M8 engine in M6 chassie, need help

Daltech · Dec 13, 2008

M8 engine in M6 chassie, need help. All figured out now!

Hi guys.

I`m new too these forum, but I see there`s a lot of knowlegde around here.

I`m doing a engineswap these days, m8 engine in a 06 M6. Figured it all out whit the motormounts, got the engine bolted up an fired it.

I`m running the M6 ecu, just took out one pick up from the M8 engine. Anybody knows why there's 2 pick ups on the800 engine?

Anyway, as we know there`s 4 coils on the M8, and only got one double coil in the M6.
So I did split the coilcable and installed another double coil to have it for the all 4 sparkplugs.

Could not get the sled to rev above 6500rpm. Took out one coil and it runs as it should.

So it seems like the ecu aren`t able to power the two coils.

But as its a M8 whit twin sparks, I can`t just run it whit two plugs. So what to doo??

Was thinking of getting the 4 coils new, but they cost over 80$ each, and whit shipping and tax to Norway it gets expensive. And then I still not know if the M6 ecu are able to power all 4. Could be waste of money. Maybe get some coils from an old yami tripple? May get them cheep over here.

Or, just find a head that`s bolts on whit only two sparkplugs? Was thinking of the head from the 800 bigbore kits for a F7. Anyone know the bore size in these kits?

Would also be an issue whit the cooler hose!

acs47x · Dec 13, 2008

your best bet will be to get an m8 ecu or a fuel control box. thats what you really need, more lickely an m8 ecu for the correct power and fuel mapping, also maybe a chassis control unit.

Daltech · Dec 13, 2008

Probely forgot to mention, but I have a BD box for the fuel mapping. Would like to run the M6 ecu because the engine is ported whit a SLP pipe on it. So there is some advance in the ignition timing on the M6 ecu. Also there are no knock senor on the M6, and the APVs are just on/of, so just get tuning easier. About the chassie control unit I don`t see the need of it.
Will also need the wiring harness from the M8 to use the ECU from an M8.

Then the costs are really rising.
Just want to know if anyone has done this before. And also what kind of head could be used instead of the OEM to get the twin spark sys kicked out of the sled.

Daltech · Dec 14, 2008

Anyone else got an opinion about it?

krom · Dec 14, 2008

I would just run it with the 600 coil, the extra spark plugs are for part throttle emisions, the machine should run fine with only 1 spark per cylinder.

Daltech · Dec 14, 2008

Yes, I agree whit that. But there`s the angle of the spark plugs that considers me. They are both in a 45 degree angle. I think the best would be to get a head whit th plug hole in the top center of the chamber.

Don`t think is good to have just one plug, that`s not in the top center.

Is looking for a head that bolts on the bolt pattern of the M8 cylinders, and who have only one center plug. Has to be a 85mm bore also.

Was thinking of the bigbore kits for the old F7, if they are 85 mm.

Ove · Dec 17, 2008

They are all 85mm and center to center between the plugholes are 14mm on the F7. (distance between the cylinders)

The stock F7 head cut for the 85mm bore is not going to fit because of the distance between the headbolts.

The heads from the tenportdesign bigborekits is wery similar to the oem 07 F8 head in distance between the headbolts.

In the pictures you can see the oem 07 F8 head and the 900ss cylinders in the other one, now the 900ss is 88mm bore.

Heads that would fit is in my opinnion from the D&d F8 kit, Speedwerx tenport design or the Blackmagic Fx8 because they are all made with the base in the Cat-racedepartment tenportdesign cast from 03.

Stay with low compression and Ebay is key.

Allso the Bm head has the highest compression of these heads, but they have closed the shop.

Ove · Dec 17, 2008

Here are the Blackmagic Billet head and Cylinder too. (I dont know what happened in this cyl pic but the odd shapes of the tranferports is actually not like that..)

Daltech · Dec 17, 2008

Thanks for usefull info. I`ll be looking around after a head I think.

Say BM has closed the shop, do you meen Bikeman Performance?

Daltech · Dec 17, 2008

Realized now that you probely ment Black magic

ndmtnsledder · Dec 17, 2008

What did you have to do to get the engine mounted. I would appreciate any info or even pictures on how you did it.

spoon · Dec 17, 2008

Contact RK tech and have him custom machine a set of domes that utilize a center plug rather than the angle, there is enough metal in his dome to do that I believe.

89sandman · Dec 18, 2008

i would say it'd be easier to just run the m8 electronics and not spend hour upon hour trying to dial in the m6 electronics. you could spend a lot of money and not get the same performance. always seems like an engine swap will be easy until you get down to the final tuning...

Daltech · Dec 18, 2008

Yes, but to to buy all the M8 elektronics is like 3000usd. And that`s expensive. And then is all the fun whit it gone. It`s always a trigger factor to don`t know how to doo it. Get some good experiense when doing it like this.
Was thinking about the RK tec head, have sendt them a email some days ago, but they don`t aswear it.

Ove · Dec 18, 2008

What mentioned above, to get the stock head modified and domes put in it is actually pretty straight forward. Have the oem plugholes stuffed and an new center hole machined in. Problem would be to get domes for the tenportcylinder.

Now i found the real deal! BMP billet head has one hole in the center!
I added an modified stock rev head allso, i had pics of an f7 head but could not find it at this point.

Daltech · Dec 18, 2008

Thanks. Think BMP is the way to go. Have ordered from them before, good customer service.

Daltech · Dec 18, 2008

ndmtnsledder said:
What did you have to do to get the engine mounted. I would appreciate any info or even pictures on how you did it.

Hi.
There is some differents whit the motormountings. The M6 engine is mounted in on the side over the recoil cover. The M8 engine is mounted in the back of the front frame. There`s welded a bracket to front cooler.

I used the stock part in the M6 chassie, just fabricated a new arm from above the recoil cover and fastened it in the stock chassie mount.

There is also a bracket in the front of the M8 engine under the trottle bodies. I did fabricate my own mount there also. But today I know better. I disambled a crashed M8 yesterday, and I did see that the OEM M8 front mount is just a "clamp" on unit for the chassie side, and a bracket for the engine. So this mount you could get OEM from arctic themself. Just have to fabricate the one in the back. Could see if I get some pictures of it tomorrow.

Daltech · Dec 20, 2008

Here are a couple of pictures of the mount I made for the recoil side. Just used som steel I had for my hand an gave it silver paint to look ok.

ndmtnsledder · Dec 21, 2008

Thanks for the info and pics.

Daltech · Mar 17, 2009

Well, this sled is now finally finished for this season. The result of it, it worked out great at the end.
Had a hard time to get it run properly, bottom end was **** all the way up to 6500 rpm. Had a BD box failure, and had to wait long time to get a new box for the sled.

We ended up whit runing 2 twin coils, so all 4 sparkplugs are in operation. After i we got it dialed in as it would run all rpm range, we took it in the Dyno.
Did put out 118HP, whit a really struggle botttom end. Man was we dissapointed after the first run.
Started cleaning up the program in the BD box, and we got 135HP. Still dissapointed.
We had allready grinded out a offset for the pick up, and placed it as much advanced timing we could, and then got 140 HP.

Still had hi extemps, like 1300f,. Throw in a 2.5 degree timing key, and bang, 150 HP.
We had tried our way whit adjustable fuel pressure before we hit the dyno, and forgot about it. So we dynoed it whit 52 psi in fuel pressure, way too high i think.
Still have a tiiiiny bog around 4000 rpm, and think it`s the fuel pressure that`s make it.

But after all the sled rips, pulls really strong. Will run it out the season like it is. And try it again in the dyno whit 4-5 degree timing keys, and around 44 psi fuelpressure. Think we will se some more horsepower.

And for you guys over there that think 150 hp is low, we don`t get US hp # in the dynos over here. For the record, a Stock summit XP 800R puts out 141 hp in the same dyno. And there`s been alot of them in this dyno, and they all put out the same hp# +/- 1 hp.

So I`m satisfied whit the #, for now

M8 engine in M6 chassie, need help

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