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RacerX

Smoothness of BMW V12

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I'm trying to post a couple pics of the M70 motor mated to the G50 transaxle' date=' but am on a dodgy Internet connection. Chelle, I'll email them to you, and perhaps you can post them up.

 

John[/quote']

 

 

Here ya go John,

This going in the GT40?

 

 

DCP_1466.JPG

DCP_1467.JPG

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Yep, that's the plan. Your engine bay looks great; keep us posted on how the mapping exercise turns out. Do you have access to a dyno for tuning, or are you just tuning for driveability? I'm with Dot, I don't think mapping is ever finished. The laptop just becomes a constant companion/nuisance in the car :oops:

 

I will say that with the assistance of another very knowledgeable AEM/Supra owner, I'm finally very happy with the AEM setup in my Supra. It has as close to stock driveability as I want, starts & idles well, and the AFR's are very stable, but this is after 3 years of fooling with it. I'm sure the GT40 project won't be any different.

 

Now I just need to get the PWM controller for my electric fan working......

 

John

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Thanx Racerx, Cold Fusion and Glenn :)

Glenn, you are running a programmable ECU too? I'm thinking I need to switch the O2 sensor to a wideband with a controller, I REALLY wish the thing would stop fouling plugs.. and I wish someone would come out with more aggressive cams for the V12...

You're right though - summer is ending - we need to start just having fun with it..

 

John,

we're trying to get everything right for October to see if we can make the Run and Gun... try and give some of the Cobra's a run for their money.. I'm planning on the firstweekend in October getting a pro with a dyno to go over it. In the mean time I just want to get it running decent and do some more chassis tweaks..

Your project sounds fun :)

Keep us informed on your progress !

Chelle

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Chelle, with the money you're spending changing 12 plugs at a time every few hours, you could probably pay for a wideband pretty quickly :icon7:

 

I know I'd be lost trying to tune without mine; it's an FJO system and one of the better ones, but it's only good down to 10:1. For the V12 project I'm definitely going to get a setup that reads lower, although they're hard to find, and most of the wideband manufacturers don't publish this shortcoming. IIRC, NTK or NGK make one now that goes down to 8:1 or 8.5:1.

 

Have you looked at Schrick's cams? They're 264 degrees with 11mm of valve lift. Not exactly wild, but probably a fair bit more than stock. Unfortunately, I don't have the stock cam specs, do you?

 

I don't think regrinding the existing cams would be a good idea for this motor, given that the cam lubrication area is one of its weaknesses.

 

It would be interesting to find out if Jay has a source for hotter cams.

 

John

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I went ahead and added a wideband, now I kinda wish I had put one in all 4 downpipes :) might still do that tho :)

I wouldn't regrind the cams either - but will likly go for the Schricks ones.. I don't have the specs either. I haven't talked to Jay in a long time - he's a great guy tho and I know he was talking about putting out a line of go-fast parts for these... in the mean time I'll get what I can out of this engine and keep eyes peeled for a new 760 v12 :)

 

 

 

Here's some video files I took yesterday :)

http://members.core.com/~blonnde/new/GTO-running1.avi

http://members.core.com/~blonnde/new/GTO-running2.avi

 

 

 

please right click and save the links to view

Chelle

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I found the cam specs for the M70 motor, so here's a little comparison between stock and the Schrick cams:

 

Stock: 246 degrees 10.5mm valve lift

Schrick: 264 degrees 11.0mm valve lift

 

Probably not enough difference with the Schricks to give it a lopey idle, but it should breathe a lot better with the extra duration and lift.

 

John

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Hi Chelle:

Sorry for the delay. I am using an old Accel DFI unit. It was modern for its day but now seems so dated. The software works on dos. I have to keep a 486 laptop around to use the software. Mapping is all numbers anyway, but a graphic interface would be nice.

 

I was thinking your fuel issues might be O2 sensor related. Sensors can be bench tested with a volt meter and a propane torch. I have had problems with my sensor as a result of silicone contamination. It really sends them for a loop. Pun intended.

 

The Jag currently runs with reground cams from Iskendarian with out problems however direct cam oil lines are standard for this motor. It is interesting how noticeably the power band moved up the rev range with the different grind. I’m not sure that a cam change can make a fuel injected motor run lumpy as the fuel mix is so efficiently distributed. But I might be wrong.

 

I was curious what pipe size and mufflers you used to get that nice V12 sound from the back end?

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:) Hiya Glenn,

We'll probably go for the Schrick cams at some point unless someone comes up with a better set ..

we went with a AEM wideband controller/gauge.. think I'm gonna get another so we have one for each bank..

The exhaust uses the stock manifolds with 4 seperate stainless steel downpipes (1.75" ID) two on each side go into a 2.5" "Y" pipe that goes to a single glasspack on each, followed by a pair of Pacesetter resonator tips.. I had to modify the tips as they are on a "Y" pipe but where the two tips join the pipe gets really small. Because of that we cut the inlet off and welded our own to it

 

Here's one of the setup screens on our computer... the Tec3r is pretty kewl.. though I wish we had gone for one of the really high end systems.. This has a ton of features, I just want more :)

TEC3.jpg

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Sounds fun Kellhammer :)

FYI I decided that my 750i V12 BMW has had long enough - if no one buys it this weekend then monday morning I'm pulling the engine and junking the rest of it. If someone wants the whole car this weekend (having whole car gives you a bunch of parts you can sell as well as all the factory computers and everything) price this weekend is $1200... monday it gets broken up - this was my daily driver till the trunk and back seat got soaked.

Chelle

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That Kirkham Cobra that Chelle posted belongs to former Datsun SCCA racer and national champion Morris Clement. The aluminum bodies I believe are made in Poland by former aircraft craftsman.

Morris used to have a gutted out green 240Z he would bring to to Blackhawk Farms Raceway in South Beloit, IL. Six of us 240 drivers from WI would drive down to BFR to run aganist the IL Z group. Morris was always the one to beat but we never could. We had a lot of fun in those days.

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Steve,

Morris still holds quite a few records I believe, and he's a great guy too. He'll be down at Gateway raceway this coming week/weekend teaching classes on setting up your car for the track at the "run-n-gun" event for replica/specialty cars. We were going to enter the competition, but the car isn't ready for serious competition yet. We MAY drive down for a day or two just to hang out and see the cars and show ours.. don't know for sure though

 

Morris's car has a body made for/by Kirkham and a stainless chassis, with a full aluminum bellypan - his attention to detail is amazing. Everywhere you look are signs of things being carefully re-engineered, and it sounds like a beast too :)

Chelle

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Another update on cams & valves; I've found (perhaps) a better set of cams and roller valve train from a wellknown M70 builder in NC. Specs are:

 

Duration: 245 intake / 255 exhaust

Valve lift: 11.5mm

Lobe centers: 110 degrees

 

The cams are custom built; the roller components and the valves themselves are out of the M73 engine and the springs and titanium retainers are high performance aftermarket items.

 

Since the cams are built for each application, duration and lift can probably be whatever the user wants, as can the peak power point.

 

These cams and this valve train are designed to make power through 7500 rpm without float. Pricing for the whole thing will probably be between $6200-$6500, with the cams representing about half of that.

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Are ya talking about Henry? His cams do require machining a notch out of the pistons. I just can't stand the prices people want for aftermarket cams for the 12. :(

I don't mind spending money for something but $6500 is a lotta money for two cams and some off the shelf valves and springs.

Chelle

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I hear ya Chelle and yes, it's Henry's setup I'm referring to. I think the cam prices are pretty dear, but the rest of it isn't that bad, considering those are all "installed" prices.

 

For my Supra motor, I have about the same amount of money in the Manley SS valves, springs and titanium retainers, which I bought at builder level prices.

 

I don't know that we'll ever get good cam prices because of the low volume. Maybe with a group buy......??

 

John

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Guest Mike

Why don't you guys get the profiles and seek quotes from other reputable cam makers? I'll bet just about anyone can beat the tar out of those prices.

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