging.

 

Anyway I took the car for its first long run with the new gasket. It really ran well, nice and smooth! I kept my conservative timing map loaded in the MS, and there was absolutely no pinging on my drive. So, I think I can safely step up the timing a little bit after studying other folks' maps in the sharing sticky. This is proof that my repair to the VR distributor is working. And that's a very good feeling!

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  • 3 weeks later...

Here are my current megasquirt maps. The car runs acceptably well. It still shoots rich and lean getting on and off the throttle, but this should be good enough for anyone with a similar setup (cough Mat cough) to get started. I'm open to suggestions!

 

Specs:

1982 Datsun 280zx NA

F54 block P79 head, stock flat-tops

Stock ZXT fuel injectors 260cc

BPR7ES plugs at 0.032"

160 degree thermostat

Magnecor wires

Locked VR distributor

Megasquirt 1 v3.0 running MSnSE v029y4

AEM 30-4100 wideband

exhaust - 2.5" downpipe to cat, 2" back

stock 280zx T3 turbo and exhaust manifold

wastegate set to approx 4.9 psi

eclipse blow off valve on stock j-pipe

GM IAT sensor, Nissan Quest TPS, Datsun CHTS

 

newhg6_fuel_timing.jpg

newhg6_afr.jpg

newhg6.zip

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Thank you!! [i just played around with your map on MegalogViewer - its so cool haha]

 

My setup is slightly different from yours, most notably the injectors:

 

N/A Flat Top F54/P79 w/ 1mm gasket [8.7 CR] with 11 lbs. flywheel

MS I V3.0

83 ZXT CAS Dizzy

Accel Super Stack Coil

KA24DE TB

Stock J-Pipe

Ford Mustang Cobra 30# [315cc] injectors

Pallnet rail w/ gauge and turbo FPR

Walboro 255 fuel pump

Stock T3 on stock boost

MSA 2.5" DP [3" SS past the DP]

 

but I'm sure this will get me up and running!

 

I'm also planning on running a Volvo intercooler - do you have plans for an intercooler later on?

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Update time.

 

Mat, at the moment, "no" on the intercooler. Ask me again though, sooner or later I'll be putting one in I'm sure!

 

I wanted to caution you people about buying an AEM 30-4100 wideband. Its not a bad unit, not at all, but it is different than the normal Innovate wideband controllers that everyone buys. Rather, be aware that its not inherently supported by Megasquirt; like using your Datsun CHTS for the coolant sensor - you have to do some configuring...

 

First of all, if you put the table from the 30-4100 user guide (AEM's PDF) into Excel, you'll discover that the numbers nearly exactly match the INNOVATE_0_5 setting. AEM_LINEAR is quite different than this sensor, so that is not correct either.

 

After you see that the slope is right and you put it in the car with the INNOVATE_0_5 setting, eyeball the difference between the gauge and the display in Megatune. You'll need to change the Y-intercept in the equation that Megatune uses to get them exact in-step. For me, Megatune read 0.7 AFR leaner than the gauge.

 

To fix it, edit the lambdasensors.ini file. I chose to use WB_UNKNOWN and edit that.

#elif WB_UNKNOWN

; afr = { egoADC * 0.01961 }

; lambda = { afr / 14.7 }

; TargetAFR = { afrtarget * 0.01961 }

; TargetLambda = { TargetAFR / 14.7 }

afr = { 9.3 + egoADC * 0.039216 }

lambda = { afr / 14.7 }

TargetAFR = { 9.3 + afrtarget * 0.039216 }

TargetLambda = { TargetAFR / 14.7 }

 

.

.

.

 

#elif INNOVATE_0_5_LINEAR

afr = { 10 + egoADC * 0.039216 }

lambda = { afr / 14.7 }

TargetAFR = { 10 + afrtarget * 0.039216 }

TargetLambda = { TargetAFR / 14.7 }

 

The downside is that you'll need to enter your AFR's in volts. There's probably a way around that' date=' but I'm still playing around. Back to excel for the quick solution:

[img']http://z.modeltrainguide.com/albums/album59/excel_adjusted_AFR_Volts.gif[/img]

 

Finally, in MegaLogViewer, again use a custom linear setting with the appropriate parameters:

mlv_custom_aem4100.gif

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Quick question - I stopped at Advanced Auto when I was out to lunch, they only had the BR7ES plugs showing up, so I bought them thinking I wrote it down wrong.

 

I got back and found there is a BR7ES and a BPR7ES plug.

 

http://forums.hybridz.org/showthread.php?t=77279&highlight=BPR7ES

 

Is there a noticeable difference or should I take them back?

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I had a note in my "z_todo.txt" file reminding me to post the numbers I used for the CHTS calibration:

 

Measured CHTS -

32F = 6040 ohms,

69 = 2220,

125 = 459

 

Suggested CHTS from hybridz.org -

14F = 9000,

68 = 2500,

122 = 840

 

Values entered for CHTS -

14 = 9000,

69 = 2450,

125 = 700

(averaged measured and suggested; seems accurate now)

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P = Protected Insulator.

 

You misread. P = Projected insulator. Some on this board have noted the difference between projected/non-projected insulators is about half a heat range (non-projected being colder I believe) and a few degrees of timing (non-projected being retarded).

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A few degrees of timing? Are you saying you can run more timing with the non-projected plugs?

 

The numerical timing number will be higher, but that's because it takes longer for the flame to get out from the non-projected plug, so the end result is the same. It's NOT a power increase. For the same amount of advance, the non-projected plugs will make LESS power.

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Forgive me for seeming dumb but as I read this thread it has helped alot with the info I am looking for but it is creating 1 big headache. I have a 77 280 and am going turbo soon, but need alittle help with head issues. Mainly what head should I run? And should I go get a 83 turbo motor to build or can I build what I have?

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