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V6 book update.
Posted: Wed Apr 05, 2006 11:08 am
by Jim K
Thought I'd collectivelly bring you guys up to date on the book saga...its a pain in the a$$ now, as stupid little (but ultimately solvable) problems keep cropping up: I originally set out for ~11.7CR (just a figure that looked nice) and a 12mm/300* cam. Well, having to precisely mill two heads plus chamber matching took me to 12.2(!!) and then back to 11.96:1 to be exact!! Then, I find that my beautifully assembled block, will not accept more than a total of 4.5/3.5mm (in/ex) valve lift, which is a joke for performance cams. If thats not enough, the V6 hi-perf valve springs I got from the US are too strong for the available installed height. Spring bases should be deepened but the enlarged ports are veeeery close underneath! So, spring tester in hand, I'm checking springs left right and center to find what I want. I have much lighter valvetrain, would like to use std springs but coil-bind won't do. I have a couple of solutions for cam profiles to safely fit with the available clearances without notching the JE's any. 11.4-11.8mm/292-296* is the ball park. Everything I consider, I run through the engine simulator program and try to optimize parameters (timing, exhaust lengths...)Fortunately, the dictated cam timing barely works within the above mech. constraints. So far I am getting
calculated power levels of 264-268hp/6700rpm with 230lbft/5200rpm for the 12v motor and thats with the CSC headers (shortened by ~25cm which is easy)!! I'm real curious as to the prediction accuracy of this elaborate software! I will iitially run the std Motronic injectors at least for the break-in period. Then we'll see; looks like I'll need ~240cc jobs (probably barbed ones...Mats likes them, heheh!)
Thats it for now, don't worry guys, in the end you
will get a bulletproof recipe or my name
ain't Al Capone!
Jim K.
Posted: Wed Apr 05, 2006 1:40 pm
by MD
What's that strange smell JK?
Are you experiencing ring burn?
No worries, mate. I am sure a I speak for all the guys here when I say we really appreciate your committment and hope you don't go broke in the process!
I can lend you a monkey that can hold a cup and turn an organ grinder. Maybe you could park him on a street corner to pick up some loose change. Just a thought. I just wanna help.

Posted: Wed Apr 05, 2006 3:15 pm
by Mats
Sounds like you need 75 turbo injectors then, 230cc/m barbed. You want me to stick my snout in the heap and find some?
"...a total of 4.5/3.5mm (in/ex) valve lift..."
I hope you mean at TDC otherwise I think you need to do some serious redesigning.
Why are you swimming over the pond to get springs that you can get here? There are sooooo many good manufacturers both mainland europe and UK, you know that, is it the exchange rate?
If you need any help, send me a smoke signal or something.
Posted: Wed Apr 05, 2006 3:53 pm
by Zamani
Mats,
Becareful, he won't sent you no smoke signal. He'll send you a trojan horse.
Posted: Wed Apr 05, 2006 7:35 pm
by Jim K
Of course at TDC Mats! I had bought the springs 2 years ago, since I also have them in the current 3liter but apparently will not work out with this project. I'm going to the Catcams rep today (the flowbench guy)to measure springs. In their site, I found two types that look good, lets see what the spring tester says. I hope he has them in stock.
Will the 1.8T injectors work with the Motronic ECU?? I don't have any lying around to measure resistance. If R checks out, I'll need 6 of them. Give you a call if I can't find them in used parts here.
Now, for the upside-down Mentally Deficient (even brainless would be an
improvement!) member I can only express my sympathy and recommend they triple the voltage for your next shock treatment. Feel free to drink some ATF first

and don't forget the cork+Loctite (for the...er, exhaust!)

Jim K.
Posted: Wed Apr 05, 2006 10:21 pm
by Micke
Speaking about injectors. I first planned to use Saab units as they come pretty cheap but now lean towards Ford ones. Really cheap and come in several capacities:
http://store.summitracing.com/egnsearch ... 115+400070
As for minor obstacles. WE STILL GET SNOW HERE

Posted: Thu Apr 06, 2006 12:03 am
by Maurizio
Set backs are always a part of a project. If it works right away the challenge wasn't big enough for you.
At least that is what I tell my boss
Jim, just a curious noob question, are you thinking of running this setup on a standard motronic ecu and a re-programmed chip?
Posted: Thu Apr 06, 2006 2:41 am
by Mats
What the hell are you doing with barbed injectors on a Motronic system?
L-Jet should be low-z but can be "fixed" with some resistors. It's really easy to fix o-ring injectors to a V6.

Posted: Thu Apr 06, 2006 10:18 am
by Jim K
Yes Maurizio, initially I will use the existing Motronic to avoid surprises and will remap after break-in (or earlier if its intractable). Mats, I really don't have a problem with the std 75 type of injectors. I use correct fuel hose so no clamps are needed (
that would look shitty!) I do have two 24v fuel rails+injectors but I want to use the 75 rails on this one (never had a problem with this setup).
Ahhhh! Today the valve spring issue was
solved...I ended up using the Arricambi outer springs with...VW Golf 16v inner ones!! Seat pressure will be fixed at ~90lbs with 32.5mm installed height, which gives ~174lbs at 10mm valve lift and ~190lbs at 11.5mm. This makes for excellent high rpm capability with the lighter valvetrain parts.With this solution, no spring base machining is needed

What you'll see in the book though is a spring length/force diagram, std and modified. If you use similar lighter parts (valves and lightened exhaust followers-34gr from 49gr)you can use the std springs for much higher rpm. However you would have to limit valve lift to less than ~10.5mm. Speaking of weights, std 3liter valves weigh 110/82gr and mine are 89/73gr. If only the std springs had more travel!
Now for the hard part, settling on the best possible cam profile. One that idles like clockwork at 800rpm, is streetable and hauls a$$ to 7800! (Emissions, say what

)If I finally go for 115* lobe centers in/ex, HC should be very reasonable. After I decide on it, it'll take two weeks to get the finished item (Germany or Italy). Thats when I button up!
Watch this space for more boring details!
Jim K.
Posted: Thu Apr 06, 2006 10:29 am
by Mats
It's just so much easier to find injectors, that's why.
The cleaner look is just a bonus.

Posted: Thu Apr 06, 2006 10:44 am
by MerrilGordon
Thanks for keeping us up to date Jim.
Besides me, I'm sure your postings are getting people quite interested in your book.
Merril
Posted: Thu Apr 06, 2006 10:48 am
by Zamani
I got HC, CO and NOx (@ 1500 and 2500 rpm under load) figures with the 10.4mm CB cams in case you are interested. NOx was high. I think with your compression automatic failure for NOx.
Posted: Thu Apr 06, 2006 12:40 pm
by Jim K
When I first used the C&B S2 cams (11mm/272*/244* at 1.25mm) with 11:1CR, HC was...~1400-1700ppm!! That was the result of closer lobe spacing.
Thanks Merril, its nice to keep in touch with this stuff, gets lonely at times!
A little but necessary modification was needed to install the old (Jetronic) water pump on the Motronic engine. The wp pulley had to be carefully pulled off and the rear lip was taken off on a lathe, as it fouled the 60-2 teeth ring of the crank pulley. Goes without saying, if you ever want to remove the crank pulley, you'll have to remove the water pump! Motronic wp's have a different, removable pulley (3 bolts).
Jim K.
Posted: Thu Apr 06, 2006 12:44 pm
by MD
Jim
Not all countries have the California air pollution control issues. The number of engines that will ultimately get your modifications in the world scheme of things is going to be inconsiquential. People who will take the trouble and money to make the modifications will be looking for performance first and foremost otherwise why bother.
My suggestion is to go for max performance specs for those that are looking for it with perhaps a back up specification for the California crew.
Posted: Thu Apr 06, 2006 2:20 pm
by Mats
Lovely Jim, thanks.
