Twin Plug DIY?

[beepbeep]

Originally posted by 125shifter


New parts:
Carrera intake
Autronic ECU for injection and ignition
Autronic CDI to fire 6 waste spark coils
Twin Plug (still haven't looked for wires for 12mm plugs)
Three angle valve job with new valves, guides, and springs (done by EBS)
JE 3.4l, 7.7:1 CR pistons
Pauter rods
ARP head studs
Patrick lightweight flywheel
Centerforce aluminum pressure plate
8:39 r&p
a ton of expensive odds and ends

Existing parts (installed by PO):
K27 with 1 bar wastegate spring
B&B exhaust
B&B dual outlet muffler ( I may build a stainless open pipe exiting on the right)
B&B intercooler (I may get a custom large intercooler to fit the Carrera intake)

Ahhh... very very sound concept! I like Carrera/Pauter/JE part the best. Very non-porsche-snobbish and very very good stuff-

Few hints (please don't take it as criticism):

1. I would ditch 1 bar wastegate spring. Autronic has built-in electronic boost controller and all you need is solenoid to contol boost line going to wastegate. It can only raise the boost from level provided by spring, so you would need 0.7 bar spring in order to allow Autronic to regulate boost from 0.7 and upwards.

2. How do those BB-headers look like? You seem to be handy and expirienced in DIY, so you could even try fabricating your own headers? As you probably know, turbocharged cars don't care for equal length headers. They just want it hot and short (at least before the turbo).

3. Spinning more on your DIY-handiness: there is lot to be saved on using some other (cheaper) sort of EFI. SDS will do both fuel, ignition and boost controlling for half the cost. Tuners don't speak it as fluently as Autronic, but you could learn a new language yourself

4. Ever tought about trying Garrett GT-series turbochargers?

That engine will rip any way you do it!

Cheers!

[lane l]

David, I live in Willis. Not to far up north of Conroe. We should hook up some time. I'll be glad to help you with your rebuild some weekend! I have an 87 930 that's down right now too. I will be doing the same things to mine so maybe we can help each other! I am also enterested in the Kart racing and wouild like to find out more about it. Looks like your doing a great job!

[PJMARKOW]

Hi David,

I see your using ARP head studs. I think you may have them the wrong way round in the case (I did the same thing). The rounded end with less threads is for the head nuts, the other (with max threads) goes into the case.

Cheers

[David]

Paul, please tell me you're kidding! I didn't see any directions on it and it seemed like bottoming the rounded end in the case would help even out the upward pull. If they are backward, what problems would this cause?

EDIT: I called EBS and asked about the studs (why didn't I do this before?) I did in fact install them backwards They said I should have used red loctite with the bullet end out (I used oil). They said since I have full thread contact on the nut, but no extra threads, I shouldn't have any problems. Let's hope I don't blow it up or have major leaks and get a chance to correct them.

beepbeep,

1) I've thought about putting a lower pressure spring in and use the Autronic controller and still may do it. I haven't completely decided on how the ECU will be set up. I'd like to have it so I don't have as much boost in 1st gear when I'm traction limited but I don't know how I'd send a gear position signal to the ECU.

2) I've also thought about building some custom headers using Burnsstainless tubing and their awsome collectors, but this project is way over budget right now.

3) My other thought on ECU is Motec so I've already lowered the cost quite a lot by going with Autronic.

4) My plan on this rebuild was to build the bottom end to handle future upgrades such as a monster intercooler, custom exhaust, and better turbo. Since these are all items I can add without opening the engine, I'm saving them for the next step.

[jpnovak]

Great work! When can I drop my heads off for this mod?

[PJMARKOW]

Hi David,

I hoped you hadn't got any further in your rebuild when I spotted the head studs. I made the same mistake and mine were locitited in. Fortunately it hadn't completely set so I was able to remove them and re-install them correctly. I'am using an EMS Stinger CPU to control my engine. It is controlling the fuel, ignition and boost. The EMS Stinger is quite a bit cheaper than an Autronic (both are made here in Australia). The Stinger retails here for $995(that's Australian dollars). It's controlling the ignition via a M & W Pro 10 Ignition unit (again made here in Australia). My system was setup by PEM here in Australia.

Cheers

[asphaltgambler]

What's this guy still doing in my garage??

[David]

Paul, thanks for letting me know about my head stud installation mistake. After thinking about if for a day, I went ahead and pulled the engine apart and changed them. Now I'll be able to sleep better.

FYI on Loctite: A Loctite rep came to our shop and gave a presentation on how to use Loctite. One tip he gave which relates to 911's is on the head studs. He said when you're using Loctite on a blind hole, put the Loctite in the hole and not on the stud. He demonstrated why with a clear plexiglass blind hole. If you put the Loctite on the stud, when you thread it into the hole the air in the hole doesn't allow the Loctite to go into the hole.

[klaucke]

Nice machining and build up! I highly doubt I'll have the balls to toss my heads on the bridgeport when I do my next build...

[89turbocabmike]

Nice tip on the loctite! Got to file that one for future reference.

Would be great to have a "1001 engine rebuilding tips" book

[PJMARKOW]

Great you made the right choice David. I know I had one sleepless night worry about those head studs. I had put the loctite on the threads, but it was the wick in variety, and some of those studs were quite hard to remove.

Cheers

[Scott Wolthuis]

Originally posted by Grady Clay
Steve, David,

There is a nice short Beru (resistor and non-resistor) connector where the wire is 90 deg that will fit a 12 mm sparkplug. The great part of this is it fits under the lower valve cover!

Once you have a twin plug that is all settled in and you rarely have to change plugs, this is a great solution for a street car. The connectors and wires are all protected by the valve covers. Yes, to change the plugs you have to remove the valve covers. That can be a pain. However with a good running engine it works great. It keeps the wires and connectors out of the debris and water path from the rear tires.

If you want to appear original single plug, this hides the second ignition.

You would not do this for a track only/race car.

Of course if you want to show off your twin plug installation; long connectors, bright retaining clips, and bright red/yellow wires work great.


Best,
Grady

Grady/Anyone,

Let's see your pictures of this plug connector under the valve cover set-up...

Thanks
Scott

[David]

It looks to me like you'd need to cut out the fins on the second plug hole to use the under valve cover plugs. I would like all the fins I can get so I'll be using plugs that go throught the valve cover.

[DonE]

Not sure if this is what you are looking for, but this is a pic of the lower valve cover on my twin plug project.

[DonE]

[David]

Don, are you using 12mm plugs on the bottom? If so, are the plug wires specific to the 12mm? What do you think about the quality of the Clewett wires?

[DonE]

I have no idea on plug size - I use Bosch FR5DTC. All the Clewett stuff I bought has been top shelf stuff. And everything has bolted right, unlike most everything else I bought.

[adomakin]

David, what sort of power output are you expecting from your engine when its complete?

Andy

[David]

I'm figuring about 500 to 550 fwhp.

[Bob Goding]

As posted by Scott Walthuis---------------
Grady/Anyone,

Let's see your pictures of this plug connector under the valve cover set-up...

Thanks
Scott.---------
And me!
Bob