Winter engine rebuild project

[boosted79]

After doing some more research on both the Clewett and the Electromotive sites I'm not sure it will even work with the COP? It's not discussed in the installation manual and all the Clewett kits show the coil packs included. I won't hijack this thread though.

[boosted79]

Found this. Looks like the TEC will not work with COP's without some kind of amplifier to increase the voltage to the COP's.

"Which is why I'm getting such a weak spark, the TEC-3 uses a normal inductive coil circuit where it draws battery voltage through the coil during the dwell period and then cuts the flow (float the ground line) to dump the coil. Oh, well, I guess COP's not going to work with TEC-3, time to go back to wasted-spark direct-fire coils and big bulky spark-plug wires... "

[boosted79]

One more comment, sorry for the hijack. The TEC3R will work with a GM LS coil near plug set up. The LS coils are inductive so only need 12v input. A bracket would need to be made to mount the coils on the valve covers and then use a short plug wire. Not sure if it's all worth it vs. just using the Electromotive DFU's.

[IMR-Merlin]

Tec3 - 6/12

http://www.electromotive-inc.com/wp-content/uploads/2013/08/tec3.pdf

Page 45 shows 6 coil leads back to the ECU, but I believe it is a wasted spark situation as there are only 3 coils per pack and each coil goes to 2 cylinders.

Originally Posted by boosted79

"looks like I'll be building a new harness this winter."

Do you have TecGT or Tec3R? I don't think the GT will drive a twin plug six cyl. with one coil per plug since it only has four inductive coils built into it. It needs the DFU's that pair two plug leads to one DFU and uses wasted spark. The 3R has six coils built in. Clewett says use the 3R for twin plug six cyl with one coil per cylinder.

[IMR-Merlin]

Sorry to jack the thread as well, but it's keeping it at the top...

I guess I can look for a different ECU too. This is a much better set up. Much easier than running new plug wires ever couple years.

[Tippy]

^ holy crap!

[JJ 911SC]

Originally Posted by boosted79

"looks like I'll be building a new harness this winter."

Do you have TecGT or Tec3R? I don't think the GT will drive a twin plug six cyl. with one coil per plug since it only has four inductive coils built into it. It needs the DFU's that pair two plug leads to one DFU and uses wasted spark. The 3R has six coils built in. Clewett says use the 3R for twin plug six cyl with one coil per cylinder.

Correct the TecGT will only do 6 plugs (1 x 3 coil pack) but can be setup to run sequentially (need to have a Cam trigger).

Here is the link to the Electromotive forum (low traffic compared to PP). Electromotive Group • Index page

[boosted79]

The problem is I think the TEC ECU only puts out 12volts to the coil packs. The motorcycle COP's have a much smaller secondary to primary winding ratio so they need a much higher input voltage to get the req'd output voltage to the plugs. I think they use CDI to drive the stick coils. So without some kind of amplifier to increase the voltage coming from the TEC ECU I don't see how it's going to work with those motorcycle stick coils. Probably the easiest thing to do is call Richard Clewett to see if he knows if it can be done.

[WinRice]

Originally Posted by b930

Hi, I'm using denso dumb coil sticks from a 600cc bike.

The coils above are CDI coils with a low turn ratio and need roughly 400V to fire properly. Something like a M&W CDI box.

[b930]

Originally Posted by boosted79

That is one nice car, you do great work. I don't understand why Ford didn't bring them into the states. I looked at the PE3 site, very interesting. Not crazy about the crank wheel though, only 12-1 pattern vs 60-2 for the Electromotive. But you can't argue with success. Looking forward to your build. Those sticks are on ebay for $30 used for four, way way cheaper than having to use two 3-coil DFU's, wires and caps. Can you tell me the Denso part number on the stick? I'd like to see what they are new. Thanks.

Hi
I run 60-2 on both cars with PE3, it can run may trigger patterns so no drama with at all.

Cheers

[b930]

I have run these coils with no CDI at 20psi with no issues. I think it depends on which bike you get them off. There are many builds using PE3, both on bikes and cars running the denso sticks directly from the internal igniters with no problems.

Cheers

[WinRice]

Originally Posted by b930

I have run these coils with no CDI at 20psi with no issues. I think it depends on which bike you get them off. There are many builds using PE3, both on bikes and cars running the denso sticks directly from the internal igniters with no problems.

Interesting!

I talked to the guys at M&W and they recommended the Denso 129700 series and said they were true CDI coils, not really intended for 12 volts.

Here's my write-up:

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/587211-935-suspension-moton-coilovers-street-4.html#post7857172

[b930]

Thanks for the thread link, great reading!

[boosted79]

b930 - Are you going to use the Bosch three channel igniters? The more I read about that PE3 the more I like it. Will you have access to a base map from them or setting up your own? Merlin - This may allow the Tec to drive COPs, external igniters driven by the ECU but I'm not positive. You have to be able to set up coil charge time in the ECU to match the requirements of the coil used and I don't think that's possible with the Tec. Pg. 41 of the Tec3r manual addresses coil per plug but only 6 cyl odd fire and then it says you have to use the Electromotive individual coils.

Edit -b930, never mind, already answered on both questions. So you are already running the PE3 on this engine. Did you get a base map from PE and then tune it yourself or put it on a dyno? Thanks.

[b930]

Yep, I already run a pair of Bosch three channel for the upper plugs, I am going to add another pair to drive lower plugs. I have dwell times for the denso coils based on bench tests PE did for running their ECU's on bikes. Just make sure your trigger from the ECU is a compatibility. I developed my own map and am happy to share it. I run full sequention using a modified distributor to provide sync to the ECU.

Cheers.

[b930]

My sync trigger, I think this was an SC distributor I gutted and fitted a mag sensor out of a cosworth distrubuter inside it. Works great.

[b930]

My 930 heads have what looks like a 60degree chamfer breaking the head seal surface to the combustion dome. The chamfer OD measures same as the stock bore where it meets the sealing surface. The 3.2 heads have a straight surface with no chamfer. 3.2 heads on right, stock on left.



Stock cylinders and heads showing how the chamfer sits.




I was looking for advice on whether to chamfer the 3.2 heads into the dome. I'll be using 100mm bores with them. Since they run bigger valves I might not be able to do 60degree with an OD of 100mm as it get very close to the valve seat.
Cheers

[b930]

Been quiet for a while. So I decided the following for my build after a bit of a financial assessment (i.e. realizing I needed deeper pockets than I have for my big bore plans). The bottom end will stay together, and I have sourced:

LN Nickies 3.5L slip fit cylinders.
JE 8.0:1 coated pistons.
LN FFA connecting rods.

Sitting on this will be Carrera heads with high flow (993) valves, 964 cams, twin plugs, the big ass intercooler pictured earlier. Should still make some stout power with the twin scroll turbine GT3582R and equal length 1.5/8" headers.

Here is the bottom end with rods in and checking deck height, supertech studs installed. Getting 1.2mm with stock base gaskets which I think is good.

[boosted79]

Looking good. What made you go with the FFA rods vs. Pauter or Carrillo? Also what did you decide on the 60 deg chamfer? It might be good just to break the edge with a slight chamfer even if you can't go all the way to 100 mm.

[jsveb]

Originally Posted by b930

My sync trigger, I think this was an SC distributor I gutted and fitted a mag sensor out of a cosworth distrubuter inside it. Works great.

Have you got more info and pictures about this?