another turbo slant build thread
here is another question what about the vacuum advance and boost?
Our car is JUST a race car. Vacuum advance only exists for fuel economy, plus, the engine probably runs cooler at cruise with more spark advance than our 18 degrees (total) of mechanical advance would provide. Might be a good idea on a street turbocharged slant 6.
I have no experience with vacuum advance on a boosted engine, but logically, as the throttle opens, the vacuum goes away, and with it, the vacuum advance. So, you'll never see
any vacuum advance if there is boost present.
One thing to consider; (enough) boost might rupture your distributor's vacuum diaphragm. The material in those vacuum diaphragms that were intended for use on engines wherein the vacuum signal routed to them was venturi vacuum (as opposed to manifold vacuum) were pretty flimsy... and possibly could rupture when exposed to significant boost through that carb reference vacuum line.
Not good...:angry7:
Tom or Ryan (or CharrlieS) could answer that one a lot better than I can...
I think the K-1 rods are probably stronger than the 198 OEM rods... especially, given their length.
Wiseco and K-1 work very closely together for a piston.ring/rod package for slant 6's. It uses the long 198 rods, provides a low (9:1) compression ratio (perfect for a turbo /6) and comes with a low-drag ring package. All you have to do is file the ring end gaps and install 'em....
If you're gong to try to economize somewhere, in this build, I'd recommend (given the cylinder presures you'll probably be experiencing) cutting corners somewhere else.
Here's the K-1 website URL:
http://www.k1technologies.com/Portals/0/Documents/K1Catalog.pdf
No... I don't work there... wish I did!:tongue5:
There are 2 cranks for /6 motors. Forged (early) and cast (late.)
I am not convinced that one is any better than the other. I've personally, never seen a broken cast crank, and they (and the K-1 rods for those cast cranks) are lighter.
Might be a better deal...:blob:
The following is JUST my opinion, but I think a solid lifter cam is a more workable deal on an engine like this. Adjusting the valves on a slant 6 is really easy, and hydraulic lifters have problem that solid lifrers don't have... Try for a duration of about 110/112-degrees at .050"-lift, and a lobe separation angle of 115 degrees. You'll want gross lift in the high /.400"-range... using stock, 1.5:1 rockers. I've tried to get a cam ground with over .500"-lift... can't be done without either roller tappets (no roller cam blanks available... unless you have $1,000.00) and even the Mopar "large size" lifters will dig into the cam due to an excessive angle on the lobe face, in an effort to comply with the small duration/high-lift "recipe."
A set of 1.6 rockers would solve that problem, but they're pricey...
Bullet Cam Co. ground our cam. The jury is still out...
Factoid I find interesting: Turbocharged slant 6's \seem to work their best when they're being "held back," somewhat like a fuel motor (Nitro engine.) That's the reason they like those 2-something rear axle ratios.
That's a fortuitous benefit for 2 reasons: The much-cheaper 8.25" complete rear ends are available in salvage yards everywhere, with ratios in the high 2's,
and,
Having a car that likes a highway gear that
also works the best on the drag strip is an unbelieveably good piece of luck! No slogging along on the highway at 60 MPH with a 5.13 gear (4,000 rpm, 26"-tall tire) going to-and-from the strip... 2,700 at 75 MPH is more better.... :)
Just my 2-cents...